Open Collections

UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Nitrogen excretion in the deer in relation to age and metabolic rate. Campbell, Gordon Alexander 1963

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
831-UBC_1963_A6_7_C18 N4.pdf [ 8.77MB ]
Metadata
JSON: 831-1.0105713.json
JSON-LD: 831-1.0105713-ld.json
RDF/XML (Pretty): 831-1.0105713-rdf.xml
RDF/JSON: 831-1.0105713-rdf.json
Turtle: 831-1.0105713-turtle.txt
N-Triples: 831-1.0105713-rdf-ntriples.txt
Original Record: 831-1.0105713-source.json
Full Text
831-1.0105713-fulltext.txt
Citation
831-1.0105713.ris

Full Text

NITROGEN EXCRETION IN THE DEER IN RELATION TO AGE AND METABOLIC RATE  toy GORDON ALEXANDER B.A., T h e U n i v e r s i t y  CAMPBELL  of B r i t i s h  Columbia,  I956  A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF • MASTER in  OF SCIENCE  t h e Department of Zoology  We a c c e p t t h i s t h e s i s a s c o n f o r m i n g required, standard  THE  UNIVERSITY OF BRITISH A p r i l , I963  to the  COLUMBIA  In presenting  t h i s t h e s i s i n p a r t i a l f u l f i l m e n t of  the requirements f o r an advanced degree at the U n i v e r s i t y  of  B r i t i s h Columbia, I agree that the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r reference  and  study.  I f u r t h e r agree that  per-  m i s s i o n f o r extensive copying of t h i s t h e s i s f o r s c h o l a r l y purposes may  be granted by. the Head of my  h i s representatives,,  written  Department of  permission.  Zoology  •  The U n i v e r s i t y of B r i t i s h Columbia, Vancouver 8 , , Canada. Date  nm^,  13.  by  I t i s understood that copying, or p u b l i -  c a t i o n of t h i s t h e s i s f o r f i n a n c i a l gain without my  Department or  (9 6 3  s h a l l not be  allowed  ii. Abstract  Total male,  and t h r e e  nitrogen  excretion  female Vancouver  c o i l e u s hemionus columbjanus), in  t h e deer  unit  l e v e l s ' r e m e a s u r e d on f i v e  I s l a n d B l a c k - t a i l e d d e e r (Odo-  which, were r a i s e d i n c a p t i v i t y  at the U n i v e r s i t y of B r i t i s h  were r a i s e d f r o m a p p r o x i m a t e l y t h r e e r e a c h e d an a d u l t various the  i n t e r v a l s throughout  deer.  deer,  body w e i g h t .  Metabolic  weight.  Nitrogen  method u s e d periods Appendix  of f a s t i n g  procedure of f a s t i n g  the  determination  nitrogen  gen  16.5  nitrogen  point  and f e e d i n g  The  i s described i n  at d i f f e r e n t  of n i t r o g e n  excretion while balance  appear f i r s t ,  of nitrogen  grams o f n i t r o g e n  t e i n requirement,  body  consisted of a l t e r n a t e  The r a t i o n used  levels  balance,  feeding.  trials,  permitted  as w e l l as  The r e s u l t s a n d  and t h e d i s t r i b u t i o n  followed  excretion r e s u l t s observed during  t o 17-3  were made o n one o f t h e  balance t r i a l s  of the point  obtained,  The  growth p e r i o d o f  a t one a n d two p o u n d l e v e l s a l t e r n a t e l y .  discussion of the nitrogen of  the prepubertal  and f e e d i n g .  I t was g i v e n  of t o t a l  they had  b a l a n c e t e s t s were made a t t h e same t i m e .  The  that  They  The measurements were made a t  a f t e r i t h a d r e a c h e d an a d u l t  i n the nitrogen  I.  weeks o f age u n t i l  rate determinations  n a m e l y t h e d o e R-5>  Columbia.  by t h a t  of the n t r o -  growth.  b a l a n c e was f o u n d t o o c c u r a t i n t a k e p e r day.  The crude  pro-  c a l c u l a t e d o n t h i s b a s i s , was a p p r o x i m a t e l y  100  grams f o r a p r o t e i n o f p e r f e c t  The to  1,400  energy  requirement  C a l o r i e s per  ment was  met  by  day  This level  requirement  the point  excretion  f o r an a n i m a l  was  concluded that  level  that  Upon f a s t i n g  A  of  level  t i m e was  less  reflected  the percentage  o f 90 p e r  cent  t h a n 75 p e r  When t h e a n i m a l  was  turned to l e v e l s the part  of t o t a l  o f v a l u e as an  adequate  than that lowest  level calcul-  level  ob-  urinary  nitro-  the fell  c e n t was  was  rapidly  obtained.  of  less  from the  the  The  nutritnon-  t h a n 85 p e r  o b t a i n e d i n one  c e n t o r more.  n i t r o g e n made up  not  status of p r o t e i n  to l e v e l s of  It  a l l o w e d f o r n i t r o g e n de-  given feed the percentage  o f 90 p e r  I.) a t  the lowest  as a p e r c e n t a g e  of u r e a to changes i n p r o t e i n  percentage  require-  o f t h e same body w e i g h t .  urea n i t r o g e n expressed  ion.  level  The  t h e t r u e endogenous l e v e l  nitrogen excretion  fasting  1,300  requirement.  e s t i m a t e d endogenous t o t a l  insufficient  total  on  much l o w e r  of n i t r o g e n balance.  gen  The  t o be  T h i s energy  f o r n i t r o g e n , based  the  and  found  s  t h e above p r o t e i n  t a i n e d approximated  pletion,  a  a l s o p r o v i d e d more t h a n  o f n i t r o g e n e x c r e t i o n o b t a i n e d , was a t e d from  w  f o r maintenance.  amounts o f n i t r o g e n t o f u l f i l l dietary  o f B-5  value.  t h e U.B.C. r a t i o n number 3&-57 ( A p p e n d i x  t h e one p o u n d l e v e l .  The  biological  case.  immediately prompt  cent.  re-  response  intake indicated  that  of u r e a n i t r o g e n might  index of p r o t e i n n u t r i t i o n a l  status for  field  on the  be  iv. studies. The c r e a t i n i n e n i t r o g e n e x c r e t i o n l e v e l a l s o r e f l e c t e d , to a s l i g h t degree, t h e changes i n n i t r o g e n i n t a k e . ease i n d e t e r m i n i n g  D e s p i t e the  c r e a t i n i n e l e v e l s , the r e l a t i v e l y  greater  c o n s t a n c y of c r e a t i n i n e e x c r e t i o n reduces t h e v a l u e of such det e r m i n a t i o n s as i n d i c e s of p r o t e i n i n t a k e . The ammonia n i t r o g e n as a p e r cent of t h e t o t a l gen r e a c t e d i n an i n v e r s e manner t o u r e a , and c o u l d be  nitro-  regarded  as a check on t h e c o n c l u s i o n s d e r i v e d from t h e r e s u l t s w i t h urea. The p a t t e r n of n i t r o g e n e x c r e t i o n d u r i n g growth showed changes w h i c h were s i m i l a r t o t h o s e o b s e r v e d by p r e v i o u s  investi-  g a t o r s on t h e c h a r a c t e r of i n c r e a s e i n body weight d u r i n g growth. The r a t e of i n c r e a s e i n t o t a l n i t r o g e n e x c r e t i o n i s c h a r a c t e r i z e d by changes i n r a t e of i n c r e a s e which occur  at s i m i l a r t i m e s , and  i n a s i m i l a r manner, t o t h o s e of body weight. The t o t a l c r e a t i n i n e n i t r o g e n e x c r e t i o n i n c r e a s e d i n a r e g u l a r manner d u r i n g growth, from v a l u e s of l e s s t h a n 1 0 0 m i l l i g r a m s p e r day, t o v a l u e s of between 4 0 0 0 a n d 6 0 0 m i l l i g r a m s . T h i s i s i n agreement w i t h t h e r e s u l t s of p r e v i o u s i n v e s t i g a t o r s , who have s t a t e d t h a t c r e a t i n i n e e x c r e t i o n r e f l e c t s t h e s i z e of the " a c t i v e body mass!'  V.  The reduced  levels  reduction which  at  time,  may  a m a j o r change i n t h e the  although  the  same r e s u l t  r e t e n t i o n of could  be  toward  age.  This  growth r a t e ,  appearance of p u b e r t y .  indicate increased  nitrogen  c a u s e d by  The  re-  at  this  reduced  nitro-  intake.  exceeded the  total nitrogen estimated  weights,  as  the  throughout  ^eer  total  a  result  nitrogen  once the  to  g r o w t h was  view of total body  endogenous e x c r e t i o n of  the  the h i g h p l a n e of growing p e r i o d .  m a i n t e n a n c e and  is difficult  during  excretion during  e x c r e t i o n r e f l e c t s the  terms of metabolic  the  functions. therefore the  growth  l e v e l , f o r a l l body nutrition  Because the  level  enjoyed.by level  of n i t r o g e n  level  The  of  intake surpassed,  excretion obtained  p a t t e r n of n i t r o g e n  considered  increase  of  solely  in  excretion  from the p o i n t  in protein stores,  amount o f p r o t e i n m e t a b o l i s m a s s o c i a t e d w i t h size.  greatly  growth r e q u i r e m e n t s have been  interpret  representing  and  in  of the  increasing  51  The  importance of  studies  i s discussed.  present  time,  the  e x c r e t i o n showed a t r e n d  a p p r o x i m a t e l y t h r e e months o f  coincides with  The  it  nitrogen  i s associated with  duction  gen  total  type of  to  The  these r e s u l t s l a c k of  used  in this  field  adequate techniques,  e n a b l e s a m p l e s t o be  analyses  i n terms of  taken from the  at  the  field  for  e x p e r i m e n t , makes t h e  appli-  c a t i o n of n u t r i t i o n a l p r i n c i p l e s , such as the type d i s c u s s e d i n t h i s experiment, v e r y d i f f i c u l t .  However the r e s u l t s of  experiments performed i n the l a b o r a t o r y may results  be seen from the  of t h i s experiment to be of great v a l u e i n attempting  to understand the r e l a t i o n s h i p environment.  between the game animal and i t  Acknowledgemen t s  The Dr. help  writer  \vishes  A. J . Wood a n d Dr. II. a n d encouragement  to express h i s s i n c e r e Nordan f o r t h e i r  and f o r p r o v i d i n g  n e c e s s a r y a p p a r a t u s and m a t e r i a l s , d i r e c t i o n needed to complete  The Dr.  writer  this  experiment.  a major  research the  Science  writer  i s also  o f Canada f o r t h e i r  f o r invaluable  g r a t e f u l to the National financial  a s s i s t a n t s h i p throughout  University of B r i t i s h  support  a n d many o t h e r s o f  i n many f o r m s . The  Council  i n con-  Science.  Departments o f Zoology and B a c t e r i o l o g y  assistance  animals  f o r the  a l s o wishes to thank a l l o f t h e graduate  students o f t h e D i v i s i o n o f Animal the  stimulus  the experimental  j u n c t i o n w i t h t h e D i v i s i o n of Animal  writer  t h e space, the  a l s o wishes to express g r a t i t u d e to  and f o r p r o v i d i n g  The  suggestions,  a n d much o f t h e o r i g i n a l  I. M c T a g g a r t - C o w a n f o r p r o v i d i n g  experiment  many  g r a t i t u d e to  support  i n t h e form of a  t h e summer o f 19&1,  Columbia f o r the a d d i t i o n a l  i n the form of a l a b o r a t o r y  Research  and to financial  instruction assistantship.  viii.  Table  of  Contents  Introduct ion . M e t h o d s and  1 27  Materials  I. A n i m a l s II. III.  Results  27  . '  Sample C o l l e c t i o n  32  .  Sample A n a l y s i s  34  and  37  Discussion  37  I. C h o i c e o f M e t h o d s II.  Nitrogen A.  B. C. D.  i n Adult  40  Deer  General D i s c u s s i o n of N i t r o g e n E x c r e t i o n R e s u l t s i n the L i g h t of P r e s e n t l y H e l d T h e o r i e s of P r o t e i n Metabolism C h a n g e s i n t h e A n i m a l Which I n f l u e n c e D i e t a r y Requirements . . . . Changes i n F e e d F o l l o w i n g I n g e s t i o n Which I n f l u e n c e D i e t a r y Requirements C a l c u l a t i o n of N i t r o g e n Requirements from U r i n a r y Nitrogen E x c r e t i o n 1. 2.  E.  Excretion  N i t r o g e n R e q u i r e m e n t s B a s e d on P o i n t of N i t r o g e n B a l a n c e  1. U r e a  Distribution  46  . . . .  57 66  the  N i t r o g e n R e q u i r e m e n t s B a s e d on t h e Endogenous T o t a l U r i n a r y N i t r o g e n Level  Nitrogen  -40  66  73 77 77  ix.  III.  2.  Ammonia  83  3.  C r e a t i n i n e and C r e a t i n e  84  Nitrogen  91  E x c r e t i o n d u r i n g Growth  A. T o t a l U r i n a r y N i t r o g e n B. C r e a t i n i n e and C r e a t i n e  Excretion  91  Nitrogen 98  Excretion Tables  100  .  F i gur e s  I l l 122  Conclusion Appendix  I.  Formulation British  Appendix I I . Appendix  C o l u m b i a Deer R a t i o n s  Ammonia F o r m a t i o n  I I I . Schematic  A p p e n d i x IV.  f o r U n i v e r s i t y of .  125  .  Representation  Formation Schematic R e p r e s e n t a t i o n and C r e a t i n e F o r m a t i o n  of Urea 127 of Creatinine  A p p e n d i x V.  Illustrations  Appendix VI.  Curve o f Per Cent T r a n s m i t t a n c e o f A l k a l i n e P i c r a t e Solutions of Varying Concentrations  Bibliography >  124  of Large Apparati  129 I 3 0  133 134  X.  List  of  Tables  Table  Page Data from M e t a b o l i c T r i a l s P e r f o r m e d on A d u l t Deer  I. II. III. IV. V.  Dry Matter  100  Relations  Nitrogen D i g e s t i b i l i t y Nitrogen Balance Water B a l a n c e  102  Data  103  Date  Nitrogen Distribution  VI. M e t a b o l i c  101  Data  late  104  Data  Determination  Data  105  N i t r o g e n E x c r e t i o n Data O b t a i n e d D u r i n g Growth VII.  R-4  and  R-6  106  VIII.  R-7  and  R-8  107  IX.  R-9  108  X.  R-l  109  XI.  R-5  and  110  R-l2 List  of  Figures  Figure 1.  Course of N i t r o g e n Balance on R-5  2.  3«  in Trial  Obtained  II  Course of N i t r o g e n Balance on R-5 i n T r i a l III  I l l Obtained  I l l u s t r a t i o n of the P o i n t of B a l a n c e i n T r i a l II  112 Nitrogen 113  xi. 4.  I l l u s t r a t i o n of the P o i n t Balance i n T r i a l III Changes I n  5-  Balance  Nitrogen  of  Nitrogen 114  Distribution  during'the  Trials  115  6. T h e C h a n g e i n C r e a t i n i n e Excretion during the Balance T r i a l s 7.  The C u m u l a t i v e Change i n T o t a l E x c r e t i o n w i t h I n c r e a s i n g Body G r o w i n g B l a c k - t a i l e d Deer  116  Nitrogen Size, in .  .  .  8.'The C h a n g e i n H a t e o f I n c r e a s e i n M a g n i t u d e of Total Nitrogen E x c r e t i o n w i t h Increase . i n Body S i z e , i n G r o w i n g B l a c k - t a i l e d Deer . . . .  117  :  9.  10.  11.  The C u m u l a t i v e Change i n T o t a l N i t r o g e n E x c r e t i o n w i t h Increase i n Age, in G r o w i n g B l a c k - t a i l e d Deer  .119  Th; C u m u l a t i v e Change i n T o t a l N i t r o g e n E x c r e t i o n w i t h I n c r e a s e i n Age, in G r o w i n g M a l e B l a c k - t a i l ed Deer . The C u m u l a t i v e Change i n T o t a l C r e a t i n i n e E x c r e t i o n w i t h I n c r e a s e i n Body S i z e , i n ' G r o w i n g - B l a c k - t a i l e d Deer  118  120 . . ..  121  Introduct ion Successful adequate  i s p r e d i c a t e d upon an  u n d e r s t a n d i n g o f two c o m p l e x i t i e s .  environmental  complex,  important p a r t , animal. ities,  game management  These a r e ; the  o f w h i c h t h e game p o p u l a t i o n f o r m s an  and t h e growth complex o f t h e i n d i v i d u a l  From an a d e q u a t e f o r example,  game  u n d e r s t a n d i n g o f t h e s e two complex-  t h e r e l a t i o n between t h e c h a r a c t e r o f t h e  f o o d p r o v i d e d by t h e r a n g e  and t h e n u t r i t i o n a l  status of the  game a n i m a l s  i n r e s i d e n c e on t h i s  range  understood.  Then t h e n u t r i t i o n a l  s t a t u s o f t h e game a n i m a l  may be a d v a n t a g e o u s l y suitable for  reforms  example,  modified,  i f necessary, by  to t h e n u t r i t i o n a l  has  t o c r e a t e an important  s t a t u s o f t h e game a n i m a l and powerful  environmental  c o m p l e x c o n s i s t s o f a g r e a t number  of d y n a m i c a l l y i n t e r r e l a t e d  f a c t o r s which  influence  the residing  i n v a r y i n g degree  example,  factors  state of f l u x : (2)  changes  I938);  game  technique.  The  For  herbage  understanding of the f a c t o r s  which c o n t r i b u t e  management  instigating  i n the character of the a v a i l a b l e  and thus t h e b e t t e r  been a p p l i e d  may become b e t t e r  (1)  interact  w i t h , and  animal p o p u l a t i o n .  such as t h e f o l l o w i n g c l i m a t e and topography  are i n a constant 1957);  (Darlington  i n p a r a s i t e p o p u l a t i o n s (Chandler  1955>  a  n  (  1  Spencer  a n d (3) c h a n g e s i n h e r b a g e a s a c o n s e q u e n c e o f c h a n g e s  i n f e e d i n g h a b i t s o f i n s e c t s and o t h e r a n i m a l s  including the  game a n i m a l s u n d e r c o n s i d e r a t i o n in plant  composition  with  climatic  I956,  a n d Muegger  Hubbard 1 9 5 7 ) . trols  and s p e c i e s  v a r i a t i o n s and c o m p e t i t i o n  (Blaisdell  chemical  The t h r e e  within  the f l o r a l  form  animals,  of environmental  f o r example,  They  s t a t e and t h e i r logical vary.  to  increase  and  character.  Swank  r e s i s t a n c e to adverse c o n d i t i o n s  .  animal p o p u l a t i o n  Also, f o r  t h e game p o p u l a t i o n ,  f o r m new s e t s o f s t i m u l i  variation  i n the composition  (Cowan 1 9 4 5  arise  f o r the f l o r a l  i s a c o n t i n u a l and o f t e n  of herbage f o r herbivorous  and a v a i l a b i l i t y  game a n i m a l s  Because of t h e complexity  tween t h e a n i m a l  tends  Thus t h e c h a n g i n g c h a r a c t e r i s t i c s o f t h e  The n e t r e s u l t  1957).  limited.  t o w a r d s browse s p e c i e s  ulation.  hart  physio-  tendency of the p o p u l a t i o n  reasons o r i g i n a t i n g w i t h i n  I956)  i n f l u e n c e s by  their physiological  i s c o n t r o l l e d and o f t e n  in selectivity  T h e game  With changes i n t h e i r  I n t h i s manner t h e c o n s t a n t  physiological changes  i n accordance with  genetic  i n size  game  i n v a r y i n g d e g r e e d e p e n d i n g on t h e e v e r -  condition their  to  con-  present  i n f l u e n c e s which e f f e c t  animals r e a c t t o t h e changes i n environmental inviability  and  important  changihgg p h y s i o l o g i c a l s t a t e of the i n d i v i d u a l s .  changes  population  I956  E l t o n 1 9 3 5 , Holmgreen  f a c t o r s mentioned  cycles  changes p r o d u c e d by  on t h e s i z e o f r e s i d i n g a n i m a l p o p u l a t i o n s .  a kaleidoscope  changes  age a n d i n r e s p o n s e t o c l i m a t i c  I95O),  (Cowan, Hoar a n d H a t t e r  (CoAvan 1 9 4 5 ) ,  and i t ' s environment  pop-  unpredictable  o f browse  (Dietz 195§  a  n  d  species Lauck-  of the r e l a t i o n s h i p besound f i e l d  observations  —7  -  are  essential  range  j> ~  f o r a c c u r a t e assessment  conditions. The  carrying  c a p a c i t y o f t h e range  game s p e c i e s d e p e n d s on t h e a b i l i t y supply t h e needs o f t h e i n d i v i d u a l a b l e temperatures, w h e t h e r an a n i m a l t h e most ability ing  of environmental or  will  important  requirements  o f t h e environment animals.  and topography  w h i c h may  i t must  suit-  determine  i n a certain  environment  t h e game a n i m a l ' s p r i m a r y need, More p r e c i s e l y ,  to  A s i d e from  or c a n enter and remain  c h a r a c t e r o f an a n i m a l ' s  to s a t i s f y  i n nutrient.  animals.  humidity,  for a particular  that  area,,  is its of tak-  supply the n u t r i t i o n a l  f o r maintenance and growth o f t h e i n d i v i d u a l  In order  appreciate f u l l y  to e s t a b l i s h  these requirements  t h e s i g n i f i c a n c e o f t h e range  and thus to  conditions, i t  i s n e c e s s a r y t o s t u d y t h e g r o w t h c o m p l e x o f t h e game a n i m a l .  Maintenance and  of a p o p u l a t i o n of animals  g r o w t h o f an i n d i v i d u a l  animal  and maintenance  a r e both problems of balance  between t h e r a t e o f s y n t h e s i s o f new body m a t e r i a l of  i t s destruction.  The e f f e c t i v e  numbers b y t h e d e a t h o f o l d a d u l t  and t h e r a t e  reduction i n population animals  i s a c o n t i n u o u s and  i n e v i t a b l e occurrence, r e g a r d l e s s of the extent o f the favourable conditions f o r survival. the a d d i t i o n  o f new i n d i v i d u a l s  T h i s must be c o m p e n s a t e d f o r b y i f a s t a b l e or i n c r e a s i n g l y  l a r g e p o p u l a t i o n i s t o be o b t a i n e d . growth t o b i r t h ,  growth through  The s u c c e s s f u l  lactation  conception,  t o m a t u r i t y , and  continued maintenance f o r a s u i t a b l e a certain  constant f r a c t i o n  pensation  required.  organism  i s also  t h e s i s or is  growth,  1945)*  natural  u n s t a b l e and  (Harper  d e s t r u c t i o n of protoplasm w i l l  is  i f t h e body f o r m  and  The  and  death  function,  reversal  accomplished  as  the r e l e a s e of c o n f i g u r a t i o n a l  materials,  disintegrating  the presence  by means o f  and w h i c h  speeding  ensues.  until  This  a,nd i n d e e d l i f e  catalytic second  the  lower  products  law o f  s u p p l i e d by  cata-  i n the n a t u r a l  "free  energy  i s t r a p p e d and  from  r e l e a s e of body  energy" which  itself,  material  i s liberated  ingested  coupled or  entrained into  s y n t h e t i c p r o c e s s e s to make them t h e r m o d y n a m i c a l l y  In e f f e c t ,  of  Uncontrolled  a s s o c i a t e d p r o t o p l a s m i c breakdown o f  is  the  1961).  syn-  c o m p e n s a t e d f o r o r r e v e r s e d by a n a b o l i c p r o -  t o be p r e s e r v e d .  energy  by  by  c o n t i n u e i f unopposed  c h a n g e s t a k e p l a c e and  b o l i s m must be cesses  i s continually  is facilitated  an  Protoplasm  enzyme s y s t e m s w h i c h a r e c a p a b l e o f  catabolic processes  irreversible  loss.  of  t h e com-  body o f  of c o n t i n u e d compensation,  This process  many r e v e r s i b l e  of the a d u l t  for a continuous natural  thermodynamically  (Brody  of the p o p u l a t i o n ensures  Maintenance  a matter  reproductive period,  energy  state  to the c e l l  thermodynamics.  the  i s t r a n s f e r r e d from  lost  to t h e body.  unavailable,  material  from  less  auto-  with  structure^must  same means t o r e p l a c e t h o s e t h a t  d e s t r o y e d or  the  m a t e r i a l s i n accordance A l s o u n i t s of  possible.  are  If ingested m a t e r i a l  the be  completely becomes  important p a r t s of the c e l l  or  _ 5 body may b e u s e d eventually  lead  f o r t h e same p u r p o s e .  constituents are sacrificed  essential  ones.  During  exceed  the replacement  mass.  During  loses  resulting  they predominate  into  and cause death.  The animal  The d u r a t i o n and extent o f is in  The p o t e n t i a l s i n -  e f f e c t s of environmental  factors  e x p r e s s i o n o f t h e g e n e t i c complex.  The  a s a s o u r c e o f energy and  major p o r t i o n  t h e extent and r a t e o f s y n t h e s i s .  of protoplasm,  t o be p r o t e i n .  e x c l u d i n g water,  largely  a process of p r o t e i n  must  t h e r e f o r e be c a p a b l e o f s u p p l y i n g s t r u c t u r a l synthesis that  synthesis.  c a n be made a v a i l a b l e  a l s o m a t e r i a l s f r o m w h i c h enough f r e e  ed a n d s i m i l a r l y course other  be made a v a i l a b l e , essential  h a s been  Biosynthesis of protoplasm  fore  Of  which  b y t h e s e means, however, a r e s e l d o m  in controlling  established  and  gradually  u n i t s f o r b i o s y n t h e s i s e x p l a i n s the importance o f  nutrition  protein  g a i n s body  f o r c e s and i n e v i t a b l y  b y t h e g e n e t i c complex.  the f u l l  processes  i s usually  endocrine c o n t r o l ,  dependence on i n g e s t e d m a t e r i a l  The  a balance  to balance c a t a b o l i c  r e a l i z e d due to t h e c o n f o u n d i n g  building  and t h e a n i m a l  i n a constant weight.  t h e animal  which prevent  t o p r e s e r v e t h e most  growth t h e s y n t h e t i c  requirements  i s a p p a r e n t l y under  turn determined stilled  early  t h e adult phase o f l i f e  its ability  anabolism  will  t o s e r i o u s c o m p l i c a t i o n s a s more a n d more  essential  maintained  This alternative  dietary  well  i s there-  T h e game  range  units for  t o t h e game a n i m a l ,  energy  c a n be  to permit p r o t e i n  liberat-  synthesis.  c o n s t i t u e n t s a r e needed to  - 6 make t h i s p r o t e i n s y n t h e s i s p o s s i b l e s u c h a s v i t a m i n s and. minerals, the  and a l s o o f course other  synthesis  plasm.  of the non-protein  to provide f o r  p a r t s o f body t i s s u e  t h e environment  information  to enable  adequacy o f range c o n d i t i o n s  to that  of the character  s u c c e s s f u l assessment i n terms o f c a r r y i n g  Once t h e r e l a t i o n s h i p b e t w e e n r a n g e c o n d i t i o n s c a p a c i t y h a s been e s t a b l i s h e d , p u r p o s e f u l conditions  problem of assessing  of the capacity.  and c a r r y i n g  management o f r a n g e  i n t e r m s o f t h e game i t s u p p o r t s  There have been p u t f o r w a r d the  proto-  E s t a b l i s h i n g t h e s e needs q u a n t i t a t i v e l y p r o v i d e s t h e  necessary complimentary of  materials  i s possible.  several  approaches to  t h e adequacy o f t h e range  i n g t h e e s s e n t i a l n u t r i e n t f o r good n u t r i t i o n a l  i n provid-  status  i n game  animals.  One herbage of  i n terms o f p o p u l a t i o n  chemical  and  o f t h e s e approaches h a s been t h e s t u d y o f range  a n a l y s i s of various  density, species  a v a i l a b i l i t y determined by f e e d i n g  normally  considered  species present, as to q u a l i t y , trials,  and quantity,  of nutrients  e s s e n t i a l t o a n i m a l m a i n t e n a n c e a n d growth.  These s t u d i e s p r o v i d e  much d a t a w h i c h must be i n t e r p r e t e d i n  t e r m s o f c a l c u l a t e d t h e o r e t i c a l r e q u i r e m e n t s o f game a n i m a l s (Bissell  and Strong  1955, Bissell  I958,  Einarsen  1952,  S m i t h 1 9 5 9 , a n d Swank I956).  e t a l . 1 9 5 5 , Cook 1 9 5 4 , B i e t z  1 9 4 6 , G o r d o n a n d Sampson 1 9 3 9 , S m i t h 1 9 5 0 , S m i t h  Another  a p p r o a c h h a s b e e n what m i g h t  be termed  a  s t u d y o f t h e b i o l o g y o f t h e game a n i m a l s f o u n d  i n particular  ranges  of the animals  under  consideration.  is  "rated"  i n terms  to  achieve certain  The "performance"  of t h e degree limits  Svihla  et a l .  (Bandy e t a l .  accurately,  are developed  f o r example,  being developed,  to  the thigh  to  the r e l a t i v e l y  of  1955> Cowan 1945> E i n a r s e n  'The p e r f o r m a n c e  length,  i s often d i f f i c u l t  status.  However,  such as t h e r a t i o  as a measure o f b u l f  short  term  stable  those determined  methods  length.  or of d i f f e r e n t  girth  respect  Once o b -  may b e compared status,  species.  approach h a s been t h e e x p e r i m e n t a l d e t e r -  mination of n u t r i t i o n a l parameters,  indirect  on animals; o f " i d e a l " n u t r i t i o n a l  localities,  A third  as a parameter  changes w i t h  thigh  cer-  t o measure  of heart or chest  t h e measures of v a r i o u s parameters  different  I956,  et a l .  or extent to which  t h e b u l k o f an animal  associated with n u t r i t i o n a l  tained,  digestive  1951, N i c h o l I938, R o s e n a n d B i s c h o f f 1952, a n d  et a l . 1955K  t a i n parameters  with  and weight,  F o r b e s e t a l . 1 9 4 1 , 1 9 4 6 , F r e n c h 1955, K i t t s  Leopold  are  size  such as those  a n d c e r t a i n c h a r a c t e r s o f b l o o d c h e m i s t r y a n d bone  marrow, f o r example  I946,  t h e y a c h i e v e or f a i l  i n v a r i o u s parameters  c o n c e r n e d w i t h body c o n f i r m a t i o n , capacity,  to which  r e q u i r e m e n t s f o r c e r t a i n o f t h e above  o r o t h e r s such as t h e time o f a n t l e r  maximum g r o w t h r a t e ,  appearance, or  u s i n g e m p i r i c a l ' f e e d i n g methods w i t h  "ideal  - 8 diets, of  range herbage  diets,  success i n domestic The  not p r e c i s e  or d i e t s used w i t h v a r y i n g  l i n e s of demarcation  also  results  sometimes  e n t a i l s an attempt nutrient,  puberty,  f o r good n u t r i t i o n a l  metabolism been used also  on  ( A l b a n e s e 1959,  Blaxter  and Wood,  Bricker  et a l .  1945,  Greaves  1924,  1926,  I929,  Murlin  to  though  exemplified  by t h e p r e s e n t  the requirement  d u r i n g g r o w t h and  status,  by d i r e c t  game a n i m a l .  experi-  for  one  following  measurements o f  T h i s approach  has  e x t e n s i v e l y on humans, many l a b o r a t o r y a n i m a l s ,  duction  the  However,  e x t e n s i v e l y on a n i m a l s a s s o c i a t e d w i t h a g r i c u l t u r a l  Mitchell  are  intermingle.  namely p r o t e i n ,  the i n d i v i d u a l  I938).  approaching  l i n e s of approach  to d e t e r m i n e  specific  ways o f  outlined previously.  represent c l e a r l y different  A f o u r t h approach, ment,  between t h e s e s t u d i e s  as t h e y a l l r e p r e s e n t d i f f e r e n t  t h e methods and  degrees  (Cowan et a l . 1955> N i c h o l  animals  t h e same c e n t r a l p r o b l e m s , t h e y do  -  et a l .  literature  1956,  Allison Block  1951,  I956, and  1948,  Blaxter Butcher  Scott, and  pro-  and M i t c h e l l  and H a r r i s  194-8,  1957.  i 9 6 0 , Majumdar i 9 6 0 ,  1950,  Munro  I946, a n d W a t e r l o w et a l . 1 9 5 9 ) . shows l e s s  and  1951, A review of  frequent a p p l i c a t i o n of t h i s  method  game a n i m a l s .  The and n u t r i t i o n  e v o l u t i o n o f t h e p r e s e n t knowledge of i s based  on  the f i r m  metabolism  f o u n d a t i o n s o f modern c h e m i s t r y  - 9 which The  were  laid  gradual  bolism  and  of  the the  traditional  ton  I923). the  invented  This  true  by  theory  nature  of  one  The  f i r s t  restricted  ments.  The  aliment  present  in  a  was  forward  by  Hippocrates  put  1923),  and  the  with  stomach  whether  the  the  the  C02> of  for  the 02»  these  n  (  b  y  that of  was  the  true  f i n a l l y  during  they E2>  to  (Mendel  requirefundamental theory  Century  B.C.  the  Century  2nd  Beaumont  similar  starchy  or  by  Butherford nature  of  A.D.  (Beauin  material  "albuminous".  the and  works  to  of  Lavoisier  combustion  Their  learned  (Mendel  processes looking  destroyed  combustion.  phlogis-  understand  This  digestive  and  the  from  Century  single  chemistry.  that  was  17th  William  a  two  strengthened  foods.  in  of  peculiar  a  a l l  Galen  Cavendish,  modern  i  of  the  1833  theory  fact a  its  meta-  heirloom  these  the  predominantely  uncovered  foundation  amounts  were  Priestly,  on  as  formation  phlogiston  who  hinged  late  by  an  attempts  to  in  in  observation  ingesta  1953)  atmospheric in  to  Scheele,  (Bourne  butions  the  led  The  laid  v e r i f i e d  of  earlier  form  of  metabolism  both  them  during  hypothesis  cryptic  seemingly  1833)  Black,  the  I948), a n d a s  (Sahyun mont  was  of  due  Century.  dissolution  thought,  and  respiration,  second  n u t r i t i o n and  of  Becher  J.  l8th  the  understanding  eventual  schools  giants.  of  deeper  and  acceptance  philosophic  theory  a  close  between  recession  of  the  of  relation  and popular  generations  ancient  toward  establishment  necessitated  by  down  great  and  contri-  recognize  to  observe  They  also  the  changes  observed  - 10 similar these  changes a s s o c i a t e d w i t h animal  experiments  Rutherford isolation  the presence  respiration,  o f n i t r o g e n was i n d i c a t e d .  D.  (Bourne) i s c r e d i t e d w i t h t h e d i s c o v e r y and f i r s t of atmospheric  n i t r o g e n i n 1772.  because o f abundant p r o o f o f i t s i n a b i l i t y tion  and d u r i n g  o r combustion.  Lavoisier  He c a l l e d  i t azote  to support  respira-  made t h e most  important and  c u l m i n a t i n g c o n t r i b u t i o n w i t h r e g a r d to b i o c h e m i c a l and nutritional  studies,  respiration  i n animals  cesses  i n the observation that  the process of  i s e q u i v a l e n t to other  i n terms o f heat  combustion  production associated with  pro-  a certain  amount o f O2 c o n s u m p t i o n a n d CO2 p r o d u c t i o n .  During  the  l8th  Century  a n d much o f t h e  19th  p r o t e i n was b e i n g d i s c o v e r e d t o b e w i d e l y d i s t r i b u t e d G e l a t i n had been p r e p a r e d  (I627-I69I)  (Sahyun  from  1948).  (I682-I766) ( S a h y u n ) f r o m early  i n the  reported of  that  a l l animal  19th C e n t u r y  noting 1850) to  G l u t e n was i s o l a t e d  of Boyle  by B e c a r r i  flour.  Z e i n was p r e p a r e d  (Gorham  1821).  tissues  (Bourne).  products  and l a i d  Fourcroy  b y J . Gorham  P. B e r t h o l e t i n  to p e r f e c t  contain a principle  in  I789 showed  ( B o u r n e ) on t h e b a s i s o f t h e i r  1786  three nitrogen  f o u n d a t i o n s f o r t h e study o f p r o t e i n by  t h e s i m i l a r i t y o f g l u t e n and f l e s h . helped  i n nature.  h e f o u n d n i t r o g e n t o be a c o n s t a n t c o n s t i t u e n t  k i n d s of animal concentration  bones s i n c e t h e time  Century,  nitrogen analysis "abounding  N i t r o g e n a n a l y s i s was s l o w  J . Gay-Lussac a n d he f o u n d  i n a z o t e " (McCollum  and c o m p l i c a t e d u n t i l  (1778-  a l l seeds  1939)'  the time of  the  Danish chemist  relatively and  J. Kjeldahl  t h e d i s c o v e r i e s made b e f o r e h i m c o n c e r n i n g  I n 1818  effort.  the i s o l a t i o n  who a  represent  Braconnot  found a s i m i l a r i t y  cheese  studied  Braconnot  Proust  amount o f  acid digest  which,  t h e s e and o t h e r  later  of p r o t e i n ,  leucine.  i n 1838  a n d 1839  probably provided  impetus f o r p r o t e i n  research  to u n i f y  thought  on t h e a l b u m i n - l i k e  or a z o t i z e d  one by one up u n t i l  t h i s time  ever  of plant  material  1838).  (Mulder  protein,  and animal p r o t e i n ,  the  materials  being  He  important.  a n d he showed t h e  holding  t h i s f a c t as  f o r t h e as y e t i n e x p l i c a b l e n u t r i t i v e v a l u e o f to animals.  H i s v i e w s and i n f l u e n c e  to strengthen the age-old b e l i e f i n a s i n g l e  aliment  phos-  with h i s e f f o r t s  i n n u t r i t i o n as b e i n g p r i m a r i l y  He c a l l e d t h e a l b u m e n - l i k e m a t e r i a l s  plant  (Sahyun).  f o u n d t o be common t o a l l p r o t e i n  initial  explanation  from  Besides nitrogen,  greatest  emphasized p r o t e i n  Braconnot,  obtained  a n d wool  from  investigators.  G. M u l d e r  the  o f legumes a n d  (I754-I876) i m p r o v -  a year  of muscle f i b r e  p h o r u s a n d s u l p h u r were a l s o  similarity  painstaking  o f g e l a t i n , a n d i s o l a t e d a w h i t e compound  termed t h i s p r o d u c t  discovered  1954,  (Hawk  t h e amount and  the proteins  s t a r t e d the a c i d h y d r o l y s i s  sulphuric  by  a great  i n a l l (Bourne).  (Bourne) s i m i l a r to that  also  developed the  r a p i d a n d v e r y a c c u r a t e ammonia method  d i s t r i b u t i o n of nitrogen  ed  (I849-I900), who  by p r o v i d i n g  protein  s e r v e d how-  fundamental  as t h i s s i n g l e a l i m e n t .  This  idea  - 12 had in  the unfortunate  l o n g term  effect  the minds of p h y s i o l o g i s t s ,  relations pertaining  to  of causing a separation,  between r e s p i r a t i o n ,  i t s continuance,  and  body  or n i t r o g e n metabolism  and  t i o n was  of as b e i n g c o n t r o l l e d  t o be  thought  amount o f a v a i l a b l e heat  and  metabolism  i t s a s s o c i a t e d phenomena.  o x y g e n , and  t o be  Respira-  l a r g e l y by  a special  c a t a b o l i s m to p r o v i d e energy  was  t o be  thought  f o r muscular  the  study of n u t r i t i o n  While  o f as  19th  by d e m o n s t r a t i n g  Century, the  unlike  n u t r i t i v e value of  the then r e c o g n i z e d t h r e e types of  later  s a c c h a r i n a , o l e o s a and  designated:  (Sahyun).  He  made a c l e a r  non-nitrogenous  foods  n i t r o g e n f o r the  and he  animal  However, t h i s  almost  years  proof  I906).  later  i n h i s exhaustive  result  foodstuffs,  a l b t t m i n o s a , by  Prout  between n i t r o g e n o u s  demonstrated  body was  (Bourne). 100  distinction  largely  work.  Magendie, at the b e g i n n i n g of the founded  the  mechanism f o r  p r o d u c t i o n a n d m a i n t e n a n c e o f body t e m p e r a t u r e .  n i t r o g e n or p r o t e i n metabolism  the  that  the o n l y source  Depretz  and  was  when K r o g h i n  not 1906  entirely gave  s e r i e s of r e s p i r a t o r y  de  Science  i n 1839  body h e a t  D u l o n g , who  (Bourne),  t h e o r i e s of  and  saw  accepted  studied respiration r e s p i r a t i o n as the  until  incontestible experiments  (Krogh and  f o r the Academie sole  source  t o g i v e t h e f o u n d a t i o n f o r t h e modern  metabolism.  of  n i t r o g e n c o n t a i n i n g foods  M a g e n d i e ' s work s u p p l e m e n t e d t h e work o f L a v o i s i e r  of  and  of  1844  In (Bourne).  He  invented the balance  and  and  of the urine,  oxygen s o l e l y  f a t were s t i l l  Along  w i t h t h i s work came f u r t h e r  the f i r s t  In I 8 4 9  bolism.  to use  Kegnault  devised a closed  the f i r s t  and  R.Q.  1  s.  e n u n c i a t i o n o f Bergman i n 1 8 4 5  weight. their  r a t e w i t h the The  heat  age  J u s t u s von  importance greatly  figure  ing,  stimulating  Reisit  respiratory  (Brody)  (Bourne).  1945  and  apparatus  McCollum and  were  f u r t h e r e d the  of the  increase i n basal to  studies.  Liebig  (1803-1873)  i s o f t e n regarded  e a r l y h i s t o r y of p r o t e i n  f u t u r e thought  that  laid He  (Liebig  1843)•  the foundations f o r the stressed  the  to u n d e r s t a n d i n g  energy  theory.  as The  o f o r g a n i z i n g and  importance  c h a n g e between f o o d and m e t a b o l i c  d e t a i l s of  (1819-  Barral  t o q u a n t i t a t e meta-  (Brody  They a l s o  diet.  catabolized  o f o r g a n i c c h e m i s t r y , w h i c h he was  mediary metabolism.  key  re-  increase i n surface area r e l a t i v e  i n the  to b i o l o g y , he  chemical  attempts  o f h i s work i s p r i m a r i l y  the p r i n c i p l e s  He  the  o f c a l o r i m e t e r s i s s a i d to have begun w i t h  production  the c e n t r a l  0 of  of n i t r o g e n i n the  t h i s method on humans  circuit  to determine  metabolic  milk.  f o r t h e p r o d u c t i o n o f body h e a t .  was  1939)  f e c e s and  c o n s i d e r e d t o be  1884)  technique  between C,H,N, and  the a b s o l u t e e s s e n t i a l l l t y  Carbohydrate by  -  studied the r e l a t i o n  maintenance d i e t affirmed  Boussingault  13  By also  bringing develop-  study of  inter-  of n o t i n g the  end p r o d u c t s a s  the  c h a n g e s r e g a r d l e s s o f t h e unknown  the metabolic paths u t i l i z e d .  H i s work l e d t o  the  - 14 ;ver i f i c a t i o n o f t h e p r i n c i p l e o f t h e c o n s e r v a t i o n o f in  the metabolism  gen  balance  of  living  technique  organisms.  He  extended  served  and  as  the o n l y source of  to p r e s e r v e the  carbohydrate  and  energy  from  the  t o modern d a y  fat,  taken u n t i l  and p r o t e i n m e t a b o l i s m  I852,  In published niques, and  the e s s e n t i a l  results  F.  Bidder  instrument  the  and  important'*  knowledge o f meta-  the n e c e s s a r y  u n i t y of  steps  carbohydrate,  accepted.  and  C.  Schmidt  1939)  (McCollum  tech-  cats.  nitrogen balance  i n t h e h a n d s o f C.  who  primarily  i n 1866  t e c h n i q u e became a Voit  showed t h a t p r o t e i n was  f o r energy  (Brody  and  structure  i n order  Liebig. energy  t o be  Sahyun).  catabolized,  Pettenkoffer confirmed source,  Voit  powerful  ( I 8 3 I - I 9 0 8 ) , and v o n not  Voit  " c i r c u l a t i n g p r o t e i n " d i d not have to enter  primary  of r e s p i r a t i o n ,  s h o w i n g an a c c u r a t e a c c o u n t i n g o f f o o d n i t r o g e n i n u r i n e  The  of von  plastic  o f n i t r o g e n b a l a n c e work u s i n g r e f i n e d  f e c e s of adult  koffer,  was  How-  activity  understanding  b o l i s m were b e c o m i n g more and more abundant be  as t h e  "primarily  Though t h e methods and  n e c e s s a r y f o r the approach  c o u l d not  nitro-  f o r muscular  s e p a r a t i o n i n thought  f a t metabolism,  p r o t e i n metabolism.  the  to s t u d i e s o f n i t r o g e n e q u i l i b r i u m .  e v e r , h i s v e r y d o m i n a n t p r o n o u n c e m e n t s on p r o t e i n principle  energy  Petten-  metabolized showed  into  the  that body  c o n t r a r y to t h e t h a t p r o t e i n was  i n t r o d u c e d many i d e a s and  insistence not  the  observa-  t i o n s which h o l d  today.  He i n t r o d u c e d  the idea that the  f u n c t i o n o f f o o d p r o t e i n was t o r e p l a c e body p r o t e i n w h i c h was inevitably  b r o k e n down t o a s m a l l d e g r e e d u r i n g  i t s operation.  He a l s o d e m o n s t r a t e d a t i m e l a g i n a d j u s t m e n t o f t h e body f r o m a high plane of  protein diet  t o a low p l a n e ,  p r o t e i n m e t a b o l i s m a n d two t y p e s  metabolic  and  needs,  types  little  availability  a n d l o o s e l y bound r e s e r v e p r o t e i n i n c e l l s  "circulating".  Rubner  i s c r e d i t e d with  confirming  thermodynamics as a p p l i e d to animal l i k e V o i t , d i s c o v e r e d many a s p e c t s still tion and  hold.  Examples o f t h e s e  o f S.D.A., f i r s t later  by B i d d e r  differences tein of  two  o f body p r o t e i n , namely;  "organ" or s t a b l e s t r u c t u r a l p r o t e i n with for  suggesting  creases  with  using  and Schmidt  refined  decreasing  (Chittenden),  fecal  which  (Chittenden  I907)  observation of different  pro-  nitrogen analysis, confirmation that  e f f i c i e n c y o f growth d e -  growth r a t e .  o f c o n t i n e n t a l E u r o p e , Lawes and G i l b e r t  (Bourne) at t h e r e s e a r c h showed t h e a g r i c u l t u r a l f o rproducing  cellulose.  nutrition  He,  o b s e r v a t i o n and q u a n t i t a -  by S a n c t o r i u s  law"; and o b s e r v a t i o n  Outside  foods  o f animal  law o f  (Brody).  i n d i e t a r y p r o t e i n a v a i l a b i l i t y with  sources,  "surface  metabolism  are:  observed  the f i r s t  station world  i n Rothamsted,  the importance of  non-nitrogenous bodies  Great  Britain,  nitrogenous  such as s t a r c h and  Before in  England  forecast  understanding important  kept  facts;  namely, he  almost  uniform.  presented  was  r e p r e s e n t e d by  an  on  realization  nitrogen  100  not  two  a l l u r e a came  was  not  Values  that that  f o r the average  such  as  the  came t h e  human m a l e  rather  t h e r e was  no  n i t r o g e n balance  the o v e r a l l  the  importance  o f h a v i n g an  In 1895  Atwater  than  caloric Earlier energy  simultaneously i n determining  p i c t u r e of n i t r o g e n balance.  r e c o m m e n d a t i o n s were b a s e d  were  increase in  s u p p l y the body's need.  balance  and  grasped  was  (Bourne) i n B e r l i n ,  e x c r e t i o n w i t h heavy e x e r c i s e , p r o v i d e d the  not  primary  l l S grams s e t by V o i t  I n I89O H i r s c h f e l d  workers had  nitro-  recommendations of  o b s e r v a t i o n s of c u r r e n t d i e t s  enough t o  re-  produced  f o r energy,  accepted d i e t a r y  t h i s movement, s h o w i n g t h a t  large  from  t h e amount o f u r e a n i t r o g e n l o s t  grams o f p r o t e i n  empirical  i n t a k e was  man.  that  e q u i v a l e n t i n c r e a s e over  that  experimentation.  started  deeper  i n c r e a s e d the urea output  i n the d i e t  unnecessarily high. on  the  by d e m o n s t r a t i n g  A s s o c i a t e d w i t h the r e a l i z a t i o n  of p r o t e i n  more t h a n  based  toward  (Bourne)  a l l d i d p r o v i d e d t h e p r o t o p l a s m i c mass  If i t decreased,  the food.  gradual  Smith  t h e f o o d n i t r o g e n m i n u s t h e amount o f t i s s u e  gained.  function  saw  I f the b u l k  gen  by  a major development  of p r o t e i n metabolism  f o o d , taut t h a t was  t h e t u r n o f t h e c e n t u r y , E.  A l s o , many d i e t  on o b s e r v a t i o n s o f d i e t  (Sahyun) s t a t e d t h e  f u n c t i o n s o f f o o d as an a l t e r n a t i v e  energy  to b u i l d i n g  of  working  yielding tissue,  or  as  -  1 7 -  the s o l e f u n c t i o n , or both, depending body's needs.  on the food and. on the  In I907, C h i t t e n d e n saw h i g h l e v e l s of p r o t e i n  i n t a k e as p o t e n t i a l l y dangerous to body h e a l t h ( C h i t t e n d e n 1907).  He f e l t  importance,  that even though i t was  p r o t e i n was  of prime n u t r i t i o n a l  not needed i n greater amounts than  carbohydrates. During t h i s e v o l u t i o n of ideas c o n c e r n i n g the t r u e purpose  and f a t e of d i e t a r y p r o t e i n s , a p a r a l l e l f i e l d of  study was  c o n t i n u i n g which was  to be of great importance  understanding the mechanisms of p r o t e i n n u t r i t i o n and T h i s study concerned  in  metabolism.  the chemical s t r u c t u r e of p r o t e i n and  m e t a b o l i c s i g n i f i c a n c e of t h i s s t r u c t u r e .  the  The o b s e r v a t i o n that  p r o t e i n s u b j e c t e d to h y d r o l y t i c a c t i o n by b o i l i n g a c i d was  de-  composed i n t o r e l a t i v e l y simple c r y s t a l l i n e substances was made near the b e g i n n i n g of the 1 9 t h 1931)  Wollaston (Vickery  i s c r e d i t e d w i t h the d i s c o v e r y of the f i r s t t r u e amino  a c i d , namely, c y s t i n e , had  Century.  i n 1 8 1 0 though V a n g u e l i n and  i d e n t i f i e d asparagine i n 1 8 0 6  c y s t i c o x i d e due  (Bourne).  He c a l l e d i t  to i t s o c c u r r e n c e i n u r i n a r y c a l c u l i .  i s c r e d i t e d w i t h l e u c i n e i n I8I9, Braconnet 1820  Bobiquet  Proust  with glycine i n  and so on u n t i l by I903, 1 8 amino a c i d s were known ( V i c k -  ery). The  20th  Century,  t h e r e f o r e , began w i t h an e n v i r o n -  ment of knowledge of p r o t e i n n u t r i t i o n and metabolism  which had  - 13 four  important  aspects.  First,  protein  though c a p a b l e o f  yielding  e n e r g y was n o t u t i l i z e d p r i m a r i l y f o r e n e r g y f o r  muscular  activity.  to  Second, a l a r g e  intake of protein  c a r b o h y d r a t e o r f a t was n o t c o n s i d e r e d  able.  Third,  there  necessary or d e s i r -  were p o s i t i v e i n d i c a t i o n s t h a t  served, two p u r p o s e s  i n t h e body,  implying  relative  protein  therefore  two t y p e s  o f p r o t e i n m e t a b o l i s m , one a n e n e r g y p r o d u c i n g f u n c t i o n , and the  other  tein  catabolism  level dant  a tissue building function.  c o u l d be e s t i m a t e d f a i r l y  of urea nitrogen evidence that  mentally  was a g r o w i n g b e l i e f  Fourth,  that  1905).  was abun-  Also  the key to understanding  funda-  i n protein  there  protein  and  handling  i n 1905J  Otto F o l i n o f Munich,  metabolism  e x c r e t i o n he d e m o n s t r a t e d t h e e x i s t e n c e of nitrogen  excretion  c o m p o s i t i o n a n d c o n s t a n c y o n a low o r n i t r o g e n showed t h a t  elevation  elevating the d i e t a r y p r o t e i n i n the r e l a t i v e  known a t t h i s  by t h e  By q u a n t i t a t i v e a n d q u a l i t a t i v e a n a l y s e s o f  an i r r e d u c i b l e l e v e l  crease  of pro-  a wide range of q u a l i t a t i v e  the dichotomy  human u r i n a r y n i t r o g e n  further  there  and m e t a b o l i s m l a y i n t h e a v a i l a b i l i t y  demonstrated c l e a r l y  of  accurately  s t r u c t u r e or arrangement.  t h e body o f amino a c i d s .  (Folin  the l e v e l  t h o u g h p r o t e i n f r o m a l l s o u r c e s was  d i v e r s i t y of chemical  by  i n the urine.  similar i t contained  nutrition  Also,  of c h a r a c t e r i s t i c free diet.  i n urinary nitrogen level,  He  e x c r e t i o n by  was a c c o m p a n i e d by a n i n -  importance of u r e a n i t r o g e n .  t i m e t o be s o l e l y a s s o c i a t e d  U r e a was  with the deamination  of  amino a c i d s .  He  e x c r e t i o n w h i c h he breakdown of of  the  suggested that termed  gave r i s e  ship  the  in I927  Matter constant  ratio.of  c r e t e d per different  2.3  to  Calorie'of  1927). 2.9  age  1.99  of  C a l o r i e per  milligrams  and  and  i n weight.  Sorg-Matter.  ported  by  nitrogen excretion  the and  The  latter as  of  e x c l u s i v e of  urine.  relationtotal and  en-  Sorg-  ex-  mature animals  fluctuations in  approach,  en-  f o u n d an  endogenous u r i n o u s Improvements  of  energy metabolism. aver-  nitrogen  per  i n h i s method were;  w h i c h c o n s t i t u t e d a more r e f i n e d  e x c r e t i o n measurements.  He  authors  and  nitrogen  the  higher  stated  and  r a t e on  His  excess  approximately  total  i n basal  measuring the metabolic  u a l s used f o r n i t r o g e n range  only,  the  Terroine  T h e y f o u n d an  the  energy,  of  level, by  found that  of  (Smuts 1 9 3 5 ) *  day  urinary nitrogen  technique,  wider  obtained  those  in  a quantitative  a basal  i n 1935> w i t h a more d e f i n i t i v e  ratio  using  of  nitrogen  represented  used f o r  energy produced u s i n g  They a l s o  of  dietary protein  milligrams  dogenous e x c r e t i o n p a r a l l e l e d Smuts,  at  e x c r e t i o n was  species.  that  establishment  (Terroine  level  exogenous n i t r o g e n  between e n e r g y p r o d u c t i o n  dogenous n i t r o g e n  lower  b a l a n c e t h i s was  to  Preliminary  the  endogenous e x c r e t i o n  body s t r u c t u r e and  amount n e e d e d to  ultimately  -  19  results value  same  also used  c o n f i r m e d t h o s e of (2.3  included  to the  above r e p r e s e n t e d r e s p i r a t o r y and  2.9  total  fecal  nitrogen  sweat- l o s s e s .  a  Terroine  milligrams)  endogenous the  individ-  re-  Much o f  20  the d i f f i c u l t y  -  i n e s t a b l i s h i n g the  n a t u r e o f p r o t e i n m e t a b o l i s m and  the  synthesis  the d i f f i c u l t y  basal ary  has  conditions^  and  basal  Activity,  beyond b a s a l  level provides  that  l e a d to  and  an  many o t h e r  in  obtaining  f a c t o r s , both  the  i m p e t u s was  provided  s t u d y by  many o t h e r  early part f o r the  A.  Kossel  energy  point  factors.  for  Studies  of  20th Century  the  chemical  aspect  analytical  p h y s i o l o g i s t s and  events  metabolism.  of  (Kossel  I900),  o f p r o t e i n meta-  work o f Van  biochemists  great  E.  Slyke  Fischer (Sahyun),  who  gradually  the  amino  d e m o n s t r a t e d t h a t p r o t e i n was  b r o k e n down t o  level  amino a c i d s were d e m o n s t r a t e d  be and  during  absorbed  i t was  f r o m an  (Cohneim 1901) digestion Kutscher  and 0.  shown t h a t  i n g e s t a of showed t h a t  i n the  chyme, and  Also  i n t o the p o r t a l c i r c u l a t i o n  finally  protein  digestion.  intestinal  amino a c i d s .  Loewi  At  1901,  the  equilibrium.  The  0.  to  blood  Cohneim in ereptic  same t i m e ,  et a l . I 9 0 2 )  ( S a h y u n ) showed t h a t  could produce n i t r o g e n  In  synthesize  amino a c i d s were f o r m e d mucosa.  acid  following digestion,  animals could  J . Seemann ( K u t s c h e r  the  studying  u n d e r s t a n d i n g of m e t a b o l i c  basal  the b r i l l i a n t  I9I4),  (Fischer  these various  minimal or  and  diet-  However, o n c e e s t a b l i s h e d ,  excellent reference  g r e a t l y to the  During the  bolism  to  levels.  i n c r e m e n t s c a u s e d by  t h i s n a t u r e add  and  i s due  energy r e q u i r e d f o r p r o t e i n  p h y s i o l o g i c a l , increase protein catabolism  production  the  b e e n and  true  F.  f o u n d them i n  amino a c i d s o f nitrogen  digestion  requirement  of  -  animals amino  t h e r e f o r e was  -  shown t o be f o r n i t r o g e n i n t h e f o r m  first  tative differences  p r o o f of the n u t r i t i v e i n p r o t e i n was  of tryptophane  L. M e n d e l in  rats,  support  e x t e n d i n g up  until  i n I9I2 showed t h a t though  life.  requirements  developed  the procedure  l y s i n e was  a n ( i  modification  tein in  in this  of  o f Eubner who  first  and  would acid  et a l 1 9 5 7 )  (Osborne  This latter  Thomas,  Osborne v a l u e of  and  Mendel,  method was  a  ( C h i t t e n d e n I907) a  n i t r o g e n e q u i l i b r i u m on h i m s e l f , the  s t a t e of the  ani-  a s s o c i a t e d n i t r o g e n requirements.  i n the p e r i o d brought  i n I9I9  In  m e a s u r e d t h e amount o f v a r i o u s p r o -  to produce  to the d i f f e r e n t  quirements  Osborne  i n amino  e s t i m a t i n g the b i o l o g i c a l  o f t h e method o f K.  Hose West  since  requirements  amino a c i d  "law o f minimum" and  O s b o r n e et a l 1 9 1 9 ) .  sources required  due  indispensi-  T.  differences  cognisance of the n e c e s s i t y of d e f i n i n g  mal  Hop-  i n d i s p e n s a b l e f o r growth  f o o d p r o t e i n u s i n g g r o w t h as t h e c r i t e r i o n  student  quali-  f o r g r o w t h and m a i n t e n a n c e were d e m o n s t r a t e d .  enunciated the  1915>  of  There has  t h e amino a c i d  the q u a l i t a t i v e  I9I5 t h e y  1912,  of the  the p r e s e n t time.  proteins deficient Thus,  i n 1906  f o r maintenance i n mice.  b e e n a g r e a t amount o f work done o n animals  importance  shown by E. W i l l c o c k and  (Sahyun) w i t h the d e m o n s t r a t i o n  bility  of  of  acids.  The  kins  21  from  I935  to  I938  t h e many e x p e r i m e n t s  together with t e s t s using p u r i f i e d  (Hose 1 9 5 5 , on  and  amino a c i d r e -  amino a c i d s .  This  - 22 brilliant  s e r i e s o f e x p e r i m e n t s showed  a c i d s r e q u i r e d f o r body s y n t h e s i s  that;  nine  of nineteen  amino  a r e e s s e n t i a l as p r e -  f o r m e d d i e t a r y c o n s t i t u e n t s f o r m a i n t e n a n c e and growth,  five  of  i n the  the r e s t are semi-essential  diet  a s p r e f o r m e d amino  d e p e n d i n g on t h e p h y s i o l o g i c a l s t a t e o f t h e  animal  and on i t s d i e t a r y c h a r a c t e r ,  essential values  as p r e f o r m e d amino a c i d s  metabolism,  of present  and t h e remainder  in diet.  provides  the requirement  an e x p l a n a t i o n  ing  effect  for  nine  p r e f o r m e d amino effect  o f t h e a n i m a l f o r amino nuclei for synthesis  and f a t .  However,  acids places  a limit  and on R u n n e r ' s i s o d y n a m i c interchangeability.  a c i d s from carbohydrate  dichotomy  i n c a r b o h y d r a t e metabolism to that  non-essential  the requirement on t h e p r o t e i n suggested of non-  illustrates  a similar  o f p r o t e i n meta-  nitrogen.  found a complete  i n 1939  interchange  b e t w e e n body p r o t e i n ,  nitrogen  spar-  to e x p l a i n the n o n s p e c i f i c i t y of the source of  Schoenheimer  a c i d metabolic  rather  o f body p r o t e i n  The s y n t h e s i s  amino  and h e l p s  conditions.  acids  law w h i c h  essential  that  obtained  o f t h e mechanism f o r t h e p r o t e i n  of carbohydrate  complete c a l o r i c  acids,  He a l s o  a r e non-  d a y k n o w l e d g e o f c a r b o h y d r a t e s and f a t  than preformed polypeptide  bolism  experimental  f o r t h e amount o f e a c h n e e d e d under d i f f e r e n t  In t h e l i g h t  sparing  acids  pool  (Schoenheimer  1942)  and  o f amino a c i d s and p a r t s  later, o f amino  and d i e t a r y p r o t e i n v i a t h e amino  of temporarily  f r e e amino a c i d s .  This  o f exogenous and endogenous m e t a b o l i s m was  showed  indis-  t i n g u i s h a b l e on in  1955  stant  a physical basis. 1959,  (Albanese  intake.  involved  and  r e a c t i o n s are  that metabolic still  1949  and  the development  mitted  the uncovering  interrelated  as w e l l  as  species  and  tial ous  extent  i n the  serve  showed t h a t  deal  of  requirements.  type  of  nitrogen,  q u a n t i t y and  the balance  q u a l i t y of  interrelated  and  exert  general  a r r i v e d at by  that  the  A l l of  these  B r o d y and  endogenous n i t r o g e n  duction  are  mal  that  and  some i n f l u e n c e on  laws o f m e t a b o l i c  area  r e l a t e d to the  e x c r e t i o n and  as  the  on  Thus Since per-  the  com-  requirements  Factors  t i s s u e c u r r e n t l y under  the p h y s i o l o g i c a l s t a t e of  the  trends.  p r o c e d u r e s has  amino a c i d  and  animal.  e q u i l i b r i u m of  t o v a r i a t i o n s i n amounts o f  of n o n - e s s e n t i a l  the  metabolites  information  ingesta,  ment o f  of  independent purposes.  a p p l i c a t i o n o f new a great  con-  independent  i n a dynamic  two  a  such  as  d i f f e r e n c e s i n p r o t e i n s t r u c t u r e , which  due  amino a c i d s , t h e  still  reactions represent  nutritional  individual  differences source  of  was  w h i c h was  f a c t o r s which a f f e c t  general  to a great  there  1  d i e t a r y m a t e r i a l may  the  1956)  Maynard  Schoenheimer s r e s u l t s  in various  interchange  is  However, a s M i t c h e l l showed  amount o f p r o t e i n c a t a b o l i s m  protein  plex  -  23  s i z e of  the  minutiae  r a t e and  do  construction, among  the  the  enzymes,  non-nitrogen-  animal  nitrogen  are a l l require-  not i n v a l i d a t e  waste per  unit  surface  b.efore  1949>  which  e x c r e t i o n and  basal  energy  others  biologically the  energy p r o d u c t i o n  animal are  a c t i v e s i z e of i n c r e a s e s the  elevated  essen-  by  show proan  ani-  endogenous  decreasing  -  increments.  The  equation  C a l o r i e s of  basal  t h e power 0 . 7 5 )  size  caloric  equation  in kilograms there  be  the  content  of  quirement the  nitrogen  creatinine, protein the of  the  to  correct to  creatine  that  percent  protein.  the  increase  f a c t that  uric acid.  rumen and  about by  i n energy  the  by  re-  Smuts  the  requirement  the  due  average The  the  re-  to  the  part  with  the  minimum  i s complicated  by  b i o l o g i c a l value  it is relatively  requirement  re-  f a c t that  i s associated  true  nitrogen  protein  A p p l i c a t i o n of  Once o b t a i n e d  easy  for a perfect  pro-  protein.  accepted pattern  brought  i n body weight  minimum  dietary protein  in estimating  This  6.25.  x  i s inaccurate  dietary  kilo-  Thus minimum p r o t e i n  ^kg;. 1000 x ' 4 5 4  of  animals presumably a p p l i e s  i n the  increase  x  actual  in  is:  1932).  Klieber  estimate the  minimum p r o t e i n  of  modifications tein  to  dietary protein.  The gastric  and  difficulty  the  1945»  endogenous e x c r e t i o n  requirement  great  tein  of  (Weight  x  i s sixteen percent.  estimated  Klieber  r e l a t i o n between b i o l o g i c a l  percent  a r i s e s from the  thus  = 70.5  (Brody  used to  body p r o t e i n  B r o d y and  r e l a t i o n established  i n pounds = 2 x 7 °  figure 6.25  The  the  r  is a 0.66  a biologically perfect  quirement  of  f©  f o r a one  Because of  above e q u a t i o n c a n for  f o r t h by  requirement  shows t h a t  quirement.  -  energy p r o d u c t i o n  grams t o and  set  24  by  the  nitrogen  metabolism  to r u m i n a n t s e x c e p t synthesis  l o s s of  i n monofor  of m i c r o b i a l  nitrogenous materials  profrom  the  rumen by d i r e c t a b s o r p t i o n  swelling  i n the digestive  crude f i b r e . a  acids. are  tract f o r delay  The rumen  supporting  of p r o t o z o a and b a c t e r i a which degrade d i e t -  and c a r b o h y d r a t e to s h o r t  These a c i d s  is a  i n the passage of  It i s f u n c t i o n a l l y a fermentation vat  large population  ary p r o t e i n  (Lewis 1957)*  a n d ammonia  chain  volatile  fatty  from the degradation of p r o t e i n  r a p i d l y a b s o r b e d f r o m t h e rumen.  Part  o f t h e ammonia,  f o l l o w i n g normal d e t o x i f i c a t i o n by t h e l i v e r ,  i s recycled v i a  the  removed f r o m t h e  saliva  into  rumen t h i s way,  t h e rumen.  However, n i t r o g e n  even t h o u g h  i t i s recycled,  ed  into b a c t e r i a l or p r o t o z o a l  as  exogenous n i t r o g e n  on;  the extent  utilized it  of  excretion.  into  released  lost  The d e g r e e o f l o s s d e p e n d s p r o t e i n may  be  animals a f t e r  t h e abomasum a n d s m a l l  intestine,  a s t h i s d e t e r m i n e s t h e amount  ammonia w h i c h c a n be u t i l i z e d  t h e amount w h i c h c a n be r e c y c l e d  synthesis  incorporat-  o r i t i s soon  i n a s i m i l a r way t o t h e m o n o - g a s t r i c  on t h e r a t e o f d e g r a d a t i o n ,  and  protein  o f d e g r a d a t i o n as u n a f f e c t e d  p a s s e s o n f r o m t h e rumen  and  cell  must be  by t h e  as urea.  omicroflora  Also  protein  by t h e m i c r o f l o r a d e p e n d s on. a n a d e q u a t e s u p p l y o f  c a r b o h y d r a t e t o t h e rumen t o p r o v i d e a d e q u a t e e n e r g y a n d c a r b o n chain  units  synthesis host flora  for utilization  of microbial  o f ammonia.  protein nitrogen  Once u t i l i z e d  i n the  i s a v a i l a b l e to the  by d i g e s t i o n o f t h e c o n t i n u o u s p a s s a g e o f e x c e s s  micro-  a l o n g t h e d i g e s t i v e t r a c t t o t h e abomasum a n d s m a l l i n -  testine.  The n u t r i t i v e v a l u e o f m i c r o b i a l  p r o t e i n has been  analysed with and  by  biological  true d i g e s t i b i l i t y values  Though t h e r e  is very  regarding  little  not  80  outstanding  i s a great  (Annison  feeding  the d e t e r m i n a t i o n  studies.  The  1959)•  70 These  value.  d e a l of m a t e r i a l i n the  empirical feeding t r i a l s  concerning  ment f r o m m e t a b o l i c  values of approximately  of approximately  show a good b u t  literature  -  f e e d i n g experiments with m i c r o b i a l p r e p a r a t i o n s  resultant  results  26  w i t h deer,  there  of p r o t e i n r e q u i r e -  material presented  here  is  d e r i v e d f r o m measurements made on n i t r o g e n m e t a b o l i s m  during  metabolic  studied  s t u d i e s on  are Vancouver faemionus  individual  animals.  The  animals  I s l a n d genotype of b l a c k - t a i l e d deer,  columbianus  (Richardson).  Odocoileus,  - 27 M e t h o d s and  Materials  Animals  Eight  coastal  Odo co ileus,,, hemionus,  or Vancouver  columbianus,  of  w h i c h t h r e e were f e m a l e ,  in  e a r l y June,  age  and  i960.  nutritional directly  nutritional  B.C.  C.  p e n s and  of  T h e y were t a k e n •  and h o u s e d  in a  special  Cowan 1 9 6 1 ) .  and  coded  B - l to R - 8 .  T h e y were  In  accordance  t h e methods d e s c r i b e d i n t h e a b o v e r e f e r e n c e , f o r t h e  warm w a t e r .  i n r a i s i n g deer  ed a w e i g h t  After  of twelve  ration.  switched from  in captivity,  a regimen  of  to f i f t e e n pounds, 1 )  After  care  t h e fawns  evaporated m i l k mixed  s i x weeks, o r when t h e a n i m a l s h a d  (see Appendix  the  i s d e s c r i b e d i n the J o u r n a l of  (Wood, Nordan,  in individual  Nothing i s  to c a p t u r e nor  r e s p e c t i v e dams.  This unit  were i m m e d i a t e l y p l a c e d on  dry  genotype),  Courtenay,  condition.  history prior  to t h e U n i v e r s i t y o f B.  and management u s e d  in  were c a p t u r e d n e a r  h i s t o r y of t h e i r  W i l d l i f e Management  with  Island  deer,  T h e y were a p p r o x i m a t e l y t h r e e weeks o f  w i l d ungulate unit.  housed  (Vancouver  i n a p p a r e n t l y good p h y s i c a l  known o f t h e i r  Island black-tailed  reach-  t h e y were weaned t o  f i v e months t h e y were  t h e w e a n i n g r a t i o n t o an a d u l t  ration.  (see  Appendix 1 )  At  a p p r o x i m a t e l y one  month o f November, and  and  month i n t e r v a l s ,  e x t e n d i n g from  i n some c a s e s J a n u a r y  I96I,  total  July  e x c l u d i n g the  t o December  metabolism  i960,  s t u d i e s of  a  twenty-four  hours'  d u r a t i o n each were p e r f o r m e d  deer  as p a r t  of a s e p a r a t e experiment.  deer  was o f t h r e e d a y s '  done i n a s p e c i a l l y contained  c a g e was  and  urine.  of  also  A d v a n t a g e was  s e p a r a t e experiment black-tailed  the f i r s t part  deer.  cage,  second p a r t  respiration  calorimeter.  doe;  The r e s u l t s o f t h i s experiment.  The  four  second  March 1 2 t h ,  was  performed  on  r e s i d e n c e i n the  and t h i r d were o n R-5>  s t a r t e d on O c t o b e r  trials  and l a s t e d  t h e growth  used.  T h e f i r s t was o n P - l , an a d u l t  reasons.  l 6 t h ,  1 3 and 1 1 days r e s p e c t i v e l y .  period.  The f i r s t  and was  I t i s thus  as i n t h e t h r e e day  white-  an a d u l t  ration.  were s t a r t e d o n J a n u a r y  and u r i n e were c o l l e c t e d d a i l y during  They a r e  c o n s i s t e d of three  trials,  d u r i n g the animal's  days f o r t e c h n i c a l and t h i r d  fro-  study r e -  and p r o v i n g t h e methods  doe, b o t h a l r e a d y o n t h e a d u l t  these t r i a l s  after  of f e c e s  to study t h e n i t r o g e n metabolism  of t h e experiment  and t h e second  black-tailed of  (see Appendix V).  ( O d o c o i l e u s v i r g i n i a n u s o c r u r u s ) and  o n one b l a c k - t a i l e d d e e r  tailed  were  c a l o r i m e t e r which  the c o l l e c t i o n  c o m b i n e d n i t r o g e n b a l a n c e and m e t a b o l i s m w h i t e - t a i l e d deer  each  taken of the u r i n e c o l l e c t i o n  of the present  of v a l u e i n e s t a b l i s h i n g  The  one  t r i a l on  The u r i n e and f e c e s s a m p l e s t h u s o b t a i n e d were  growing  present  growing  A l l of these studies  c o n s t r u c t e d to f a c i l i t a t e  zen f o r s t o r a g e . this  The f i n a l  constructed respiration  a g a l v a n i z e d i r o n animal  The  from  duration.  on t h e  stopped  incomplete. 1 5 t h and Feces trials  29  The  feeding  s i s t e d of  an  initial  take test  period,  schedule used during starvation period,  and  a final  t o d r i n k i n g w a t e r was vation period This  length  of d i e t a r y m a t e r i a l ant. age  Also, to  the  organisms  due  to  associated  ure  of  pound of  w i t h the the  fashion  intake  in nitrogen  ration.  If t h i s  f a i r l y well trial,  days.  given  values  during well  consumed a t  the  the  feed  each day  consumed a t two  consumed one  the  rumin-  pound  pound of  absorpDuring was  lowered  period  was  level The  to  e x c r e t i o n at  a l l consumed the  level  was  one  level. feed  one within  s e c o n d day. to  75%> be-  test  pound l e v e l However,  only  If  alternated  a f i v e day  the  meas-  various  begun w i t h  example, up  of  ex-  of p r o t e i n .  on  rough-  rumen m i c r o -  origin.  amount was  consumed, f o r and  of  the  was  p o u n d s were g i v e n  also well  f e e d was  R-5  l a s t e d four  a new  test  adult  The  star-  a decreased  to  Be-alimentation  tween t h e s e two  of  maintenance catabolism  decrements  again  initial  of u r i n a r y n i t r o g e n  intake.  p o u n d was  third  activity  feed  t h i s ' a m o u n t was  period.  level  c o n t r o l l e d feed  access  incoming c a r b o h y d r a t e or  metabolic  the  Free  in-  ensure complete passage  b y - p r o d u c t s of m i c r o b i a l  t w e n t y - f o u r h o u r s two  one  l a c k of  in curvilinear  increments or  l e v e l s of  the  period  to drop  object  to  trial  i s markedly decreased causing  food-free  pected  necessary  The  through the d i g e s t i v e t r a c t  rumen, t h e  t i o n of m e t a b o l i c this  third  con-  a c o n t r o l l e d feed  throughout.  s e c o n d and  t i m e was  these t r i a l s  starvation period.  provided  i n the  of  -  after  and  in  the  it  had  been r e p e a t e d l y  presented  for  three  p o u n d on  the  f o u r t h day  l y more t h a n one pounds. point.  The  f e e d i n g p e r i o d was  Following  the  comparable  verification  of  to  the  first,  were s e l e c t e d a c c o r d i n g  that 454  The of  weight  the  relationship pregnant,  of  The  non  during  these  between b a s a l -lactating  l e v e l s of  was  and  bolism  P-l.  i s assumed t o  and  others  two  d o e s w o u l d be  and  0.73  w  a  2,672^and  r a t i o n contained  ible  energy per  pound.  starvato  intake weight  203  was  this  allow  following used of  the  pounds,  100  and  pounds  periods.  The  and  or  general  adult,  f o r homeotherms,  x  Weight  used  s  non-  has  the  in kilograms  (Brody  for basal  C a l o r i e s per  requirement  twice  have suggested,  deer  1,142  caloric be  at  be:  power o f  If the  the  energy requirement,  Calories = 7°«5  1,336  t o be  feed  to  experimental  body w e i g h t ,  to  level  approximately  d i g e s t i b l e energy requirement  calculated E-5  metabolic  more a c c u r a t e  total  two  t h e w h i t e - t a i l e d doe  been s t a t e d p r e v i o u s l y  Basal  The  b l a c k - t a i l e d doe  kilograms,  instituted  slighttwo  a second  resting urinary nitrogen  in  does.  terminated  was  intake.  consumed  when o f f e r e d  therefore  a measured f e e d these t r i a l s  and  realimentation period,  tion period,  the  days,  the  basal  1945)J  a n t  requirement,  Therefore,  1,300 the  was deers  f o r m a i n t e n a n c e meta-  C a l o r i e s per  approximately  the  f o r the  as  maintenance requirement  2,248  *  metabolism day  ®'75  day.  of  The  C a l o r i e s of  feed  Brody  i n t a k e was  the adult  digestset  to  alternate tenance  between t h e b a s a l  energy  energy  requirement  requirement.  According  to the r e l a t i o n s h i p  between b a s a l  e x p e n d i t u r e and endogenous u r i n a r y n i t r o g e n stated previously,  the requirement  bolism  a p p r o x i m a t e l y 2.3  and  f o r S-5  endogenous  The n i t r o g e n  gram.  The a d u l t  nitrogen  until est  o r 11.3  i n t a k e was  i n t a k e was m e a s u r e d f o u r  from  also  the feces,  collection,  deer  ration  grams o f  therefore well  nitroabove  loss,  nitrogen balance  times d a i l y  which  on s t a n d i n g  was m e a s u r e d t h r e e  included  trials  to the nearest  a fraction  eva-  following defecation times d a i l y  and  to the near-  milliliter. In a c c o r d a n c e  respiration dioxide,  t r i a l s.  calorimeter,  w i t h the normal  f u n c t i o n i n g of the  measurements o f methane,  and h e a t p r o d u c t i o n  consumption  meta-  requirement.  I n s e n s i b l e water  porated  excretion,  grams o f n i t r o g e n p e r day,  D u r i n g t h e second and t h i r d t h e water  energy  f o r endogenous n i t r o g e n  grams p e r day.  a p p r o x i m a t e l y 2.49%  gen p e r p o u n d . the  was  f o r P - l i t was 3-8  contained  and t h e m a i n -  were c o n t i n u o u s l y  (by c a l c u l a t i o n ) , recorded  carbon  and oxygen  throughout  a l l the  _ 32 Sample  Collection  The  illustration,  included  i n AppendixY,  animal  c a g e w h i c h was u s e d t o c o n f i n e  within  the calorimeter  visions built are  and p l a c e d  both f e c a l  members.  of the animal  The s c r e e n  larger i n overall  losses.  could  galvanized  sided funnel,  secured  fecal  dimensions than the  to t h e cage  collection.  was support from  On r e m o v a l into a  and t h e n f r o z e n f o r s t o r a g e .  which d r a i n e d  into a shallow  four-  a c e n t r a l l y through a short  piece  was u s e d f o r c o l l e c t i n g  Urine  urine.  The frame o f t h e s c r e e n  i r o n t r a y shaped  of the calorimeter  flasks.  galvanized  m a t e r i a l was b r u s h e d c a r e f u l l y  c o l l e c t i n g pan, weighed, A  to a frame f o r  t h u s be w i t h d r a w n e n t i r e l y  to f a c i l i t a t e fecal  attached  c a g e , f u r n i s h e d t h e means f o r  t o s l i d e on s i d e t r a c k s  the screen,  front  The p r o -  collection  and s e p a r a t i o n o f f e c e s from  to prevent  calorimeter  of p i p e ,  sample  i m m e d i a t e l y below t h e t h i c k  collection  cage f l o o r  of  mesh s c r e e n i n g ,  s c r e e n was s l i g h t l y  arranged  trials.  animals  .  i r o n mesh f l o o r  the  the metabolic  shown.  support,  the experimental  i n t o t h e cage to f a c i l i t a t e  Fine wire  The  during  shows t h e  urine.  to f a c i l i t a t e  The d r a i n was n e a r t h e handling  of c o l l e c t i n g  was c o l l e c t e d u n d e r a t h i n f i l m o f m i n e r a l o i l  i n narrow-necked f l a s k s  of approximately  five  liters  capacity.  Upon r e m o v a l o f put  a urine  sample,  i n the o l d one's p l a c e  pyrex laboratory funnel to  prevent  in  the f u n n e l  volume of liter,  or  l o s s of u r i n e .  placed  the u r i n e  and  the  size  i n the as  the  origin.  sample was  specific  an  facilitate  same manner a s and  cleaning.  s e p a r a t e l y from the  origin.  The  t r a y was  d r i e d with paper Both the  The  fitting  urine  fecal  the  regime of  were o f f s e t due  spillage  balance. t r a y was  the milli-  The  a  urine  arranged  being  the  last  t r a y was  to  same  distilled two  collection  epidermal  water  balance  and  trials. after  i n the  calorimeter  media.  each  T h i s c o u l d not  the n i t r o g e n balance  d r i n k i n g water pans the  collect-  p r i m a r i l y of  growth s t u d i e s .  toward the f r o n t of onto the  detri-  weighing  s c r e e n were steam c l e a n e d  done w i t h  food  set  collection  screen,  T h i s was  the  The  flask  immediately below i t , to  c o l l e c t i o n period during continuing  each  large  g l a s s wool  m e a s u r e d by  washed down w i t h  the  A  the u r i n e w i t h  brushed from the  feces.  the wire  and  of  analytical  the  Chaff  fibre  quickly-  measured to t h e n e a r e s t  towels during  t r a y and  of  Following  g r a v i t y was  a l i q u o t on  screen  i n the neck of  A pa,d  then f r o z e n f o r storage.  slide  ed  to prevent  contamination  epidermal  five milliliter was  f l a s k c o u l d be  was  prevented  -  a new  s p i l l a g e of u r i n e .  tus of f e c a l  33  animal  be  tests.  cage  to prevent  un-  - 34 Sample  Analysis  As mentioned  previously,  measured as to volume and s p e c i f i c removal second  a t t h e end o f e a c h and t h i r d  added.  I n most  cipitates bute  formed  Kjeldahl  1951)'  micro Two  phosphate catalyst.  was p r e f e r r e d  u r i n e was  mixture  since  in 31 ;  ratio  were u s e d  A two p e r c e n t b o r a t e s o l u t i o n ,  t h e ambient  t r a p p e d ammonia was  i t was f e l t  that  pre-  contri-  n i t r o g e n by t h e  made f r o m  indicator,  distillation.  a c i d was d i s t i l l e d  758*8 mm.  Hg.  cresol  was u s e d t o  d i r e c t l y w i t h N/14  f o r t i t r a t i o n was  calculations.  w i t h brom  a stock s o l u t i o n of constant  a barometric pressure of  the s o l u t i o n used  potassium  as t h e d i g e s t i o n  ammonia d u r i n g  titrated  The c o n s t a n t b o i l i n g  subsequent  immediately f o r  s u l p h a t e and d i b a s i c  or d i s s o l v e d  at  was  method u s i n g steam d i s t i l l a t i o n ( C o n s o l a z i o  trap  acid.  recorded.  a n d t h e r e f o r e no a c i d  analysed f o r t o t a l  grams o f c o p p e r  acid,  In the  error.  r e d added as mixed  chloric  upon  o f t h e s a m p l e s were f r o z e n f o r s t o r -  g r e e n and methyl  The  period.  d u r i n g t h e f r e e z e - t h a w p r o c e s s might  to a n a l y t i c a l The  hour  c a s e s a l i q u o t s were t a k e n  This procedure  immediately  t h e pH was a l s o  g r e a t e r t h a n 7*21  a n a l y s i s and t h e remainder age.  gravity  twenty-four  balance t r i a l s  The pH was n e v e r  t h e u r i n e samples were  hydroboiling  a t 109°C. a n d  The n o r m a l i t y o f  selected  to f a c i l i t a t e  The components: mined.  d i s t r i b u t i o n of urea,  U r e a and  determined using 1957)-  the urea  ammonia c o n t e n t the  u r i n e and  w e l l , and  after  standing  at  Following  this  l i d was  potassium  c a r b o n a t e was and  the  above p r o c e s s e s  described trapped  above, p l a c e d  ammonia was  a c i d made b y m i n e d by  repeating of  the  was  (Conway  the u n i t .  t o one  trapped  i n the as  the process  ground  Conway.  b u f f e r e d u r e a s e were  s i d e and  the  two  hour.  The  l i d was  standing  Liberated  at  ammonia  i n the b o r i c a c i d s o l u t i o n  center  well  initially.  above, u s i n g  N/28  The  hydrochloric  P r e - f o r m e d ammonia was without  the  t h e Conway method was concentration. s t e p s had  they  saturated  well. left  For  placed  After mixing  to f o u r hours.  was  was  g  t h e method o f  deter-  no  a d d i t i o n of  deterenzyme.  established using Variations in effect  on  the  re-  the reliabil-  method.  The 1951)  s mples  from f i n e l y  u n i t s were a g a i n  times used f o r the v a r i o u s of  obtained  added, t o t h e o u t e r  f r o m N/14-  a g e n t s o f known n i t r o g e n  ity  slid  titrated  dilution  reliability  i n the u r i n e  room t e m p e r a t u r e f o r o n e - h a l f  room t e m p e r a t u r e f o r t h r e e from the  c r e a t i n i n e , was  t h e u n i t s were s e a l e d ,  tilting  were l e f t  replaced  n i t r o g e n among i t s  Conway m i c r o d i f f u s i o n method  m a t e r i a l s were m i x e d by  quickly  total  i n accordance with  the  -  ammonia, c r e a t i n e and  determination  the outer  The  the  A u r e a s e p r e p a r a t i o n was  J a c k bean m e a l ,  in  35  a l k a l i n e p i c r a t e method o f F o l i n  used to d e t e r m i n e the  c r e a t i n e and  (Consolazio  creatinine  content  -  of  the urine.  one-half  36 -  The c r e a t i n i n e p i c r a t e  hour f o r c o l o r  concentration  d e v e l o p m e n t , was d e t e r m i n e d  m e t r i c a l l y u s i n g a Coleman spectrophotometer, standard  curve  was p r e p a r e d  amounts o f c r e a t i n i n e . VI.  Those samples  The r e s u l t s a r e p r e s e n t e d  intended f o r determination  c r e a t i n i n e were made a l k a l i n e w i t h ide,  w i t h no p r e v i o u s  determination to  treatment.  of creatine  alkaline.  erature. total  percent  f o r more t h a n o n e b e f o r e b e i n g made  as f o r pre-formed  i n a l l cases,  creatinine  to cool  t o room temp-  s u b t r a c t e d from t h e  to determine t h e newly  Since t h i s process  complete  of pre-formed  intended f o r  P r e - f o r m e d c r e a t i n i n e was t h e n  creatinine.  i n Appendix  Those samples  t h e f l a s k was a l l o w e d  creatinine present  t o known  i n d i r e c t l y hy c o n v e r s i o n o f c r e a t i n e  T h e same t r e a t m e n t  followed t h i s after  i s considered (Consolazio  converted  t o be o n l y  I95I),  1.16.  eighty  t h e amount o f  n e w l y f o r m e d c r e a t i n i n e was m u l t i p l i e d by a c o r r e c t i o n of  A  sodium h y d r o x -  a t 121°C. and 15 pounds p r e s s u r e ,  hour,  11A.  t e n percent  c r e a t i n i n e were a u t o c l a v e d w i t h p i c r a t e  half  photo-  model  r e l a t i n g transmittance  following  factor  - 37 R e s u l t s and D i s c u s s i o n C h o i c e o f Methods  In the animal at  order  to u n d e r s t a n d  body and  fully  i t s ingested foodstuffs,  t h e o u t s e t , t o m e a s u r e and  i n t h e f e e d and  has  the d i g e s t i v e  into  the a b s o r p t i o n of a f r a c t i o n changes which occur body f o l l o w i n g quantitation  the  i n the absorbed  absorption.  and  of  chemical  The  i n the animal  tract,  factors  first  two  i s p a r t of the  and  a n a l y s i s o f f e e d and  characteristics  of  living  ist  draws upon e n t i r e f i e l d s  cells of  and  study,  the  the  i n the  study.  The  unlimited tical of mal  area,  f o r innumerable  study of n u t r i t i o n  scope  purposes,  with the  indefinite  the  The  in relation  the  nutrition-  such as t h e f i e l d  of  bio-  this of  t h e r e f o r e , becomes one  boundaries.  to  s t a t e of the  ani-  i t s feed intake relying primarily  growth, m e t a b o l i c  alysis  body c o m p o s i t i o n  rate,  of  However, f o r p r a c -  s t u d y o f n u t r i t i o n u s e s more l i m i t e d p a r t s  s t u d i e s of and  third  methods and p r o c e d u r e s  itself,  by  activities  t i s s u e s and  a l l t h r e e a s p e c t s to a s s e s s the n u t r i t i v e body  animal  f e c e s , accompanied  c h e m i s t r y o r p h y s i o l o g y , a l l o f w h i c h a r e c o n v e r g i n g on same c e n t r a l  feed  associated with  origin.  g r e a t e r study of a l l of  and  after  are accomplished  by methods o f d e t e r m i n i n g f e c e s o f m e t a b o l i c aspect  the  i n g e s t e d f e e d , and nutrient  between  i t i s necessary,  a n a l y s e the f o l l o w i n g !  changes which occur been t a k e n  the r e l a t i o n s h i p  respiratory  quotient,  cha,nges t o a s s e s s t h e  on urin-  internal  changes. are  Body c o m p o s i t i o n  often unavailable,  because they the  involve  animal under  t h e y may  r e s u l t s of  the  other  a n a l y s i s were u s e d of  the  metabolic actions was  to  i960, of  1959  the best  nitrogen  synthesis  i t provides  for  It  Fecal to  animal.  and be an  well  and  Since  feed  re-  metabolism of  u s e d to the  nitrogen establish  f a s t i n g catanitrogen  balance  A l b a n e s e 195'9>  catabolism.  Also,  extent  of  defined  baseline the  for  character  conditions  in  i f the p o i n t  estimated for c e r t a i n well  and  Darke  i t i s , in principle,  study the  excellent  be-  metabolic  consisted  1951,  the  and  protein  Though t h e  be  Urinalyses  study the  (Allison  from  e s t a b l i s h the  f o r p r o t e i n and  requirement  m e t a b o l i s m under other  in part  f e e d used.  methods a v a i l a b l e t o  dietary protein  conditions  combined.  of  i f they cannot  estimated  used to  experiment,  morten a n a l y s i s  However,  Waterlow i 9 6 0 } ,  e q u i l i b r i u m can  conditions,  post  urinalyses  errors and  in this  b a l a n c e method was  i n the  built-in  vivo protein  the  nitrogen  of p r o t e i n  Wallace  and  towards the  n u t r i t i v e requirement  method h a s  case  absorbed n u t r i e n t .  The  though extremely u s e f u l ,  experiment  of p r i m a r y concern the  bolism  one  studies  in this  animal  the  the  l e a s t be  s t u d i e s were a l s o  analyses. the  as was  slaughter  at  -  studies,  investigation.  performed,  havior  38  of  defined  estimating of  protein  s u c h as  range  deer.  i s c h a r a c t e r i s t i c of  the  study of n u t r i t i o n that  - 39 s i n g l e measurements o f changes i n t h e body d u r i n g f e e d i n g or f a s t i n g do in fact This  not  often represent  important  be due  to a  l o s s of water or  there are u s u a l l y parameter.  For  necessary  two  For  i t may  Secondly,  example, w e i g h t  to  In o r d e r  example, w e i g h t be  e q u a l l y due  agency.  f o r a change  loss  single highly probable a single  event.  many p o s s i b i l i t i e s e v e n t h e most which bear  together  By  activities  l a r g e l y of  result  exacting experimental  limited  interpretation.  of n u t r i t i o n a l  experiments  apply  to the c o n d i t i o n s of the  i n an  Several  may  to p o i n t to  set of  be o b t a i n e d .  procedures Also,  give  a  causes of  However, results  i t i s most c h a r a c t e r -  that experimental  experiment,  interpretation.  such  elimination  both  c a n o n l y a p p l y t o o t h e r more g e n e r a l  m o d i f i c a t i o n s of  loss  a s s o c i a t e d w i t h a body  cause or to a d e f i n i t e  a unified  changes  ambiguities i t i s  i n f o r m a t i o n which tend  a process  a  single  i s o f t e n b o t h water  to overcome such  istic  known, and  in a  the  loss  to  the b o d i l y  employ s e v e r a l methods s i m u l t a n e o u s l y .  change p r o v i d e p i e c e s of  proper  they  t h e measurement  i n most o f  or more c a u s e s  measurements o f c o n c u r r e n t  are  First,  c a t a b o l i s m of body m a t e r i a l p a r t i c i p a t i n g  unknown r a t i o n .  for  reasons.  interpretation.  c a t a b o l i s m o f body f a t .  and  do  o f t e n d o e s n o t p r o v i d e t h e means o f d i f f e r e n t i a t i n g  cause r e g a r d l e s s of may  not  o f t e n p i n down t h e c a u s e o f a c h a n g e t o a s i n g l e  i s so f o r two  itself  single processes,  results  known and  conditions with  Nutritional  t h e r e f o r e f r a u g h t w i t h d i f f i c u l t i e s , and  un-  they test  experiments the  - 40 ingenuity  of  techniques  the  best  experimenter s u i t e d to  m e a s u r e d change.  The  were c h o s e n w i t h ed by  to  reveal  the  the  choice  illusive  s e v e r a l methods u s e d  t h e s e v i e w s and  s e v e r a l methods o f  Nitrogen  as  -  Excretion  causes of  in this  a i m s i n mind and  i n t e r p r e t a t i o n of  i n Adult  o f methods  the  and  the  experiment are  accompani-  data.  Deer  General D i s c u s s i o n of N i t r o g e n E x c r e t i o n R e s u l t s i n the L i ^ h t of P r e s e n t l y H e l d T h e o r i e s of P r o t e i n Metabolism  The presented tailed the  r e s u l t s of  i n Tables  doe,  and  nitrogen  r e l a t i o n s are  in  Table  I,  in  Table  VII.  gen  the  data  the water balance,  the  b l a c k - t a i l e d doe  1  and  2.  parameters of  of  the  nitrogen the  two are  with  3 "to  the  the data  are  whitewith  completed for  the  changes  i n dry  IV,  oxygen uptake,  and  matter,  complete n i t r o g e n  balance  shown g r a p h i c a l l y i n  experimental  i n t a k e and  test  the n i t r o g e n  shown i n F i g u r e s  The  constitute a  These f i g u r e s i n c l u d e the  total  e a c h day  H-5  using  technical d i f f i c u l t i e s  f o r the  the  balance t r i a l s  trial,  i n Table  r e s u l t s of  e x c r e t i o n throughout  during  first  Included  on  i n c l u d e the  are  experiment.  The  to  nitrogen  t h e r e f o r e d o e s not  balance  Figures  The  h a l t e d due  nitrogen  trials  three  I to VI.  P - l , was  calorimeter,  the  total  urinary  periods.  They  nitroalso  true d i g e s t i b l e intake  feeding period. excretion obtained  Several  other  during  these  6.  urinary nitrogen  e x c r e t i o n of b o t h the  white-  trials  - 41 t a i l e d , a n d b l a c k - t a i l e d d o e s a p p e a r e d t o b e c h a r a c t e r i z e d byoccasional hour  sudden l a r g e  increases  collecting period.  Following  c r e t i o n decreased to that  a  following ample,  the fourth feeding  in Trial  at  excess  level, days.  normally  at just  day i n the l a s t  trial.  role  However,  from  F o r ex-  output  T h i s was n o t a c c o m p a n i e d  seasonal  i n these animals.  other  i f renal  by a  (1,260 C a l o r i e s ) a n d o c c u r r e d  and i n t h e o v e r a l l  b e e n shown w i t h  I958).  These  t h e wrong t i m e s ,  These l a r g e  ruminants  i n the  v a r i a t i o n which increases  due t o v a r i a t i o n s i n u r e a r e t e n t i o n a t t h e r e n a l  has  t h e ex-  as i n the case o f t h e c o l l e c t i o n  (21 g r a m s ) .  in caloric  occurs  a 24  f o r t h e most p a r t u n -  a t i m e o f t h e o r e t i c a l maximum n i t r o g e n d e p l e t i o n  balance t r i a l  be  within  I I I , o n t h e n i n t h d a y , a l a r g e amount o f n i t -  r o g e n was e x c r e t e d large  o f view,  on p r e v i o u s  and remain,  T h e y seemed t o o c c u r  theoretical point  the elevated  obtained  i n c r e m e n t s were u n e x p e c t e d , explained.  which o c c u r r e d  l e v e l as  (Schmidt—Nielsen  r e g u l a t i o n had p l a y e d  i n the excretion p a t t e r n of these  a  could  1957,  significant  e x p e r i m e n t s , much lower  l e v e l s o f e x c r e t i o n would have been d i s p l a y e d d u r i n g  the periods  of  restricted  the status  of  renal  intake.  In order  r e g u l a t i o n of urea,  to a c c u r a t e l y assess  plasma urea concentrations  h a v e t o be c a r r i e d o u t t h r o u g h o u t m i n a t i o n s were made a t v a r i o u s deer, to  during  secure  their  residence  f r e s h whole b l o o d  the tests.  times,  Blood  urea  would deter-  on a l l o f t h e b l a c k - t a i l e d  i n t h e deer  enclosure.  In order  f o r t h i s purpose advantage had to  - 42 be  taken of  their  ing  r a r e due  from t h i s  rogen value blood. 100  of 33-2  values  these  high  nitrogen, next  two  the  collection  pen,  present  13-28,  periods,  in nitrogen  level  of  nit-  whole  with  The  milligrams  of b l o o d r e s p e c t i v e l y . the h i g h e s t  in this  level  levels  level  was  obtained  be  last  obtained  of u r i n e  i n the  first  on  f i r s t day  i s no  during  the  day  of  to  the  s e c o n d day by  the  the  i n the  and  collection,  on  the the  of  fact  amount  some e x t e n t  bladder  of  residence  residence  i n the urine  of  r e c o r d of  one  grams o f  explained p a r t l y  the  high  deer.  25.4  of  the  Though t h e r e the  A  per  those  1956).  experiment began w i t h  retained during  storage  a urea  8-20  and  result-  milligrams  (Spector  a p p a r e n t u r i n e r e t e n t i o n must  actual  to  i s understandable c o n s i d e r i n g the  excretion.  released during this  goats  6-27,  However, t h i s may  calorimeter.  25.0  of  status maintained  of  had  milliliters  r e p r e s e n t a t i v e of  o r more t h a n t w i c e  u r i n e was  urine  This  R-5  compare f a v o u r a b l y  milliliters  second balance  levels  residence. that  are  of n u t r i t i o n a l  The these  100  100  a value  sheep and  animals are  f o r R-5  ranges.  had  These v a l u e s  n i t r o g e n per  values  level  m i l l i g r a m s per  cattle,  for these  of urea The  with  side effects  In; M a r c h 1962,  I962, R-5  milliliters.  a d u l t d e e r due  T h e s e o p p o r t u n i t i e s were  to t h e u n d e s i r a b l e  treatment.  In A p r i l  obtained  in  i m m o b i l i z a t i o n p r o c e d u r e s on  extreme r e f r a c t i l e n a t u r e .  necessarily  -  in of  deer reelevation second  day to  of residence, the bladder  must  during  43  represent the f i r s t  -  nitrogen  eliminated  day i n t h e c a l o r i m e t e r .  r e t e n t i o n was p r e s u m e d t o be a s s o c i a t e d w i t h by  the transference  of the animal  l a b o r a t o r y and c a l o r i m e t e r  The t o t a l  the w h i t e - t a i l e d deer, 23.I of  grams  Even it  c a n be seen t h a t  was n o t g r e a t cretion This  authors with  nitrogen per kilogram ruminants Morris for in  differs  Lower v a l u e s  various  Majumdar  i n part  level  a n un-  level  excretion  the nitrogen  ex-  i n a l l cases.  f r o m t h e r e s u l t s ob-  both monogastric  a n i m a l s and  o f between 0 . 0 4 and 0 . 0 5 grams o f  i960,  animals  the general  various  H u t c h i n s o n and values  ( B r i c k e r , Kinsman and M i t c h e l l ) r e l a t i o n s h i p between  e x c r e t i o n a n d body w e i g h t  in  nitrogen  excretion,  19415,  with  M i t c h e l l I929) and s i m i l a r  nitrogen total  to a  however,  e f ^ b o d y w e i g h t were o b t a i n e d  monogastric  accordance with  of feed,  i n nitrogen  and t h a t  ( B r i c k e r , Kinsman and M i t c h e l l ,  I936,  from a l e v e l of  e x c e s s e s a r e discounted;,  the f a s t i n g decrease  i n general  to t h e  o f 4 3 - 2 grams r e s u l t e d .  o f f at a rather high  by p r e v i o u s  ruminants.  increase  i n any o f t h e t r i a l s  levelled  result  tained  restriction,  Upon r e s u m p t i o n o f f e e d i n g  e a r l y and l a r g e  i f t h e l a r g e 24-hour  enclosure  I946}.  immediately f o l l o w i n g withdrawal  expectedly  caused  e x c r e t i o n decreased markedly i n  upon f e e d  a b o u t 9 grams p e r d a y .  The  stimulation  from the deer  (Fulton  nitrogen  i n part  (Brody 1945)*  e x p e c t e d and o b t a i n e d  T  n  endogenous e  decrease  to a degree,  - 44 is  caused  by  changes  a characteristic 1959,  Tut t i e  i n the  turnover  and  Wallace  l a b i l e p r o t e i n s t o r e s which have  (Allison I959).  1951,  1953,  I956,  Block  These s t o r e s are f u l l y  main-  t a i n e d o n l y d u r i n g p e r i o d s of h i g h plane p r o t e i n intake otherwise istic  g  high  a high  are  exhausted  quently, with  protein  and  the  As  areas  the case  cretion  nitrogen excretion.  i n s i z e because of of  rate,  r e d u c t i o n of  the  s i z e of p r o t e i n s t o r e s  proportionately.  slower  turnover  these  consequently  and  g i v e up  areas  and  essential  despite continued  f o r continued  fasting,  body  (Annison  Lewis  1957).  As  this  In the  than  process  nitrogen  This level  expro-  i s the  ruminants,  i s u s u a l l y present  a  continued  i n t h e rumen and  s u p p l i e s of m i c r o b i a l p r o t e i n are and  amino  associated with v i t a l  r e s t r i c t e d n i t r o g e n metabolism  small  and  i n s m a l l e r volume  existence.  there  the  amino a c i d s .  g i v e up  consequently  of p r o t e i n metabolism.  their  conse-  When t h e  of the h i g h plane p r o t e i n s t o r e s .  a p p r o a c h e s a minimum l e v e l  of  to  On  highest  at a r a p i d  o f body p r o t e i n b e g i n  endogenous l e v e l  host  are a s s o c i a t e d with  and  continues, p r o t e i n catabolism,  tinued  consequently  first,  a c i d s much more s l o w l y and  level  they have a c h a r a c t e r -  s t o r e s a r e n e a r l y e x h a u s t e d , more s l o w l y m o v i n g  Because of t h e i r  cesses  time  t h i s happens the a r e a s  e x c r e t i o n decreases  important  in  this  stores r a p i d l y decrease  r a t e of a c t i v i t y .  nitrogen  at  o f n i t r o g e n c a t a b o l i s m and  these  turnover  and  r a t e of turnover  level  fasting high  adequ te diet,  with  g i v e n up  conto  the  These a d d i t i o n s of p r o t e i n to  - 45 the  intestinal  nitrogen acids.  tract  of the host  provide  to t h e a n i m a l ' s m e t a b o l i c This process  i s the case with  monogastric  and  level  of approximately  6 . 9 grams d u r i n g  relatively  constant  the t h i r d  r a p i d catabolism of  animals.  11  nitrogen  e x c r e t i o n to t h e  grams d u r i n g  trial  the second  represents  the  respective fasting  the  fourth fasting  day of t h e second t r i a l  3.2  grams o f t o t a l  nitrogen.  The e x p e c t e d  during  T h e r e was one c o l l e c t i o n  endogenous l e v e l  when t h e l e v e l  of nitrogen  may be c a l c u l a t e d f r o m t h e e x p e r i m e n t a l  relation  trial  the closest  a p p r o a c h t o t h e endogenous l e v e l periods.  o f amino  p r o t e i n d e p l e t i o n as q u i c k l y  The l e v e l l i n g o f t h e t o t a l average  supplies of  by a b s o r p t i o n  prevents the constant  l a b i l e p r o t e i n s t o r e s from causing as  pool  small  on was  excretion  t o body w e i g h t  of Brody, v i z . E.U.N. = 1 4 6 W * 0  (Brody  7 2  1945)  where E.U.N, c o r r e s p o n d s t o t h e amount o f endogenous u r i n a r y nitrogen grams.  excretion, This  lactating, From t h i s  and W c o r r e s p o n d s t o body weight  relation  a p p l i e s , however,  to a non-pregnant, non-  a d u l t m o n o g a s t r i c mammal u n d e r b a s a l relation  t h e endogenous l e v e l  doe a t 2 0 3 p o u n d s s h o u l d black-tailed  conditions.  f o r the w h i t e - t a i l e d  be 3 . 8 0 grams p e r day, a n d f o r t h e  doe a t 1 0 0 pounds  9 0 pounds 2 . 1 1  in kilo-  i t should  be 2 . 2 8 grams a n d a t  grams o f n i t r o g e n p e r day.  From t h e r e l a t i o n o f  - 46 Smuts o f  2 milligrams  of  k i l o c a l o r i e of basal c r e t i o n w o u l d be 1,900,  mately  associated with  1,138  for  the  relation  but  are  approximately  close It  to  the  ment o f obtained  e x c r e t i o n of  The  of 3 . 2  to d i s c u s s  to t r y and  experiment  about 4 . 8  to 8 . 7  average basal 1,138  increase  for activity,  C a l o r i e s , and  al  increment,  1,700  during  the  the  grams i s t h e r e f o r e nitrogen  i n t e r p r e t the  level  of u r i n a r y  Influence  1,700  per  the  day  allowing  total  per  very  excretion. require-  elevation nitrogen day  Dietary  over  the  an  Requirements that  a d d i t i o n a l 50  T h i s would  feeding period, ingested  C a l o r i e s of  and  the  f o r the b l a c k - t a i l e d  energy requirement per  Calories.  dynamic a c t i o n c a u s e d by  If  body w e i g h t  for theoretical considerations,  d e e r was  approximately  formula  level.  energy p r o d u c t i o n  be  kilogram  values  body w e i g h t ,  grams o f n i t r o g e n p e r  Changes i n t h e A n i m a l w h i c h Assuming,  and  approxi-  These  the d i e t a r y p r o t e i n  further  i n the  day.  Klieber's  endogenous u r i n a r y t o t a l  i n order  e x p e c t e d endogenous  using  heat p r o d u c t i o n  level  ex-  c a l o r i e o u t p u t s of  1 k i l o c a l o r i e per  expected  in this  basal  per  l e v e l s of  k i l o c a l o r i e s per  between b a s a l  these deer  urinary nitrogen these  than those obtained  1932).  i s important  1,055  and  slightly  (IQieber  lower  total  energy p r o d u c t i o n ,  are  hour  excreted  due  i n c l u d e an to t h e  abosrbed  energy had  percent day  addition-  specific  food.  t o be  would  supplied  e n t i r e l y by p r o t e i n catabolism, tein, ed per  47 4  2  5 grams of m e t a b o l i z a b l e  e i t h e r from f e e d or body sources, day.  The  would have to be  proutiliz-  same amount of absorbed p r o t e i n as body p r o t e i n  would be needed because both s u f f e r the same l o s s e s to u r i n e (Brody 1945» ncL Maynard I956), thus p r o v i d i n g the same amount a  of c u t i l i z a b l e energy per  gram to the body.  t e i n c a t a b o l i s m would r e s u l t c r e t i o n of 68 grams per  T h i s amount of  in a total urinary nitrogen  ex-  day.  However, some of the energy would be s u p p l i e d by l i m i t e d amount of carbohydrate s t o r e d i n muscle and e s p e c i a l l y d u r i n g the  pro-  initial  stages of f a s t i n g  i n the  the liver,  catabolism.  A l s o , d u r i n g the u t i l i z a t i o n of s t o r e d carbohydrate, some of energy would be ing  s u p p l i e d by c a t a b o l i s m  the exhaustion  of the carbohydrate supply,  would then be d e r i v e d from storage obtained  of body f a t , and  by f a t catabolism,  fat.  follow-  a large proportion  If a l l the energy  I 9 0 grams of f a t would be  was  required,  and  there would be a r e s u l t a n t weight l o s s of t h i s amount per  day  as compared w i t h a l o s s of up to 4 pounds i f a l l was  ed by p r o t e i n c a t a b o l i s m .  The  the  obtain-  f i g u r e of 4 pounds i s suggested  because of the f a c t that body p r o t e i n i s a s s o c i a t e d with body water i n a r a t i o of I p a r t to 3 (Brody, and Kinney 1 9 5 9 ) . When body p r o t e i n s are c a t a b o l i z e d t h i s water i s f r e e d , and may completely ance.  be  e l i m i n a t e d depending on the c o n d i t i o n s of water b a l -  T h i s balance i s determined on the one hand by the  physio-  - 48 logical The an  s t a t e of  weight  the  animal,  loss obtained  i n the  a r b i t r a r y a v e r a g e to be  from the was  not  total due  If level,  and  4.69  the  grams i n t h e  and  115  Calories.  C a l o r i e s per  day 170  r e q u i r e about per  day  with  a t 310  this  to  to 39°  ing  of  the water  up  The  to 388  i n the  grams p e r  day  of 0.8  or  6 pounds f o r  seven f a s t i n g days.  d a i l y weight  l o s s w o u l d be  total  loss for  eight  day  310  fasting  This  loss  balance  data  above t h e p r e d i c t -  i n the  the  second  trial  c o n t r i b u t i o n of  f a t catabolism. set  This  would  would r e s u l t which  is  the weight  above two  pounds w i t h During the  Includloss  instances  a total third  would  l o s s of  trial  4 pounds.  in  character-  the  grams o r n e a r l y i p o u n d and  d a y s w o u l d be  loss  associated  from f a t metabolism.  the  grams  1,600  and  the weight  gaseous exchange  a value  28.8  representing  b e t w e e n 1,500  body p r o t e i n ,  first  as  day  t h e n 5 4 * 5 grams and  O.72,  derived  associated with  days.  fat catabolism  about  energy p r o d u c t i o n  which would occur be  of  pounds per  T h i s would  amount o f p r o t e i n and  a r e s p i r a t o r y quotient istic  fat.  grams.  calculated  a v a i l a b l e , thus  s u p p l i e d by  grams o f  2.3  increment  T h i s would l e a v e  be  was  intake.  same p e r i o d .  represented  energy p r o d u c t i o n ,  the water  the water  grams p e r  o f p r o t e i n r e s p e c t i v e l y w o u l d be 218  as  excretion  third,  by  p o u n d s i n 13  kilograms f o r the  nitrogen  other  second t r i a l  loss,  c o n s i s t i n g of 8 . 7 2  body p r o t e i n t o  the  approximately  to o b s e r v e d w a t e r 2.1  on  l o s s o f 30  weight  shows a g a i n o f  ed  and  -  The  the  smaller d a i l y  l o s s of  less  is  sole  energy  d e n s i t y of f a t r e l a t i v e  u r e s show t h a t  -  the observed  source r e f l e c t s  to p r o t e i n .  elevation  not a c t u a l l y v e r y l a r g e from  the p o i n t  due  tein  compared t o f a t .  energy  As w i l l  fuel  be  erous.  The  relatively in the order  the c a l c u l a t e d  constant a i r temperature  to  enforce limited physical  to be  The  as t h e b a s a l e n e r g y  ciated with a c t i v i t y  postural  rest  d u c t i o n has  and  slightly i s due  muscles  standing.  in  i s too  gen-  surroundings with  activity.  requirement.  fined  The  cent  pro-  space  in  V a r i o u s workers  and  the  specific  l e s s than h a l f  to the  p l u s those dynamic  increased tonal  12 per  been s t a t e d by Kinney (Kinney 1 9 5 9 ) .  for  the  may  be  increments  effect  i s said  to other p h y s i o l o g i c a l  A f i g u r e of  k i n d of a c t i v i t y ,  cent h i g h e r than  maintenance requirement  requirement  a  15°C., which i s w i t h -  of  20 to 25 per  energy  with  basal level,  approximately  figure  protein  have estimated the maintenance requirement  basal  this  fig-  i n f e r i o r i t y of  zone o f t h e r m o - n e u t r a l i t y , and w i t h l i m i t e d  energy  SDA.  of  i n c r e a s e of 50 per  a n i m a l s were p l a c e d i n q u i e t  i n c l u d i n g Brody  Of  above  of view  to the r e l a t i v e  shown, t h e  energy p r o d u c t i o n over  The  the  in nitrogen excretion  c a t a b o l i s m f o r energy, as an  4  t h a n a p o u n d compared t o about  pounds w i t h p r o t e i n as the caloric  49  activity  cent of the t o t a l  asso-  of feeding.  t o be due  efforts  de-  of  to the  associated energy  as t h e f r a c t i o n u s e d  pro-  in this  Therefore, a f i g u r e of  15  per  cent  would not  under for  the  the  about  seem u n r e a s o n a b l e  total  1,340  energy p r o d u c t i o n  C a l o r i e s per  catabolism  the  total  weight  water  be up  The metabolic from the per 4  day  P.M.  for  f l u s h i n g out  occurred  are  chamber was  130  about  and  with  p e r i o d w h i c h was and  with  grams p e r  slightly  body  day  and  would remain n e a r l y the  same.  t h e above a c t i v i t i e s the water  rates obtained i n Table  a b o u t an h o u r  t h e chamber.  each t e s t  m e a s u r e d and  the  f o r the  would  production  VI.  chamber the  the h i g h e s t  during  the  T h e y were the  three  The  three  computed  test  5 hours r e s p e c t i v e l y , s t a r t i n g  tube that p r o v i d e d  back to  to  about  at  periods about  r e q u i r e d between e a c h p e r i o d o x y g e n c o n s u m p t i o n was  cal-  t h e p e r c e n t a g e oxygen decrement period. recorded  The on  oxygen content  a continuous  a p p a r a t u s w h i c h c o n s t a n t l y sampled a i r f r o m bleed  deer  to  i n c l u s i v e of  recorded  f r o m d a t a made on during  deer  fat oxidation.  6 , 1 0 , and  e a c h day,  these  revised figure  amount o f o x y g e n consumed d u r i n g of  culated  day,  of  black-tailed  lowered only  JR.Q.  basal metabolic  trials  the  associated with  grams p e r  associated with  of  w o u l d be  The  case  T h i s would r e v i s e the f i g u r e s  The  l o s s w o u l d be  liberation  to 3 6 0  day.  requirement  pounds i n 3 ° days.  The  i n the  conditions indicated.  fat  10  5 0 -  a circuit again.  Even d u r i n g  the  1 1 P.M.  a c t i v i t y obtained  the  recording  chamber v i a a  of a i r through the  t e n hour p e r i o d from r a t e s of  the  of  which  recorder  longest until with  the  test 9  A.M., resident  animals, to  t h a t c o u l d he  the metabolic  rate,  considerations  The  to  i n accordance  carbon  measure t h e  The 1,400  Values  average  C a l o r i e s per  C a l o r i e s per  obtained  l a r g e l y from  i t agrees R.Q.  with one  p e n d i t u r e of 4*83 only  slightly  mental  results  formula of rate  recorder  dioxide during quotient  were  the v a l u e s f o r  included i n Table  the t h i r d  VI.  second  trial  it  trial was  0.82.  The  average  was  i n the  third  trial,  by p r e v i o u s  an R.Q.  calorie o f Q. 7«  above f o r the heat than  Klieber  the  The  investigators.  o f o x y g e n consumed r e p r e s e n t s t h e  higher  relationships.  carbon  the values obtained  Calories.  B r o d y and  in similar  T h e s e v a l u e s were c a l c u l a t e d on  less with  are only s l i g h t l y  During  the v a l u e s used  quoted  recorded  p r o d u c t i o n during the  R.Q. , w h i c h was  liter  consumptions  2 4 h o u r p e r i o d s , and  day.  day.  the average  this  heat  i n f l u e n c e on  using a continuous  are  time  VI.  f o r the r e s p i r a t o r y  trial  a t any  physiological  oxygen  shown i n T a b l e  i n the t h i r d  b a s i s of  and  total  i n percentage  f o r some o f t h e  those obtained  1,300  The  an  standard  d i o x i d e p r o d u c t i o n was  increment  period.  calculated  was  with  to t h e oxygen consumption,  each t e s t  At  1956).  (Guyton  decrease  c o n s i d e r e d to have had  each 2 4 h o u r p e r i o d a r e  fashion  -  the oxygen c o n c e n t r a t i o n d i d not  levels  for  51  expenditure The  ex-  would  be  a,verage e x p e r i -  production  obtained  t h e v a l u e s computed f r o m f o r t h e body w e i g h t  the  metabolic  -  The  individual values  however more i l l u s t r a t i v e  of  metabolic  the  activity  more i n f o r m a t i o n this  a n i m a l by  during  as  the  to the  crease  during periods  singly  they  During  an  in  t h e pen,  intake of  v a t i o n with to  1,170  at  about  of 100  for  level  the  with of  This  R-5  level  the basal  animal  and  1,170  pounds.  corresponds to a and  represents  caloric  requirement  study  of  in  various  of  de-  Taken  the  inanition,  character  i n the  of  of  96  feeding, of  the  test  increment  during  the  showing a v e r y  presfeed. R-5  for  state,  the  feeding period  over  the  the  is  predicted  second  same p e r i o d slight  lower,  pound, o f  the maintenance requirement During  star-  the  the p r e d i c t e d v a l u e  before  given  i t went  during a  1,640  of  hours of  the p o s t a b s o r p t i v e  12%  second  f e e d as  this  about 3 / 4  of  conditions.  output  extent  inanition.  Following  c l o s e to  of R-5  the  Calories after  Following  output  by  pounds s t a n d a r d  second day  i s very  supply  the  dropped from a l e v e l  1.7  utilization  in  as w e l l .  to water.  the  are  r e s t i n g metabolism  and  p e r i o d of  1,300  of  above d e s c r i b e d the  and  inactivity  r a t e of R-5  f r e e access  average c a l o r i c 1,330.  feeding,  first  of  They a l s o  change i n r e s p o n s e t o  approximately  C a l o r i e s on  level  basal  the  to a  umed a b s o r p t i o n The  test periods.  character  in this  the metabolic  on  changes which o c c u r r e d  e n a b l e a more a n a l y t i c a l  p r o t e i n metabolism  trial,  of  -  f o r d a i l y heat p r o d u c t i o n  the  degree of  changes i n the p a t t e r n of  52  of  R-5  trial  i s within  degree of  1%  physio-  logical  activity  probably  on  explains  r a t i o n presented to  to  i t s r e a c t i o n to  Following  the  of R-5  output  the b a s a l  relative  i t for the  level.  at  i n the  first first  trial  days,  trial  cent  however  This  the deer  trial  a 4 per  reduced to o n l y last  time.  consecutive  r a t i o n i n the  In the  this  i n d i f f e r e n c e of  several  feeding period was  -  of R-5  the p a r t  the  53  the  R-5-  caloric  increase  i t was  to  compared  with the  fact  10  over  per  cent  higher.  The in  these  e x p e r i m e n t s w o u l d not  expenditures take of during short day  of  a d e q u a c y by short  and  Therefore  on  only  bolism  of  hydrate, applies the  the  not  caloric 1,837  by  269  and  day  on  discrepancy  grams o f  number o f  amounts. the  short  On  for  each f e e d i n g  f o r the  by  grams o f first  two  c a l o r i e s needed from  the  523 an  day,  example,  first  feeding  920  by  exact  nitrogen  even t h o u g h  s a t i s f i e d by  367  grams o f  a m i x t u r e of days of  Cal-  Calories.  entire feeding period  t h u s be  large  calories fell  t h i r d day  surprising that  body f a t , or  e s p e c i a l l y to the  encountered  replace dietary i n -  second t r i a l ,  i t was  could  l e s s than 367  to  the d i e t a r y i n t a k e of  entirely  C a l o r i e s and 204  i n the  C a l o r i e s , on  achieved  rates  expected to n e c e s s i t a t e  i n order  significant  fifth  i t i s not  b a l a n c e was total  However,  feeding period,  i t was  be  o f body r e s o u r c e s  calories. the  ories,  r e l a t i v e l y moderate m e t a b o l i c  the  the  body the last  the  was cata-  carbotwo.  This  trial  where  endogenous s o u r c e s was  more  -  than.1,000- C a l o r i e s p e r  day.  sis  period  during  that as  this  feeding  t h e y show t h e  a source of  54  The  increasing  r e s u l t s of  are very  However, on portance. caloric of  the  the On  third  the  output, caloric  and  on  in late  i n d i c a t e that  R-5  had  s o u r c e of  explain.  high It  The is  general not  body mass, o r the  of  weight  together  feeding energy  output. in  half  imthe cent  w i t h know-  b l a c k - t a i l e d deer  reasons other  which  i n a s t a t e of  depleted  than d i e t a r y ,  seems  reached a state wherein i t ' s  body p r o t e i n as  l o s s i n the  the  sufficiently nearly  second t r i a l  a predominantly  i n r e s p o n s e to a h i g h  enough t o  i n the u r i n a r y indicate a  dietary protein  same t i m e t h e  stores  sole  energy.  elevation  great  h i s t o r y of  i s i n d i c a t i v e of  t y p e body w a s t a g e  one  f a t s t o r e s were d e p l e t e d  use  endogenous  The to  the  analy-  i t s u p p l i e d 99 per  observation,  finally  little  caloric  almost  t h e y t e n d t o be  several  body c a r b o h y d r a t e and to n e c e s s i t a t e  f o u r t h day  of  two  i t suddenly.rose  i t supplied  natural  spring  for  large d e f i c i t  This  first  supplied very  f o u r t h day  the  output.  energy r e s e r v e s to  and  t h i r d day  ledge c o n c e r n i n g the shows t h a t  rather  nitrogen  body p r o t e i n  During the  d a y s m e n t i o n e d above, body p r o t e i n the  the  i n t e r e s t i n g however, i n  importance of  endogenous e n e r g y .  toward r e c t i f y i n g  -  is difficult  l e a n body mass  total  metabolic  rate.  nitrogen  excretion  level  l a r g e p a r t i c i p a t i o n of  i n the p r o d u c t i o n  of  w a t e r b a l a n c e d a t a shows a g a i n  lean  energy. of  a few  At kilo-  grams i n 13 but  this  days.  should  This  in  the case  following to  animals  a good n u t r i t i o n a l  l e a n body mass c o n s i s t s o f  plus  a s s o c i a t e d water. LBM  loss.  For  kilogram a  loss  l o s s of  of  0.50  vation storage  a daily  0.54  kilograms  k i l o g r a a i s or type  of  about  b o h y d r a t e s t o r e s and  has  the p r e v i o u s n u t r i t i o n a l age  and  gram mammal o f 200  itself.  composition  of  this  the  of  The  loss  of  the  1,400  of  weight O.65  Calories,  This  a  early until  loss star-  the  of the  car-  i s dependent  animal,  and  to  s t o r e i n a 70  history  on  on i t s  i n f l u e n c e the use  nutritional of  loss  Calories,  extent  loss  carbohydrates  is  Calories a  1,300  The  type  c o n d i t i o n which  F o l l o w i n g the use  kilogram of  1,7°0  For  loss  This  i n weight h o l d s  loss  tends  1959)  total  of  history  i s capable  the  i s needed.  good p r e v i o u s  grams, w h i c h  t o 3 clays  1 pound  of  which n u t r i e n t s are put.  loss.  (Kinney  body f a t .  b e e n u s e d up.  thus  l |  a p r o d u c t i o n of  i s needed.  composition  carbohydrate  physiological  cent  of  c a l o r i e s per  For  energy,  body p r o t e i n s t o r e s  energy p r o d u c t i o n of  i s needed.  of  t h e mammalian body  composition  2,600  produces approximately  means f r o m  labile  20 per  and  source  s t a r v a t i o n which  l e a n b o d y mass.  This  cent  early  history,  l o s e a h i g h p r o p o r t i o n of  The  the o n l y  slow r a t e of weight  to Kinney d u r i n g  of monogastric  about 8 0 per  -  l e a v e s f a t as  give a f a i r l y  According  55  average,  kiloabout  s u p p l y i n g o n l y 8 0 0 C a l o r i e s by this  "emergency" e n e r g y  changes to a p p r o x i m a t e l y  store  50 p e r  cent  the lean  - 56 tissue tion It  and  per  contributes  cent  depot  fat.  1,400  about  ^,000  C a l o r i e s per  an  energy requirement  C a l o r i e s , a 0.28 1,300  required.  dicative  of  provided  there  logical  the  The  functions,  no for  during  As the  the  of  fat  gradient  in size,  with  the  i n endogenous n i t r o g e n turnover  l e a n mass.  The  and  lowering  day  or  i s thus i n This  other  and  body w a t e r .  is  so,  physioin  environment, Unfortunately  d a i l y weight f l u c t u a t i o n  and  to  the  spare  basal  There  lean tissue  fact  that  the  lean t i s s u e .  As  energy production, the  s i z e of  i s a l s o an  r e d u c t i o n of  endogenous n i t r o g e n  of  energy  the  and catathe which lean  inevitable  e x c r e t i o n because of  maintenance requirement  reasons f o r the of  both the  o r d e p e n d e n t on  i n e v i t a b l y decreases.  f o r the  l o s s per  despite  i s l a r g e l y designed  is  ed dynamic  and  trials.  in size  reduction  For  n e a r l y h a l f a pound  between animal  l o s s of  lean t i s s u e decreases  body mass,  required,  catabolized.  body mass i s u s e d up,  closely associated  day.  to  example, body t e m p e r a t u r e r e g u l a t i o n  f a t depots decrease  bolism  l o s s or  catabolism.  kilograms  C a l o r i e s per  a v a i l a b l e f o r determining  the metabolism  on  0.34  l o s s w o u l d be  kilogram  t i s s u e combina-  kilogram  overriding endocrinal  adverse temperature  method was  1,700  t i s s u e being  w h i c h demand a d i f f e r e n t i a l no  type of  l o s s of  r a t e of weight  t y p e of are  of  kilogram  C a l o r i e s , a 0.26  w o u l d be  an  This  would thus p r o d u c e a d a i l y weight  satisfy  for  50  -  the  the  decreas-  smaller  production  excretion  are  - 57 essentially  the  same.  These f a c t o r s ,  the p r o t e i n  and  energy  requirements  equilibrium  throughout  provides  c a n be  carried  Below a v e r a g e any  level  though  to  subnormal  especially  l i m i t s with  which p r o v i d e s continued l i f e normal  and  or permanently  fairly  held  lower  and n i t r o g e n  This  indirectly  f o r the animal  during  s i n c e the p r o c e s s  extreme b o d y w a s t a g e .  m a i n t e n a n c e r e q u i r e m e n t s may  several  porarily  survival  restriction,  steadily  f o r energy  the f a s t i n g p e r i o d .  g r e a t e r chance of  p e r i o d s of n u t r i e n t  however,  be  established  at  i n an  individual,  even  important  f u n c t i o n s a r e tem-  i n abeyance through wastage of  tissue.  Changes i n F e e d F o l l o w i n g I n g e s t i o n w h i c h I n f l u e n c e Dietary Requirements The from  establishment of r e s t i n g metabolic  the measurements of f a s t i n g  t i m a t i o n of n u t r i e n t nutrient,  o r T.D.F.  ingestion,  study,  directly  are determined  experiment  ment o f f a s t i n g requirements  can a l s o  be  es-  digestive  f e e d under  f e e d i n g experiments.  was  combined w i t h t h e  in single  In establish-  experimental runs.  These  e x p r e s s e d a s m e t a b o l i z a b l e energy,  m e t a b o l i z a b l e n i t r o g e n , and tests.  the  p r o v i d e d the changes which  i n the p a r t i c u l a r  from  the f e e d i n g t e s t requirements  i n terms of t o t a l  I956),  take p l a c e , f o l l o w i n g  this  catabolism, permit  requirements (Morrison  requirements  Once t h e s e f a c t o r s  as net are  energy,  established,  or  following metabolic and  expressed  in  t e r m s o f one can  express  such  the t e s t  animals'  a s , f o r example,  dictions, i n order on  o r more o f t h e a b o v e c a t a g o r i e s , t h e  of course,  tors  to  d e p e n d on  basis.  show t h e  chemical  Feeding  exact  Also, the  trials  requirements.  such as d i g e s t i b i l i t y  dicted.  for natural  browse s p e c i e s f o r d e e r .  effect  cannot  feed  These p r e -  a n a l y s e s of the  t o compare t h e c o n t e n t w i t h t h a t  a d r y weight  ever,  requirements  investigator  of the f e e d  are  still  browse  tested  needed, how-  T h i s i s so b e c a u s e  a l w a y s be  o f amino a c i d  fac-  accurately pre-  imbalance  and  chemicals  w h i c h a c t a n t a g o n i s t i c a l l y w i t h i n t h e m e t a b o l i c m a c h i n e r y , must at present ment.  As  be  e s t a b l i s h e d or d i s c o v e r e d through  stated previously,  the use  of  requirement  Annison  use  n i t r o g e n metabolism  1959).  several  The  most  ly  important  use of  these  days.  i n t h e rumen n e e d a r e a d y  synthesis.  The  and  carbohydrate  a need f o r carbon  and  microbial protein  synthesis.  to  the  i s , that  Lewis  ruminant  useful  information  i n t e r p r e t a t i o n of  t h e rumen m i c r o b i a l  r e s t r i c t e d w i t h i n a few  orits•  even i n h i s t r e a t i s e on  careful  s t a r v a t i o n of ruminants,  due  ( A n n i s o n and  a r g u m e n t s w h i c h show t h a t  be o b t a i n e d f r o m  method.  c a n be m i s l e a d i n g .  i n ruminants  o f t h e rumen o r g a n i s m s  However, t h e r e a r e ,  metabolism, may  little  experi-  the n i t r o g e n balance  method f o r d e t e r m i n i n g p r o t e i n c o n s i d e r s i t of  direct  during  this complete  activity  i s severe-  T h i s o c c u r s b e c a u s e t h e symfeisource of carbohydrate  requirement  for oxidative  i s twofold.  energy  Therefore  i n order  to  for  bio-  There  is  effect  i t i s necessary,  as  was  - 59 done i n t h i s  experiment,  days w h i l e n o t i n g care  to s t a r v e the ruminant  i n i n t e r p r e t a t i o n as mentioned  addition,  to f i e l d  previously  stores  is useful  i s not  infallible  indication  b a l a n c e method  here, growth  and  refers  animals. adult  to l o s s ,  Nitrogen i s also  bolic  fecal  iment  to account  metabolic  epithelial lost  fecal  loss,  T h e r e was  cells  by  that  t h e amount o f MFN  the  and h a i r  similar  epithelium,  Adult  replacement from the i n -  means f r o m but  are i s used  sebum.  this  oral  fraction  i n t h e e s t i m a t i o n o f metaan a t t e m p t  made i n t h i s  calculated,  exper-  loss.  as mentioned  on t h e b a s i s o f t h e r e s u l t s o f M i t c h e l I , 1 9 4 3 ( M a y n a r d stated  value  of negative  as t h e term  f o r both these sources of n i t r o g e n n i t r o g e n was  diet,  to those a l r e a d y p r e s e n t  Dermal  i t s inclusion  nitrogen.  nitro-  level  o n e s most o f t e n m e n t i o n e d  from the d i g e s t i v e  a c c o u n t e d f o r by  the  e r r o r s of  and c o n s e q u e n t l y c o n t i n u a l  tegument.  is  The  c o n t a i n e d i n sweat and  of c o r n i f i e d  the  Hence t h e  the appearance  i s added The  by growth,  s u r f a c e s and  in a diet.  inadequacy.  growth.  to n i t r o g e n  refers  of  i n ruminants  with monogastric loss  shown t h a t  the  In  and o t h e r s on t h e b i o l o g i c a l  o f f e e d p r o t e i n were c o n c e i v e d u s i n g  dermal  enters into  i n an u n d e r n o u r i s h e d a n i m a l , on a low  many e x p e r i m e n t s o f M i t c h e l l  of  i n d e t e r m i n i n g the s t a t e of  in detecting deficiencies  b a l a n c e as an  Part  or o t h e r c o n d i t i o n s .  a l t h o u g h t h e above r e a s o n i n g h a s  gen b a l a n c e method protein  f o r 4 o r more  the d e c r e a s e i n n i t r o g e n output.  e x t r a p o l a t i o n of r e s u l t s  it  -  The  previously, 1956),  d e p e n d e d on t h e amount o f d r y  who  -  matter  excreted..,  of  are  MFN  Mitchell  roughage d i e t ,  age  d i e t s was  used  with  T h i s m a t e r i a l was  not  would, of c o u r s e gram p e r  a v a l u e of 0 . 5 6 v a l u e of stated sheep  0.7  for  E-5  determined was  integumental  The  of  although  f o r each  from  low  rough-  experiment,  in  the  flakes  Under  sweat  23-141  which would  indicate  f o r R-5-  day  day  a  Maynard  f o r 100 from  pound dermal  physiological  m i l l i g r a m s of n i t r o g e n  been g i v e n i n t h e ideal  literature  conditions provided  s h o u l d have been v e r y  t h e amount o f  However  gave  c o n d i t i o n s and  the  day.  1949 J  Mitchell,  amount o f n i t r o g e n l o s t  of  per  of  less  source.  sweat have  day  small.  i n s e n s i b l e water  Un-  loss  was  of r e s i d e n c e i n the c a l o r i m e t e r , t h e r e  separating this l u n g s and  surface.  and  The  of n i t r o g e n l o s s of  grams o f n i t r o g e n p e r  f o r humans.  no method o f  released  grams  low  gram o f d r y m a t t e r  a level  this  Values  t h e amount of  fortunately,  one  environmental  the animal.  i960)  from  1956).  100 m i l l i l i t e r s  (Darke  in this  i n terms of h a i r  l e s s t h a n a gram p e r  s o u r c e s d e p e n d s on  per  v a l u e f o r the  grams / m e t e r ^ / day,  a v a l u e of  s t a t e of  a  analysed for n i t r o g e n content.  indicate  day  somewhat  (Maynard  The  on  0.2  t h e c h a r a c t e r o f t h e U.B.C. r a t i o n s u s e d .  g r o w t h o b t a i n e d w i t h R-5  t h a n one  approximately  grams a r e e x c r e t e d w i t h  i n the c a l c u l a t i o n s  s k i n amounted t o a p p r o x i m a t e l y  it  0.5  while approximately  grams o f h i g h r o u g h a g e d i e t .  adult  that  grams o f d r y m a t t e r  100  accordance  -  stated  100  excreted per  60  Using  collection  t h e component  into  the  component  e x c r e t e d from  t h e maximum f i g u r e  f o r the  the nitro-  - 61 gen  content  water 0.5  of  sweat,  l o s s to be  grams p e r  assuming 50 p e r  and  sweat, t h e  day  using  the  l e v e l s are  in  second f a s t i n g p e r i o d per  s i d e r a t i o n s a v a l u e of sidered and by  a  safe  adult the  gen  estimate of  growth.  dotted  The  line  excretion  the  of  the  d e t e r m i n a t i o n of  1  and  matter  content  be  of  the  to  diet,  endogenous u r i n a r y n i t r o g e n i n monogastric  can  be  e a s i l y achieved for  known endogenous among t h e This  animals,  members o f  would r e s u l t  contents,  level  and  of  the  i n the  much o f  day  of  con-  was  con-  nitrogen  loss  total  is  indicated  urinary  nitro-  conventional  ruminants,  approach  is  metabolic  nitrogen.  M i t c h e l l found  roughage content  stated previously.  and  i t i s doubtful reasons  that  the  fecal  body  true  stated previously. catabolism  rumen m i c r o f l o r a liberation w o u l d be  of  and  the  dry  Though  i s p r e s u m a b l y r e l a t e d to  protein  this  per  above  from  amounts o f  the as  the  in  r e s u l t s shown  b a l a n c e method w i t h  actual  proportional  obtained  be  2.  endogenous u r i n a r y  to  of  this value  level  major problems w i t h the  M.F.N,  as  c a u s e d by  and  the  combined dermal  nitrogen  the  light  nitrogen  shown b e l o w t h e  one  nitrogen  the  error  iii Figures  In u s i n g the  gram o f  l o s s would  water  by  insensible  2 where t h e y r a n g e  Trial  In t h e  the  nitrogen  exemplified  of  day. one  of  l a r g e s t volumes of  trial.  613-698 m i l l i l i t e r s  cent  maximum d e r m a l  either the  These  -  size,  level An  would a l s o  the  un-  obtain  microfauna.  ammonia t o  the  absorbed d i r e c t l y  rumen through  - 62 the  rumen w a l l , c o n v e r t e d  part  to  the  in part  sumption of  carbohydrate  would r e s u l t  a  calculated for 0.3  matter  0.8  grams f o r a one  0.3  grams compares w i t h  gram d r y m a t t e r  remained nearer  time of passage. the  values  last The  t h i s was  while  t o r y o f H-5 daily on  fecal  high  recycled  average  January  During  i t was  M.F.N, v a r i e s f r o m  digestibility  i n t a k e of. 17»3  grams  i n t a k e and  grams on  low  1.3  one  pound  intake  1.3  previous  p o u n d s and  start  December The  i t was daily  on  slower  of  the  of a l l that  much  animals  nutritional  one  level  level  recognized diet  3  grams compares  i n terms of monthly  1 pound.  after  showing a p o s s i b l e  a  of  However, t h e  of  dry  intake value  nitrogen obtained  the p r e v i o u s  i s between 0.8  metabolic  The  i t must be  uniform  excretion.  amount o f  i m m e d i a t e l y upon t h e  The  re-  true  intake value  enclosure.  ammonia  the  The  thus  However,  is fairly  a 30-day b a s i s .  during  not  second t r i a l .  f o r the  c o n t r i b u t e d by  i n the deer  low  pound  trial,  obtained  starvation periods. of  the  the v a l u e  i n the  f o r the  intake.  4 days s t a r v a t i o n i n the  with  This  bacteria until  part  roughage d i e t  the very  t o 690  starvation  The  e a c h f e e d i n g day.  650  to  intake.  low  grams d u r i n g  to  to the  M i t c h e l l ' s values  n i t r o g e n on  about  recycled in  i n i n e v i t a b l e a d d i t i o n s to u r i n a r y  Using  was  and  rumen v i a r e s i d u a l s a l i v a r y f l o w .  or u r e a would remain u n a v a i l a b l e  fecal  to u r e a ,  his-  intake.  The  pound c a l c u l a t e d 0.8  pounds,  intake  itself,  and however,  shows a d e f i n i t e 2.8  cycling  63 -  or f l u c t u a t i o n  p o u n d s a s a maximum h i g h v a l u e  common h i g h v a l u e . nated the  amount o f f e e d p r e s e n t e d  The d i e t a r y  very  similar  regimen. trials, those  are usually  T h e r e was no r e l a t i o n  to the animals,  t h e amount  level  i n terms o f t o t a l  given  i n i t i a l l y present  i n the feed  i n the feeding test  period i s  The v a l u e s f o r t h e second f a s t i n g p e r i o d s of t h e i n both  t h e second and t h i r d runs,  were lower  chosen to represent estimates  The v a l u e s  M.F.N, were t h e r e f o r e c o n s i d e r e d  reasonable  o f t h e t r u e M.F.N.  The  coefficient  varied  Schneider  than  one r e f l e c t i n g t h e s m a l l e r o v e r a l l i n -  take of the r e l a t i v e l y short f e e d i n g p e r i o d s .  is  between  t o t h e i n t a k e on t h e above m e n t i o n e d a d l i b i t u m  of the i n i t i a l  tained,  alter-  mass v i s i b l e t o them, a s t h e c o n s u m p t i o n d o e s n o t  correlate well with pan.  1 . 7 pounds as a  and w i t h  The h i g h a n d low l e v e l s  and l a s t f o r 3 t o 5 days.  apparent  ranging from 0 . 2 to  f r o m about  o f d r y matter d i g e s t i b i l i t y ob60 to 9 0 per cent.  According to  a n d M a y n a r d t h e n o r m a l v a l u e f o r most  65 per cent.  The h i g h e r  values obtained here  ruminant  feeds  of 75 percent  and  8 7 per cent,  averages of t h e second and t h i r d t r i a l s a r e  not  unreasonable  f o r two r e a s o n s .  in  the diet  effects  seems t o r e d u c e t h e p a s s a g e t i m e  of previous  indicating  T h e low amount o f r o u g h a g e  ad l i b i t u m  greatly,  as t h e  f e e d i n g appear f o r 3 t o 4 days,  t h e normal passage time  o f up t o 2 d a y s f o r t h e  -  -  64  major p o r t i o n o f  the feed.  roughage reduces  t h e amount o f p r o t e c t i o n a g a i n s t  and  d i g e s t i v e enzyme a t t a c k .  however, t h a t getic of  Meanwhile,  of  a larger  than  amount  be b o r n e  by  of  bacterial i n mind,  a t t a c k reduces  the f e e d i n g process  amount o f f e e d  the  raising  ener-  the  w o u l d be  so w i t h  less  energy u n a v a i l a b l e to the extensive attack.  methane p r o d u c t i o n were v e r y however, affects While cent  Also, Mitchell  experimental c o u l d be  level  protein  a t t h e one  occurred. per  In t h e  pound  level.  85  per  below the  cent  ibility part,  as  ratios  such  i s , i n many c a s e s , the n u t r i t i v e  as  levels  level  t o 90 p e r level. per  are this  cent At  cent  used  one.  i s widened.  in  level this  60 p e r on  two  cent  were o b t a i n e d  91  per  lowered  cent.  with  the d i g e s t -  f o r the  i s due  with  this  feeds  Actually,  This  and  occasions.  n e a r l y twice and  for  variation  associated with  only apparently  ratio  per  f o r e n e r g y and  1 pound l e v e l  t h e v a l u e v a r i e s b e t w e e n 77  narrow n u t r i t i v e  65  the maintenance  v a l u e s o f about  1 pound  High d i g e s t i b i l i t i e s  ration.  However, c o n f u s i n g  at the  of  nutrition  f e d a v a l u e of  The  the maintenance  were o b t a i n e d  just  possible.  levels  of  a given  a t or n e a r  second t r i a l ,  third trial  level  level  In t h e  cent  while,  c e n t was  e x p e r i m e n t were n e a r  were f u l l y  deer  experiment,  showed t h a t t h e p l a n e  animals  obtained,  The  small during t h i s  the d i g e s t i b i l i t y o b t a i n e d w i t h  a v a l u e o f 80 p e r  the  low  p r o d u c t i o n o f m e t a b o l i c a l l y u n a v a i l a b l e methane, t h u s mak-  ing  70  It should  extensive bacterial  efficiency  the  most  to the  fact  - 65 that  a constant  constant  amount o f M . F . N , t e n d s t o he  amount o f  of f e e d n i t r o g e n . example,  feed dry matter, This  c e r t a i n sources  evocating system.  effect  on  With feeds  the  of  higher  carbohydrates  by of  available.  The  values,  a different  from the the  or  feed.  digestibility p a t t e r n with  higher  Contrary  At digestibility available of ous  to  nitrogen.  values  the  o f 90 the  larger be  utilized  d o e s c o n t r i b u t e to i n a t t a c k on  the  utilization  of n i t r o g e n variation  gave  different  i n intake  digestibility  level  during  c o e f f i c i e n t s when t h a t  t e n d s t o a g r e e more c l o s e l y w i t h  the  lower  per  cent,  the  intake  of  total  n i t r o g e n wastage per  to the  trials,  by  levels.  intake with  i s approximately  According  third  of  for  the  s e c o n d and  of  n u t r i e n t s more  to t h e d r y m a t t e r  pound l e v e l  deer  endocrine  results,  during  one  differential  the  greater  The  for  i n v e r s e l y p r o p o r t i o n a l to that  r u l e of M i t c h e l l ' s i n b o t h the having  This  digestibility  nitrogen d i g e s t i b i l i t y  ratio,  a  percentage that,  v i a the  stimulating bacterial  seems t o be  i s low.  fact  to have a  i n t u r n makes o t h e r  percent  dry matter with h i g h dry matter  the  the  i t i s p r o t e i n which can  dry matter d i g e s t i b i l i t y .  second t r i a l  to  i t is N.P.N.,  the  carbohydrates  and  due  of p r o t e i n tend  whether  digestibility  the h i g h e r  rigid  narrow n u t r i t i v e  rumen o r g a n i s m s ,  creased  r e g a r d l e s s of  d i g e s t i v e enzyme o u t f l o w  amounts o f n i t r o g e n , by  i s not  associated with  the  observed  digestible protein 58  grams o r 9-5  r e l a t i o n of Brody f o r  u n i t body w e i g h t ,  this  grams endogen-  amount  i s more  - 66 t h a n enough t o logical uing of  course,  The  of  somewhat  ministration  grams o f n i t r o g e n sufficient  probably  about  i n the  Also,  one  the  pound l e v e l , current  Nitrogen Nitrogen  as  of  6 and  stated.being  b r i u m , was tion  of  very  nitrogen  of  the  interesting.  an  of  as w i l l  The  be  Later,  to At  caused near  effect  feed  ad-  effect  and  15  provided  was  requirement.  the  Urinary  Point  of  excretion after  repeated  nitrogen,  immediate n i t r o g e n  first,  as  expected,  following absorption grams o f  gram a b s o r p t i o n ,  or  and  nitrogen,  e q u i l i b r i u m of n i t r o g e n  f o l l o w i n g a 12.16  to  shown l a t e r ,  showed a 6 gram d e f i c i t  a d d i t i o n a l 15  value.  metabolizable  Requirements from  nitrogen  contin-  fasting  have  t h e n 9 grams o f m e t a b o l i z a b l e  6 grams n i t r o g e n  utilization  later,  of  the  bio-  i t would,  w h i c h made between 12  maintenance  insufficient  nitrogen balance.  with  pound l e v e l  R e q u i r e m e n t s B a s e d on Balance  behavior  a  biological  trial  for retention.  C a l c u l a t i o n of N i t r o g e n Nitrogen Excretion  absorption  a perfect  third  two  a  grams o f n i t r o g e n ,  a v a i l a b l e r e s p e c t i v e l y , should  below the  The  11  However, w i t h  have been s u f f i c i e n t  second t r i a l  extra nitrogen the  t h a n 100.  7 grams s h o u l d  i n the  e q u i l i b r iumi even w i t h  even w i t h  s i m i l a r intake  retention.  energy at  of  inadequate  about  nitrogen  lower  catabolism  be  nearly  level  establish nitrogen  value  fasting  -  9  the -. 6  both equili-  absorpgrams  probable 9  balance.  grams o f Still  grams c a u s e d  -  retention. in  Though t h e two h i g h e r  i n t e r p r e t i n g the r e s u l t s ,  pound l e v e l thus  of feed  simultaneously  deer,  basal metabolic  the of  -  levels  the greater  to s a t i s f y  introduce ability  the nitrogen  t h e energy requirement  showed t h e p r o g r e s s i v e  nitrogen  67  reduction  rate associated with  appearance of negative 3 ' 2 grams o f n i t r o g e n  80 C a l o r i e s of s t o r e d  nitrogen  represents  o f t h e one  requirement,  and  of the b l a c k - t a i l e d  i n nitrogen  the reduction  s t o r e s caused by the s t e a d y  complications  turnover  in labile  loss of nitrogen balance.  and  during  The f i n a l  retention  2 0 . 0 grams o f b o d y p r o t e i n , a n d 8 0 grams o f  a v a i l a b l e energy,  lean  body mass. The on  the several  estimation  r e s i s t a n c e to establishment occasions  o f 2 pound f e e d i n g  and t o t h e f a s t i n g  level  f o l l o w i n g near  o f 9 grams o f n i t r o g e n tion  i n e x c r e t i o n o f 9 grams.  further absorption  with  a deficit  The be  absorbed,  explained,  o f 13  an a b s o r p t i o n  a negative  difficulty  absorption the reducnitrogen  associated  nitrogen.  i n achieving  a s s u g g e s t e d above,  to  o f "J.8 grams o f n i t r o g e n ,  o f 7 - 8 9 grams o f n i t r o g e n was grams o f t o t a l  more  resistance.  even t o e q u a l  Following  to  is difficult  e q u i l i b r i u m from  1 2 grams f a i l e d  b a l a n c e o f 3 grams w i t h a  excretion,  T h e r e were two m a r k e d e x a m p l e s o f t h i s  In t h e s e c o n d t r i a l  balance  when, a c c o r d i n g  of nitrogen  t h a n a d e q u a t e n i t r o g e n was a p p a r e n t l y explain.  of n i t r o g e n  nitrogen  equilibrium  by t h e u s e o f i n g e s t e d  may  protein  -  for of  energy. total  68  -  The p e l l e t e d r a t i o n u s e d  e n e r g y p e r pound,  contained  2,000 Calories  and 1 , 3 0 0 C a l o r i e s o f  metabolizable  e n e r g y p e r p o u n d c a l c u l a t e d on an a v e r a g e d i g e s t i b i l i t y o f 6 5 per  cent.  This  one p o u n d  level  this  to 1 , 0 9 9  of d r y matter  quirement third  however,  1= p o u n d was  t h e one p o u n d  assuming  The t o t a l  level  a s t e a d y 11  t h e lower  have been r e a l i z e d .  second  trial,  during  feeding,  of 2.6  endogenous c a t a b o l i s m .  an  During the t h i r d  indicates that  amount was,  i n fact,  and 8 9 6  losses i n  The  for essential  trial,  of 7  grams catabolism.  grams p e r d a y grams  than expected l o s s i n the  a l o w e r e d endogenous  representing It also  t h e 3 one p o u n d  r e t e n t i o n of I.72  lower  re-  i n the  have been 7 . 8  should  nitrogen  t h e energy  and  amount  6 8 2 , 910  Following  loss during  less nitrogen  reflects  a smaller  level  wastage f o r energy de-  the l a c k of r e t e n t i o n i n d i c a t e s  elevation i n protein catabolism  This  the actual  and 5 4 6 C a l o r i e s s h o r t  grams r e f l e c t s  perhaps  on  between 5°Q and 6 0 0 C a l o r i e s  grams o f n i t r o g e n  a total  energy  C a l o r i e s per day maintenance  nitrogen  should  ficit.  With  endogenous u r i n a r y n i t r o g e n  trial  The  of the second t r i a l  i t gave 7 9 5 ,  was  i n the second t r i a l  the t h i r d  Calories total  consumed.  i n the second t r i a l ,  days  C a l o r i e s p e r gram.  the l a t t e r part  absorbed,  trial.  feeding  With  gave 1 , 2 1 3  of the c a l c u l a t e d 1,300  short  to 2 . 9  Calories i n the third.  the 4 occasions  digestion,  in  of feed  b a s i s throughout  1,037  on  i s equivalent  above t h e endogenous  absorbed  i s inadequate.  up t o 4 0 0 C a l o r i e s p e r d a y s h o r t  level. The  of the  - 69 calculated the  deer  requirement  during  the last  two f e e d i n g  days,  b e g a n t o consume s i g n i f i c a n t amounts o f f e e d .  t h o u g h most o f t h i s e n e r g y c o u l d  be s u p p l i e d  when Even  by body f a t ,  some body o r d i e t a r y p r o t e i n w o u l d be e x p e c t e d t o be u s e d . The  d i s c r e p a n c y o f 14.28  grams between a r e t e n t i o n  grams, a s a t h e o r e t i c a l f i g u r e , a n d t h e a c t u a l of  16  grams n i t r o g e n ,  i s equal  amount o f p r o t e i n ,  from  would  l8o  s u p p l y about  to u r i n e ,  t o 89.3  either  C a l o r i e s p e r day.  cannot  completely replace  function,  because  i t cannot  supply  only  be s u p p l i e d  essential a nutrient  of the c i t r i c  which a r e k e t o g e n i c .  of choice,  to a c e r t a i n extent,  metabolism urine  cipates  levels.  in this  Protein  actively i n this stimulation.  i s therefore  f o r energy  on  stimulate  of i n c r e a s i n g  Non-protein nitrogen  These  or c e r t a i n of the  production.  several  equilibrium  i n t h e r u m i n a n t may  i n t h e rumen t o t h e e x t e n t  nitrogen  f o r energy,  acid cycle.  f o r the i n a b i l i t y  o c c a s i o n s to e s t a b l i s h expected n i t r o g e n a d d i t i o n of f o o d s t u f f s  f o r energy,  e s s e n t i a l t w o - c a r b o n com-  by metabolism o f glucose,  explanation  loss  reasons.  and u t i l i z e d  amino a c i d s  Another  This  source  caloric  carbohydrate or p r o t e i n  pounds needed f o r t h e o p e r a t i o n can  After  f o r the following  being mobilized  balance  grams o f p r o t e i n .  endogenous o r exogenous  even w i t h adequate f a t supply,  it  l."J2  negative  p r o t e i n w o u l d be e x p e c t e d t o be u t i l i z e d  Though f a t i s a l r e a d y  of  i s that, nitrogen b l o o d a.nd  i n the feed  parti-,  The i n t e r f e r i n g f a c t o r s  - ?o are: to  increased  the  diet  blood  of  absorption  stream,  the host.  d u r a t i o n <of culty.  and  The  of  ammonia and  amount, r a t e and be  time of  urea v i a s a l i v a ,  ammonia i s l o s t  to  simply  The  of n o n - p r o t e i n  effect  of  tein.  This  time,  i n c r e a s i n g the  fermentation  r e l e a s e of  to  i s excreted  value  fatty  the  feces  b o t h t h e m i c r o f l o r a and  the  host.  value. this  f u n c t i o n s d e p e n d s on  i n the The  along  diet  The  graphs  c a l c u l a t i o n s of  the  by p l o t t i n g  shown on  the  dietary  and  body w e i g h t ,  At  the  the  The  level  pro-  the  same  reducing consequent  released  thus becoming  the  nitro-  unavailable  b a l a n c e between  amount o f  non-protein  good  i n the  these  biological  r a t i o n used  in  low.  in Figures  the  abscissa,  ordinate,  this  to p r o t e i n of  nitrogen  the p o i n t  obtained  gram o f  relative  non-protein  e x p e r i m e n t was  the  of  rumen h a s  acids with  Much o f  with  nitrogen  i n the  t h e n i t r o g e n w a s t a g e by  amino acid, n i t r o g e n .  antagonistic  on  nitrogen  short-chain  and  b e c a u s e o f mass a c t i o n .  biological  increases  and  diffi-  some u r e a  i n t u r n r e d u c e s the n i t r o g e n wastage.  d i e t a r y p r o t e i n to  gen  the u r i n e  the  appearance  a n t i c i p a t e d only with  r e c y c l i n g of  utilization  rumen  increased microbial protein i n  t h e s e e f f e c t s can  Despite  u r e a from the  on  of  and  nitrogen  effect  on  3>  of  show t h e  balance.  balance  grams o f n i t r o g e n  shown on  result  of  T h e s e were  the n i t r o g e n  the n i t r o g e n  the  4,  intake  i n grams,  i n grams, balance per  a second o r d i n a t e , t o  the  shown kilo-  left  of  the first. themselves gen  The p o i n t o f i n t e r s e c t i o n o f t h e two and. w i t h  balance.  balance  T h i s m e t h o d o f o b t a i n i n g t h e point o f  (Majundar  i960),  data.  A sv e r i f i c a t i o n  Jumna. P a r i  goats  of  of analysing  of this he used  this  7°-94  pounds.  than  those  nitromethod  results  However,  authors have stated that the nitrogen requirements the above method are higher  to  t h e r e s u l t s of t h i s t e c h -  s e v e r a l o t h e r s t o a n a l y s e h i s own n i t r o g e n b a l a n c e  obtained with  by  of  According  1937)-  compare favourably with other methods  gen balance  nitro-  nitrogen  i s a modified version of the graphical method  the work of Majundar  and  with  the abscissa indicates the point of  Leitch and Duckworth (Leitch and Duckworth  nique  lines  other  calculated  obtained from  for the endogenous urinary total nitrogen excretion  values  alone.  T h e p o i n t o f i n t e r s e c t i o n i n t h e f i r s t t r i a l w i t h B-5 i s a t about  17.3  A s the  grams,  and i n the second  excretion.  The nitrogen balance  index was  and i n which;  B Q  calculated for  equals  the  balance  Bj represents the nitrogen balance  intake,  and B  balance  with n ointake, and I represents the nitrogen  The numerical feed  grams.  f i g u r e f o r the e n d o g e n o u s l e v e l o f n i t r o -  e a c h o n e pound f e e d i n g d a y , w h e r e B j index,  16.5  f o l l o w i n g r e s u l t s show t h i s v a l u e i s a great d e a l h i g h e r  than the most p r o b a b l e  gen  triali t i s at  Q  represents the nitrogen excretion or  nitrogen  value of this index appears above the one  level columns on the histograms  of nitrogen  during  intake. pound  balance.  - 72 The  index r e f l e c t s  the  nitrogen  stant  the  on the other  even w i t h  stores  animal  using  conditions  If  intake  increase  i s given,  level  the degree of r e t e n t i o n  i s obtained  level  remains  It also  reflects  source.  on a n y p a r t i c u l a r  balance  absorbed;  balance  day  of the t h i r d  index  one p o u n d  the b i o l o g i c a l  The n i t r o g e n  d a y may be  bal-  represented (Albanese  index i s the f r a c t i o n of n i t r o g e n  The f r a c t i o n  of the feed protein.  nitrogen  t h e change  i n question  b y t h e e x c r e t i o n a t zero, i n t a k e  the  constant.  i f t h e endogenous n i t r o g e n  intake.  will  the absorbed  which r e f l e c t s  of the curve at the point  The n i t r o g e n  value  As the  a s i s t h e c a s e when  t h e maintenance  even t h o u g h t h e f e e d  dependent o f n i t r o g e n logical  easy to o b t a i n  balance per day i s p l o t t e d against  retained of that  stores  f o r the a l -  ance index o f t h e i n t a k e  represented  When t h e p r o t e i n  is  a t about  o f t h e p r o t e i n used as t h e f e e d  1959).  it  and f e e d i n g ,  the animal's p r o t e i n stores.  t h e tangent  are full,as  status,  i t is relatively  con-  a regimen of a l t e r n a t e f a s t i n g  when f e e d  the nitrogen  value  by  hand,  with  amounts o f d i e t a r y p r o t e i n .  n i t r o g e n p e r day, a c u r v e in  retention.  g r a d u a l l y become d e p l e t e d ,  ternate periods gradually  small  i s under  a feed  numerically  o f good n u t r i t i o n a l  to obtain n i t r o g e n  are depleted,  protein  increase  When t h e p r o t e i n s t o r e s o f a n a n i m a l  they a r e during  retention  o f a b s o r b e d n i t r o g e n p e r day on  b a l a n c e and should  intake.  difficult  the effect  increased level  i s constant represents  In t h e f i r s t  trial  excretion, and i n the biowith  B-5  f r o m 0 . 6 t o 1.1 a n d o n t h e  feeding  a r e t e n t i o n was  obtained.  -  73  -  N i t r o g e n R e q u i r e m e n t s B a s e d on Urinary Nitrogen Level  On the  lowest  This  total  value  was  fifth  level  achieved. The  the  day  of n i t r o g e n level  was  an  at  b a s i s of  average value  authors this  (Brody). t i m e but  using  v a l u e , w h i c h was  not  the  this  the  i n a s s o c i a t i o n with  e n c e c a u s e d by  i n the The  ing  heat p r o d u c t i o n  c l o s e indeed  endogenous u r i n a r y t o t a l  day  of  3-225  grams.  output  estimated  B. Q.  third  trial  and  was  e x c r e t i o n and  nitrogen  0.82,  of  an  differ-  actual  i s not  r e l a t i o n s h i p between basal  the Calories  exist  b e t w e e n a d u l t mammals o f  different  size  age.  I t seems j u s t i f i a b l e ,  fore,  to  cretion gen  suggest is a fair  e x c r e t i o n and  that  of  r e p r e s e n t a t i o n of  total the  there-  urinary nitrogen  ex-  endogenous u r i n a r y  nitro-  t h u s t h e minimum n i t r o g e n r e q u i r e d o f R - 5 ,  therefore represents an  t h i s value  rest-  calorie,  known to and  great.  c a l o r i e s of  of heat p r o d u c t i o n species,  1,457  of  probably  n i t r o g e n per  e x c r e t i o n and  This  recommended  second t r i a l ,  milligrams to t h e  instead of  was  fasting.  a caloric  a c t u a l B.Q.  a v a i l a b l e i n the  r e l a t i o n s h i p between n i t r o g e n  i s very  an  average value  i s 2.21  fifth  t i m e was  trial,  starvation  as m e n t i o n e d p r e v i o u s l y t h e  The  which  on  obtained  as  0.7  excretion during  obtained  the  Endogenous T o t a l  second n i t r o g e n balance  e x c r e t i o n at  by p r e v i o u s nearer  the  nitrogen  C a l o r i e s c a l c u l a t e d on obtained  of  the  a d u l t non-pregnant  t h e minimum amount o f n i t r o g e n r e q u i r e d female Columbian b l a c k - t a i l e d  In c a l c u l a t i n g  deer.  t h e minimum p r o t e i n r e q u i r e m e n t s  of  and by  - 74 animals the plied  by  value for  endogenous u r i n a r y 6.25.  a f a c t o r of  the  b i o l o g i c a l v a l u e of  for  example,  factor  x 2  of  x 6.25  gen  i f the  protein. value of  represents  the  result  value for  these  the  e i t h e r on  nitrogen  be  itself  the  a s s o c i a t i o n w i t h the  over  and  lowest lowest  keeping with Therefore,  the  smallest  s i z e of  maintenance of  additional  tional  trials, status.  remains the  the b i o l o g i c a l  represents.the  of  normal  requirement,  the  achievement  The  starting point of  the  Losses i n -  of  source  matter.  Once  requirement realized  minimum  protein  turn-  loss, possibly stores,  body f o r m and  assoin  function.  made i n a r r i v i n g at  b a s e d on a high  nitrogen  p l a n e of  nutri-  f o r t h i s p r o c e s s , , however,  l e v e l s of  in  catabolism,  body amino a c i d  be  fac-  t h e n be  labile protein  for  establishment  dry  of p r o t e i n  c o r r e c t i o n s must  most d e s i r a b l e p r o t e i n  balance  level  the  i r r e v e r s i b l e amino a c i d n i t r o g e n  c i a t e d w i t h the  for  protein  I t must  level  nitro-  metabolizable  the p r o t e i n  on  the  v a l u e thus obtained represents b a s e d on  obtained.  on  or  that  the  be  a  for  value  trials  the  in  may  i s 5°>  protein  accounted f o r , using  terms of  requirement  consideration,  f o r d i g e s t i b l e crude p r o t e i n . also  for  endogenous u r i n a r y  new  l o s s e s have been a c c o u n t e d f o r  the  the  been c o r r e c t e d  b e i n g used,  d i g e s t i o n must  feed  is multi-  i s then corrected  minimum r e q u i r e m e n t  t o r s obtained from d i g e s t i b i l i t y being used,  nitrogen  d i e t a r y p r o t e i n under  The the  protein  during  the  t h i s v a l u e has  minimum r e q u i r e m e n t curred  The  b i o l o g i c a l v a l u e of  i s used.  After  -  nitrogen  excretion  o b t a i n e d tinder b a s a l  The calculated, p e r day  a 45 kilogram adult  b l a c k - t a i l e d deer.  I)  this day  feed of  crude p r o t e i n  With  an a v e r a g e  of 8 4 - 8 5 per t h i s would 24.856  c e n t , a minimum f e e d  t h e a b o v e method. to s a t i s f y  To  with a nitrogen found  in R-5  used  total  crude p r o t e i n  in this  requirement  of  ration, 159-8  grams p e r d a y i s  satisfy  l e v e l s of f e e d which  crude p r o t e i n  the  caloric  would,  that i s ,  s u p p l y more t h a n requirement  supply s u f f i c i e n t  day.  as  calculated  digestible  crude  s u c h as R - 5 -  or  e x p e r i e n c e d by a n i m a l s  to m a i n t a i n a n i t r o g e n b a l a n c e i s a s s o c i a t i o n  e x c r e t i o n of about  immediately  level  four  the  after  12  grams p e r  s t a r v a t i o n was  o f 6 0 0 grams o f U.B.C. p e l l e t t e d  This  15-55  namely,  day,  as  begun, 9  o f d i e t a r y c r u d e p r o t e i n w o u l d be n e e d e d n e c e s s i t a t i n g sumption  per  the n i t r o g e n c a t a b o l i s m a s s o c i a t e d with  h i g h plane of n u t r i t i o n more s p e c i f i c a l l y ,  matter  i n d i c a t e a minimum r e q u i r e m e n t f o r  grams p e r day, w o u l d  t i m e s t h e minimum t o t a l  protein  non-pregnant,  n i t r o g e n and d r y  T h i s would not, of course,  approximately 700  grams  the e x p e r i m e n t a l l y determined v a l u e f o r  needs of the a n i m a l , but  by  of R - 5 i s  c e n t f o r t h e U.B.C. r a t i o n  the percentage of crude p r o t e i n  indicated.  female,  grams o f d i e t a r y  and c o n s i d e r i n g  per  requirement  t h e b a s i s o f t h e above f o r m u l a i s 2 0 . 8 8 7  f o r R-5»  (Appendix  -  conditions.  digestible  on  digestibility  75  of n i t r o g e n requirement  was grams  2  the  f e e d d r y matter is reflected  to  conper  a  - 76 greater of  d e g r e e by  t h e p r e v i o u s method w h i c h u s e d t h e  the p o i n t of n i t r o g e n balance  ments. take  The  17  b a l a n c e p o i n t of  to  indicate  calculation  the d i e t a r y r e q u i r e -  grams o f d i e t a r y n i t r o g e n i n -  i n d i c a t e s a need f o r a p p r o x i m a t e l y  1 0 0 grams o f p r o t e i n  d a i l y f o r maintenance of minimal n i t r o g e n s t o r e s alone. result  i s , of  course,  too h i g h f o r the p u r p o s e s of  m i n i m a l n i t r o g e n s t o r e s and values of  the  two  v a l u e o f 92  ted  feed obtained  methods i s o f  voluntary feed  deer ly  maintained  during the  significance  a high plane  in fact,  i n t a k e o f R-5  at U.B.C,  and  although  600  grams o f  ruminants.  pounds per  tein  requirement  represent  others of  the  nor-  black-tailed  t h e m a l e s commonly  eat  carried  R e c e n t l y Majundar f o u n d  poor-  1 , 0 0 0 pounds l i v e f o r maintenance.  weight  t o be  This result  was  kilogram  i n these  terms  to Maynard  t r i a l s with  The  result  is 0.07I  (Maynard  ruminants  of  grams p e r  this  of  t h e minimum  per  l i v e weight.  out  a value  endogenous u r i n a r y n i t r o g e n e x c r e t i o n w h i c h was  bolic  deter-  w e l l the  the  According  pellet-  season of r u t .  O.65  pressed  i f i t had  experimentally  T h e r e h a v e b e e n many n i t r o g e n b a l a n c e s with domestic  than  the  of p r o t e i n n u t r i t i o n .  c a l c u l a t i o n from  mined n i t r o g e n e x c r e t i o n does, mal  less  grams o f d i e t a r y p r o t e i n and above by  maintaining  t h e r e f o r e t h e agreement b e t w e e n  been f o r the maintenance of The  This  obtained  from  O . 0 5 2 grams  experiment  kilogram  pro-  live  exweight.  1936), t h e r e s u l t s o f many meta-  indicate  a requirement  for  true  - 77 d i e t a r y p r o t e i n of 0 . 5  digestible  digestible dietary protein, These v a l u e s a r e equal and live  280  grams o f t o t a l  body w e i g h t .  requirement  100.  249  of  digestibility  The  this  85  o f about  and  No  similarily  and  those o b t a i n e d with domestic  weight.  protein  pounds of  indicate  a biological  v a l u e , as  a a  value of  i s commonly o f 249  grams  r e f e r e n c e s were made i n  t h e r e f o r e these r e s u l t s  w i t h v a l u e s f o r o t h e r members o f  Nitrogen  body  total  crude p r o t e i n with  to n i t r o g e n balance  the  1,000  the requirement  correspondingly increased.  and  live  experiment  biological  ruminants,  literature pertaining  pounds of  grams o f t r u e d i g e s t i b l e  r e s u l t s of  coefficient  ruminants,  pounds of  d i g e s t i b l e p r o t e i n per  U s i n g f e e d s o f a lower  w o u l d be  wild  to 225  1,000  or 0 . 6  grams o f d i e t a r y t o t a l  the case with domestic  the  per  pounds,  experiments  cannot  be  compared  the f a m i l y C e r v i d a e .  between t h e r e s u l t s o b t a i n e d ruminants  in this  with  However, experiment  i s reasonable.  Distribution  Urea Folin and  investigated  the changing  ammonia e x c r e t i o n w i t h c h a n g e s  (Folin  1905).  nificantly  He  found  the  level  of u r e a  ruminants  and  e x c r e t i o n dropped  restricted  w i t h the r e t u r n of normal n i t r o g e n i n t a k e .  and domestic  and  rose  sig-  again  S i n c e F o l i n many  e x c r e t i o n i n both monogastric have  urea  i n n i t r o g e n i n t a k e i n humans  when n i t r o g e n i n t a k e was  authors have s t u d i e d u r e a  l e v e l s of t o t a l  animals  i n general corroborated F o l i n s 1  -  results.  However, p r i o r  78  t o t h e work o f S c h m i d t - N i e l s e n  (Schmidt-Nielsen  1 9 5 7 and 1 9 5 § )  c r e t i o n of urea,  formed from  was  ambient  a d e t o x i f i c a t i o n m e a s u r e a s shown ed b y means o f s i m p l e of  glomerular  ulated.  tubules.  ammonia  that  The amount  of urea  filtration,  in  t u r n t o t h e amount  The  requirements  independent clearance,  I I I was  and t h e o c c u r r e n c e  ing  that  with other  a n c e may  intake.  sensitive  absorbed.  rate  subsequent remaining  un-  Schmidt-Nielsen  were met by t h e camel t o Work-  ruminants  clear-  as w e l l he f o u n d  that  r e s t r i c t e d w h i l e t h e r e was rate with d i f f e r e n t  i n salt  intake.  the urea little  interference  of nitrogen intake.  T h i s was  but v e r y especially  (I958) f o u n d a q u a l i t a t i v e -  Schmidt-Nielsen  ly  i n non-ruminants such  situation  caus-  The c l e a r a n c e r a t e was f o u n d t o  of the plasma c o n c e n t r a t i o n of urea,  to the l e v e l  change i n  l e v e l s of n i t r o g e n  so a s l o n g a s t h e r e was no  t r u e d u r i n g growth. similar  due  during periods of nitrogen r e s t r i c t i o n .  T h i s was  independent  filtration  and  l e v e l s of blood urea.  filtration  ed by c h a n g e s  post-  therefore associated  filtration  these requirements  be h i g h l y  glomerular  e x c r e t i o n was  o f excess n i t r o g e n i n g e s t e d and  with the glomerular  great degree  at the  f o r m e d and t h e amount f o r m e d was  r a t e s of glomerular  found  effect-  f o r the proof of tubular r e g u l a t i o n only, are:  changed at d i f f e r e n t (1957)  e x c r e t e d was  t h e ex-  of the b l o o d as  i n Appendix  No r e g u l a t i o n o f u r e a  d i r e c t l y w i t h t h e amount  be  thought  u r e a r e t e n t i o n was due t o s i m p l e b a c k d i f f u s i o n  collecting  a  -  as r o d e n t s , dogs and  man,  79 -  b u t r e s u l t s were q u a n t i t a t i v e l y v e r y much s m a l l e r .  posed  a counter-current m u l t i p l i e r  system f o r r e c o v e r y and  centration of urea during clearance, principle  for  similar  a q u a t i c and wading t e r r e s t r i a l  c o n s e r v i n g body h e a t  body h e a t in  being  carried  the major a r t e r i e s  applied  returning vessels before  extremities  and l o s t  same f u n c t i o n a l ulated  ruminants  from  t h e rumen p r i m a r i l y  c a n a n d do r e c y c l e u r e a , i n the form  secretion.  the s a l i v a of Merino  c u l a t i n g blood urea. s a l i v a was  He  He  the renal  (Somers 1961)  which has been  o f ammonia,  sheep was r e l a t e d  t h e b l o o d appeared  quate d i e t .  into  result  probably  content cir-  inadequate  showed t h a t a much  on an adequate p r o t e i n d i e t  This latter  absorbed  of urea i n  was r e c e i v i n g  amount  injected  show  back i n t o t h e  showed t h a t t h e c o n t e n t  He a l s o  the animal  post-  t o t h e amount o f  amounts o f d i e t a r y p r o t e i n .  with  The  collecting  showed t h a t t h e u r e a  g r e a t e s t when t h e a n i m a l  of u r e a  f a r into the  back d i f f u s i o n of c l e a r e d urea.  that  of  surrounding  stream  closely  to the environment.  e x t e n s i v e s t u d i e s o f Somers  rumen v i a s a l i v a r y  systems  1  i n v o l v i n g u r e a d i f f u s i o n was  f o r the r e t e of venules  The  t h e temp-  I* t h e s e  to s e v e r a l  i t i s carried  by c o n d u c t i o n  principle,  t u b u l e s to p r e v e n t  1955)*  i n ex-  to the e x t r e m i t i e s v i a the blood  r a p i d l y conducts  con-  mammals  a t t h e expense of r e g u l a t i n g  erature of the e x t r e m i t i e s (Scholander  pro-  i nfunctioning  t o t h e a r r a n g e m e n t o f b l o o d v e s s e l s he f o u n d  t r e m i t i e s of singular  He  larger  i n the urine  than on an  reflects  inade-  the renal  - 8o r e g u l a t i o n of u r e a found the  salivary  recycling  Houpt two  (Houpt  direct  Schmidt-Nielsen,  however,  as w e l l  as  effect. 1959)  mechanisms f o r u r e a  c y c l e u r e a by  by  -  found  that together  with  the  above  c o n s e r v a t i o n ruminants could also r e -  a b s o r p t i o n from the  blood back into  the  rumen.  The that  work o f D.  blood urea  Lewis  concentrations  i n c r e a s e d ammonia p r o d u c t i o n the a  above r e s u l t s  together  their  by  The  a direct  them t o c o n s e r v e  shortages  such  s e a s o n when t h e n i t r o g e n c o n t e n t  exceedingly  low  of  n i t r o g e n to  the f l o r a  and  thus  of  evolved  nitrogen  these  levels,  and  and  c o n s e r v i n g mechanisms t h e h o s t  "second chance" f o r the  some r e c y c l e d u r e a may c a t a b o l i s m p r o v i d i n g an  drops  can  use  loss  to the  host.  restore  i t once  s y n t h e s i s of m i c r o b i a l p r o t e i n  e s s e n t i a l l y p r o v i d e the host  f r o m what w o u l d h a v e o t h e r w i s e  during  represents  inevitably  in  deaminate  of herbage  t h i s deamination  consequently  to  as a p p e a r  "wasted" n i t r o g e n to the m i c r o f l o r a which w i l l given a  result  shows t h a t r u m i n a n t s have  rumen m i c r o f l o r a c o n t i n u e  to  By means o f  demonstrated  t h e rumen m i c r o f l o r a , t i e s a l l  enable  amino a c i d s d e s p i t e i m p e n d i n g dry  which  wasted d u r i n g p e r i o d s of n i t r o g e n r e s t r i c t i o n  environment.  the hot  1957)>  i n c r e a s e as  and  s e r i e s o f mechanisms w h i c h  w h i c h w o u l d be  (Lewis  with  amino a c i d  been waste n i t r o g e n .  a r i s e from additional  endogenous h o s t opportunity  to  nitrogen Presumably  body p r o t e i n recapture  -  what  f o r monogastric  animals  81  -  i s u n q u e s t i o n a b l y wasted, o r  lost  nitrogen.  Phillipson must  be a c e r t a i n  microflora vision  available  under  that  c h a i n s as w e l l  thus  i t cannot  to the p r e s e n c e  and l e v e l  The r e s u l t s  graphically  a r e shown  inanition,  the percentage  v a l u e s of 90 per cent  the t o t a l  nitrogen.  t h e most u n i f o r m nutritional lar  response  t o t h e one p o u n d l e v e l  level  level  level,  rises  to that  10-15  trial  per cent  present  The p r e v i o u s trial  was  The s i m i l a r i t y  simi-  of the  a b s o r b i n g one pound, t o t h e  i s not s u r p r i s i n g .  steeply  provided that  to t h e second  of feeding.  initial  experiment.  to v a l u e s of 7 7 - 8 5 p e r cent  to p r o t e i n n u t r i t i o n .  nitrogen after  of the  During periods  The v a l u e s o f t h e s e c o n d  urea percentage  the  i n F i g u r e 5»  and o v e r  significant  of p r o t e i n  in this  urea n i t r o g e n drops  h i s t o r y of R-5 p r i o r  fasting  to a  of u r e a n i t r o g e n as a p e r c e n t a g e  n i t r o g e n responds  pro-  starvation.  i n a l l of the t r i a l s  of  The p r o -  as n i t r o g e n f o r the  be u n d e r t a k e n  intake q u i t e markedly  from  t o t h e rumen  s e t on t h e c o n s e r v a t i o n o f n i t r o -  c o n d i t i o n s of complete  The l e v e l  of  there  f o r r e c y c l e d u r e a t o be u t i l i z e d .  The l i m i t a t i o n  i s , of course,  total  that  s y n t h e s i s ' o f amino a c i d s i s n o t an u n r e a s o n a b l e  position.  degree  h a s shown  of carbohydrate  o f exogenous c a r b o n  microbial  gen  amount  i n order  i960)  (Phillipson  Upon r e a l i m e n t a t i o n  found preceding the f a s t i n g  the feed i s accepted  and consumed t o t h e  - 82 extent  o f more t h a n a f r a c t i o n  case during gradual  the  i n percentage with  consumption of of  a l m o s t one  of  the  total the  n e a r l y one pound,  third  the  longer  second, t r i a l ,  trial,  possibility  of  the p a r t i c u l a r might  tive  excretion. day  of  cent  are  with  respect  to  72  per  nitrogen  and  indicative,  in this  of  by  to B.-5  Also,  with  nutri-  the  relative  total  nitrogen absorption  absorption  l e v e l s b e l o w 85  experiment, of  the  i n d i c a t e that  e x c e p t f o r one  i n d i c a t e recent  the  after  the p r o t e i n or n i t r o g e n  cent,  nitrogen.  Follow-  cent,  i n t h e doe  w h i t e - t a i l e d deer  per  within  support  These data  cent  consumption  larger absorption  e x c r e t i o n compared w i t h  above 9°  per  cent.  than 84 per  first  consumption  s h a r p l y t o 95  short passage time  estimate  The  the  r a p i d l y again,  times less  second  p e r i o d of  about  p e l l e t e d r a t i o n used.  amounts o f  The the  three  grams o f n i t r o g e n ,  significant  for  a fairly  Levels  7-08  of  the  trial.  during  These time r e l a t i o n s l e n d  be p o s s i b l e t o  of u r e a  the  fell  fell  c o n d i t i o n of b l a c k  level  During  the  not  caused a v a r i a b l e curve  brief  low  third  i n the  A f t e r the level  T h i s was  the  each day  pound.  and  level  f o r t y — e i g h t hours.  it  p e r i o d of  a dip  to a new  lasting the  a pound.  the percentage rose  nitrogen.  twenty-four hours, ing  test  c o n s u m p t i o n o f more f e e d  increase  during  feeding  of  -  a fasting  of  per  state  to d i e t a r y p r o t e i n .  simplicity  determination  of  t h e Conway m i c r o - d i f f u s i o n method  o f u r i n a r y and  blood  urea  n i t r o g e n makes  - 83 it  a n a t t r a c t i v e method f o r r e s e a r c h .  o f v i e w i t w o u l d be p a r t i c u l a r l y  advantageous f o r conducting  survey of t h e p r o t e i n n u t r i t i o n a l game a n i m a l s . ditions.  The t e c h n i q u e  However, t h e d i f f i c u l t i e s  time, p r a c t i c a l l y be  captured  taining normal  within  t h e sample c o l l e c t i o n , samples c o u l d  justment  t o t h e new  i s suitable forf i e l d of obtaining urine  conditions  insurmountable.  and c o n f i n e d  a  status of a population of  itself  f r o m game a n i m a l s u n d e r f i e l d  From a t h e o r e t i c a l p o i n t  Also,  are,  samples  at the present  even i f a n i m a l s  the necessary  con-  could  s t r u c t u r e f o r ob-  i t i s extremely u n l i k e l y that  be t a k e n w i t h o u t  a lengthy p e r i o d of ad-  surroundings.  Ammonia The  level  o f u r i n a r y ammonia n i t r o g e n  i n v e r s e manner t o t h a t it  agrees with  an  opposite  other  index,to  of urea  previous  i n this  experiment.  f i n d i n g s which have  urea nitrogen,  rises  to 4 p e r cent  to v a l u e s  cent,  f o r example,  nitrogen,  b a s e r e g u l a t i n g mechanisms.  measure.  shown i t t o be  greater  Dur-  range of 1  than 5 per  7 - 5 t o 10 p e r c e n t .  because t h e i r p r o d u c t i o n  ammonia i s b r o u g h t  I n t h i s way,  from a normal  U r e a a n d ammonia f l u c t u a t e i n o p p o s i t e part  i n an  of p r o t e i n n u t r i t i o n .  ing p r o t e i n s t a r v a t i o n the level of total  behaves  about  This process  directions in  i s inextricably involved The p r o d u c t i o n  by t h e l i v e r  i n acid-  of u r e a from  free  as a d e t o x i f i c a t i o n  i s shown s c h e m a t i c a l l y  i n Appendix I I I .  - 84 Ammonia  i s produced  by d e a m i n a t i o n o f amino a c i d s a n d i t c i r -  culates  t h r o u g h t h e body f l u i d s  lease of h y d r o c h l o r i c reverse of  Appendix  in the  ammonia i s b r o u g h t  about  The f o r m a t i o n  f i x e d bases  such as  with m e t a b o l i c a l l y produced  o r d e r t o p r e v e n t abnormal f o r m a t i o n o f ammonia  pH.  by t h e k i d n e y s as shown i n  I I , i n order to p r e s e r v e b o d i l y  w h i c h h a v e combined  The r e -  a n a c o n v e r s i o n o f ammonia t o g e t h e r  e x c e s s i v e e l e v a t i o n o f body f l u i d  urinary  sodium  acid  a s ammonium c h l o r i d e .  l o w e r i n g o f pH.  acids  The e x t e n t o f  i s then a r e f l e c t i o n of the metabolic  a c i d p r o d u c t i o n and o f t h e f u n c t i o n o f t h e a c i d - b a s e r e g u l a t i n g mechanism  i n elevating  body pH.  During f a s t i n g of the  f a t metabolism  the increase  in relative  importance  tends to produce m e t a b o l i c a c i d o s i s .  d e a m i n a t i o n o f amino a c i d s d e c r e a s e s w i t h t h e d r i f t  t e i n metabolism  t o lower  levels  Also, of pro-  associated with protein deple-  tion.  C r e a t i n i n e and C r e a t i n e In  the s e r i e s o f experiments mentioned  Folin  found t o t a l  stant  f r o m d a y t o d a y a n d t o be r e l a t i v e l y  gen  intake,  creatinine  observations. metabolism  e x c r e t i o n t o be r e l a t i v e l y  unlike urea excretion.  time, many e x p e r i m e n t s  the results  Burroughs  of F o l i n ,  independent  conof n i t r o -  T h e r e h a v e been, s i n c e of which  et a l h a v e s a i d  which  previously  support  that  this  Folin's  t h e endogenous  r e p r e s e n t s t h e summation o f t h e  - 85 - - • irreversible exemplified  reactions  of nitrogen,  (see A p p e n d i x V) a r e  by t h e b o d i l y c o n v e r s i o n  which r e p r e s e n t s  of c r e a t i n e to c r e a t i n i n e  an i n e v i t a b l e l o s s of n i t r o g e n  (Burroughs, Burroughs and M i t c h e l l 1 9 4 0 ) . t r i b u t i o n data of Blaxter indicate  that  a n d Wood  12 p e r cent  about  metabolism of t h e growing c a l f volves per  t h e above  cent  involves purine  reactions gators  terminating  have  creatinine  and t h a t  the  formed  free diet, i n -  For comparison 25  I9I3.  normal  amount o f body  a c i d chain,  arginine  I94I)•  1942).  formed  l a b i l e methyl  Glycine  the guanidine i s methy-  groups  from  (see Appendix I V ) .  Schaffer presented only part  (I908)  showed t h a t  creatinine excretion r e -  o f endogenous n i t r o g e n m e t a b o l i s m a n d t o o k  p l a c e p r i m a r i l y i n muscle. showed t h a t  nitro-  amino a c i d s were i n v o l v e d i n  (Schoenheimer  using  of  urinary  creatine  and Block  of creatine  l a t e d by t r a n s m e t h y l a t i o n  investi-  i s the bodily precursor  Scho enheimer  three  involves  Several  a n d t h e compound g l y c o c y a m i n e t h u s f o r m e d  methionine;,  nitrogen  m e t a b o l i s m and 50 p e r cent  creatine  showed t h a t  the f a t t y  nucleus,  reaction.  with a significant  biosynthesis  o f t h e endogenous on n i t r o g e n  dis-  a n d Wood 1 9 5 1 )  (Blaxter  creatinine i s the only  (Myers a n d F i n e  Schoenheimer  The n i t r o g e n  i n u r e a a n d ammonia.  shown t h a t  constituent gen,  irreversible  f r o m t h e body  Palmer,  Means a n d Gamble  c r e a t i n i n e e x c r e t i o n was p r o p o r t i o n a l  (1914)  to metabolic  - 86. rate  i n man.  excretion  C a t h e r w o o d and  t o be  Stearns  a f u n c t i o n of  (1937) f o u n d  body w e i g h t  to  creatinine  where m u s c l e mass u s u a l l y d o m i n a t e s t h e  endogenous  metabolism.  young a n i m a l s  Also  the  p e o p l e removes t h e functional  adults  firmed  that  that  size. lar  (Macy 1 9 4 2 ) .  i t was  for adult  McCluggage  Macy f o u n d a  an  men  and  similar coefficient  i n d i c a t o r of  the  excretion  as  ference  remains constant,  et  65  of  al  and  Groot  i n BMR  per  cent  et a l s t u d i e d  creatinine excretion  the  of  that and  and  c r e a t i n i n e to w i t h no falls  of  fat  inter-  off after  m u s c l e mass.  the  Wuthier  is related  l e a n b o d y mass  the p r e v i o u s c o n s t a n c y of  (De  the  to  (Wuthier  Groot  above m e n t i o n e d  i960).  i n v e s t i g a t o r s had  In t h e i r  paid  c r e a t i n i n e e x c r e t i o n per  Butcher of  and  H a r r i s had  creatine  stated  excretion,  that  since  constancy  opinion  sufficient hour or  tence of p o s s i b l e v a r i a t i o n i n e x c r e t i o n d u r i n g  level  simi-  1957).  none o f to  c r e a t i n i n e was  serum c r e a t i n i n e c o n c e n t r a t i o n  composition  De of  c h i l d r e n , and  with decrease  a l showed t h a t  carcass et  excretion  along  (I942) c o n -  Macy  s k e l e t a l muscle  of  same r e l a t i o n  m u s c l e mass i n a d u l t s  age  with  women u p o n c o r r e c t i n g f o r f a t d i f f e r e n c e s .  (I93I) f o u n d t h e  the  and  i n d i r e c t l y r e l a t e d t o body w e i g h t  excellent  showed t h a t  nitrogen  npn-metabolically  ( 1 9 3 6 ) and  Talbot  c r e a t i n i n e was  Talbot  leanness of  d i s t u r b i n g e f f e c t of  f a t weight.  normal  and  usual  0.9  t h e power o f  the  to  the  day.  ruminants had  t h e y w o u l d not  attention  exhibit a  a  exis-  Also high  constant  creatinine is  excretion.  constant  during  excretion during low  the  Groot  day  short  and  even d u r i n g  therefore  periods  that high  of  are  average  l e v e l s of  i n r u m i n a n t s does not  alter  the  24  and  hours  Gaebler  also  that  i s not  constant  as  an  u r i n e volume, and  day  be  as was  minute a l l  creatine  c r e a t i n e and postulated  or  excretion  the  total  volume of  i t s constant  night the  as  found excre-  creatinine  during  by  and  Harding The  relative  i s shown i n F i g u r e  creatinine  de  because  wide v a r i a t i o n s i n  Groot.  show t h a t  the  T h e r e has  c o n s t a n c y of  creatinine  the p r o t e i n  (I958)  showed t h a t  the  on  the  level  al  (1949) f o u n d a s i g n i f i c a n t v a r i a t i o n b e t w e e n d i f f e r e n t  of  c r e a t i n i n e and  species  of beef  species  ( H e r e f o r d s ) of  steers  (2 y e a r s ) w h i l e he individuals  of  and  I n p a r t i c u l a r Hehyami  a r g i n i n e had. a p o s i t i v e creatine  excretion.  between i n d i v i d u a l s of  s i m i l a r weight,  found r e l a t i v e l y  i n a l l these categories.  to  b e e n some  e f f e c t e d by  level  intake.  5-  may  e x c r e t i o n w i t h time from hour  shown by  y e a r s to  show-  excretion  expelled urine  fairly  by day  He  creatinine  H a r r i s demonstrated that  constancy despite  and  work done o v e r can  and  index of  its relative  hour  of  creatinine  excretion.  constancy of  creatinine nitrogen  Butcher  of  sum  per  (1922) from t h e o r e t i c a l c o n s i d e r a t i o n s .  c o n s t a n c y of  serve  the  excretion  immediately balanced  large creatine  large  creatinine  l e v e l s of  level  the  tion  that  showed t h a t  interval  l e v e l s g i v i n g a constant  long ed  a  De  (300  constant  influence  Dining  the  same  k i l o g r a m s ) and levels within  These r e s u l t s  et  are  age  - 88 confirmed  in this  creatinine and  excretion within  i n the light  extent  experiment  reflect  differences  that  inherent  reaction  t o newly  i s that  I961).  (Brinkerkink  of an e q u i l i b r i u m  This  of  chromogenic m a t e r i a l s .  partly  t h u s compounding t h e a p p a r e n t  to t h e author the present  with creatine  by t h i s  fairly  variability  equilibrium  accurate.  author's  as t h e other  known c r e a t i n e c o n t e n t .  s i t u a t i o n and a r e a c c o r d i n g  i n obtaining  According  i n reverse  under  excretion.  samples are, on t h e o t h e r  These r e s u l t s a r e  experience  depend  excretion,  of c r e a t i n e  s t a n d a r d s when t h e s e a r e i n c l u d e d  c a n even p a s s  i s because  The r e s u l t s t h e r e f o r e  d e t e r m i n a t i o n s on s e p a r a t e  hand, u n a f f e c t e d  tion  formed  s u c h a s pH a n d t e m p e r a t u r e a n d t h e p r e s e n c e  on t h e v a r i a t i o n i n c r e a t i n i n e a n d c r e a t i n e  Creatinine  says  s i t u a t i o n i n which the  p r e - f o r m e d and newly formed c r e a t i n i n e as w e l l  other  He  i s r e l a t e d t o t h e amounts o f c r e a t i n e  variables  of  or perhaps a l l of  i s due t o e r r o r s o f u n -  of c r e a t i n e  standard  by  part  i n t h e a l k a l i n e p i c r a t e method.  error  degree of conversion and  p r o b a b l y t o some  i n the presence of pre-formed c r e a t i n i n e i s subject  1 0 - 5 0 p e r cent  the  i s concerned,  composition.  excretion  the degree of conversion  creatinine to  i n body  to B r i n k e r k i n k ,  variation i n creatine  known e x t e n t  i n d i v i d u a l animals  o f t h e above c o n s i d e r a t i o n s  According the  as f a r as r e l a t i v e c o n s t a n c y o f  corroborated  variable results i n urine  to Brinkerkink,  samples  the reac-  suitable conditions  such  - 89 that the  the p r e - f b r m e d c r e a t i n i n e i s c o n v e r t e d result  i s an  creatinine was  apparently  than the  also obtained  In t h e  light  of  i n the present  the  not  discussed  in detail.  The  r e s u l t s of  during  general, to  relative  nitrogen  of  total  support  nitrogen  the p r e v i o u s  The  (Figure 6) reduction  as de  time  duction active this the  t e n d e d t o be  fairly  day  in nitrogen f o u n d t o be  reduction  respond to  balance t r i a l s ,  the  and  changes  percentage  constant However,  intake the  a  showed a and  case.  fasting  skeletal  i n c r e a t i n i n e e x c r e t i o n thus r e f l e c t s Although  appeared,  during the  slight  excretion, The  slight  i s not  unrea-  i n p r o t e i n s t o r e s which occurs  i n v o l v e s p r o t e i n from the  body mass.  are  determinations  experiment  excretion.  in creatinine excretion during  tendency to two  this  e x c r e t i o n per  changes  result  statements regarding  nitrogen  new  following puberty  as  G r o o t ha,d  sonable because the this  of  and  s i g n i f i c a n c e of  creatinine nitrogen,  excretion,  reflect  the  and  occasion.  levels  creatinine nitrogen  tendency to  This  creatinine excretion  wide f l u c t u a t i o n s i n t o t a l total  of pre-formed  creatinine nitrogen  the balance t r i a l s  intake.  creatine  e x p e r i m e n t upon  g r o w t h and  the  independence of  in  sum  above c o n s i d e r a t i o n s  creatine results during  obtained  smaller  to  o r i g i n a l pre-formed value.  the  in  -  the  muscles.  a reduction  creatinine excretion  changes  t h e y d i d not  The  in nitrogen  at  rein  showed  intake  within  show a c o r r e s p o n d i n g  ten-  -  90  -  d e n c y between t r i a l s .  A s shown  of  e x c r e t i o n was  creatinine nitrogen  nitrogen grams  surrounding carefully  animal.  creatinine excretion  showed a t e n d e n c y t o d e c r e a s e  total  volume of u r i n e f l o w  these determinations  of  increased.  differed  they  milliliters  were i n t e r m e d i a t e  however, t h e v a l u e s of u r i n e output, grams w i t h  2.3 milligrams  milligrams  values were  with  1,272  milligrams  1 milligram with  577 m i l l i l i t e r s  of p o s s i b l e and H a r r i s have the  with  milliliters. In the t h i r d  with  37°  385 m i l l i l i t e r s ,  and 0 . 3 w i t h  concentration  per m i l l i l i t e r  2 milligrams  between these. 1.2  the r e s u l t s of  q u a n t i t a t i v e l y b e t w e e n t h e two  was 4 1 2 m i l l i l i t e r s ,  and 1 . 7  of  f a s h i o n as t h e  Although  showed e v i d e n c e o f b e i n g  c r e a t i n i n e n i t r o g e n was  period.  i n regular  F o r example, i n t h e s e c o n d t r i a l ,  the u r i n e output  o f an  per m i l l i l i t e r  a s an i n d e x o f u r i n e volume, a s B u t c h e r  suggested.  level  a s t h e samples o f  concentration  urine  value  be  T h e r e were no measurements a v a i l a b l e o n t h e  Creatinine nitrogen  R-5,  the conditions  t o i n t e r p r e t them i n  u r i n e were c o l l e c t e d o n l y o n c e i n e a c h 2 4 h o u r  with  7.5  I I , a n d about  that  c o n s t a n c y o f c r e a t i n i n e e x c r e t i o n p e r hour  trials  total  o f c r e a t i n i n e e x c r e t i o n must  standardized.when attempting  terms of t h e c h a r a c t e r i s t i c  level  s i m i l a r at l e v e l s of  I I I . These r e s u l t s suggest  the determination  individual  the general  1 4 grams i n T r i a l  e x c r e t i o n o f about  in Trial  6,  i n Figure  1,646  when 658 There  trial,  milliliters 0.8 milli-  milliliters.  Values for t h i s a  r e l a t i o n s h i p w o u l d h a v e to be  l a r g e r amount of d a t a ,  to  e l i m i n a t e the  in nitrogen  and  as  individual  If the  animal.  f o u n d t o be provide output the  reliable  a valuable using  urea  an  as  tool  a small  Nitrogen Total  in  o f u r i n e volume i t w o u l d  above, t h e  the  form  The  Nitrogen  As  ease of  even s m a l l  nitrogen  i s the  case  conducting  with the  samples o f u r i n e  work, under  Growth Excretion  total  urinary nitrogen  g r o w i n g p e r i o d on deer  are  in Figures  increase  increase  i n body weight  7 and  arithlog  on  total  an  was  makes i t a good method f o r f i e l d  grid  the  7  to  in total  excretion  t h r e e f e m a l e and  shown i n T a b l e s  the n i t r o g e n d i s t r i b u t i o n data.  graphic  the  sample o f d e e r u r i n e .  r e s u l t s of  male b l a c k - t a i l e d with  for  creatinine nitrogen  for determining  of  remains.  Urinary  tained during  u r i n a r y output  index  Excretion during  The  total  of  analysis described  conditions  bf  actual value  level  the problem of o b t a i n i n g  field  c a u s e d by f l u c t u a t i o n s  to determine the  index  an  creatinine determination but  effects  i n order  creatinine nitrogen  from  under normal d i e t a r y c o n d i t i o n s  interfering  stores,  obtained  The  VII  t o XI,  results  are  obfive  along shown  11.  nitrogen  i s shown on i n F i g u r e 8.  excretion with  arithmetic The  total  grid  the  in Figure  nitrogen  excretion, form  as  i l l u s t r a t e d , i n F i g u r e 7,  of a curve which  increases with  or w i t h n e g a t i v e a c c e l e r a t i o n , is  similar  age  i s gross form  i n c r e a s e i n body  a c c e l e r a t i o n phase,  The illustrative total  s i z e w i t h age  The  data  expressed  o f change i n t o t a l  indicate  least  two,  l o g of  increase  relatively  curve  the  aver-  or  negative  form  i s more  the  from  increasing  i n the  i n body weight  For  a body w e i g h t  body w e i g h t  be  example,  increase i n total  These  curve  stated  shows  that i s , day  as  the r a t e  a of  i n terms of  i n the f i r s t  4 kilograms  to  phase, about  nitrogen excretion  i s proportional  of  In a c c o r -  i n Figure 8,  i n kilograms,  o f about  several  change i n the r a t e  n i t r o g e n e x c r e t i o n per  n i t r o g e n e x c r e t i o n may  the r a t e of  the  increase.  these phases.  e x p r e s s i o n used  in deer  shows t h a t  r a t e s of  inflections  three, of  a power v a l u e o f b o d y w e i g h t . which extends  the  s m a l l amount o f d a t a a v a i l a b l e  grams o f t o t a l  t h e change  p e r i o d of  n i t r o g e n e x c r e t i o n c o n s i s t s of  and p o s s i b l y  in total  8 kilograms  later,  i n t h i s manner  the areas of r a t h e r abrupt  The  f u n c t i o n of  with  in arithlog  "breaks" or  d a n c e w i t h t h e method o f the  This  to express  during the  constant percentage  p h a s e s a r e s e p a r a t e d by  increase.  increments,  growth.  same d a t a e x p r e s s e d  phases of d i f f e r e n t  at  o f t e n used  the  of the c h a r a c t e r of the changes which o c c u r e d  (Figure 8 ) .  which  to t a k e  ever d e c r e a s i n g  n i t r o g e n e x c r e t i o n d u r i n g the growing  pattern  seen  as g r o w t h p r o g r e s s e s .  to t h a t  of animal  c a n be  t o t h e power 4 - 0  -  of  body w e i g h t .  body w e i g h t , c r e t i o n on crease  the  in total  the  The  two  r a t e of  grams o f  of  of  an  about  increase  to about  i n magnitude of  total  period  is proportional  to  involved  the  to  0.73  small  the  statistical  and  of  nitrogen  of  the p a t t e r n  excretion,  appear  considering  represent  of  the  to  the  of 8  growth.  r a t e of  35  of  intake  the  total  The of  is the  hazards nitrogen meta-  simultaneously,  in arriving  at  these  values.  changes i n magnitude  However,  the i l l u m i n a t i o n  total  a q u a l i t a t i v e nature, underlying  in-  kilograms  Because of of  kilo-  this  this period  i n magnitude of  the  presence  kilograms.  c h a n g i n g body c o m p o s i t i o n ,  approximations of  to u n d e r s t a n d  power  excretion during  a v a i l a b l e , and  employed  even i f l a r g e l y of  1.08  suggest  The  body w e i g h t .  not  change  constant  pwer o f body w e i g h t .  caloric  in-  growth from 8  kilograms.  and  ex-  body w e i g h t  body w e i g h t  a p e r i o d of  1.06  in  r a t e of  to the  s i g n i f i c a n c e to v a l u e s  nitrogen  nitrogen  a single  increase during  excretion during  attempt  22  increase  If the  k i l o g r a m s to over  power o f  a n a l y s i s was  They t h e r e f o r e  i n an  r a t e of  in attaching  rate,  data  amount o f d a t a  excretion without bolic  cent.  nitrogen  s e c o n d p h a s e e x t e n d s f r o m 22 and  cent  in total  is proportional  extends over  crease  relatively  4 per  phases f o l l o w i n g the  these  proportional  increase  i n terms of  However, t h e  body w e i g h t  body w e i g h t  f o r a 1 per  e x c r e t i o n f o l l o w i n g the  i s expressed  separate  first  be  nitrogen  of body w e i g h t . of  will  order  of 8 kilograms value,  T h i s means t h a t  there  -  93  nitrogen can  mechanisms  serve  involved  - 94 in  bringing  these changes  The nitrogen deer,  t y p e o f change i n r a t e o f i n c r e a s e  output,  i s very  illustrated  w i t h a d v a n c i n g age, o r i n c r e a s e  (1945) and many o t h e r  ready achieved ing puberty yet  the  phase  second  during  the pre-pubertal  creasing point  p e r i o d o f growth.  i n terms of t h e a d u l t  i s characterized i s characterized  body w e i g h t .  by p o s i t i v e a c c e l e r a t i o n , by n e g a t i v e  acceleration.  Follow  age, a m a j o r  meters a s s o c i a t e d  while The p e r -  a n d when t h e d a t a f o r t h e body w e i g h t ,  i n f l e c t i o n occurs  i n similar fashion  s t r a t e d by the n i t r o g e n  The  i n body s i z e i s m a r k e d l y d i f f e r e n t i n  logarithmically, are considered  of puberty  fashion  Brody  t h e g r o w t h r a t e a p p e a r s t o be a f u n c t i o n o f t h e s i z e  two p h a s e s o f growth,  expressed  i n t h e above manner.  i n v e s t i g a t o r s s i n c e , h a v e shown t h a t t h e  centage r a t e o f increase the  i n body  i n body s i z e i s d e p e n d a n t o n t h e growth a l -  t o be a c h i e v e d  first  growing  i t resembles t h e changes i n  when g r o w t h d a t a a r e h a n d l e d  rate of increase  i n size of  b y t h e above r e s u l t s w i t h  i n t e r e s t i n g because  growth r a t e o b t a i n e d size,  about.  as a f u n c t i o n o f  i n the curve at the  to t h e i n f l e c t i o n s  e x c r e t i o n d a t a above.  with metabolic  demon-  When o t h e r  function are treated  a similar pattern,  endogenous n i t r o g e n  f o r example,  excretion, or i n basal  a d v a n c i n g age, ( B r o d y  I945).  para-  i n this  a s a f u n c t i o n o f i n c r e a s i n g age o r body s i z e t h e y  tend to f o l l o w  in-  also  t h e change i n  metabolic  rate  with  _ 95 The gen  r a t e of and in  p o i n t s a t w h i c h t h e two  e x c r e t i o n curve occur,  correspond  -  t o t h e a g e s and  The  first  weights  the v a l u e f o r the  d a t a and  and  not w i t h  bably r e f l e c t s following  deer  inflection  t h e age.  a less  c a p t u r e on  from  i s found  birth  weight  date of b i r t h experiment.  The  rapid  100 both  age  and Wood. the  i s not  d a y s o f age  l a c k o f agreement  1955  and p r e s u m a b l y h a d  A l s o , as  inflection  inflection  used  c u r v e and er  further  individuals.  the growth c u r v e than that  rapid  in  and  the  exact  approximately in;terms  e s t a b l i s h e d by Cowan and  i n the growth c u r v e at t h i s  significance  experi-  of  w i t h t h e g r o w t h c u r v e d a t e o f Cowan  appearance of naked a n t l e r i n two  weeks  i n the present  T h i s agrees  a s s o c i a t e d w i t h the appearance of puberty,  tility  pro-  higher  a  extremely  occurs at  experiment.  and b o d y w e i g h t  to  stated previously,  known f o r t h e d e e r  in this  i n age  were r a i s e d  access  and  weight  i n the present  experiment  :  change  growth r a t e d u r i n g t h e f i r s t  i n the  second  I t was  (Cowan  d a y s i n t h e d a t a o f Cowan  the p a r t of the deer  gain.  The  to change  c o i n c i d e s with the  p l a n e of n u t r i t i o n d u r i n g the p e r i o d of important  weight,  t h e r e f o r e o n l y agrees w i t h the body  ment, w h e r e a s t h e d e e r captivity  wherein  body  nitro-  and  g r o w t h r a t e w h i c h o c c u r s a t IA  Wood, however,  i n the  i n t e r m s o f age  growth o f b l a c k - t a i l e d  Wood 1955)*  inflections  buds and The  Wood t h a t  age  and w e i g h t  as  s i g n a l l e d by  the demonstration  of  is the  fer-  agreement between t h e n i t r o g e n  i n t e r m s o f body w e i g h t o f age,  as  suggested  i s of  earlier  great-  due  to  the  fact  that  environmental status,  and  influences,  degree of  upon the passage of  exact  values  of  nitrogen  obtained in  to  tained  p a t t e r n of ner  nitrogen  For  of  i s so  example,  reduced r a t e of  surpassed.  extent  to  and  that  a f f e c t e d , due  increase expect at  upon  growth it is  excretion  level  to f l u c t u a t i o n s excretion  the  ob-  to t h e  changing regular  man-  growth  pro-  c h a n g e i n m a g n i t u d e as expected that  the  as  grows l a r g e r .  that  the the  animal level  of  f o l l o w i n g an  the  animal  inflection  level  of  nitrogen  a l e s s e r r a t e when t h e  growth r a t e of  increase  Therefore,  i n p a r t due  same way  i t w o u l d be  increase  activity  large  dur-  changes i n p h y s i o l o g i c a l c o n d i t i o n  i n the  i t appears to  e x c r e t i o n would metabolic  growth,  reasonable  a very  However, t h e p a t t e r n o f  excretion should  i s also  excretion obtained  f l u c t u a t i o n s i n the  growth.  growth r a t e  i n which  gresses.  It  and  i s more s u g g e s t i v e  associated with  nitrogen  e x p e r i m e n t would, be  intake during  upon  itself.  i n t a k e o n c e t h e m a i n t e n a n c e and  assume t h a t  in this  time  depends to  r e q u i r e m e n t s h a v e been met reasonable  i s p r i m a r i l y dependent  e s p e c i a l l y those a f f e c t i n g n u t r i t i o n a l  i n g normal f e e d i n g p e r i o d s the  -  "physiological aging"  not  The  96  general  assumes i n the  a growth  curve.  The trated  increase  in Figures  i l l u m i n a t i o n of  9 and  in nitrogen 10 p r o v i d e  the u n d e r l y i n g  excretion useful  metabolic  with  age  information  illusfor  mechanisms w h i c h  the  - 97 influence the data in  level  i n t h e s e f i g u r e s show ^  output  evident again  at  the  i n the  within  age  data  a short p e r i o d of  be  reasonable  during  to  The  point  increased  time the  the  time.  increased  This  nitrogen  reduction  excretion  result  I t would  increased  i s an  example o f  i s emphasized,  nitrogen  uniform  i s a reasonable  a critical  estrogens  the  because of  r a t e of  of  til  the  the  l a r g e e l e v a t i o n of  kilogram  the f a c t  endogenous l e v e l  of  excretion  the n i t r o g e n  b a s e d on  predicted  endogenous l e v e l  of  the  i s very  nitrogen  body period.  during  slight  shows t h a t  excretion  ana-  growing  e x c r e t i o n over  body weight  this  nitrogen  During the  depots  i s c o n t r o l l e d l a r g e l y by  of  that  growth b e g i n s to d e c r e a s e markedly.  ed  The  f a t storage  such  established.  e n t i r e growing  e x c r e t i o n p i c t u r e to a c e r t a i n e x t e n t . build-up  period  the p r o t e i n  i s well  e x c r e t i o n per  throughout  result  and  At  g r o w i n g p e r i o d t h e m u s c u l a r mass d o m i n a t e s t h e  p e r i o d the  formation  s t r u c t u r a l r e - o r g a n i z a t i o n wherein  a n d r o g e n s and  is fairly  retention  needs of p r o t e i n f o r t i s s u e  of puberty  total  rises  is indicative  retention. of  The  is especially  The  certain periods  i n muscle  of  The weight  growth.  need f o r d i e t a r y p r o t e i n would a r i s e .  growth  effect  This  from the male deer.  expect  o f p h y s i o l o g i c a l and  This  t h r e e months.  g r o w t h when g r e a t e r  arise.  bolic  of  excretion during  marked t e n d e n c y f o r a  a short p e r i o d of  of  an  of n i t r o g e n  un-  However, the  estimat-  the  level  intake.  i s shown i n  - 98 Figure over  8.  the  This high  endogenous l e v e l  to  suggest  as  i t was  that  of  than the  actual  reiterated  of  the  in this  the  results  status,  and  ideal  level  C r e a t i n i n e and  the of  increase  increases  body w e i g h t .  weight  This  1959)-  is largely  p e r i o d of  growth.  result As  The  and  should,  crease  be  nitrogen  gen  e x c r e t i o n per  pre-  11.  the  with  The  the  level  increase  in  considerations  increase  i n body  a c t i v e b o d y mass d u r i n g  a representative  the degree of  total  conditions  excretion  theoretical  creatinine nitrogen  i n body weight d u r i n g  the  pro-  excretion  the  represents  l o s s from t h i s f r a c t i o n of body m a t e r i a l ,  therefore,  i n f l u e n c e d by  be  Excretion  mentioned p r e v i o u s l y , by  i t should  reserves.  manner w i t h  agrees with  the  intake,  d e v e l o p m e n t and  i s shown i n F i g u r e  represented  unavoidable nitrogen  the  growth,  reflects  ideal  in creatinine nitrogen  in a linear  seem  the degree of  growth under  Nitrogen  would  nitrogen  However,  of p r o t e i n  Creatine  increase  cent,  increase  excretion during  represent  thus with  i n body w e i g h t  excretion  (Albanese  also  associated with  an  The  per  an  e x p e r i m e n t , more t r u l y  growth r e q u i r e m e n t s .  catabolism  s e r v a t i o n of  1,000  animals t e s t e d , i n terms of  that  nutritional  o f about  the p a t t e r n of n i t r o g e n  obtained  behavior  tein  e l e v a t i o n , which r e p r e s e n t s  this period. nitrogen  excretion kilogram  of  index of Also,  i n t a k e to  i s affected.  The  body w e i g h t was  the  in-  i t i s not  the  extent  that  creatinine nitrouniform  throughout  -  99  -  the growing p e r i o d of a l l the i n d i v i d u a l s and was v a l u e from one The  individual  to  similar in  another.  c r e a t i n e n i t r o g e n e x c r e t i o n was  very v a r i a b l e  and ranged from v a l u e s of 10 to 1 5 0 m i l l i g r a m s . are s i m i l a r to those quoted f o r humans.  These v a l u e s  The c r e a t i n e n i t r o g e n  e x c r e t i o n tended to reach peak v a l u e s with each i n d i v i d u a l , i n both sexes,  at about 1 2 0 to 1 3 5 days and with body  of between 16 and 2 2 kilograms.  and  weights  T h i s peak e x c r e t i o n c o i n c i d e s  w i t h the establishment of puberty.  T a b l e s and  figures  -  TABLE I. Date  Dry Matter  D.M. Fecal I n t a k e D.M. i n Gr. in Gr. *  17 18 19 20  15/16 16/17 17/18 18/19 19/20 20/21 21/22 22/23 23/24 24/25 25/26 26/27 27/28  -  Relations  Total True True % Dig. Nut- Dig. Dig. % rient D.M. N u t Dig. ( a p p a r . *) r i e n t * D.M. i n Gr. i n Gr. Trial  1  Oci tober (I - l )  Trial  2  Jai l u a r y (.1*-5)  Dig. Cals.  Total Cals.  3  no data  421.4  72.9 10. 1 J_5.5 X  322. 690.4 421.4 657.O 421.4  1  ,186.6 45.9 6.9 11.9  262. 2 522. 1 274.1 590.6 .234.8  Trial  12/13 13/1A 14/15 15/16 16/17  100  V .  3  81.8 75,5 65.1 89.9 55.7  272. 2 532.1 284.1 600.6 244.8  84 77 67 i 58 9  Mew r c h (R-[5) -  "68.-5 56.2 64.3 25.0  none 17.3 142.2 ~T3. 2 31.2 18/19 378.8 19/20 357-7 64.7 20/21 22.5 21/22 22/23 18.0  759-8 1,513.8 794-6 1, 222 1,713.9 68I.5 1,222  •\  N  4.1 110. 0 308.6  42. 2 14.1 77.4 s 120.0 ,324.1 ^318.6 $6.3  IV  82 § §5 89 5  II8.9 319.0 910.6 1,098 896.I 1,037  ;. -  TABLE I I . Dat e  101  Metabol ic Fecal N.  Fecal N. •  i  -  Nitrogen D i g e s t i b i l i t y  Feed N..  •  Appar. Dig. N.  Data True Dig. N.  Trial  I  October ( P - l )  Trial  2  January  (R-5)  ~5,67 13.75 8.57 10.85 8.66  6.31 15.13 9.41 1 2 . 16 9.50  Digestibility ' or Coefficient (true)  True Dig. N./kg. Body Wt.  16/17  17/1818/19 19/20  15/16 16/17 17/18 18/19 19/20 20/21 21/22 22/23 23/24 2.4/25 25/26 26/27 27/28  10.48  ' 8 " . 61' 17.18 10.48 16.35 10.48  0.62T 1.38 0.84 1.31 \O.84  2.30 0.32 0.51 2. 0 5 "2TJ4-  3,43 1.91 5.50  1.82 ^0723 0.46  Trial 12/13 13/14 14/15 15/16 16/17  17/18  18/19 19/20 20/21 21/22 22/23  0.43 3-54 9. 4 2  8.90  O.346 0.284 0.758 ,0.715  3  0.383 1.095 2.349 1.723 0.734 0.628  March  0.047 2. 4 4 5  7.08I 7.177  ll  90 74 91  0.139 0.334 0. 207 0.268 0.209  (R-5)  0.08 2.73  7.83 7.89  19 83 89  0.002 0.060 O.I73 0.174  TABLE Date  III.  Nitrogen Balance Data  True N. . Urinary •' N. Dig. N. i n G. B a l a n c e B a l y4Cg. N. IN Q. b. wt. i n G.  1  Trial 16/17  18/19 19/20  0.28  23.124 8.806 9.200 43.221  15/16 16/17  17/18  18/19 19/20 20/21 15.31 21/22 9 . 4 1 22/23 1 2 . 1 6 23/24 9 . 5 0 24/25 2^/26 26/27  27/28  25.384 12.096 12.929 _3..„225.. 11.719 15.531 10.252.14.537 6.343 8.900 11.501 10.413  16/17  17/18 18/19 19/20 20/21 21/22 22/23  2.73 7.83  67'834"  8 . 068 10. 836 N 2 i 000 032 437  Cal. Equiv. of t h i s amt. Body Prot.  Cals. Req'd. from Body CHO &/or Fat  October ( P - l )  144.5 55.0 57.5 271.2  :  2  612.7 233.3 243.8 1,145.0  January (R-5)  -25.384 -12.096 -12.929 ^3^225 - 5.409 - 0.221 - O.842 - 2.377 - 1-157 8.900 -11.501 -10.413  Trial  6. 002 6. 6 7 4 17. 702 6. 720 0 . 0 8 K 8 . 488  Gr. b. Prot. Used for Energy  •23.124 0.509> . 8.806 0.194 • 9.200 0.202; •43.221 0.953  Trial  12/13 13/14 14/15 15/16  102 -  3  0.560 0.267 0.285 0^071 0.119" 0.005 0.019 0.052 0.070 0.196" 0.254 0.230  March  • 6.002 • 6.674 • 17.702 • 6.720 ^8.488 • 6.754 • 5.338 • 3.006 .13.110  158.6 80.8 20.2  .672. 6 320.4 342. 6  55.7 71.9 65.1  143.1 53.0 21. 2 63.6 _ 84._8 23578 304.7 275.9  37.5 42.7 111.0 43.0  159.0 176.9 469.0 178.1  77.7 14.9 i£i7_  1,636.5 219.6 1,010.0 1,104.6 1,229.1 269.0 80.7 919.8 44.4 97079 899.0 959.5  (R-5)  0./132 0.147 0.390 0.148 0.187 6.149 0.118 0.066 0.289. 7.032 0 . 1 5 5 6.437 0 . 1 4 2  __53..._i_  42.2 33.4 18.8: 82.1 43.9 40.2  2 140.5 80.0  3A-LA  18673  170.6  1,388.3 1,096.4 538.3 946. 2 .775950 955-5 110.0 16.8 1,000.7 972.9  - 103 TABLE I V , Water Balance Data Date  Water from Feed  Dr ink- Metaing bol ic Water Water from Feed ' Tri«i l  16/17 17/18 18/19 19/20  32.2  2,600 1,300 1,828 Tri<i l  15/16 16/17 17/18  I8/19  19/20  20/21 21/22 22/23 23/24 24/25 25/26 26/27 27/28 12/13  13/14 14/15 15/16 16/17  17/18  18/19 19/20 20/21 21/22 22/23  1  Insens- Fecal Urine ible Water Water Water Loss Loss Loss  0ctober (1 - l ) 3  no data  2  Water. Balance  no dat<  887 +1,713 428 + 872 406 + 166 1,882 - 29  J a n u a r y ( l*-5)  696 700 514  + 206 490 962 343 89 - 768 435 19 . 1,664 434 , 36 •828 - 249 24.6 \l,172 14 -. 7 1,443 - 918 52.8 1 6 ~ 1 6 3 1,424 319 • 2882 117 258 + 120 32. 2 1 1 9 4 ,606 171 224 50.7 1,686 - 28055 92 2 053 32. 2 2, . 6 9 8 5 8 1,099 - 195 . 471 360 613 58 2,126 ^ 495 " i 410 *47 619 4 705 627 57I 22 450 632 437 28 394 - 423 634 Tr:tal 3 Viarch (R-• 5) 590 142 63 64 377 - 520 1,209 493 ." 832 837 • 374 597 \ I 382 - 638 446 680 A none 346 1.3 \ 179 367 1,990 " " 9 372 - 676 10.9 57 754 6 2 29.0 72 3 551 - 535 18 103 1,5 1,493 98 +1,281 27.3 194 3 628: 37. 1,12 \ 310 0 - 615 191 4 20 • 320 3 6 1 -1,076 216 400 2 9 6 - 167 2 9 242 1  . /  x  7  6  9  -  T A B L E  V.  Date  Total Nitro-gen  Nitrogen Distribution U r e a f» N. T.N. Trial  16/17 17/18  23.360 8.806  I8/19  9.200  I9/2O 4 3 . 221  16/17 17/1$  18/19 19/20 20/21 21/22 22/23: 23/24 25/26 26/27 27/2$  25.385: 12. 096 12.929 3. 225 11.719 15.531 10.252 14.537 6.343." ,8.-899 11.501 10.413  6. 002 6.674 13/14 14/15 I 7 . 7 0 2 6.720 15/16 16/17 8." 488 17/18 6.834 8 .068 18/19 1 0 .836 19/20 21". 000 20/21 7 . 0 32 21/22 22/23 6/437  90 93 82 96  Trial  2  24.001 10.292 10.884 2.713 10.147  95 85 84 84 87  9\746 13.788 -5.725 8.281 9.950 8.682  95 95 90 93 87 83  14.640 94  5.421 5.985 14.785 5.193 6.703 5.754 • 6.847 9-033 19.926 5.047 5.687  Data  Nitrogen Distribution A:nm. ~f Cr ' T N. T.N. N. T.N. 0  Cr^ N.  %  T.N.  Total  %  1 ; October ( P - l )  20.990 8.211 7.618 41.507  Trial 12/13  104 -  0. 086 GO. 4 0.044 0.5 2. 1 0.194 0.5 0.199  0 . 5 3 0 2.3 0.283 3 * 2 O.315 3 - 4 1.446 3 - 3  0.162 0.023 0.023 0.069  0.7 92.9 0.3 97-2 0.3 85.6 0 . 2 100.0  (R-5)  January  0.734 2.9 0.913 7.5 1.299 10. 1 0.^274 8.5 7.6 0:889 0.254 1.7 0.124 1.2 0.217 1.5 0.115 1.8 0.196 2. 2 3.8 0.431 0.621 6. 0  0.601 0.438 0.570 0.145 0.595 0.566 0.358 0.524 0.246 0.257 0.371 0.361  2.4 3.6 4.4 4.5 5.1 3.7 3.5 3.6 3.9 2.9 3.2 3.5  0.049 0.153 0.176 0. 002 0.0S9. 0.071 0.025 0. 000 0.016 0.015 0.064 0.050  0. 2 1-3 1-4 0. 1 0.8 0.5 0. 2 0. 0 0.3 0.2 0.5 0.48  0.213 0.076 0.144 0.366 0.467 0.448  3.5 1.1 0.8 5.4 5-5 6.6  0.473 0.612 0.687 O.390 0.334  5-9 5.7 3.3 5.4 5.2  0.004 0.019 0.064 0.137 0.061 0.023 0.008 0.183 0.000 0.002 0.055  0.1 0.3 0.4 2.0 0.7 0.3 0.1 1-7 0.0 0.0 0.9  100.  o!  97-4  100.0: 97.2 100. o; 100.0: 100.0 99.9 96.3 98.4 94.0 93.3  3; March ( R - 5 ) 90 90 84 77 79 $4 85 83 95 72 88  0.421 0.7 0.068 1.1 0.518 2.9 0.516 .' ' 7 . 7 0.641 7.6 0.609 8.9 0.740 9.2 1.007 ' 1 1.8 0.372 0.246 3.5 0.361 5.6 9  1 1  94.6 92.2 87.6 92.4 92.8 100.0 100.0 100.0 99-9 80.9 99.9  -  TABLE V I .  Date  O2 C o n s - V a l u e umpt i o n of 0 in in Liters Cals at R.Q. o f 0.82  Grams o f Body Fat f o r NPN C a l s  1  Trial  Trial  339-lS. 2 5 2 . 76 275.73 302.00 272.45 242.91 331-53 359-73 377-49 269.17 251.76 249. 48 256.04  ,636:5 ,219.6 ,330.4 ,457.2 ,314.6 ,172.0 ,599.6 ,736.0 ,821.4 , 298.7 ,214.7 ,203.7 ,235.4 Trial  12/13 13/14 14/15 15/16 16/17 17/18  1S/19 19/20 10/21 21/22 22/23  320.68 263.89 188.04 233.02 207.33 237.78 293.35 228. 20  2 6 l . l 6  246.01 246.01  1,547.3 1,273.3 907.3 1,124.3 1,000.4 1,147.3 1,415.4 1,101.1 260.1 1,187.0 1,143.5  Grams of Body CHO f o r NPN C a l s  Pounds o f T o t a l Wt. Loss Prot. Prot. Ass. Water A l o n e  October ( P - l )  no  10/19 19/20 20/21 21/22 22/23 23/24 24/25 25/26 26/27 26/27 27/28  -  M e t a b o l i c R a t e D e t e r m i n a t i o n D a t a , and R e q u i r e d Changes i n Body C o m p o s i t i o n a t t h e R.Q. o f 0 . 8 2  2  16/17 17/18  105  data  2  January 100.7  75-1  81.9* 89.7 ' 80.9 72.1 \ 98.5 IO6.9 112. 1 80. 0 74.8 74.1 . 76.0 3  March 95.2 78.4 55.9 69. 2 61.6 70. 6 87.1 67.8 77:6 73.1 70.4  (R-5) 1 3 . 2-  15.0 I6.4 17.9  16. 2 14.4 19.7 21.4 22.4 16. 0 17.0  16.8 17.2  724.5 400.7 430.8 177.9 221.7 145.4 159.1 194-1 174.8 314.6 378.5 353.6  248.7 173.9 188.4 117.3 120.3 125.0 136.0 149.4 115.7 147.5 162.8 158.3  264. 2 264.9 511.1 255. 0 286.3  151.7  (R-5) 19.0 15.7 11. 2  13.8 12.3 16. 1 '17.4 [13. 5 15.5 14.6 14.1  255.5 238.1 156.5 421. 5 263.3 245.3  136.S 178.1 126.0 127.0 128.8 137.9 100.0 175.2 131.6 124.7  TABLE V I I . Dat e  Nitrogen  Aug. 3 Sept Oct. Dec.  D u r i n g Growth  V e i g h t Volume Age i n Kg. in of Ur i n e Days in cc. (appr.)  Time Int e r val Taken for Trial (hours)  Male  I960 July Aug.  Excretion  24/25 4/5 17/18 31ep t . 1 15/16 20/21  2/3 3/4 4/4 4/5  35 '45 55  1°  .85 122 I65  6.8 8.2 9.3 13.8 19.3 27. 2  11  ti it  11  11  11  Total Nitrogen Excreted in Urine Gr./dy  Black-tailed  Ammonia Nitrogen %T.N. T o t a l i n Gr,  Urea Nitrogen %T. N. T o t a l I n Gr  Great i n i n e Nitrogen $T. N. T o t a l i n Gr.  Total Nitrogen Expressed as N./Kg./dy  Creatinine Nitrogen Expressed as N./Kg./dy  Deer  430 400 657  2 1 . 5, 18 18  4. 728 9.552 8. 0 6 4  3.04 1.20 7.22  1.440 0.115 Ov582  -28. 5 96. A 94.6  1.-350 9. 2 0 8 7.629  562 518 862 1,369 1,100 420  18 17.3 12. 2 24 24 12 12  6.792 9.408  9.70 5.94  90.3 68.7  6.133 6.463  16.339 13.877 10.104. 14. 2 3 2  2.13 3.06 J2.472.52  0.659 ,0.559 0.944 0.348 0.425 0.324 0.359  90.7  14.819 12,475 8. 9 2 2 7.500  56O  Creat ine Nitrogen ^TTN. Total i n Gr,  88.3 52.7  0.64 1.15 1.33  0.0310. 110  -I.-44 1. 2 6 1.82  0. 0 6 8 0. 120 0.147  0. 6 9 5 1. I 6 5 O.867  0. 001 0.015 0. 016  1.54  0.145 0.301  0.682  0.016 < 0. 016 0.032  0.107 0.93 0.87 0.89  0.087 <  0.142  5.36 9.25  0. 9 3 5  0.601 0.510 0.371 0.523  0.163 0.112 0. 239 0.424 0.414 0.341 0. 289 0.379  0.457 0 . 621 0.562 0.536 0.674 0.730 0.517 0.393 0.468  0.876  0 . o 90  O.O34  ;  i960 July 26/27 Aug. 2 5 / 2 6 Sept. 6/7 20/21 Dec. 6/6 7/7  7/  B-6:Male 35  & 80  92 170 11  it  8  S/8 8/9  8.6 11.6 14.7 17.9 30.8  it  11 11  460 742 442 773 850 910 780 620 780  Black-tailed _  18 ' 22 19.3 12.5 12 12 12 12  3.936 7. 200 8. 265 9. 6 0 0 20.76O 22.495 15.912 12. 096 I4.424  Deer 11.30 1.96 3.31 3.14 O.58 0.84 2 . 66 1. 6 4 2. 96  0.445 0.141 0.273 0.301 0. 120 0.189 0.423 0.198 0.427  94-3 94- 5 95- 6  6. 7 9 0 7. 8 0 2 9.178  94.7  21.303  97.2  14. 0 2 0  1.42 0.61 0.96 0.11 0.81 0.63 0.77 0.17  0.102 0. 050 0.092 0. 023 0.182 0.100 0. 093 0. 0 2 5  2. 27 I.36 2.49 2. 0 4 I.84 2 . 14 2.39 2. 63  0 . 014 0 . 008 0.013 0.014 0.013 0. 011 0.009 0. 012  TABLE V I I I .  i960 Aug.  Excretion  Weight Volume Age i n Kg. of in Dr ine Days i n cc. (appr.)  Date  I960 July Aug.  Nitrogen  R-7: 29/30 10/11 23/24  1/2 11/12 24/25 S e p t . 12/13 23/24 Nov. 1/2 Dec. 19/19 19/20 20/20 20/21 21/22  42 52 65  8.6 10.7 12.2  18.5  11.6 •' —  15.5 20. 0 19.1 18.8 36.3 11 11 11 n  554 592 617 537 556 790 1,220 1,040 1,620 1,860 1,180  Growth  Total Time Inter- Nitrogen Excreted val in Urine Taken Gr./dy for Trial (hours)  Male  Black-tailed 21 16. 5 18.1  330 428 312  P.-8: 40 50 65 •85 95  During  Male  4 . 944 7.224. 7.512  Black-tailed 18 18.5 17.7 16 10.8 13 11 12 12 12  Ammonia Nitrogen %T. N. T o t a l i n Gr,  2. 83 2.39 6.67  0.140 0.173 0.501  Creatinine Nitrogen %T.N. T o t a l i n Gr,  Total Nitrogen Expressed as N./Kg./dy  Creat inine Nitrogen Expressed as N./Kg./dy  93.7 33.3  6.769 2.501  1.86  0.134  2. 01 2.04  0.145 0.153  0.464 0.464  0.014 0.013  55.1  3.450 0.154 0.960 6 570 8. 213  1.50  0. 094 2. 26 0.154 0 . 1 4 9 10. 99 2. 35 0.120 0.094 3- 19 0.931  0.142 0.207 0. 211 0.190 0.300 0.405  0.540  0.012  0.124 0.356  0. 014 0. 011 0.016 0. 022  De'er 3.59  1.920 9.648 9.408  3.13 3.12 8.59  0.228 0.543 0.060 0.310 0.808  23.112 16.200 20.046 21.672  0.10 1.25 1. 00 1.28 1.49  0.203 0.2S9 0.162 .0.257 0.323  -  Great i n e Nitrogen J6T.N. T o t a l i n Gr  Deer  6. 264  -  Urea Nitrogen Total i n Gr.  -  -  52.0 68.1 87.3  7-77 1.24 1.00  20.260 0.98 90.9 21.009 9 5 - 5 15.471 1 0 . 4 8 100. 0 2 0 . 0 4 6 0.10 96.1 20.872 0.86  0. 226 0.340 0.016 0.186  2. 2. 2. 2.  03 81 54 12  —  O.469 0.577 0.509 0.459  e-. 493  -  0. 634 0.637 0.466 0.552 0.597  0.013 0.016 0.014 0.013  TABLE IX.  Nitrogen  Date  W e i g h t Volume Age i n Kg. of in TJr i n e Days in cc. (appr.)  2/3 29/30  Sept.13/14 O c t . 18/19  Nov. 29/30 1961 Jan.  Growth  Time Interval Taken for Trial (hours)  Total Nitrogen Excreted in Urine Gr./dy  16/17 18/19  sa. 30  3.6  85 120 I65  70  7.8 10.4 15.9 23.1  214 it  V  40  •1  2  11  ;  300 325 365 365 592 373 .  21 17.7 19.5 18.3 17 ' 12  860 450 160  24 24 24  Urea Ammonia N itrogen Nitrogen %T.N. Total foT. N. T o t a l i n Gr. i n Gr.  Creat ine Creatinine Total Nitrogen Nitrogen Nitrogen ^T.N. T o t a l Expr e s s e d #T.N. T o t a l i n Gr. as ^. i n Gr. N./Kg./dy  • x•  Creatinine Nitrogen Expressed as N./Kg./dy  \  E-9: M a l e B l a c k - t a i l e d  I960 July Aug.  E x c r e t i o n During  2.352  3.209 '  5.736  10.560 12. 698 7.608 8.472 12.504  Deer  9.77  •  1  O.23O 100. 0  .  • •-  --  1.32 O.75  0.032 0.157 0.052 0.139 0.095  1.67 1.61  0.035 0.046 0.090 0.130 0.176 0.204  0.664 0.550  0. 010 0.011 0.012 0.013 0.011 0.009  1.27 0. 56 O.34  0.097 0.047 0.043  5.68 0.432 2. 92 0.247 4.94 0.618  0.275 0.306 0.451  0.016 0.009 0.223  O.97 2.73  O.55 ^7.51  0.018 0.431  77.2  2.477  6.00 2.12  0.634 0.269  75.3 77.1  7.9529-790  2.01 2.08  0.153 0.176  91.0 6.923 94.4 7.98S 88.2 11.029  1  •I  •' \  / .  '  I.48 1.43 1-57  0.653 0.782 0.735  TABLE  X.  Date  i960 July Aug.  21/22 3/4 16/17 30/31 Sept 1/2 14/15 22/23 Oct. 19/20 Nov. 3 0 Dec. 1 1961 Jan. 11/11 11/12 12/12 12/13 13/13 13/14  Nitrogen Excretion  During  Weight Volume Age i n Kg. of in Urine Days in cc. (appr.)"  R-l: 30 45 55 70 70 $5 90 120  1:1  9.8 12.5  I5o0 20.0  165 204 •»  89.5 II  it  II ,  11  II •  11  II  Growth  T ime Int e r ;val Taken for Trial (hours)  Total Nitrogen Excreted in Urine Gr./dy  Female B l a c k - t a i l e d 2.112 5.232 7.128 3.600  576 372 285  21 18 18 18.5 18 18.6 18 16.5  5^808 3.384 12.936  588  -riT6  6 . ,768  420 020  12 12 12 24 12 12  370 379 620 ,718  820  84O  Ammonia Nitrogen %T. N. T o t a l i n Gr,  io.i4.88 16.608 17.544 17.424 15.936 20.328  Urea Nitrogen Total i n Gr,  Creatinine Cr e a t i n e Nitrogen Nitrogen Total J6T.N. T o t a l i n Gr, i n Gr.  Total Nitrogen Expressed as N./Kg./dy  Creatinine .., N i t r o g e n Expressed as '• N./Kg./dy  Deer  1.55 3.36 9.70 18.4 5.69 9.83 19.03 5-59 1.20"^ 0.87 1.21 0.38 0.99 -0.92 0.32  0.033 0.176 0.691 0.662  65.8 75.2 88.4  1^89 3- 934 6.508 3.182  0.571 0.644 0.723  68.3  3.967  0.081  90.5  6.125  0.091 0 . 201 0.067 0.172 0.147 0.077  91.7  9.617  8l?6  16.588  0.092 0.105 0.115 0.064  0.289 0.608 0.727 0.288  0.126 0:012 0.012 0.005  0.100 0.233 0.228  0.3S7  0.007  0.420  4.37 2.01 1.62 1.79 2.39 1.72 6.88 1.76  6.47  0.114  0 . 61 0.45  O.O57  0.064 0.075 0. 100  2.26 3.36 2.35  0.23 0.558 0.412  0. 00S 0.019 0.014  o~68  0.138  2.40 2 . 21  0.382 0.449  0.356 0.563 0.595 0.591 0.540 0.689  0.50 1.34 0.96 0.50 1.34  6. o i l 0.070 0.068 0.018  3 . 25  0.100  0.013 0. 015  TABLE X I . Date  I960 J u l y 28/29 Aug. 9/10 19/20 S e p t . 7/8 Oct. 13/14" 24/25 26/27 . 27/28 Dec. 1 2 / 1 2 12/13 13/14 14/14 14/15 i960 July Aug.  25/26 8/9 18/19 21/22 S e p t . 1/2 19/20 ;  Nitrogen  Excretion  During  Weight Volume Age i n Kg. in of Ur i n e Days in cc. (appr. )  R-5:  42 ll  8.9  10. 2 12.7  115  130 175 11 ti »•  22. 7 22:7 29.0 11  11  11 .  11  »i  35  7.5  60 65  10. 1 10.8 13.0  70 90  2  428  80  125 11  41  Time Total Int e r - N i t r o g e n Excreted val in Urine Taken Gr./dy for Trial (hour s)  Female  440  Black-tailed  20.5  19.8 19.8.  19.6 24 12 12 12 12 12 24 12 12  647 1, 260 884 676 706 680 1,280 1, 260 420 680 R-12: Female 650 820 491 778 791 847  Growth  20 16 18 18  19 19  5.6AO 7.464 7.776 6.312 13.142 18. 120 12.816 16.680 16. 704. 16. 242  Urea Ammonia Nitrogen Ni t r o g e n /oT.N. T o t a l %T. N. T o t a l i n Gr. i n Gr,  4. 6 l 1. 56  0.344 0.121  O.59 1.68 1.95 1.71 0.61  0,. 078 0.304 0. 250 0. 285 0.101  84.7 91, 2 97.4  4- 777 6.807 7.574  9.6.5, 95-9 98.3 95.7 97-8 97.5  1.19 1. 03 0. 01 0.28 I  12. 603 17.812 12. 265 16.313 16.286  0.067 0.077 0. 008  o»oi8  2. 29 2.28 O.98  2. 17  0.013 0.170 0.076  Great inine Nitrogen Expr essed as N./Kg./dy  0.637 0. 7 3 2 0.612  0.015 0.017 0. 006  O.565 O.565 0.735 0.576 O.560 0.372 O.714  0.013 0.013 0.015 0.009 0. 010 0. 021  0.137  o i 11  0.014  3.42  0*84 0.36 0.49  0.108 0.060 0.079  2~2S I.83 2. 73  0.64 0. 25  0.067 0.052  O.305 0.444 0. 260  2.75 2.-92  O.-289  1.46  0.087  2. 19  0.013  0.449  0.292  0.-604  Deer  7.032 6. 072  1.13  4-152  3.83 9.86  6. 600  Creat inine Total Nitrosen Ni t r o g e n J6T.N. T o t a l Expressed i n Gr, as N./Kg./dy  Deer  10.496 20. 692 Black-tailed  Creatine Nitrogen Total i n Gr,  5.91  44--3  2. 590  78.4  1.045 2. 080  46.3  0. 112  O.938  0.411 0.508.  0. 203  F i g . 1.  C o u r s e % f nitrogen balance obtained.-.on R-5 i n T r i a l I I .  + 20  -30 I  1  0  '  '  1  •  2  1  3 24  F i g . 2.  4 HOUR  1  •  «  '  5 6 7 8 PERIODS IN CALORIMETER  '  '  <-  9 1 1 ) 1 1  Course of nitrogen.; balance obtained on R-5 i n T r i a l I I I .  FASTING  Fig.  DAYS  5.  DAYS  ON  Changes"i~n  FEED  nitrogen  p e r ..cent" t o t a l of  fasting  .-.shown  in  FASTING  and  the  distribution  riit"rogerrcyf of  lower  DAYS  urea,  FASTING  during  the  ammonia,  balance  and  hand  corner.  trials,  creatinine  feedingv--'-The-amouti-t-ef^g^isi^rble right  DAYS  .  ..  DAYS  ON  showing  nitrogen,  nitrogen  FEED  the  changes  during  intake,  in  FASTING  DAYS  in  -periods—-----— grams,  is  /  22  • 5  i 10  i  BODY  _  15 " "~ WEIGHT IN  L_  20 KILOGRAMS  1—; 25  _.Fig..'.J8.._.The^c_h.gng.e i n r a t e o f i n c r e a s e i n m a g n i t u d e o f t o t a l n i t r o g e n w i t h i n c r e a s e i n b o d y s i z e , i n -grossing b l a c k - t a i l e d d e e r .  1  :  30  . — excretion  L_  35  F i g . ;• 10.  The cumulative change i n total nitrogen excretion with increase i n age, i n growing male b l a c k - t a i l e d deer. * .  %  1.00  Q  Fig. H i the curtailative change in total creatinine excretion with increase in body size, la-growing blackmailed deer.  - 122 Conclusion  The  crude p r o t e i n requirement  c a l c u l a t e d , o n the for to  the be  b a s i s of the  endogenous l e v e l  approximately  25  most a c c u r a t e e s t i m a t e for  of  of  a p r o t e i n of p e r f e c t  digestibility,  experimental  total  grams.  This value  biological  a 100  comparative  a male of  interest.  The  crude p r o t e i n  of n i t r o g e n balance This  latter  protein  i s taken  ideal  the  p o u n d doe the  the r e s u l t s  are based  85  per  the  cent  species.  and,  The  therefore,  s p e c i e s w o u l d be  requirement  based  on  of  the p o i n t  requirement.  as a r e p r e s e n t a t i v e v a l u e f o r  nutritional  there are  s t a t u s w i t h r e g a r d to  limitations  to the n i t r o g e n  ments on  nitrogen require-  a r e of c o n s i d e r a b l e v a l u e because  on d i r e c t  i n an  experimental  animal.  t h e c h a r a c t e r o f n i t r o g e n m e t a b o l i s m on  as t h e one  used  in this  significance  because they  gen  associated with  turnover  they  measurements o f t h e c h a r a c t e r and  n i t r o g e n metabolism  such  as  requirement,  v a l u e and  b a l a n c e method a s a method o f d e t e r m i n i n g  of  obtained  nutrition.  Although  ments,  been  i s taken  i n d i c a t e s a much l a r g e r  estimate  the maintenance of  value  t h e minimum p r o t e i n  v a l u e s were o b t a i n e d on  has  urinary nitrogen excretion  f o r a r e p r e s e n t a t i v e of  v a l u e s from  o f R-5  experiment  are r e l a t e d an a n i m a l  are of  to the  extent  Measurean  animal  particular  extent  which has  of  nitro-  a l a r g e amount  - 123 of p r o t e i n r e s e r v e s .  They a r e i n d i c a t i v e o f t h e e x t e n t , a n d  character  intake  of n i t r o g e n  of p r o t e i n n u t r i t i o n a l requirement of  animal under Therefore, obtained under  status  may be s t a t e d  similarity  required  i n a s i m i l a r animal.  consideration,  from  experiments  inprinciple  i n this  these r e s u l t s to range animals,  on  adult  animals,  The conditions  obtained  t o be  associated  The same a p p l i c a t i o n  as d i s c u s s e d  measurement o f n i t r o g e n and of m e t a b o l i c  i n providing  in field  understood.  above f o r t r i a l s  i s theoretically possible.  o f growth,  t o be o f v a l u e  experiment,  requirements  o f growth.  of  i sproperly  e x c r e t i o n made d u r i n g t h e  i n d i c a t i v e of the nature of nitrogen t h e r a t e and c h a r a c t e r  one t o a n i m a l s  t h e r e l a t i o n s h i p between t h e  a n d t h e game a n i m a l s  growing p e r i o d have been found,  established.  to extend t h e r e s u l t s  such as t h e p r e s e n t  Measurements o f n i t r o g e n  with  This  animal, and t h e second  h a s been t h o r o u g h l y  range c o n d i t i o n s , , p r o v i d e d animal  plane  i n q u a n t i t a t i v e terms once t h e d e g r e e  between t h e e x p e r i m e n t a l  i t i spossible  experimental  to produce a high  studies,  significance of f i e l d  e x c r e t i o n under rate,  complementary f o r the greater  conditions  varying  c a n t h u s be s e e n  information  to that  understanding of the  i n terms o f t h e s u c c e s s f u l  management o f game a n i m a l s .  i  - 124 Appendix I F o r m u l a t i o n f o r U n i v e r s i t y of B r i t i s h Beer Weaning R a t i o n . No. 36-S-6Q.  Const i t u e n t G r o u n d No. 5 f e e d wheat Ground oat g r o a t s G r o u n d wheat b r a n Ground y e l l o w c o r n F i s h meal (70%) herring S o y b e a n meal (50%) S k i m m i l k powder ( s p r a y ) Dehydrated grass Dicalcium phosphate Iodized salt S t a b i l i z e d animal f a t Vitamin pre-mix  Pounds per ton  Pounds p e r 100  660 260 200 200 200 100 200 100 10 15 50 : 5 2, 000  33-00 13.00 10. 00 10. 00 10. 00 5.00 1.0.00 • 5.00 0.50 0.75 2. 50" 0.25 100.00  F o r m u l a t i o n f o r U n i v e r s i t y of B r i t i s h A d u l t R a t i o n f o r Deer. No. 36-57-  Constituent Ground y e l l o w c o r n G r o u n d No. 5 f e e d wheat G r o u n d wheat b r a n Molasses (cane) Ground beet p u l p D e h y d r a t e d g r a s s meal S o y b e a n meal (50%) F i s h meal (70%) herring Steamed bone meal Iodized salt  Columbia  Columbia  Pounds per ton  Pounds p e r 100  600 250 275 150 200 200 175 110 20 20 2,000  30.00 12. 50 13.75 7.50 10.00 10. 00 8.75 5.50 1. 00 1.00 100.00  - 125 Appendix  II  Ammo n i a f o rmat i o n  The amino ary al  ammonia. tract  /  i  a c i d s s e r v e as t h e s o u r c e o f b l o o d and  T h e p r o d u c t i o n o f ammonia w i t h i n t h e g a s t r o i n t e s t i n -  by.the  a c t i o n of i n t e s t i n a l  b a c t e r i a on n i t r o g e n o u s  s t a n c e s a c c o u n t s \ f o r t h e h i g h ammonia c o n t e n t blood.  The k i d n e y a l s o p r o d u c e s  blood of the r e n a l in  the l i v e r  of  amino  vein.  a c i d s n o t t a k e n up  However,  f r a c t i o n depending in protein  a small remainder  duced by t h e k i d n e y This process fixed  base,  tubule c e l l s  i s an i m p o r t a n t  o f amino  acids  upon t h e s u r p l u s  synthesis.  Most o f  this  a s shown i n A p p e n -  and a n i m p o r t a n t  i s excreted into  portion  pro-  the urine.  mechanism f o r t h e c o n s e r v a t i o n o f  s e e below.  Glutamine ammonia f r o m  of the p o r t a l  Oxidative deamination  ad.ds a f u r t h e r  sub-  ammonia and adds i t t o t h e  ammonia i s c o n v e r t e d t o u r e a w i t h i n t h e l i v e r d i x LTX  urin-  i s t h e most  d e a m i n a t i o n , as  . cHi.  _J  important  s»  cH^  coow i s shown b e l o w o f t h e mechanism f o r t h e  e l i m i n a t i o n o f h y d r o g e n i o n s by c o m b i n a t i o n the tubule c e l l  source of  follows:  C O O H  A diagram  amino a c i d  or i n the t u b u l a r  filtrate.  w i t h ammonia w i t h i n  - 126 -  BLOOD  H  COa.  No?"  +• or- ftnuiJo PS-IBS  —> N B j  '  TUI3V1-E'  -  \  CEi-L.  -  _.  -v-  CL*  • •  -  -  127  Appendix I I I .  A of u r e a into  schematic  i s shown on  the  s e r i e s of  a t i o n o f u r e a by  the of  of  a  most  r e t u r n of to  the  i s necessary cycle.  s e r i e s of  which  acid cycle.  This  aspartic  the  arginine-ornithine  acts  as  three  a transfer  other  agent  amino a c i d s  arginine,  is  formed  i n two  is  r e a d i l y a v a i l a b l e by the  citric  Ornithine  and  f o r m a t i o n of succinic  ric  i s the  enable  i t to  the  ornithine  con-  catalytic  with  arginine,  carbamyl  carbamyl  group  group.  There  connected with urea  and  the  a s p a r t i c a c i d molecule  carbamyl  citrulline.  acid cycle,  citrulline urea.  The  enters  the  and  i s also  acid  f o r m a t i o n of  arginine  splitting  oxaloacetic  o f f of  acid cycle,  during from  the  acid  actual  arginino-  fumaric  cycle.  It  ornithine.  thus l i n k i n g  arginine-ornithine  thus  formation.  Aspartic  formed from  a r i s e from a r g i n i n e  citric  a c i d c y c l e w i t h the  t r a n s a m i n a t i o n of  to  are  ways i n a s s o c i a t i o n w i t h u r e a f o r m a t i o n . the  car-  segment  f o r m a t i o n of  the  form-  formation  integration with a  entrance of  directly  enter  cycle  integration provides a  The  the  a c t i v a t i o n of  connected with urea  f o r the  a c i d r e s u l t s i n the  which then  an  c y c l e , where i t r e a c t s the  to  enters  p h o s p h a t e to f o r m  arginine-ornithine  cycle.  These are  from  to  acid, formed d u r i n g  b e g i n n i n g of  formation  B l o o d ammonia  and  i n order The  of  bodily  which l e a d u l t i m a t e l y  reactions  phosphate to f a c i l i t a t e the  the  This process represents  important  citric  of  f o l l o w i n g page.  reactions  arginine-ornithine sists  the  combining with  bamyl p h o s p h a t e . ammonia w h i c h  representation  acid the  cit-  - 128 -  i i o  CC  or  7.  2 it o  F x  c  s- <c~  rl  3r  Oil-  ul X  •Z  i l l  2-  0 J  X  of CL  - 129 Appendix I V . Creatinine  and  Creatine  Formation  i  riw - c CH-i  C = COOH C,iif .rJiOoP>tcT>c :,  H  C-NHv C O O H  — <CH  s^  3  1  Livers  HM  -  C  SJ - e - c = o  OftSYrTINtiNJe  The  f o r m a t i o n of c r e a t i n i n e  schematically acid  above.'  by t h e r e m o v a l  Creatinine  for  it  to the t i s s u e s .  the purpose  facilitate  of h i g h  and  Creatine bond  group.  storage,  This  lost  action  t h u s formed  and  creatine  i s of v a l u e t o t h e t i s s u e s  is outlined  guanidoacetic  i s produced  Because  p r o d u c t , i t i s n o t as e a s i l y  creatinine.  from  the c r e a t i n i n e  energy  energy metabolism.  i s formed,  a waste  and  creatine  i s formed  o f a. s i n g l e m e t h y l  takes place' i n the l i v e r transported  and  is  i n the  tissues  therefore remains  rather  to  where  than b e i n g  to the u r i n e  as  -  A p p e n d i x V.  experimental  fecal  screen  floor  of  the  the  animal  being  and  is  while  shown  animals urine  cage,  prepared.  respiration  -  of  the  Large Appar at i  Above  the  130  at  a  sketch  during  tray A.  front  The  entire  calorimeter,  were  The  the  the  of  the  cage  outlined  metabolic  placed  doors  on  on  shown  placed page  used  to  restrain  t r i a l s .  tracks  could.be  cage,, was  cage  below  shut  to  on  page  within 132a.  The  a  I  .[ j.  '  [  the  restrain  f !  1 3 2 was large  .'  - 131 -  i  RESTRAINING  ftiSES "THIS  uJEUU  TViC THe-  lis/ WHEW  CAC,e II IN c f t u o d i A I sr-nrR.  Fee-j>  TRAY  ( P f t S S C S OUT T W A O « H  O F t-\ND  THE  R O N T ON  The  front  fastened t  supplies  to  end o f  the cage,  water  CASTORS  SV'tK ' GACK  and feed  to  T H E -  C O N N E C T S  shown  above,  130, d u r i n g metabolic the animal  ad.  " T S  wPTeaTU<j  L(=<Ssr  is  u r t U .  CAU0fiime'"T4i"R  ^\QuNT-f?t>  t h e a.nimal-ca/ge page  t  T H E  t r i a l s  libitum.  The  above  sketch  respiration  calorimeter.  calorimeter  on  indicated.  The  to are  the  water  adjusted  renewed.  castors water  supply such  as  that  is  that  of  an.outline  The  cage  is  moved  which hose  run  from  indicated as  the  on the at  animal  the cage A.  into  wooden is The  drinks,  of  the  the  planks  then  attached  levels the  so.  of  supply  water is  -  133  AppendiX-_YJ,.  90 . 8 0  70  : .60 . 5,0 40 7. TRANSMITTANCE  30 20 AT- 520  10  -  134 -  Bitaliography  A l b a n e s e , A.A.  1959  P r o t e i n a n d Amino A c i d N u t r i t i o n . A c a d e m i c P r e s s , New Y o r k .  A l l i s o n , J.B.  1951  I n t e r p r e t a t i o n of Nitrogen Balance Data. Fed. P r o c , 1 0 : 6 7 6 - 6 8 2 .  A n n i s o n , E.F. , and. D. L e w i s .  1959  M e t a b o l i s m i n t h e Rumen. & Co. L t d . , London.  Bandy, P . J . , I.McT. Cowan, W.D. K i t t s , and A . J . Wood.  1956  A Method f o r t h e Assessment o f t h e N u t r i t i o n a l S t a t u s o f W i l d Ungulates. Can. J o u r , o f Z o o l . , 3 4 ' 48-52.  Beaumont, W.  1833  E x p e r i m e n t s a n d O b s e r v a t i o n s on the G a s t r i c J u i c e and t h e P h y s i o l o g y o f D i g e s t i o n . F.P. A l l e n , Plattsburg.  Bissell,  1952  N u t r i t i o n a l S t u d i e s on C a l i f o r n i a B i g Game. 32nd P r o c . An. C o n f . W e s t e r n A s s o c . S t a t e F i s h a n d Game C o m m i s s i o n e r s , pp. I 7 8 - I 8 4 .  B i s s e l l , H.D., a n d H. S t r o n g .  1955  The C r u d e P r o t e i n V a r i a t i o n s i n t h e Browse D i e t o f C a l i f o r n i a Deer. C a l i f . F i s h a n d Game, 4 1 : 1 4 5 - 1 5 5 -  B i s s e l l , JI.D., B. H a r r i s , H . Strong, and. F. James.  1955  The D i g e s t i b i l i t y o f C e r t a i n N a t u r a l a n d A r t i f i c i a l F o o d s E a t e n by Deer i n C a l i f o r n i a . C a l i f . F i s h and Game, 4 1 : 5 7 - 5 8 .  B l a i s d e l l , J.P. and W.-F.;;Muegger.  1956  S p r o u t i n g o f B i t t e r b r u s h (Pur sh i a t r i d e n t a t a ) Following Burning or Top R e m o v a l : I n f l u e n c e d by b o t h G e n e t i c and E n v i r o n m e n t a l F a c t o r s . Ecol., 37: 367-370.  B l a x t e r , K.L. a n d H.H. M i t c h e l l .  1948  The F a c t o r i z a t i o n o f t h e P r o t e i n Requirements o f Ruminants and o f the P r o t e i n Values o f Feeds, w i t h P a r t i c u l a r Reference to t h e S i g nificance of the Metabolic Fecal Nitrogen. J o u r . A n i m a l S c i . , Ji 351-369.  H.D.  Methuen  -  135 -  B l a x t e r , K.L., and W.A. Wood.  1951  The N u t r i t i o n of the A y r s h i r e C a l f . Br. Jour, of Nut., 5 : 1 1 - 2 5 .  Block, R.J.  I956  P r o t e i n Requirements of Animals I n c l u d i n g Man. Borden's Review of N u t r i t i o n a l Res., 1 ? : 7 5 - 9 6 .  Block, R.J., and R. Schoenheimer.  I94I  The B i o l o g i c a l Precursor of Creatinine. Jour. B i o l . Chem., 1 3 8 : 167-I94.  Borsook, H., and G. K e i g h l e y .  1935  The C o n t i n u i n g Metabolism of N i trogen i n Animals. Proc. of t h e Royal Soc. of London, B l l 8 : 4 8 8 521.  Bourne, G.  1953  B i o c h e m i s t r y and P h y s i o l o g y of Nutrition. Academic Press, New York.  1945  The P r o t e i n Requirements of Adult Human Subjects i n Terms of the P r o t e i n Contained i n I n d i v i d u a l Foods and Food Combinations. Jour, of Nut., 3 0 : 269-28.3.  B r i c k e r , M. , II.H. M i tch.e 11,;  Kinsman.  and  G.M.  B r i n k e r k i n k , P.C.  I96I  Determination of C r e a t i n e i n Urine. C l i n . Chem. Acta., 6 : 5 3 1 - 5 3 7 -  Brody, S.  1945  B i o e n e r g e t i c s and Growth. Reinh o l d Publ. Corp., New York.  Burroughs, E.W., H.S.. I94O Burroughs, and H.H. Mitchell.  The Independence of t h e Endogenous and Exogenous Metabolism of N i t r o gen. Jour, of Nut., 1 9 : 2 7 1 - 2 8 3 .  Butcher, J.E., and L.E. H a r r i s .  1957  C r e a t i n i n e as an Index M a t e r i a l f o r E v a l u a t i o n of Ruminant N u t r i tion. Jour. Animal S c i . , 1 6 : 1020.  Catherwood, S., and G. Stearns.  1937  C r e a t i n e and C r e a t i n i n e E x c r e t i o n i n Infancy. Jour. B i o l . Chem., 119: 201-214.  I955  I n t r o d u c t i o n to P a r a s i t o l o g y . 9 ed., John Wiley & Sons, Inc., New York.  Chandler,  A.C.  t  n  Chittenden,  R.H..  Cohneim, 0.  136  -  1907  The N u t r i t i o n o f Man. & Co., New Y o r k .  1901  D i e Unwandlung des E i w e i s s D u r c h Darmwand. Z. P h y s i o l . Chem., 33: 451-456.  F.A.  Stokes  I95I  M e t a b o l i c Methods. St. L o u i s .  Conway, M.  1950  M i c r o d i f f u s i o n A n a l y s i s and V o l u metric Error. C. Lockwood, London.  Cook, CW. , L.A. Stoddard, and L.E. H a r r i s .  1954  The N u t r i t i v e V a l u e o f W i n t e r Range P l a n t s i n t h e G r e a t B a s i n as D e t e r mined w i t h D i g e s t i b i l i t y T r i a l s w i t h Sheep. B u l l . 372. U t a h S t a . A g r i c . C o l . A g r i c . Exp. S t a .  I945  The E c o l o g i c a l R e l a t i o n s h i p s o f t h e Food of the Columbian B l a c k - t a i l e d Deer 0. Hemionus c o l u m b i a n u s , (Richardson), i n the Coast F o r e s t Region of Southern Vancouver I s l a n d , B.C. E c o l . Monographs, 15  Consolazio,  F.  Cowan, I.McT.  C.V.  Mosby  Co.,  1  III-I39.  Cowan, I.McT., and A . J . Wood  1955  The Growth R a t e o f t h e B l a c k t a i l e d Deer (0. Hemionus c o l u m b j a -  nus).  J o u r . W i l d l . Mgt.,  19:  331-  33S. Cowan, I.McT., W.S. Hoar, and J . H a t t e r  1950  The E f f e c t o f F o r e s t S u c c e s s i o n u p o n t h e Q u a n t i t y and upon t h e N u t r i t i v e V a l u e o f Woody P l a n t s u s e d as F o o d by Moose. Can. J o u r . Res., 28: 249-271.  Darke,  i960  The C u t a n e o u s L o s s o f N i t r o g e n i n African Adults. B r i t . Jour, of Nut., 14: I I 5 - I I 9 .  S.J.  Darlington, Dietz,  D.  P.S.  I957 1958  Zoogeography. John Wiley I n c . , New Y o r k .  &  Sons,  S e a s o n a l P r o g r e s s i o n i n t h e Chemic a l C o n t e n t o f F i v e Key Browse Species i n Colorado. P r o c . Soc. o f Amer. F o r e s t e r s , U t a h .  -  137  -  D i n i n g , J.S. , W. D. G a l l u p , and. H . M . -Briggs.  I949  E x c r e t i o n o f C r e a t i n i n e and Creat i n e by B e e f S t e e r s . Jour. B i o l . Chem., 1 7 7 : I57-I6I.  Einarsen,  I946  Crude P r o t e i n D e t e r m i n a t i o n s of Deer F o o d a s a n A p p l i e d Management T e c h n i q u e . T r a n s . N. Amer. W i l d l . Conf., 1 1 : 3 0 9 - 3 1 2 .  1935  Animal Ecology. w i c k •& J a c k s o n ,  1914  Chemistry of the Proteins. Man, London.  1905  A Theory of P r o t e i n Metabolism. Amer. J o u r , o f P h y s i o l . , 1 3 ' H7138.  I94I  The D i g e s t i v e C a p a c i t i e s o f t h e W h i t e - t a i l e d Deer. Jour, of W i l d l . Mgt., 5 : 1 0 8 - 1 1 4 .  F o r b e s , E.B. , B.F. E l l i o t , H.W. Swift, W.H. James, a n d V . F . Smith.  I946  V a r i a t i o n s i n Determinations of the D i g e s t i v e C a p a c i t y o f Sheep. Jour. Animal S c i . , 5 : 2 9 8 - 3 0 5 .  F r e n c h , C.E., a n d L.C. McEwen.  1955  N u t r i t i v e Requirements of Whitey t a i l e d Deer f o r Growth and A n t l e r Development. B u l l . 6 0 0 . Penn. S t a t e U n i v e r s i t y ( C o l . o f A g r i c . ),  Fulton,  I946  Howell's Textbook of Physiology. W.B. S a u n d e r s Co., P h i l a d e l p h i a and London.  Gordon, A., and A.W. Sampson.  1939  C o m p o s i t i o n o f Common C a l i f o r n i a F o o t h i l l P l a n t s as a Factor i n Range Management. Cal. Agric. Exp. S t a . B u l l . 6 7 6 .  Gorham,  J.  1821  A n a l y s i s of I n d i a n Corn. Annals of Philosophy, 17:  G r e a v e s , J.P., a n d P.P. S c o t t .  i960  N u t r i t i o n of the Cat. o f Nut., 1 4 : 3 6 1 - 3 6 9 .  Elton,  C.  Fischer, Folin,  Forbes,  L.F.  A.S.  E.  0.  E. B.,  and  Marcy.  J.F.  Rev. ed., S i d g L t d . , London. G.  The 470.  Brit.  Jour,  de  G r o o t , T. , a n d J . H. A a f j e s .  i960  138 On t h e C o n s t a n c y o f C r e a t i n i n e Excretion i n the Urine of the D a i r y Cow. B r i t . V e t . Jour.,  116:  Guyton, A.C.  I956  409-418.  Textbook of Medical Physiology. W.B. S a u n d e r s Co., P h i l a d e l p h i a and London.  H a r d i n g , V.J., and O.H. G a e b l e r .  1922  On and ren of  H a r p e r , H.A.  1961  Review o f P h y s i o l o g i c a l C h e m i s t r y . 8 t h ed., L a n g e M e d i c a l Publishers, Los A l t o s , C a l i f o r n i a .  Hawk, P.B., B.L. O s e r , and W.H. Slimmer son.  1954  P r a c t i c a l P h y s i o l o g i c a l Chemistry. The B l a c k i s t o n Co., New Y o r k .  E l Hehyami, M .  1958  Studies on t h e Metabolism of Creat i n e a n d C r e a t i n i n e i n t h e Dog. I. U r i n a r y E x c r e t i o n i n A n i m a l s under Different Experimental Conditions. B r i t . V e t . Jour., 114: 4 8 O - 4 8 3 .  H o l m g r e e n , B.C.  1956  Compit i t i o n between A n n u a l s a n d Young B i t t e r b r u s h ( P u r s h i a t r i d e n t at a) i n Idaho. E c o l . , 37*  the Constancy of t h e C r e a t i n e Creatinine Excretion i n Childon a H i g h P r o t e i n D i e t . Jour, B i o l . Chem., 54* 5 7 9 - 5 8 7 -  370-377.. Ho up t ,  T.B.  I959  U t i l i z a t i o n o f B l o o d U r e a i n Ruminants. Amer. J o u r , o f P h y s i o l . ,  197:  H u b b a r d , K.L.  1957  H u t c h i n s o n , J.C.D. a n d 1936 S.M. M o r r i s  115-120.  The E f f e c t o f P l a n t C o m p e t i t i o n on t h e Growth a n d S u r v i v a l o f Bitterbrush Seedlings. Jour, o f W i l d l . Mgt., 1 0 : 1 3 5 - 1 3 7 The D i g e s t i b i l i t y o f D i e t a r y P r o t e i n i n t h e Ruminant. I . Endogenous N i t r o g e n E x c r e t i o n o n a Low N i t r o g e n D i e t a n d i n S t a r v a tion. Biochem. J o u r . , 3 ° : 1 6 8 2 -  1693.  -  139 -  H u t c h i n s o n , J.D.C., and S.M. M o r r i s .  1936  The D i g e s t i b i l i t y o f D i e t a r y P r o t e i n i n t h e Ruminant. I I . T h e D i g e s t i b i l i t y of Protein Following a Prolonged Fast, with a Detailed Study of t h e N i t r o g e n Metabolism. Bioch. Jour., 3 0 : 1 6 9 5 - 1 7 0 4 .  Kinney,  1959  I n f l u e n c e o f I n t e r m e d i a r y Metabo l i s m on N i t r o g e n B a l a n c e a n d ¥/eight L o s s : Some C o n s i d e r a t i o n s B a s i c t o an U n d e r s t a n d i n g o f I n j u r y . Metabolism, 8 : 8 0 9 - 8 2 6 .  K i t t s , W.D. , P . J . Bandy, A . J . Wood, and I.McT. Cowan.  1956  E f f e c t o f Age a n d P l a n e o f N u t r i t i o n on the Blood Chemistry of the C o l u m b i a n B l a c k - t a i l e d Deer ( 0 . h e m i o n u s columbianus).., / Can. J o u r , o f 2ool., 34:477-484.  Klieber,  1932  Body S i z e a n d M e t a b o l i s m . 6: 315-353.  K o s s e l , A., a n d F Kutscher.  1900  B e i t r a g e zur K e n n t n i s s d e r E i w e i s s korper. 2 . f u r P h y s i o l . Chem., 3 1 " 165-214.  K r o g h , A.  1906  E x p e r i m e n t a l R e s e a r c h e s on t h e E x p i r a t i o n o f F r e e N i t r o g e n from t h e Body. Skand. A r c h . P h y s . , 1 1 8 : 364-420.  K u t s c h e r , F., a n d J . Seeman.  1902  'Zur K e n n t n i s s d e r V e r d a u u n g s v o r gange i n Dunndarn. I . Z. f u r P h y s i o l . Chem., 3 4 : 5 2 8 - 5 4 3 .  Lauckhart,  1957  Annual Wildl.  L e i t c h , I . , and J . Duckworth.  1937  The D e t e r m i n a t i o n o f t h e P r o t e i n R e q u i r e m e n t s o f Man. Nut. A b s t r . & Revs., 7 : 2 5 7 - 2 6 7 .  L e o p o l d , A.S., T. R i l e y , R. M c C a i n , and L. T e v i s  1951  The Jawbone Deer H e r d . Game B u l l . , 5 : 1 - 1 3 9 -  Lewis,  1957  Blood. U r e a C o n c e n t r a t i o n i n R e l a t i o n to Protein U t i l i z a t i o n i n the Ruminant. Jour. A g r i c . S c i . , 4 8 : 438-446.  J.M.  D.  M.  J.B.  Hilgardia,  C y c l e s and Food. Jour. Mgt., 2 1 : . 2 3 0 - 2 3 3 .  Calif.  - 140 L i e b i g , L.  1843  Animal Chemistry. London.  Lusk,  I928  The E l e m e n t s o f t h e S c i e n c e o f Nutrition. W.B. S a u n d e r s Co., Philadelphia.  1931  C r e a t i n i n e E x c r e t i o n i n Abnormal S t a t e s of N u t r i t i o n . Amer. J o u r . Med. S c i . , 1 8 1 : 3 4 9 - 3 5 5 -  1939  T h e Newer K n o w l e d g e o f N u t r i t i o n . The M c M i l l a n Co., New Y o r k .  1942  N u t r i t i o n a n d C h e m i c a l Growth i n Childhood. V o l . I . C.C. Thomas, Springfield, Illinois.  Majumdar, B.N.  i960  S t u d i e s o n Goat Jour, of A g r i c .  Nutrition. I. S c i . , 54: 329-334.  Majumdar,  i960  S t u d i e s o n Goat Jour, o f A g r i c .  Nutrition. II. S c i . , 54: 335-340.  M a y n a r d , L.  I956  Animal N u t r i t i o n . M c G r a w - H i l l Bk. Co. I n c . , New Y o r k .  M e n d e l , L.B.  1923  N u t r i t i o n , The C h e m i s t r y o f L i f e . Y a l e U n i v e r s i t y P r e s s , New Haven.  Mitchell,  1924  A Method o f D e t e r m i n i n g t h e B i o l o g i cal Value of Protein. Jour. B i o l . Chem., 5 8 : 8 7 3 - 9 2 9 .  G.  M c C l u g g a g e , H. B. , G. B o o t h , a n d F.A. Evans. McCollum,  E.V.  Macy, I.G.  R.N.  H.H.  Mitchell, H . H .  Grey,  I 9 2 6  Mitchell, H . H .  Mitchell, H . H . , G. G. Carman.  William  The B i o l o g i c a l U t i l i z a t i o n o f P r o t e i n s and P r o t e i n Requirements. B u l l . N a t l . Res. C o u n c i l No. 5 5 .  and  I924  The B i o l o g i c a l V a l u e f o r M a i n t e n a n c e and Growth o f t h e P r o t e i n s o f Whole Wheat, Eggs a n d P o r k . Jour. B i o l . Chem.; 6 0 : 6 1 3 - 6 2 0 .  I948  The B i o l o g i c a l U t i l i z a t i o n o f P r o t e i n s and P r o t e i n Requirements, i n M. Sahyun, P r o t e i n s a n d Amino A c i d s in Nutrition. R e i n h o l d Publ. Corp., New Y o r k .  Morrison,  Mulder,  F.B.  G.  141  -  1956  Feeds and F e e d i n g . 2 2 n d ed.., M o r r i s o n P u b l . Co., I t h a c a , New Y o r k .  I838  Zusanimensel zung v o n F i b r i n , A l b u m i n , L e i m z u c k e r , L e u c i n v.s.w.; L i e b i g s A n n a l e n d e r Chemie, 2 8 : 7 3 - 8 2 . 1  Munro,  H.N.  1951  Carbohydrate and F a t as F a c t o r s i n P r o t e i n U t i l i z a t i o n ' and M e t a b o l i s m . P h y s i o l . Rev., 3 1 : 4 4 9 - 4 8 8 .  M u r l i n , J.R. ,~ L.E. Edwards, E . E . Hawley, and L.C. C l a r k .  I946  The B i o l o g i c a l V a l u e o f P r o t e i n s i n R e l a t i o n t o t h e Amino A c i d s w h i c h T h e y C o n t a i n . I . The Endogenous N i t r o g e n o f Man. J o u r . Nut., 3 1 : 533-554-  M u r l i n , J.R., L . E . Edwards, E . E . Hawley, and L.C. C l a r k .  I946  The B i o l o g i c a l Value of P r o t e i n s i n R e l a t i o n t o t h e Amino A c i d s w h i c h They C o n t a i n . I I . I n t e r c o n v e r t i b i l i t y of B i o l o g i c a l Value I l l u s t r a t e d b y S u p p l y i n g E g g and Soy P r o t e i n w i t h E s s e n t i a l Amino A c i d s . J o u r . Nut., 3 1 : 5 5 5 - 5 6 4 .  M y e r s , V.C., a n d M.S. F i n e .  1913  The C r e a t i n e C o n t e n t o f M u s c l e u n d e r Normal C o n d i t i o n s ; I t s Rel a t i o n to the U r i n a r y C r e a t i n i n e . J o u r . B i o l . Chem., 1 4 : 9 - 2 8 .  Nichol,  1938  E x p e r i m e n t a l F e e d i n g o f Deer. U n i v e r s i t y o f A r i z . Exp. S t a . T e c h . Bull., 75;- I - 3 9 .  Osborne, T.B., a n d L.B. M e n d e l .  1912  The R o l e o f G l i a d i n i n N u t r i t i o n . J o u r . B i o l . Chem., 1 2 : 4 7 3 - 5 1 0 .  O s b o r n e , T.B., a n d L.B. M e n d e l .  1915  The C o m p a r a t i v e N u t r i t i v e V a l u e o f C e r t a i n P r o t e i n s i n Growth, a n d t h e P r o b l e m o f t h e P r o t e i n Minimum. J o u r . B i o l . Chem., 2 0 : 3 5 1 - 3 9 0 .  O s b o r n e , T.B., L.B. Mendel, and E.L. Ferry.  1919  A Method o f E x p r e s s i n g N u m e r i c a l l y t h e Growth P r o m o t i n g V a l u e o f P r o teins. J o u r . B i o l . Chem., 3 7 2 2 3 229.  A.A.  :  -  142  -  P a l m e r , W.W. , J.H. 1914 Means, and J . L . Gambia  B a s a l M e t a b o l i s m and C r e a t i n i n e Elimination. J o u r . B i o l . Chem., 19: 239-244.  P h i 11 i p s o n ,  The The  i960  A.T.  N u t r i t i o n o f t h e Ruminant. V e t . Rec. , 7 2 : 6l3-6l6.  1955  The Amino A c i d R e q u i r e m e n t s o f Man. 15. V a l i n e Requirements: Summary and F i n a l O b s e r v a t i o n s . J o u r . B i o l . Chem., 2 1 7 : 989-995.  Rosen, M.N., and A. B i s c h o f f .  1952  The R e l a t i o n o f H e m a t o l o g y to C o n d i t i o n s i n C a l i f o r n i a Deer. T r a n s . N. Amer. W i l d l . C o n f . , 17: 482-496.  Sahyun, M.  1948  P r o t e i n s and Amino A c i d s i n Nutrition. R e i n h o l d P u b l . Corp., New Y o r k .  Rose, W.G., B.L. H.B". L o c k h a r t , G.F. Lambert.  Wixom, and  Schmidt-Nielsen,  B.  1957  U r e a E x c r e t i o n i n t h e Camel. Amer. J o u r , of P h y s i o l . , 1 8 8 : 477-484.  Schmidt-Nielsen, and H. O s a k i .  B.,  1958  R e n a l R e s p o n s e to Changes i n N i t r o gen M e t a b o l i s m i n Sheep. Amer. Jour, of P h y s i o l . , I 9 3 : 657-661.  S c h m i d t - N i e l s e n , B. , I958 H. O s a k i , H.V. Murdaugh, and R. O ' D e l l .  Renal R e g u l a t i o n of Urea E x c r e t i o n i n Sheep. Amer. J o u r , o f P h y s i o l . , 194: 221-228.  R.  1942  The Dynamic S t a t e o f Body C o n s t i t u ents. Harvard U n i v e r s i t y Press, C a m b r i d g e , Mass.  P.F.  1955  C o u n t e r - c u r r e n t V a s c u l a r Heat Exc h a n g e i n t h e F i n s o f Whales. Jour. Appl. P h y s i o l . , 3 : 2 7 9 - 2 8 2 .  Schoenheimer,  Scholander,  Smith,  A.D.  1950  S a g e b r u s h as a W i n t e r Feed, f o r Deer. J o u r , o f W i l d l . Mgt., 14: 285-289.  Smith,  A.D.  1952  D i g e s t i b i l i t y o f Some N a t i v e F o r a g e s f o r M u l e Deer. Jour, of W i l d l . Mgt., 16: 309-312.  - 143 1959  A d e q u a c y o f Some I m p o r t a n t Browse S p e c i e s i n O v e r w i n t e r i n g o f Mule Deer. J o u r , o f Range Mgt., 1 2 : 8 13.  Smuts, D.  1935  The R e l a t i o n b e t w e e n t h e B a s a l M e t a b o l i s m a n d t h e Endogenous N i t r o g e n Metabolism, w i t h R e f e r e n c e to t h e E s t i m a t i o n o f t h e M a i n t e n a n c e Requirement o f P r o t e i n . Jour, o f Nut., 9 : 4 0 3 -  Somers, M.  1961  Factors Influencing the Secretion o f N i t r o g e n i n Sheep S a l i v a . I. The D i s t r i b u t i o n o f N i t r o g e n i n t h e M i x e d a n d P a r o t i d S a l i v a o f Sheep. A u s t r a l i a n J o u r , o f Exp. B i o l , and Med. S c i . , 3 9 : 1 1 1 - 1 2 2 .  Somers, M.  I96I  Factors Influencing the Secretion o f N i t r o g e n i n Sheep S a l i v a . I I . The I n f l u e n c e o f N i t r o g e n I n t a k e upon B l o o d U r e a N i t r o g e n a n d u p o n the T o t a l N i t r o g e n and Urea N i t r o gen i n t h e P a r o t i d S a l i v a o f Sheep. A u s t r a l i a n J o u r , o f Exp. B i o l , a n d Med. S c i . , 3 9 : 1 2 3 - I 3 I .  Somers, M.  1961  Factors Influencing the Secretion o f N i t r o g e n i n Sheep S a l i v a . I I I . Factors Affecting the Nitrogen Fractions i n the Parotid S a l i v a of Sheep w i t h S p e c i a l R e f e r e n c e t o t h e I n f l u e n c e o f Ammonia P r o d u c t i o n i n t h e Rumen a n d F l u c t u a t i o n s i n L e v e l of B l o o d Urea. A u s t r a l i a n Jour, of Exp. B i o l , a n d Med. S c i . , 3 9 : 1 3 3 143.  Somers, M.  1961  Factors Influencing the Secretion o f N i t r o g e n i n Sheep S a l i v a . IV. The I n f l u e n c e o f I n j e c t e d U r e a o n the Q u a n t i t a t i v e Recovery o f Urea i n t h e P a r o t i d S a l i v a and t h e U r i n a r y S e c r e t i o n s o f Sheep. Austral i a n J o u r , o f Exp. B i o l , and Med.  Smith,  A.D.  Sci.,  3 9 : I45-I56.  - 144 Spector,  W.S.  1956  Handbook o f B i o l o g i c a l D a t a , Res. C o u n c i l . W.B. Saunders Philadelphia.  Spencer,  G.J.  I938  E c t o p a r a s i t e s o f Deer i n P r o c . E n t o m o l . Soc. B.C.,  Natl. Co.,  B.C. 35:  39-'  ,'45. S u l l i v a n , M.X., F. I r r e v e r r e .  and  1958  A Highly S p e c i f i c Test f o r Creatinine. J o u r . B i o l . Chem., 233s  530-534.  S v i h l a , A., H. Bowman, 1955 and R. P e a r s o n .  Blood P i c t u r e of the American B l a c k Bear ( U r s u s a m e r i c a n u s ) , J o u r . Mammo 1~ 3b: 134-I35*  Swank, W. G.  1956  P r o t e i n and P h o s p h o r u s C o n t e n t o f Browse P l a n t s a s an I n f l u e n c e on S o u t h w e s t e r n Deer H e r d L e v e l s . T r a n s . N. Amer. W i l d l . Con-f., 2 1 : I4I-I58.  Talbot,  N.B.  1936  B a s a l E n e r g y M e t a b o l i s m and C r e a t i n i n e i n t h e U r i n e . I. Observat i o n s on C h i l d r e n . Amer. J o u r . Dis. C h i l d r e n , 52: 16-24.  E.  I927  L o i Q u a n t i t a t i v e de l a Depense A z o t e e M i n i m a d e s Homeotherms Validite Interspecific. A r c h , de Internat. , P h y s i o l . 29: 121.  S.G.  1959  E s s e n t i a l Amino A c i d R e q u i r e m e n t s o f O l d e r Men i n R e l a t i o n t o T o t a l Nitrogen Intake. Metabolism, 8:  Terroine,  Tuttle,  61-72.  Vickery,  H.B.  1931  The H i s t o r y o f t h e D i s c o v e r y o f Amino A c i d s . Chem. Revs., 9 169:  318.  Wallace,  W.M.  1959  N i t r o g e n C o n t e n t o f t h e Body and I t s R e l a t i o n t o R e t e n t i o n and L o s s of Nitrogen. F e d e r a t i o n Proceedi n g s , 18: II25-II30.  - M-5 Waterlow, J.C., and V.G. Wills.  i960  -  Balance Studies i n Malnourished Jamaican I n f a n t s . I. A b s o r p t i o n and R e t e n t i o n o f N i t r o g e n a n d Phosphorus. B r i t . J o u r , o f Nut., 14: I83-I98.  W a t e r l o w , J . C. , V.G. i960 W i l l s , a n d P. G y o r g y .  Balance Studies i n Malnourished Jamaican I n f a n t s . I I . Comparison of A b s o r p t i o n and R e t e n t i o n o f N i t r o g e n a n d P h o s p h o r u s f r o m Human M i l k and a Cow's-milk M i x t u r e . B r i t . J o u r , o f - N u t . , 14: 199-206.  Waterlow, J . C . , V.G. W i l l s , a n d K. Standard.  1959  I n d i r e c t I n d i c a t o r s o f M u s c l e Mass in Malnourished Infants. Amer. J o u r , o f C l i n . Nut., 7: 2 7 I - 2 7 9 .  West, E.S. , a n d R.T. Todd.  1957  Textbook of Biochemistry. M c M i l l a n Co., New Y o r k .  Wood, A . J . , I.McT. I96I Cowan, a n d H. Nordan.  Wuthier,  P.O.  P.R.,  and  Stratton.  I957  The  The C a r e a n d Management o f W i l d Ungulates f o r E x p e r i m e n t a l Purposes.  J o u r , o f W i l d l . Mgt., 25: 295-302.  The C r e a t i n i n e L e v e l o f B l o o d S e rum a s a n I n d e x o f C a r c a s s C o m p o s i tion. J o u r . An. S c i . , 16: 9 6 I - 9 6 6 .  

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0105713/manifest

Comment

Related Items