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Factors affecting the utilisation of dietary energy Kese, Adu Gyamfi 1977

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FACTORS AFFECTING THE  UTILISATION  OF DIETARY ENERGY  by  ADU GYAMFI KESE  D . T . A . , U n i v e r s i t y o f S c i e n c e and T e c h n o l o g y ,  Kumasi,  Ghana,  1961  B.Sc,  University of  Rhode  Island,  Kingston,  R.I.,  U.S.A.,  1965  M.Sc,  U n i v e r s i t y o f Rhode  Island,  Kingston,  R.I.,  U.S.A.,  1967  A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE -REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY  in  THE  FACULTY OF GRADUATE  Department o f P o u l t r y  We a c c e p t t h i s  thesis  to the r e q u i r e d  as  STUDIES Science  conforming  standard  THE UNIVERSITY OF B R I T I S H COLUMBIA February,  1977  0 A d u Gyamfi K e s e ,  1977  In  presenting  this  thesis  an advanced degree at the L i b r a r y s h a l l I  f u r t h e r agree  for scholarly by h i s of  this  written  the U n i v e r s i t y  make  it  It  financial  gain s h a l l  Depa rtment  2075 Wesbrook Place Vancouver, Canada V6T 1W.5  Date  4  --4'- 7 7  for  Columbia,  Columbia  I agree  reference and this  that  not  copying or  for  that  study. thesis  by the Head of my Department  is understood  permission.  The U n i v e r s i t y of B r i t i s h  of B r i t i s h  the requirements  f o r e x t e n s i v e copying o f  purposes may be granted  for  fulfilment of  freely available  t h a t permission  representatives. thesis  in p a r t i a l  or  publication  be allowed without my  ABSTRACT  Seven d i f f e r e n t but i n t e g r a t e d e x p e r i m e n t s the f a c t o r s  were c o n d u c t e d  a f f e c t i n g the u t i l i s a t i o n o f d i e t a r y energy.  two e x p e r i m e n t s  involved feeding  either  or corn  corn o i l  a t two p r o t e i n l e v e l s . the high b i o l o g i c a l  starch  b r o i l e r chickens  as  value of  its  diets  the supplementary  H e r r i n g meal was  first  of  diets  energy  because  of  A l l d i e t s were c a l c u l a t e d  t o be i s o c a l o r i c a n d t o c o n t a i n t h e same b a l a n c e o f amino  acids;  minerals  for  and v i t a m i n s  study  containing  source  used i n a l l  protein.  The  to  w e r e a d d e d t o meet t h e r e q u i r e m e n t s  these  nutrients. Live weight calorie:protein starch diet  in  g a i n and t h e e f f i c i e n c y o f regime were not  isocaloric diets.  in promoting  i m p r o v e d when  The s u p e r i o r i t y  the highest  o f t h e c l a i m t h a t added d i e t a r y  effect.  Birds  fed the h i g h - f a t  that in evaluating  energy  and p r o t e i n  is  substituted  of the l o w - f a t  f a t has  for  high-protein  questions  the  an " e x t r a - c a l o r i c "  l o w - p r o t e i n d i e t w h i c h had a  r a t i o , d e p o s i t e d more a b d o m i n a l  cating  supplementary  f a t was  m e t a b o l i s a b i l i t y of energy,  validity  calorie:protein  food u t i l i s a t i o n w i t h i n  adipose  lower  tissue,  growth  performance,  the balance  of greater  significance  than  indi-  between  the source  of  energy.  Formulation  of  isocaloric diets  has  necessitated  the  inclusion  the s o - c a l l e d n u t r i t i o n a l l y - i n e r t i n g r e d i e n t s  s u c h as  the d i e t s  "extra-caloric effects"  used t o t e s t t h e main h y p o t h e s i s  attributable  to d i e t a r y  fat  of  cellulose.  of  incorporated c e l l u l o s e , the e f f e c t of  Since  the  iii  latter  on t h e p h y s i o l o g i c a l  high l e v e l s effects energy  of  inclusion  parameters  under study,  c e l l u l o s e depressed  m e t a b o l i s a b i l i t y were a l s o c e l l u l o s e which  abdominal  adipose  Results  is  evident.  posthatching.  studies  have shown s i g n i f i c a n t  residual  g r o w t h and e n e r g y  u t i l i s a t i o n as values,  did not i n f l u e n c e food conversion of the experimental period.  food conversion  efficiency resulting  found to o c c u r  residual  yolk  with residual  i n t h e f i r s t week  of  the groups mately  It  Absence  measured  However,  the  depression of  retaining yolk  yolk  without  compared t o  birds  posthatching.  as  and t h o s e w i t h o u t y o l k  sacs  the  evidenced  from food r e s u l t e d in the death of  sacs  first of  residual  was n o t e d t h a t b i r d s  i n t h e f i r s t week p o s t h a t c h i n g  abstinence  by  The  does n o t c o n t r i b u t e s i g n i f i c a n t l y towards  the chick  by t h e f a c t t h a t  influence  performance  e f f i c i e n c y in  r e t a i n e d a g r e a t e r amount o f n i t r o g e n yolk  three  respectively.  from the removal  i n t h e s e c o n d week.  The r e s i d u a l y o l k nourishment  w i t h i n the f i r s t  d i d not i n f l u e n c e the  and t h i r d weeks  was  efficiency of  c o n s i d e r e d and t e s t e d .  g a i n and m e t a b o l i s a b l e e n e r g y  yolk  decreased  differences  i n body w e i g h t g a i n ,  i n q u e s t i o n was  excised surgically,  on t h e b a s i s o f  body w e i g h t  that i t  The p o s s i b i l i t y t h a t t h e r e s i d u a l y o l k may  the m e t a b o l i c parameters  birds  Adverse  A n o t h e r e f f e c t o f .added  f o o d u t i l i s a t i o n and m e t a b o l i s a b i l i t y o f e n e r g y  of  gain.  tissue.  o f t h e above  sac,  At  e f f i c i e n c y and  particularly interesting is  among t h e d i f f e r e n t t r e a t m e n t g r o u p s  of the y o l k  tested.  body w e i g h t  o f a d d e d d i e t a r y c e l l u l o s e on f o o d c o n v e r s i o n  dietary  weeks  was  at  both approxi-  t h e same t i m e .  The p r e s e n c e o f a l a r g e  b a c t e r i a l p o p u l a t i o n i n the avian  caeca  1V  and e x t r a p o l a t i o n o f t h e f e a t u r e s symbiosis led  in ruminants  to speculation  proteolytic nutrient using  and o t h e r  animals  that the avian  functions.  The  associated  caeca  relevance  i n t a c t and c a e c e c t o m i z e d c h i c k e n s of  the domestic  study to  fed d i e t s  used i n  the p r e v i o u s  studies.  prompted  investigate  an  Metabolisable  isabi 1 i t y of the d i e t s .  experiment of  and  cockerels  energy  f o r measuring  were  values  and  dietary  Caecectomy d i d not a f f e c t the m e t a b o l -  Metabol i s a b i l i t y o f the d i e t  more v a r i a b l e and s l i g h t l y  U r i c a c i d e x c r e t i o n was  and  the e f f e c t  New H a m p s h i r e  u r i c a c i d e x c r e t i o n w e r e u s e d as t h e c r i t e r i a and p r o t e i n u t i l i s a t i o n .  have  caeca-mediated  t h e c a e c a on t h e u t i l i s a t i o n o f d i e t a r y e n e r g y  C a e c e c t o m i z e d and i n t a c t c o n t r o l  s t a r c h was  chicken  p e r f o r m some c e l l u l o l y t i c  protein.  energy  bacteria-host  of the concept of  u t i l i s a t i o n to the t o p i c under  the e x c i s i o n  to  with  similar  incorporating  lower with the caecectomized  f o r t h e c a e c e c t o m i z e d and t h e  corn birds.  intact  birds. Macroscopic revealed  that regeneration  ized birds onset that  and h i s t o l o g i c a l  that survived  of the regeneration the degree  tomized birds  of the caeca  until  autopsy  may be r e s p o n s i b l e birds.  of  of  sections  had o c c u r r e d 85 weeks  o f t h e c a e c a was  (or the absence)  r e p o r t e d w i t h such  examination  in four  later.  i t would  of the caeca  for the discrepancies  in the  caeca  caecectom-  Although  not observed,  regeneration  of the  in  the appear caecec-  findings  V  TABLE OF CONTENTS  Page ABSTRACT  i i  TABLE OF CONTENTS  v  LIST OF TABLES  vi i i  LIST OF FIGURES/PLATES  x  ACKNOWLEDGEMENTS  xi  Chapter 1  GENERAL INTRODUCTION  2  REVIEW OF LITERATURE 2.1  -  The U t i l i s a t i o n of Energy from Alternate Sources  2.1.1 2.1.2  H i s t o r i c a l perspective on energy u t i l i s a t i o n Effect of d i e t a r y source of energy on the performance of poultry 2.1.2.1 Dietary source of energy 2.1.3 Fat as a d i e t a r y source of energy 2.1.3.1 Fat d i g e s t i b i l i t y and a b s o r b a b i l i t y 2.1.4 The s p e c i f i c e f f e c t of dietary f a t on growth rate 2.1.5 The importance of n u t r i e n t balance 2.1.5.1 C a l o r i e : p r o t e i n r a t i o 2.1.5.2 C a l o r i e - n i t r o g e n storage r e l a t i o n s h i p 2.1.5.3 Implications of changing n u t r i e n t proportions 2.1.5 Protein-carbohydrate i n t e r a c t i o n s 2.1.7 Protein-fat interactions 2.1.8 Fish meal q u a l i t y 2.1.9 Effects of d i e t a r y factors on body composition 2.1.10 Effects of c e l l u l o s e on m e t a b o l i s a b i l i t y 2.1.11 Species, breed, s t r a i n and sex e f f e c t on energy metabolism 2.2  The Avian Caeca and E f f i c i e n c y of U t i l i s a t i o n of Dietary Protein and Energy  2.2.1 2.2.2 2.2.3 2.2.4 2.2.5 3  PART 1.  1 3 .3 3 3 3 5 7 8 9 9 10 10 11 12 13 14 15 17 18  Overview Carbohydrate and crude f i b r e d i g e s t i b i l i t y Protein d i g e s t i b i l i t y and u t i l i s a t i o n Absorption of nutrients Uric acid production  18 18 20 21 22  THE EFFECT OF SUBSTITUTION OF FAT FOR STARCH ON THE PERFORMANCE OF BROILERS  24  vi  Page  3.1  Experiments 1 and 2  24  3.1.1 Introduction 3.1.2 M a t e r i a l s and methods 3.1.2.1 Experiment 1 3.1.2.2 Experiment 2 3.1.3 Experiment 1 - R e s u l t s 3.1.4 - Discussion 3.2.1 Experiment 2 - R e s u l t s 3.2.2 - Discussion 3.3  The E f f e c t of Added C e l l u l o s e on the Performance of B r o i l e r Chicks  3.3.1 3.3.2 3.3.3 3.3.4 3.4  24 25 27 27 29 38 42 47  Experiment 3 -  Introduction M a t e r i a l s and methods Results Discussion  The E f f e c t o f R e s i d u a l of Chicks  51 52 55 67  Y o l k on the Performance 70  3.4.1 Experiments 4 and 5 3.4.1.1 I n t r o d u c t i o n 3.4.2 Experiment 4 - M a t e r i a l s and methods 3.4.3 - Results 3.4.4 - Discussion 3.5  The E f f e c t o f R e s i d u a l  3.5.1 3.5.2 3.5.3 3.5.4 3  PART 2. 3.6  Y o l k on S u r v i v a l  70 70 72 75 83 of Chicks  Introduction M a t e r i a l s and methods Results Discussion  THE AVIAN CAECA AND EFFICIENCY OF UTILISATION OF DIETARY ENERGY AND PROTEIN  The Role o f the Caeca i n Energy and P r o t e i n Metabolism  3.6.1 3.6.2 3.6.3 3.6.4 3.7  Experiment 5 -  Experiment 6 -  Introduction M a t e r i a l s and methods Results Discussion  Regrowth of the A v i a n Caeca F o l l o w i n g Caecectomy  3.7.1 3.7.2 3.7.3 3.7.4  Experiment 7 -  51  Introduction M a t e r i a l s and methods Results Discussion  86 86 86 86 90 91 91 91 93 98 105 108 108 110 110 115  vi i  Page  4  GENERAL SUMMARY AND CONCLUSIONS  118  5  REFERENCES  125  vi i i  L I S T OF TABLES  Table  Page  1  Composition of experimental d i e t s  2  E f f e c t o f d i e t a r y f a t and p r o t e i n l e v e l s on body gains i n Experiment 1  3  4  i n Experiments  6  E f f e c t o f d i e t a r y f a t and p r o t e i n l e v e l s o f energy E f f e c t o f f a t and p r o t e i n l e v e l s t i s s u e weight Metabolisable  9  Composition of d i e t s  11  12  12a  13  14  15  16  body 32  conversion 33  efficiency  8  10  30  E f f e c t o f d i e t a r y f a t a n d p r o t e i n l e v e l s on f o o d efficiency Protein conversion  energy  26  weight  E f f e c t o f d i e t a r y f a t and p r o t e i n l e v e l s on w e e k l y weight gain  5  7  1 and 2  36 on m e t a b o l i s a b i l i t y 43  on mean a b d o m i n a l  adipose 44  i n t a k e p e r gram body w e i g h t g a i n  46  fed in Experiments  53  E f f e c t o f source o f supplementary d i e t a r y energy c e l l u l o s e on t o t a l body w e i g h t g a i n  and  E f f e c t o f source o f supplementary d i e t a r y energy c e l l u l o s e on w e e k l y body w e i g h t g a i n  and  E f f e c t o f source o f supplementary d i e t a r y energy c e l l u l o s e on f o o d c o n v e r s i o n e f f i c i e n c y  and  56  57  60  E f f e c t o f source o f supplementary d i e t a r y energy w i t h o u t c e l l u l o s e c o m p o n e n t on f o o d c o n v e r s i o n e f f i c i e n c y  61  E f f e c t of source of supplementary c e l l u l o s e on m e t a b o l i s a b l e e n e r g y  63  d i e t a r y energy values  and  E f f e c t o f source of supplementary d i e t a r y energy c e l l u l o s e o n mean m e t a b o l i s a b l e e n e r g y v a l u e s  and  E f f e c t of source f i n a l (six-week)  of supplementary energy adipose t i s s u e weights  Composition of experimental  diet -  64  and c e l l u l o s e on  Experiment 4  66 74  ix  Tabl e  17  Page  E f f e c t of residual  yolk  on w e e k l y body w e i g h t s  body w e i g h t g a i n  and  total  .  76  18  E f f e c t of  residual  yolk  on f o o d c o n v e r s i o n  19  Effect of  residual  y o l k on m e t a b o l i s a b l e e n e r g y  20  E f f e c t o f y o l k sac  21  Composition of d i e t s chickens  f e d t o i n t a c t and c a e c e c t o m i z e d  22  MetaboTisable retention)  values  on t h e s u r v i v a l  energy  80 87  (corrected for  nitrogen 99  24  Apparent nitrogen nitrogen ingested  absorption  gains of  expressed  100 as  a percentage  of 101  25  Body w e i g h t  26  B a c t e r i a l content of excreta of p e r c e n t on a d r y m a t t e r b a s i s of  values  96  Uric acid concentration in excreta  Length  78  of chicks  of d i e t s  23  27  efficiency  individual  i n t a c t and r e g r o w n  chickens individual  caeca  103 chickens, 104 113  X  LIST OF FIGURES AND  PLATES  Figure/Plate  Page  1  E f f e c t o f d i e t a r y f a t and p r o t e i n l e v e l s  on body w e i g h t  2  E f f e c t o f d i e t a r y f a t and p r o t e i n l e v e l s conversion e f f i c i e n c y (cumulative)  on  3  4  5  E f f e c t of source of supplementary c e l l u l o s e on body w e i g h t g a i n  food 35  d i e t a r y energy  and  and  E f f e c t o f source o f supplementary d i e t a r y energy c e l l u l o s e on m e t a b o l i s a b l e e n e r g y v a l u e s  and  on t o t a l  6  E f f e c t of residual  yolk  7  Effect of residual efficiency  y o l k on c u m u l a t i v e f o o d  8  E f f e c t of r e s i d u a l  yolk  on a p p a r e n t  9  E f f e c t of residual  yolk  on t h e l i v a b i l i t y  62  79 nitrogen retention of  starved chicks  11  Regrown c a e c a f r o m c a e c e c t o m i z e d c h i c k e n and caecum unoperated chicken section  77  conversion  R e g r o w n c a e c a f r o m 85 week o l d c h i c k e n s  Transverse  65  body w e i g h t  10  12  added 58  E f f e c t of source of supplementary d i e t a r y energy c e l l u l o s e on f o o d c o n v e r s i o n e f f i c i e n c y  sac  31  through  the mid-caecum  82 89 111  from 112 114  xi  ACKNOWLEDGEMENTS  Throughout receive  the course  supervisor,  e x t e n d e d t o me d u r i n g  graduate  programme,  o f many p e o p l e .  deserves  special  thanks  the course  of this  study  I was  fortunate  Professor  B.E.  f o r the guidance  to  March,  and  support  and i n t h e p r e p a r a t i o n  of  manuscript. Sincere  Drs.  this  t h e a d v i c e and encouragement  my r e s e a r c h  this  of  D.B.  appreciation is  Bragg,  in diverse  T.L.  also  e x t e n d e d t o members  C o u l t h a r d , W.E.  Kitts  o f my t h e s i s  committee:  and M. T a i t , f o r h e l p g i v e n me  forms.  The u n f a i l i n g e n c o u r a g e m e n t  of Professor  J. Biely  is  gratefully  acknowledged-. Gratitude Kumasi,  Ghana,  financial also  is  f o r a generous study  assistance  gratefully  dependents  It  of  the Canadian  t o t h a n k my w i f e ,  and t h e e l d e r s and d e p r i v a t i o n s  is  and  Technology,  l e a v e and f i n a n c i a l s u p p o r t . International  The  Development  Agency  my f a m i l y a n d  other  is  acknowledged.  I would l i k e  hardships  extended to the U n i v e r s i t y of Science  my p l e a s u r e  Afua Nyarko,  and p e o p l e o f A k y e r e n s u a d u r i n g my e x t e n d e d s t a y  f o r t h e i r acceptance in  the t e c h n i c a l s t a f f  Canada.  to i n c l u d e a n o t e o f a p p r e c i a t i o n to Mrs.  T a i t f o r her help i n the preparation of the sections and f a r m o p e r a t o r s  for services  of  Barbara  from the caeca so o f t e n and  and  congenially  rendered. To a l l have  those  p e o p l e who h e l p e d me w i t h t h i s  been o m i t t e d i n a d v e r t e n t l y o r o t h e r w i s e ,  p r o j e c t and w h o s e names  I extend a p p r e c i a t i v e  thanks.  1  1.  GENERAL  E n e r g y u t i l i s a t i o n has metabolism.  Accumulating  of d i e t a r y  energy  of d i e t a r y  The  indications  produces caloric  are  content of  Nearly  all  fat,  broilers. are  have  Since  with  regard  efficient tives  of  that  towards  h e r e i n was,  the research  were:  to  of  the  of  obtain  high f a t  levels.  calories  for  by  the  diet. "extra-caloric"  ratios  by means  of chickens  individual  of  other  than  differences  on v a r i o u s  physiol-  the u t i l i s a t i o n of  energy  indeed.  therefore,  of the s t a t e of  the adjustment  u t i l i s a t i o n of energy  i n the l i g h t  on t h e  differences  r e s t r i c t e d one  t h e advancement  to the e f f e c t s , o f  of  sources source  possible  containing  and e v e n  understanding  t o be r e p o r t e d  is  nutrient  our  be a v e r y  it  c a n be a c c o u n t e d  o r marked  general  energy  changing  and c a t e g o r i e s  strain  energy.  of f a t f o r glucose  significant  by p o u l t r y may w e l l  contribution  turkeys  breed,  is  components  of  level  and m o s t e c o n o m i c  data a v a i l a b l e  the adjustment  species,  phenomena,  The w o r k  than  nutrient  and  u t i l i s a t i o n of  the d i e t a r y  fed d i e t s  e f f e c t higher  concerned  that the source  however,  observation  the s i g n i f i c a n t  known t o e x e r t  ogical  trend,  t h a t the s u b s t i t u t i o n  e f f e c t a t t r i b u t a b l e to dietary  This  being  the e n e r g y - y i e l d i n g  of  the e f f i c i e n c y of  are the p r i n c i p a l  from chickens  an e n e r g e t i c  in  the e f f i c i e n c y of  and c o n s i s t e n t  performance  role  indicates  with carbohydrates  u s e d more e x t e n s i v e l y .  excellent  evidence  and f a t s  energy  the widespread  a central  influence  Carbohydrates  INTRODUCTION  of  c a r r i e d o u t as knowledge  nutrient  by b r o i l e r c h i c k e n s .  The  ratios  of on  specific  a nutrition the. objec-  To determine the e f f e c t o f d i e t a r y f a t on the performance o f b r o i l e r chickens, To determine the e f f e c t of added c e l l u l o s e i n d i e t s  incorporating  v a r y i n g l e v e l s o f d i e t a r y f a t on energy m e t a b o l i s m , To determine whether the y o l k s a c i n f l u e n c e s  energy metabolism i n the  e a r l y l i f e o f the c h i c k e n , and To determine the r o l e of the caeca on energy and p r o t e i n m e t a b o l i s m .  3  2.  2.1  The U t i l i s a t i o n o f  2.1.1  Historical The c e n t r a l  Energy from A l t e r n a t e  perspective  been r e c o g n i z e d  i n f l u e n c e of the source energy  utilisation.  among  the consulting  or  computer  2.1.2  nutritionists  energy  values  E f f e c t of d i e t a r y source  nutrients source  source  amino a c i d s  (Vohra,  1972),  cost  is  values  because  or  of  oil  the  is  inclusion on  the  1971).  w i t h the former  the purpose  o f compounds f a t t y acids  growth  demonstrating  popular  w h e r e use  energy-containing  of supplying  b u t r a t h e r compounds  precursors  When soyabean  are  on t h e p e r f o r m a n c e o f  are the primary  used f o r  energy  the  g r e a t l y dependent  (De G r o o t e e_t a ] _ . ,  of energy  been  nutri-  metabolisable  poultry diets,  stuff  poultry  and B r a m b i l l a , 1965;  being the  1969).  glycerol  in a  appears, se  and  the absence  of  finding  for  carbohydrate-  were  moiety of the f a t  This  It  or f a t per  r a t e and f o o d c o n s u m p t i o n  Allred,  dietary  being o x i d i z e d  were i n c l u d e d  t h a t the g l y c e r o l  macro-  energy.  s u c h as  capable of  f a t t y a c i d u p t a k e and u t i l i s a t i o n i n  (Hill  energy  has  of  energy  and f a t s  free diet for chicks, depressed  t i m e , as  t h a t t h e body d o e s n o t r e q u i r e c a r b o h y d r a t e  the supply  energy.  of  i n t h e economy  on t h e e f f i c i e n c y o f  used i n p o u l t r y f o r m u l a t i o n s  more w i d e l y  however,  metabolism  formulation o f least  Carbohydrates  utilisation  Currently, metabolisable  useful  2.1.2.1 D i e t a r y  for  of energy  Sources  for a long  r e j e c t i o n of a p a r t i c u l a r feeding  metabol i c a l l y  for  on e n e r g y  importance o f energy  e n t u t i l i s a t i o n has  made o f  LITERATURE REVIEW  severely is  essential  carbohydrate forms  the  basis  4  of the wel1-documented f a c t that the use of e i t h e r carbohydrate or f a t in the form of t r i g l y c e r i d e s as the exclusive source of non-protein energy does not r e s u l t in depressed growth or impaired e f f i c i e n c y of . feed u t i l i s a t i o n . Accumulating evidence in the l i t e r a t u r e shows that "carbohydratef r e e " d i e t s or d i e t s in which the source of non-protein c a l o r i e s i s predominantly f a t , have produced favourable growth response. al.  Donaldson et  (1 957) and Rand et al_. (1958) showed that the chick can use high  l e v e l s of f a t as a source of energy.  The l a t t e r workers reported that  the s u b s t i t u t i o n of f a t c a l o r i e s f o r glucose c a l o r i e s resulted in improved weight gains and greater protein and energy u t i l i s a t i o n .  Evi-  dence presented by Begin (1961) indicated that carbohydrate energy can be replaced c a l o r i e for c a l o r i e by f a t .  S i m i l a r r e s u l t s were obtained  with growing turkeys by Yacowi tz et al_. (1956), Waibel (1958), Touchburn and Naber (1 966), and Jensen et al_. (1970).  Forbes et al_. (1946),  French et. a_l_. (1948), and Swift and Black (1949) demonstrated s i m i l a r physiological response in r a t s .  No adverse e f f e c t s were noted in the  growth r a t e , feed conversion e f f i c i e n c y and nitrogen retention of chicks (Renner and Elcombe, 1964, Renner, 1964) and rats (Dror et al_., 1 973) when f a t supplied p r a c t i c a l l y a l l the non-protein c a l o r i e s . Favourable growth response has been shown also in chicks fed d i e t s in which a l l the non-protein c a l o r i e s were supplied.by glucose 1964).  (Donaldson,  However, in the work c i t e d above, chicks fed " f a t - f r e e " d i e t s  oxidized f a t t y acid maximally at one day of age with the a b i l i t y to o x i d i z e f a t t y acid d e c l i n i n g with age. While carbohydrates have been the dominant source of d i e t a r y energy and can e f f e c t i v e l y replace f a t s in t h i s regard, i t i s evident that under  5  c e r t a i n conditions at l e a s t , the energy needs can be more e f f i c i e n t l y met by supplying a part of the food energy in the more concentrated form of f a t .  The i n t e r e s t being c u r r e n t l y shown in the incorporation  of f a t into the d i e t s of poultry a t t e s t s to the v a l i d i t y of the above statement.  2.1.3  Fat as a d i e t a r y source of energy .  .  The concept on q u a n t i t a t i v e use of f a t as dietary source of energy has undergone extensive r e v i s i o n .  Recent advances in n u t r i e n t metabolism  have changed the view from one suggesting minimal use of d i e t a r y f a t on account of i t s reported interference in the d i g e s t i o n , a b s o r p t i o n ' and normal metabolism of other nutrients to that recommending the i n c l u sion of f a t in the d i e t in substantial amounts for improved e f f i c i e n c y of u t i l i s a t i o n of other n u t r i e n t s . Vermeersch and Vanschoubroek  (1968) c a r r i e d out a comprehensive  review on the subject of f a t supplementation to poultry d i e t s in an •attempt to e s t a b l i s h a q u a n t i t a t i v e e f f e c t of increasing l e v e l s of various f a t s on the performance of c h i c k s . As a r e s u l t of a d e t a i l e d analysis of the data in the l i t e r a t u r e these authors reported that the f a t s studied: soyabean o i l , soyabean soapstock, maize o i l , l a r d and t a l l o w , were s i m i l a r in t h e i r e f f e c t s on food consumption.  The food consumption decreases s i g n i f i c a n t l y with r i s i n g  percentages of d i e t a r y f a t s according to a l i n e a r f u n c t i o n .  No d i f f e r -  ences were noted with regard to kinds of f a t on food consumption.  While  the incorporation of 2 to 20% of f a t s in the d i e t s of growing chicks was found to improve body weight gain, there was absence of a r e l a t i o n s h i p  6  between body weight gain and the l e v e l of d i e t a r y f a t . A c o r r e l a t i o n was shown between e f f i c i e n c y of food conversion and the kind and level of f a t : here the improvement i s c o r r e l a t e d with the l e v e l of f a t added - the higher the l e v e l of f a t , the better the e f f i c iency of food conversion.  Regarding the kind of f a t , the degree of  improvement in the e f f i c i e n c y of food conversion was, in an ascending order: t a l l o w , l a r d , grease, maize o i l , soyabean soapstock and soyabean oil. The general conclusion from the review which covered 60 papers spanning the years 1954 to 1966 was that the incorporation of f a t in poultry d i e t s r e s u l t s in a decrease in food consumption and in an improvement in the e f f i c i e n c y of food conversion. The review by Herstad (1970) encompassing 15 papers covering f a t supplements in b r o i l e r d i e t s confirmed the features established by Vermeersch and Vanschoubroek the rate of gain of b r o i l e r s .  (1968).  The various f a t s studied increased  The f i r s t 3% of soyabean o i l or grease  increased feed consumption; more than 3% f a t in the d i e t decreased food consumption, although metabolisable energy consumption increased.  The  increase in consumption of food which incorporated c e r t a i n f a t s was a t t r i b u t e d to the poor d i g e s t i b i l i t y of the p a r t i c u l a r f a t s . Vanschoubroek et_ aj_., 1971, reported studies on the comparison of the e f f e c t of c e r t a i n f a t on the performance of b r o i l e r c h i c k s .  Soya-  bean o i l included at a l e v e l of 4.5% of the d i e t improved feed conversion by 4.5% over l a r d to 4 weeks and by 3.3% to 8 weeks, in agreement with the r e s u l t s previously c a l c u l a t e d by Vermeersch and Vanschoubroek using data from the l i t e r a t u r e .  (1968)  7  2.1.3.1  Fat d i g e s t i b i l i t y and a b s o r b a b i l i t y  Poor d i g e s t i b i l i t y and a b s o r b a b i l i t y mainly account for the avoidance or the i n c l u s i o n at a minimal l e v e l of f a t in poultry diets in the early days.  A change or reversal in the a t t i t u d e of n u t r i t i o n i s t s occurred  as a r e s u l t of remarkable n u t r i t i o n a l advances made in the ensuing  years.  The metabolisable energy content of a f a t is the product of i t s gross energy content and i t s a b s o r b a b i l i t y (Whitehead and Fisher, 1975). Several factors are now known to a f f e c t the d i g e s t i b i l i t y and absorba b i l i t y of f a t s .  These factors include the type, melting point, f a t t y  acid p r o f i l e , and the structure of the t r i g l y c e r i d e s ( i . e . chemical chara c t e r i s t i c s ) of f a t ; the number of f a t s in the d i e t (Young, 1961), the nature of the basal d i e t , the l e v e l of contamination of the environment by microorganisms,  the l e v e l of i n t e s t i n a l bacteria and the age of the  birds. In general, vegetable o i l s with high l e v e l s of unsaturated f a t t y acids are more completely digested than animal f a t s .  The d i f f e r e n c e in  u t i l i s a t i o n between fats which contain s i m i l a r l e v e l s of f a t t y acids may be a t t r i b u t e d to the d i f f e r e n c e in the d i s t r i b u t i o n of f a t t y acids on the t r i g l y c e r i d e s of the f a t s concerned (Renner and H i l l , 1960; Mattson, 1967). Young et_ al_. (1963) found that the absorption of lard f a t t y acids was greater when fed in a d i e t containing 28 or 30% protein as compared to a 24% protein d i e t .  An improvement was observed in the d i g e s t i b i l i t y  of f a t in four week old chicks fed a n t i b i o t i c s (Young et_ aj_., 1963). Supplee (1960) observed a 20% growth response when 13.3% corn o i l was added to the d i e t in the presence of 50 mg of oleandomycin per kg of d i e t , but only a 10% increase in growth in i t s  phosphate absence.  8 0  Results published by Mattson (1967) of a study on the e f f e c t of d i e t on the bacteria found in the i n t e s t i n a l t r a c t of rats showed that the addition of a n t i b i o t i c s reduced caecal coliforms 50 times and t o t a l approximately three times.  aerobes  Cleanliness of chick b a t t e r i e s (Donaldson,  1962) and laboratory (Young et al_., 1963) has f a c t o r a f f e c t i n g the u t i l i s a t i o n of f a t s .  been mentioned as a  These reports suggest that  the u t i l i s a t i o n of f a t may be enhanced by c o n t r o l l i n g the l e v e l of contamination of the environment by microorganisms tinal microflora.  or the balance of i n t e s -  Variations in these factors may account for some of  the v a r i a t i o n in response to f a t as reported in the l i t e r a t u r e (Salmon, 1972).  2.1.4  The s p e c i f i c e f f e c t of d i e t a r y f a t on growth rate The improvement in growth rate and e f f i c i e n c y of food u t i l i s a t i o n  r e s u l t i n g from feeding high l e v e l s of f a t to poultry has led to the recognition of f a t as having an " e x t r a - c a l o r i c " e f f e c t (Touchburn and Naber, 1966; Jensen e_t al_., 1970).  Donaldson (1966) explained that i f  the t o t a l energy a v a i l a b l e for t i s s u e synthesis were s i m i l a r for chicks fed both f a t and " f a t - f r e e " d i e t s , the f a t - f e d chicks would have the advantage of not having to synthesize tissue f a t t y acids and thus might have r e l a t i v e l y more energy a v a i l a b l e f o r t i s s u e protein  synthesis.  Marion and Edwards (1963) stated a s i m i l a r hypothesis and referred to the amino-acid-sparing  e f f e c t of dietary f a t .  9  2.1.5  The importance of n u t r i e n t balance The myriad of problems associated with feeding d i e t s containing  p a r t i c u l a r nutrients in excess of normal concentrations, could be a t t r i b uted l a r g e l y to improper balance r e s u l t i n g from such processes.  Studies  on the r e l a t i o n s h i p of proportions of dietary nutrients to the overall e f f i c i e n c y of u t i l i s a t i o n of nutrients have made i t i n c r e a s i n g l y clear that n u t r i e n t metabolism i s a f f e c t e d not only by the composition of i n d i v i d u a l feedingstuffs but also by the t o t a l composition of the d i e t . Studies in this area have stressed the importance of balancing nutrients in r e l a t i o n to the energy level and amino acid balance. work of B i e l y and March (1954), Munro and Wikramanayake  The  (1954), Thomson  and Munro (1955), Munro et al_. (1959), contributed towards the development of the concepts that i n t e r a c t i o n existed between dietary p r o t e i n , carbohydrate and f a t and that d i e t a r y carbohydrate "spared" the protein of the d i e t by increasing the nitrogen balance of the animal in a p o s i t i v e direction. Annison (1971) suggested imbalances in r a t i o s between e s s e n t i a l amino acids and energy, inadequate consumption of vitamins or trace elements, or' the occurrence of t o x i c factors in f a t s as factors respons i b l e for the poor r e s u l t s experienced by some investigators who fed d i e t s , the energy of which was l a r g e l y contributed by f a t to poultry.  2.1.5.1  Calorie:protein ratio  The c r u c i a l role of the r a t i o e x i s t i n g between energy and protein in poultry n u t r i t i o n was demonstrated by B i e l y and March (1954) who showed that supplementation with f a t increased the l e v e l of protein  10  necessary f o r maximum growth of both chicks and poults. was confirmed by Waibe.l (1958).  This f i n d i n g  Donaldson et al_. (1955.) showed.that  the r a t i o of energy to protein in the d i e t influenced the c a l o r i c intake, feed e f f i c i e n c y , growth rate and carcass f a t and that further widening of the c a l o r i e : p r o t e i n r a t i o resulted in impaired growth and increased f a t deposition of b r o i l e r chickens. March and B i e l y (1972) showed that the optimum d i e t a r y l e v e l of e f f e c t i v e protein i s dependent upon the combined energy input from e n v i r onmental temperature and dietary metabolisable energy and.that energy in the form of e i t h e r responsible f o r aggravating  increased  heat or d i e t a r y metabolisable energy  is  the depressing e f f e c t of d i e t a r y amino  acid imbalance on feed consumption and growth r a t e . 2.1.5.2  C a l o r i e - n i t r o g e n storage  relationship  Ahrens et al_. (1966) showed that for young rats fed two l e v e l s of c a l o r i e intake, there were higher nitrogen gains when rats in the high c a l o r i e group received the nitrogen as casein rather than as a mixture of amino acids simulating casein.  This e f f e c t was not shown in rats  of the same age fed diets providing s i m i l a r nitrogen intakes at a lower c a l o r i e l e v e l , thus i n d i c a t i n g the dependence of nitrogen  storage  on c a l o r i e intake rather than the source of nitrogen. 2.1.5.3  Implications of changing nutrient  proportions  The s u b s t i t u t i o n of one nutrient for another has i t s metabolic complications.  The lack of consistency in the findings reported in  the l i t e r a t u r e on the e f f e c t of dietary f a t on body weight gain was soon recognized to be due to r e s t r i c t i o n of nutrient consumption as a r e s u l t  11  of reduced food intake when diets containing high f a t l e v e l s were f e d . The requirement for methionine (Baldini and Rosenberg, 1955), and l y s i n e (Schwartz e_t al_., 1958) has been shown to be dependent on the d i e t a r y energy l e v e l .  Not only protein requirement i s affected (Aitken et a l . ,  T954; Slinger e_t al_., 1955) but other d i e t a r y requirements also were found to increase when f a t was added to the d i e t .  The requirement for  f o l i c acid (March and B i e l y , 1955) and choline (March and B i e l y , 1956) was shown to increase in the presence of a high level of dietary f a t . Other studies have shown that the i s o c a l o r i c s u b s t i t u t i o n of f a t for carbohydrate in the d i e t of the chick increases i t s requirement for vitamin B]2 (Looi and Renner, 1974a) while i t appears not to a f f e c t i t s requirement for methionine (Looi and Renner, 1974b).  2.1.6 Protein-carbohydrate i n t e r a c t i o n s The e f f i c i e n c y of protein u t i l i s a t i o n is l a r g e l y influenced by the extent to which the amino acids in the p r o f i l e are a v a i l a b l e to the animal.  Factors that a f f e c t or i n t e r f e r e with protein d i g e s t i b i l i t y  w i l l also a f f e c t or i n t e r f e r e with amino acid a v a i l a b i l i t y and ipso f a c t o , the e f f i c i e n c y of protein u t i l i s a t i o n . Lea and Hannon (1950) studied extensively reactions that occur between proteins and carbohydrates and reported that in the presence of a considerable amount of carbohydrates with reducing sugars, proteins containing amino acids with free amino groups such as l y s i n e w i l l  react  to form a protein-carbohydrate complex which may not be u t i l i z a b l e to  12  the a n i m a l .  Nesheim  (1965) d i s c u s s e d  suggested two p o s s i b i l i t i e s .  the f a t e of such a compound and  The compound c o u l d be degraded to y i e l d  p r o d u c t s o f l i t t l e or no n u t r i t i o n a l v a l u e to the animal o r i t c o u l d be c o m p l e t e l y d e s t r o y e d . Lack o f a f r e e amino group (on a p r o t e i n c o n t a i n i n g an amino a c i d such as l y s i n e ) as a r e s u l t o f t h e l i n k a g e between i t and the c a r b o h y d r a t e would make the p r o t e i n r e s i s t a n t t o h y d r o l y s i s enzymes.  In such s i t u a t i o n s  by p r o t e o l y t i c  the p r o t e i n - c a r b o h y d r a t e complex  should  be expected to appear i n the e x c r e t a p r o v i d e d i t had not been a t t a c k e d by the m i c r o f l o r a o f the lower g u t .  M i c r o b i a l d e g r a d a t i o n o f the  p r o t e i n - c a r b o h y d r a t e compound may l e a d to the p r o d u c t i o n and of n i t r o g e n i n a form o t h e r than amino a c i d s . suggested t h a t the n i t r o g e n may be absorbed  Barnes and Kwong (1964)  i n the form o f ammonia, a  p r o d u c t of b a c t e r i a l f e r m e n t a t i o n i n the d i g e s t i v e  2.1.7  absorption  tract.  Protein-fat interactions A v a i l a b l e evidence i n d i c a t e s i n t e r a c t i o n between p r o t e i n and f a t  s i m i l a r i n n a t u r e to t h a t o c c u r r i n g between p r o t e i n s and  carbohydrates.  Lea e t al_. (1960) r e p o r t e d a drop i n p r o t e i n q u a l i t y as a r e s u l t of the r e a c t i o n between f a t o x i d a t i o n p r o d u c t s and amino a c i d s , lysine.  There was a f a l l  particuarly  o f 8% and 4% r e s p e c t i v e l y i n the a v a i l a b l e  l y s i n e of u n t r e a t e d and a n t i o x i d a n t - t r e a t e d h e r r i n g meal s t o r e d a t 20°C for  12 months compared to the a v a i l a b l e l y s i n e c o n t e n t of f r e s h  herring  meal. It  is  suggested (Nesheim,  1965)  t h a t under s t o r a g e  conditions  which would p e r m i t o x i d a t i o n or a u t o o x i d a t i o n o f f a t , c a r b o n y l  products  13  l i b e r a t e d d u r i n g the o x i d a t i o n o f the f a t c o u l d r e a c t w i t h the f r e e amino groups o f l y s i n e i n p r o t e i n s to produce bonds r e s i s t a n t to the a c t i o n s o f d i g e s t i v e enzymes o r a compound not u s e f u l as a source  of  lysine.  2.1.8  F i s h miaal q u a l i t y H e r r i n g meal i s w i d e l y used as a source o f high q u a l i t y p r o t e i n .  I t c o n t a i n s a c o n s i d e r a b l e q u a n t i t y of h i g h l y u n s a t u r a t e d f a t t y a c i d s and t h i s accounts f o r i t s chemical and n u t r i t i o n a l r e a c t i v i t y . t h a t a f f e c t the n u t r i t i v e v a l u e o f f i s h meal a r e w e l l Lakany, 1972).  and s t o r a g e ,  to o x i d a t i o n .  documented  Depending  and s t o r a g e .  During  the p o l y - u n s a t u r a t e d f a t t y a c i d s are s u b j e c t e d upon the c o n c e n t r a t i o n o f  polyunsaturated  f a t t y a c i d s and the r a t e of o x i d a t i o n , the f i s h meal may undergo taneous  h e a t i n g which c o u l d r e s u l t i n the d e s t r u c t i o n o f amino  (Laksevela,  (El-  The b i o l o g i c a l v a l u e o f h e r r i n g meal has been r e p o r t e d  to d e c l i n e c o n s i d e r a b l y as a r e s u l t o f p r o c e s s i n g processing  Factors  1958; Lea e_t a l _ . , 1960), p a r t i c u l a r l y l y s i n e ,  c y s t e i n e and h i s t i d i n e . ( B o g e ,  1960).  Laksevela  the d e t e r i o r a t i o n t h a t r e s u l t e d from spontaneous magnitude as to cause a s e r i o u s  spon-  acids  trypsin,  (1958) r e p o r t e d t h a t h e a t i n g was o f such  r e d u c t i o n i n growth r a t e o f c h i c k e n s .  There are c o n f l i c t i n g r e p o r t s on the e f f e c t o f s t o r a g e on the n u t r i t i v e q u a l i t y of f i s h m e a l .  B i e l y e_ta]_. (1951) and M i l l e r (1 955)  d i d not f i n d any adverse e f f e c t on the n u t r i t i v e q u a l i t y of f i s h meal s t o r e d under v a r i o u s  temperatures f o r p e r i o d s o f t h r e e to t w e l v e months.  However, Stansby (1948), A l m q u i s t  (1956) and Lea e t al_. (1958)  t h a t d e t e r i o r a t i o n o f t h e n u t r i t i v e v a l u e o f f i s h meal o c c u r s  showed under  14  various storage c o n d i t i o n s .  March e t al_. (1961) showed t h a t low s t o r a g e  temperature f a v o u r e d the f o r m a t i o n of p r o t e i n - 1 i p i d complex which l e a d s to a d e c l i n e i n the n u t r i t i v e q u a l i t y o f h e r r i n g m e a l . In g e n e r a l , f i s h meal q u a l i t y processing occurs  varies  and s t o r i n g o f the meal.  w i t h the methods o f d r y i n g ,  A marked d e c l i n e i n a v a i l a b l e l y s i n e  i n d i e t s i n which f i s h meal o f reduced n u t r i t i v e q u a l i t y i s  the  o n l y source o f p r o t e i n .  2.1.9  E f f e c t s o f d i e t a r y f a c t o r s on body c o m p o s i t i o n The e f f e c t s o f d i e t a r y f a c t o r s on body c o m p o s i t i o n o f c h i c k e n s  were f i r s t d e s c r i b e d by Fraps  (1943), who was a b l e to produce  chickens  w i t h w i d e l y v a r y i n g amounts o f body f a t by a d j u s t i n g d i e t a r y components. Subsequently,  Donaldson  and W i l k i n s o n  (1957), Combs e t al_. (1964), Davidson e t al_.  Summers e_t al_. (1965), (1967),  e_t aj_. (1956, 1958), Rand et_ al_. (1957),  Spring  (1964),  Yoshida e t al_. (1966, 1970), Thomas and Combs  Yoshida and Morimoto (1970a, b ) , Thomas and Twinning  and Kubena e t al_. (1972),  (1971),  i n v e s t i g a t e d the s p e c i f i c e f f e c t s o f d i e t a r y  p r o t e i n , energy and c a l o r i e : p r o t e i n r a t i o on the body c o m p o s i t i o n o f c h i c k s and p o u l t s .  Through these s t u d i e s ,  i t was e s t a b l i s h e d t h a t as  the d i e t a r y c a l o r i e : p r o t e i n r a t i o widened, energy i n t a k e and c a r c a s s d e p o s i t i o n i n c r e a s e d , w h i l e body water c o n t e n t d e c r e a s e d . (1966, 1970) and Yoshida and Morimoto  (1970a,  changes  Thomas and Twinning  Yoshida e t a l .  b) have r e p o r t e d t h a t the  e f f e c t of d i e t a r y p r o t e i n c o n c e n t r a t i o n on c a r c a s s and r e v e r s i b l e .  fat  f a t content i s  (1971) t o o , observed  rapid  considerable  i n c a r c a s s f a t c o n t e n t , as e a r l y as 10 days a f t e r a l t e r a t i o n s  15  were made in protein concentrations. The s p e c i f i c e f f e c t of d i e t a r y f a t on body composition i s not yet c l e a r . While most of the reports reviewed above appear to e s t a b l i s h that increasing the amount of d i e t a r y f a t increased carcass f a t while i t decreased i t s protein content, Edwards and Hart (1971) f a i l e d to observe any change in t o t a l carcass composition when a l l the non-protein energy was derived from various o i l s .  Bartov et_ al_. (1974) reported that d i e t a r y o i l supplementation  per se did not increase the amount of carcass f a t as long as the c a l o r i e : protein r a t i o was kept constant.  If there existed any consistent trend at  a l l , i t appeared to act in the opposite d i r e c t i o n : towards a decrease in carcass f a t .  2.1.10 E f f e c t of c e l l u l o s e on m e t a b o l i s a b i l i t y The increased i n t e r e s t in energy n u t r i t i o n of the chicken and progressive increase in the level of f a t and, consequently, the density of d i e t s used f o r p o u l t r y , has led to the present accepted p r a c t i c e of formulating experimental d i e t s to contain varying l e v e l s of fibrous materials usually in the form of c e l l u l o s e .  There i s c o n f l i c t i n g evidence regarding the e f f e c t of c e l l u -  lose on some p h y s i o l o g i c a l parameters of the chicken.  Reports which i n d i c a t e  that growth and food u t i l i s a t i o n are impaired when d i e t s containing fibrous ingredients are fed to chickens, have been presented by Penquite Sheehy (1939),  Heuser et al_. (1945),  Roberts (1974a, b). and Combs (1950),  Fraps (1946),  (1936),  Carrick and  Scott et al_. (1947),  Robertson et ajL (1943),  Panda  H i l l and Dansky (1954),  Peterson et al_. (1954),  Mraz  e_t al_. (1956), and Richardson et al_. (1956),  have explained the  16  d e l e t e r i o u s e f f e c t ( a t t r i b u t a b l e to f i b r e ) on the b a s i s o f r e d u c t i o n energy ients.  i n t a k e mediated by the e n e r g y - d i l u t i n g Hainan  (1930), Robertson  e t al_. (1948), and W e l l s  uted t h i s e f f e c t to the i m p o s i t i o n o f p h y s i c a l of d i g e s t i b l e  p r o p e r t y of f i b r o u s (1963)  l i m i t a t i o n on the  ingredattribintake  nutrients.  There a r e , however,  some r e p o r t s which i n d i c a t e t h a t f e e d i n g  amounts o f f i b r o u s m a t e r i a l s may i n c r e a s e growth and improve the i s a t i o n o f food above t h a t o b t a i n e d on the low f i b r e basal ejt al_. (1932), W i l c k e and Hammond (1940), Record Briggs  in  (1 943),  moderate util-  diet.  Morris  Davis and  (1947, 1948), Olsson (1948), and S a i t o e t al_. (1959) are among  those who are o f the o p i n i o n t h a t f i b r e may be o f b e n e f i t i n  poultry  diets. S i b b a l d and S l i n g e r  (1960) f e d d i e t s of which c e l l u l o s e formed up  to 42% and o b t a i n e d data which i n d i c a t e t h a t d i l u t i o n of a c h i c k d i e t w i t h c e l l u l o s e does not change the m e t a b o l i s a b l e energy  starter  content.  T h i s f i n d i n g was s u b s t a n t i a l l y c o n f i r m e d by P o t t e r ejt a]_. (1960) who showed t h a t a l p h a - c e l l u l o s e had zero or l e s s . m e t a b o l i s a b l e energy v a l u e . Begin (1961) u s i n g i s o c a l o r i c d i e t s and a c o n s t a n t n u t r i e n t t e c h n i q u e demonstrated  t h a t the a d d i t i o n of woodpulp c e l l u l o s e  n e i t h e r a growth-depressing  nor a g r o w t h - s t i m u l a t i n g  ded i n the d i e t o f t h e c h i c k .  had  e f f e c t when  inclu-  He e x p l a i n e d t h a t the major a t t r i b u t e  o f c e l l u l o s e when i n c l u d e d i n the d i e t w i t h o u t supplementary a depression  balance  energy  i n growth and feed u t i l i s a t i o n and an o v e r a l l decrease  was in  the u t i l i s a t i o n of the d i e t as measured by the percentage o f t h e g r o s s energy  t h a t was m e t a b o l i s e d .  A c c o r d i n g t o Begin (1961), c e l l u l o s e  i n e r t i n r e s p e c t o f i t s e f f e c t on m e t a b o l i s a b i l i t y o r n i t r o g e n  is  retention.  .  17  2.1.11 S p e c i e s , b r e e d , s t r a i n and sex e f f e c t on energy metabolism D i f f e r e n c e s occur i n the response o f d i f f e r e n t breeds 1971)  (Gardiner,  and s t r a i n s of c h i c k e n s t o d i e t s w i t h t h e same (Nowland e t a l . ,  1971) or w i t h d i f f e r e n t energy c o n c e n t r a t i o n s  ( F a r r e l l , 1972).  Wells  (1963) noted d i f f e r e n c e s i n energy u t i l i s a t i o n w i t h r e s p e c t to the sex of the b i r d . There i s e v i d e n c e i n the l i t e r a t u r e which p o i n t s to s p e c i e s d i f f e r e n c e r e g a r d i n g metabol i s a b i l i t y o f energy.  S l i n g e r ejt al_. (1964) showed t h a t  c h i c k s m e t a b o l i s e d more energy from a h i g h - e n e r g y  d i e t than t u r k e y p o u l t s .  C o n v e r s e l y , p o u l t s m e t a b o l i s e d more energy from Tow-energy d i e t than chicks.  A l s o , a s l o w - g r o w i n g . b r e e d o f c h i c k s m e t a b o l i s e d more energy  from a h i g h - e n e r g y  d i e t than a f a s t - g r o w i n g  breed.  Sudgen (1974) noted  d i f f e r e n c e s between the bantam c h i c k and t h e b l u e - w i n g e d t e a l  (duck)  r e s p e c t of t h e i r a b i l i t y t o m e t a b o l i s e energy from v a r i o u s d i e t a r y  in  sources.  S I i n g e r ejt al_. (1964) and Sugden (1974) concluded t h a t m e t a b o l i s a b l e energy v a l u e s measured w i t h one k i n d o f b i r d cannot v a l i d l y be a p p l i e d to another k i n d . Data p r e s e n t e d by Leeson ejt aj_. (1974), do not support the above conclusion.  The l a t t e r group of a u t h o r s found no d i f f e r e n c e between  t u r k e y s and c h i c k e n s i n t h e i r a b i l i t y to m e t a b o l i s e energy.  Values  ob-  t a i n e d w i t h the t u r k e y f o r more f i b r o u s m a t e r i a l s , however, appeared to be s u b s t a n t i a l l y g r e a t e r than have been found w i t h the c h i c k , s u g g e s t i n g t u r k e y s w i t h t h e i r l a r g e r d i g e s t i v e t r a c t s might have a g r e a t e r c a p a c i t y for digesting fibrous  foods.  18  2.2  The A v i a n and  2.2.1  C a e c a and E f f i c i e n c y o f U t i l i s a t i o n o f D i e t a r y  Energy  Overview Very  little  is  the avian caeca.  known a b o u t  animals,  b)  digestion  of  c)  microbial  synthesis  d)  absorption  of non-protein  e)  absorption  of water,  f)  biosynthesis  t h e s e perhaps  of  has  to  of:other  been s u g g e s t e d t h a t t h e caecum  cellulose;  and a b s o r p t i o n  have  vitamins;  nitrogen  been a d v a n c e d popular  has  to support  these  suggestions  been t h e one a t t r i b u t i n g a  o f c e l l u l o s e and p r o t e i n and t h e  and  of  rumen-like  biosynthesis  vitamins.  Carbohydrate  and c r u d e  Kaupp and I v e y  fibre digestibility  (1922) o b t a i n e d c r u d e f i b r e d i g e s t i b i l i t y c o e f f i c i e n t s  poultry varying  percent for oats.  of  and/or  digestion of  and p r o t e i n ;  antigens.  t h e most  in the  and a b s o r p t i o n  of  carbohydrate  Various, hypotheses  anuses,  It  of  for:  microbial digestion  digested  as  the a v i a n caeca are s i m i l a r to those  a)  with  or n u t r i t i o n a l r o l e  t h e r e h a v e been s p e c u l a t i o n s  p a r t i c u l a r l y the horse.  may be a s i t e  function  the p h y s i o l o g i c a l  F o r many y e a r s  whether the f u n c t i o n s o f  2.2.2  Protein  f r o m 2.2  Hunter  percent for  e x t r a c t e d s o y b e a n meal  to  11.7  e t a l _ . ( 1 9 3 0 ) r e p o r t e d t h a t f i b r e c a n be  i n t h e a v i a n caecum.  Maas  (1934) u s i n g  reported d i g e s t i b i l i t y c o e f f i c i e n t s of  fowls with 2.4  artificial  percent f o r the  crude  19  f i b r e of r y e and 3.6 f o r t h a t of wheat. Hainan o f Radeff  (1949) p r e s e n t e d an e x c e l l e n t r e v i e w embodying t h e work  (1928) and o t h e r s on crude f i b r e d i g e s t i o n .  While the crude  f i b r e i n b a r l e y was not d i g e s t e d by e i t h e r normal o r caecectomized f o w l s t h a t of wheat was b e t t e r d i g e s t e d by the normal fowl than the caecectomized fowl (1.4 p e r c e n t ) .  (4.6-5.7  percent)  An even more remarkable  d i f f e r e n c e was shown w i t h the crude f i b r e o f maize o f which the normal fowl d i g e s t e d more (17.1  p e r c e n t ) than the caecectomized fowl which  showed zero p e r c e n t . d i g e s t i b i l i t y .  The source of f i b r e appears to be  of s i g n i f i c a n c e i n r e l a t i o n t o i t s d e g r a d a t i o n i n t h e c a e c a .  Variations  w i t h i n the same food have been r e p o r t e d by Mangold (1934) who found t h a t t h e c o e f f i c i e n t s o f d i g e s t i b i l i t y o f crude f i b r e f o r b a r l e y from 0 to 31.5 w h i l e those o f o a t s ranged from 0 t o 6.9  percent.  That the a v i a n caeca possess some c e l l u l o l y t i c f u n c t i o n i s shown by Dukes (1955) and N i t s a n and Alumot (1963). Willcox  Thornburn  (1965a) s t u d i e d t h e s i g n i f i c a n c e of t h e caeca i n t h e  o f d r y m a t t e r , crude f i b r e , c e l l u l o s e , pentosans,  ranged  also and  digestion  and s t a r c h by p o u l t r y  and r e p o r t e d a r e d u c t i o n i n the o v e r a l l d i g e s t i b i l i t y o f dry m a t t e r i n the food a f t e r caecectomy. idual  C e l l u l o s e d i g e s t i b i l i t y was reduced i n  b i r d s a f t e r caecectomy, but when they were compared w i t h i n t a c t  b i r d s o f i d e n t i c a l age, the r e d u c t i o n i n d i g e s t i b i l i t y was not evident.  always  V a r i a t i o n i n t h e c a e c a ! f l o r a between b i r d s was used t o e x p l a i n  the i n c o n s i s t e n c y o f r e s u l t s birds  iridiv-  between the i n t a c t and the c a e c e c t o m i z e d  (two i n each c a s e ) . Not a l l e v i d e n c e , however, i s  findings.  The o b s e r v a t i o n  i n a c c o r d w i t h the  above-mentioned  by Masson (1954) o f the presence o f p o t a t o  s t a r c h i n the caeca makes the hypotheses o f s t a r c h d i g e s t i o n  i n the  20  caeca l e s s a c c e p t a b l e .  Thornburn and W i l l cox (1965b) f a i l e d t o produce  c o n c l u s i v e e v i d e n c e on the d i g e s t i b i l i t y of c a r b o h y d r a t e s caecum.  Evidence p r e s e n t e d by S c o t t (1955),  and N o r r i s lysis  i n the i n t a c t  G r i m i n g e r (1957),  (1961), McBee (1971), a l s o d i s p u t e s the c l a i m o f  i n the a v i a n c a e c a .  Nelson  cellulo-  The r e p e a t e d f a i l u r e to f i n d i n the domestic  b i r d s c a e c a l b a c t e r i a c a p a b l e o f h y d r o l y s i n g c e l l u l o s e must have prompted McNab (1973) t o express doubt about the caeca as being an organ o f s i g n i f i c a n c e i n the d i g e s t i o n o f c e l l u l o s e or crude  2.2.3  fibre.  P r o t e i n d i g e s t i b i l i t y and u t i l i s a t i o n The r o l e p l a y e d by the a v i a n caeca i n the u t i l i s a t i o n o f p r o t e i n  i s e q u a l l y f a r from c l e a r .  Maumus and Launoy  (1901) and Maumus (1902)  both c i t e d by McNab (1973) s t u d i e d the a c t i o n of d i f f e r e n t s u b s t r a t e s o f c a e c a l j u i c e from c h i c k s , ducks and geese and r e p o r t e d t h e p r e s e n c e , i n the c a e c a , of a p r o t e o l y t i c enzyme s i m i l a r i n a c t i o n to t r y p s i n . N i t s a n and Alumot (1963) examined the c a e c a l c o n t e n t s o f c h i c k s which had been f e d d i e t s based on raw and heated soyabean meals f o r p r o t e o l y t i c a c t i v i t y and noted high a c t i v i t y on both d i e t s up to f o u r weeks o f age.  D i f f e r e n c e s were noted i n enzyme a c t i v i t y i n the s i x t h week between  b i r d s f e d the heated and those f e d the raw beans - the former showing a marked decrease and the l a t t e r o n l y a s l i g h t decrease i n enzyme a c t i v i t y . Increased  p r o t e o l y s i s was observed a t e i g h t weeks o f age when the c h i c k e n s  were t r a n s f e r r e d from a heated to a rawsoyabean based d i e t . F i s h e r and G r i m i n g e r (1966) t e s t e d the h y p o t h e s i s o f c a e c a l p r o t e o lysis  and f a i l e d to a c c e p t the s u g g e s t i o n  o f N i t s a n and Alumot  (1963)  t h a t the observed i n c r e a s e i n p r o t e o l y t i c a c t i v i t y i n the e i g h t week o l d  21  c h i c k e n was a t t r i b u t a b l e to compensatory obviate i n h i b i t e d proteolysis  p r o t e o l y s i s which o c c u r r e d to  i n the small  intestine.  good growth r a t e of t h e caecectomized c h i c k s unoperated c o n t r o l s . F i s h e r and G r i m i n g e r  On the b a s i s  i n comparison w i t h t h a t o f  (1966) concluded t h a t c a e c a l  d i g e s t i o n of raw soyabean p r o t e i n i s of n e g l i g i b l e consequence growing  of  i n the  chicken.  Nesheim and C a r p e n t e r  (1967) fed undamaged and heat-damaged  meal to normal and c a e c e c t o m i z e d b i r d s and r e p o r t e d t h a t . a  significant  p r o p o r t i o n of t h e p r o t e i n and p e p t i d e s which escape h y d r o l y s i s t i o n i n the small  and  absorp-  i n t e s t i n e e n t e r s the caeca and i s fermented i n such a  way t h a t the n i t r o g e n i s l i b e r a t e d as ammonia or some o t h e r o f no n u t r i t i o n a l v a l u e . and Coates  fish  T h i s view i s s t r e n g t h e n e d  substance  by the work o f  (1971) who concluded t h a t m i c r o b i a l a c t i v i t y d i d l i t t l e  Salter to  i n c r e a s e the a v a i l a b i l i t y o f p r o t e i n to the c h i c k . Payne e t al_. (1971) i n v e s t i g a t e d the e f f e c t of caecectomy on a p p a r ent d i g e s t i b i l i t y o f p r o t e i n and found t h a t caecectomized b i r d s had a p r o t e i n d i g e s t i b i l i t y c o e f f i c i e n t t h a t was c a n t l y ) s m a l l e r than t h a t of normal findings,  slightly  intact birds.  (though not s i g n i f i D e s p i t e the above  Payne e t al_. (1971) argued t h a t the l a r g e e x p e r i m e n t a l  c o u p l e d w i t h the s m a l l number o f o b s e r v a t i o n s  per t r e a t m e n t (5  error birds)  accounted f o r the l a c k o f s t a t i s t i c a l s i g n i f i c a n c e and concluded t h a t proteins  t h a t a r e d i g e s t e d w i t h i n the caecum a r e absorbed from the  caecum and on t h a t b a s i s the caeca a r e i n v o l v e d i n p r o t e i n  2.2.4  Absorption of  digestion.  nutrients  The f a c t t h a t microorganisms  i n h a b i t i n g the alimentary t r a c t of  22  ruminants are r e s p o n s i b l e f o r a c t i v i t i e s o f n u t r i t i o n a l s i g n i f i c a n c e to the host animals has g i v e n r i s e to c o n s i d e r a b l e s p e c u l a t i o n on the i n v o l v e m e n t o f i n t e s t i n a l microorganisms t i o n o f n u t r i e n t s by the domestic  i n the d i g e s t i o n and/or  absorp-  fowl.  The presence o f a l a r g e p o p u l a t i o n o f microorganisms  i n the  ali-  mentary t r a c t , p a r t i c u l a r l y the c a e c a , has been r e p o r t e d by Shapiro and S a r l e s (1970). bial  (1949),  Barnes and Shrimpton  (1957), and Barnes and Impey  A l t h o u g h the a v i a n caecum i s one o f t h e areas of g r e a t e s t m i c r o -  p r o l i f e r a t i o n and a c t i v i t y (Barnes and Impey, 1970),  t h e r e i s no  c l e a r e v i d e n c e t h a t m i c r o b i a l a c t i v i t y i s b e n e f i c i a l or d e t r i m e n t a l to the h o s t . One p o s s i b l e way i n which the presence o f microorganisms  can be  regarded as b e n e f i c i a l to the domestic fowl i s t h a t c a r b o h y d r a t e s p r o t e i n s o f d i e t a r y or endogenous  or  o r i g i n t h a t escape d i g e s t i o n i n the  upper gut might be c a t a b o l i z e d by m i c r o b i a l a c t i o n i n the lower gut w i t h subsequent a b s o r p t i o n of t h e end p r o d u c t s such as monosaccharides disaccharides  or  i n the case o f c a r b o h y d r a t e s , and amino a c i d s or amino  a c i d degradatory products  i n the case of p r o t e i n s .  T h i s would be i n  agreement i n p a r t w i t h the s u g g e s t i o n s o f Thornburn and Iii 11 cox (1 965b) and Nesheim and C a r p e n t e r  (1967).  A l t e r n a t i v e l y , they might be o f no n u t r i t i o n a l v a l u e , i f , f o r the i n s t a n c e , l a c t i c a c i d i s / e n d p r o d u c t o f c a r b o h y d r a t e c a t a b o l i s m and b i o l o g i c a l l y u n a v a i l a b l e p e p t i d e s or e x c e s s i v e ammonia a r e the end p r o ducts of p r o t e i n breakdown. 2.2.5  Uric a c i d production S i n c e some p r o t e i n h y d r o l y t i c f u n c t i o n i s suggested  f o r the c a e c a -  23  and u r i c a c i d i s  t h e main n i t r o g e n o u s  the p o s s i b i l i t y e x i s t s  excretory  substance  t h a t u r i c a c i d c o u l d be i n v o l v e d  i n the  i n the  bird  metabolism  o f t h e c a e c a l m i c r o f l o r a and t h a t t h e m i c r o f l o r a w o u l d c o n t a i n a ficant  population of  Barnes  uric acid-utilizing bacteria.  a n d Impey ( 1 9 7 2 )  ing anaerobes  the u r i c a c i d degradatory of  lC)8-109/g.  flora  of  chicks  uric  acid.  3 hours  and 14 d a y s  t h e 1 4 - d a y p e r i o d , a p p r o x i m a t e l y 100  it  showed  E x c e p t w i t h a few s t r a i n s u r i c a c i d as  t h e main s o u r c e  tinual  presence  the avian  anaerobic  only  p l a t i n g method  t h e r e has  requirement  been l i t t l e  source.  However,  of nitrogen.  of a large  Barnes  known  initiate  Akester  (1972)  re-absorption  explains  flow of  for  that the  the  urine  have  could diverted  synthesized  r e p o r t e d t h a t an  i n d u c e d by t h e a p p r o p r i a t e  the coprodeum which then  results  and f i n e p a r t i c l e s o f d i g e s t a  con-  bacteria  o f w a t e r and any  o r amino a c i d s  et a l , ( 1 9 6 7 )  mechanism,  contraction of  retrograde  the  (1972)  t h a t a major f u n c t i o n o f the caeca  v o l a t i l e fatty acids  physiological  to  uric  evidence  population of uric acid recycling  the caeca w i t h the p o s s i b l e  the microorganisms.  utilized  total  for  Barnes  the  t h e u r i c a c i d u t i l i s i n g b a c t e r i a u t i l i z e d ammonia  caeca suggests  of the vitamins,  and  percent of  be t h e m e t a b o l i s m and r e u t i l i s a t i o n o f t h e e x c r e t o r y p r o d u c t s into  the caecal  four percent of the  an a b s o l u t e  a carbon  in  a c t i v i t y d e c l i n e d w i t h age  represented  isolates  f o u n d t h a t a number o f  in  conventional  that  at a minimal  aged b e t w e e n a p p r o x i m a t e l y  None o f t h e  of  present  found  changes  i n one c a s e  utilisation  acid-decompos-  studied  a c i d up t o t h e t h i r d d a y b u t t h i s  flora.  of usic  ( B a r n e s e t a l _ . , 1972)  o r g a n i s m s were always  i s o l a t e d through  extent that  as  study  isolates  Mead a n d Adams ( 1 9 7 5 )  reported that during organisms  found three  and i n s u b s e q u e n t  level  signi-  other by un-  stimulus in  the  into  the  caeca  24  3.  PART 1.  THE EFFECT OF SUBSTITUTION OF FAT FOR STARCH ON THE PERFORMANCE OF BROILERS  3.1  Experiments 1 and 2  3.1.1  Introduction The i n c r e a s i n g w o r l d shortage o f g r a i n s w h i c h , h i t h e r t o , have  been the predominant d i e t a r y source o f energy f o r p o u l t r y , has s t i m u l a t e d i n t e r e s t i n the search f o r a l t e r n a t i v e d i e t a r y s o u r c e ( s ) o f  energy  for poultry. A number o f r e s e a r c h e r s  have s t u d i e d energy u t i l i s a t i o n and have  demonstrated the p o t e n t i a l v a l u e o f f a t not o n l y as an a l t e r n a t i v e , but a l s o as an economic source o f d i e t a r y energy.  The attempts being made  are i n the d i r e c t i o n o f e s t a b l i s h i n g a d i e t a r y energy c o n c e n t r a t i o n t h a t would promote an e f f i c i e n t u t i l i s a t i o n of n u t r i e n t s , p a r t i c u l a r l y p r o t e i n . Data p u b l i s h e d by Touchburn and Naber (1966) and Jensen e t a l . (1970) appear to. e s t a b l i s h a concept t h a t supplemental d i e t a r y f a t has an " e x t r a - c a l o r i c " e f f e c t on the u t i l i s a t i o n o f m e t a b o l i s a b l e energy by turkey b r o i l e r s .  In a s e r i e s o f experiments these groups o f workers  showed t h a t added d i e t a r y f a t improved u t i l i s a t i o n o f m e t a b o l i s a b l e energy and t h a t " a w i d e r c a l o r i e : p r o t e i n r a t i o c o u l d be t o l e r a t e d when f a t was added t o the r a t i o n than when no f a t was  used".  There i s l i t t l e or no d i r e c t i n f o r m a t i o n on the b r o i l e r c h i c k e n r e g a r d i n g the e f f e c t o f added d i e t a r y f a t on the u t i l i s a t i o n o f m e t a b o l i s a b l e energy and t o l e r a n c e o f a w i d e r c a l o r i e r p r o t e i n r a t i o .  A study  has, t h e r e f o r e , been made o f the e f f e c t o f p a r t i a l s u b s t i t u t i o n o f d i e t a r y f a t f o r g l u c o s e c a l o r i e s on m e t a b o l i s a b i 1 i t y o f energy, body weight g a i n , e f f i c i e n c y o f food c o n v e r s i o n and c a r c a s s  f a t c o n t e n t of b r o i l e r c h i c k e n s .  25  3.1.2  Materials  This  phase o f  and  the study  Methods  comprised  broiler  chicks.  ments.  The c o m p o s i t i o n o f t h e d i e t s  diet  linoleic  to supply  acid,  fat,  the d i e t a r y e s s e n t i a l  hundred.and  consisting  and w e r e f e d a h o l d i n g  two m a j o r l o t s o f  stock  c o n t i n u e d t o be b r o o d e d  specified. involved  of  o f t h e mash,  and more  of the parameters  22%.  battery brooders  with raised  The two l o t s o f  into  chicks  i n t h e manner d e s c r i b e d e a r l i e r , f e d t h e same  was  is  the  otherwise  chicks  One l o t o f c h i c k s , c o n s i s t i n g  of  randomly r e d i s t r i b u t e d i n t o f o u r groups  p e r r e p l i c a t e were a s s i g n e d t o one b a t t e r y compartment. the f i r s t  for  and d i s t r i b u t e d r a n d o m l y  f o r t h e two e x p e r i m e n t s .  i n t h e two e x p e r i m e n t s . six,  screen  practical-type broiler starting diet  Food and w a t e r w e r e p r o v i d e d ad 1 i b i t u m t o a l l  for  under  supplementary  t h e number o f d i e t a r y t r e a t m e n t s w i t h t h r e e r e p l i c a t i o n s .  the stock  disorders  d i e t s , and k e p t i n t h e same room e x c e p t w h e r e i t  h u n d r e d and f i f t y  basal  particularly  two l e v e l s o f  18% and  The c h i c k s w e r e t h e n w i n g - b a n d e d  experimental  The  s i x t e e n c h i c k s were housed i n a t h e r m o s t a t i c a l l y -  c o n t r o l l e d e l e c t r i c a l l y - h e a t e d metal  two d a y s .  using  i n T a b l e 1.  fatty acids,  would a f f e c t the e x p r e s s i o n  4% and 8% f e d a t two p r o t e i n l e v e l s  floors,  presented  t o keep down d u s t i n e s s  There were f o u r d i e t s  Four  to  is  the l a c k of which would p r e c i p i t a t e m e t a b o l i c  which, consequently, study.  conducted  The same f o r m u l a t i o n o f d i e t s was u s e d i n b o t h e x p e r i -  c o n t a i n e d 3% c o r n o i l  importantly,  two e x p e r i m e n t s  experiment.  This  one according  The 13  chicks  constituted  26  Table  1.  Composition  of diets  used i n experiments  Low P r o t e i n Low F a t  Ingredient, or c a l c u l a t e d analysis  1  High Fat Diet  1 and  2.  High  Protein  Low F a t Number  High  2  3  Fat  4  Percent Herring Wheat  meal (12.45)  (72%)  13.0  13.0  21 .3  21.3  70.9  70.9  53.0  53.0  3.0  11.0  Corn  oil  3.0  7.0  Corn  starch  9.6  -  Bone meal  1.5  1.5  1.5  1.5  Limestone  1.0  1.0  1.0  1.0  0.5  0.5  0.5  0.5  0.5  0.5  0.5  0.5  5.6  —  11.2  Iodized  salt  Premix^ Cellulose Protein Fat M..E.  (kcal/kg)  19.2  -  18.19  18.19  21.93  21.93  5.57  9.57  6.08  14.08  3345  3347  3382  3385  M i c r o n u t r i e n t s s u p p l i e d p e r kg o f d i e t : manganese s u l p h a t e , 132 mg; r i b o f l a v i n , 3 . 1 2 mg; m e n a d i o n e , 0 . 4 8 mg; c a l c i u m p a n t o t h e n a t e , 9.62 mg; f o l a c i n , 0 . 5 5 mg; v i t a m i n B 1 2 , 0 . 1 3 meg; p y r i d o x i n e , 2 . 8 7 mg; b i o t i n , 0 . 0 9 mg; c h o l i n e c h l o r i d e , 1.32 g ; v i t a m i n A , 4 4 0 0 I . U . , v i t a m i n D 3 , 440 L C . U . ; v i t a m i n E, 18 I . U . ; z i n c b a c i t r a c i n , 27 mg; c h l o r o t e t r a c y c l i n e , 1 2 4 . 9 mg; a m p r o l i u m , 11 mg.  27  There was a s l i g h t m o d i f i c a t i o n i n the r e p l i c a t i o n o f the d i e t a r y t r e a t m e n t groups of the s t o c k used f o r the m e t a b o l i s a b l e energy There were f i v e r e p l i c a t e d l o t s o f 13 c h i c k s each.  study.  T h i s was done i n  o r d e r to a l l o w each c h i c k the same f l o o r space as i n the f i r s t e x p e r i m e n t . With 13 c h i c k s i n each r e p l i c a t e t h e r e were 65 c h i c k s f o r each o f the f o u r d i e t a r y t r e a t m e n t g r o u p s , making a t o t a l  o f 260 c h i c k s m a i n t a i n e d  under the same management c o n d i t i o n s as the f i r s t e x p e r i m e n t . 3.1.2.1 Experiment 1 T h i s study was. designed t o i n v e s t i g a t e the e f f e c t s o f  diets.varying  i n f a t and p r o t e i n l e v e l s on the performance o f b r o i l e r c h i c k e n s  using  body w e i g h t g a i n , f o o d c o n v e r s i o n e f f i c i e n c y and e f f i c i e n c y o f p r o t e i n u t i l i s a t i o n as the c r i t e r i a f o r e v a l u a t i n g performance. The c h i c k s were i n d i v i d u a l l y weighed a t weekly i n t e r v a l s the e x p e r i m e n t a l p e r i o d which l a s t e d seven weeks.  throughout  Food consumption was  determined on group b a s i s and was done a t the time o f weighing the c h i c k s . S p i l l e d food was removed from the e x c r e t a by screening and added t o the r e m a i n i n g feed i n the troughs  b e f o r e the f e e d weigh-back.  on body w e i g h t g a i n , food ( c o n v e r s i o n )  Data c o l l e c t e d  e f f i c i e n c y and p r o t e i n e f f i c i e n c y  r a t i o v a l u e s were t r e a t e d by a n a l y s i s o f v a r i a n c e (Snedecor, 1956)  and  s i g n i f i c a n t d i f f e r e n c e s among t r e a t m e n t means were i d e n t i f i e d by S t u d e n t Newman-Keuls m u l t i p l e range t e s t . 3.1.2.2 Experiment 2 The second experiment i n v o l v e d 240 c h i c k s .  At 1, 2, 4 and 7 weeks  o f age, 60 c h i c k s made up o f t h r e e c h i c k s from each q u i n t u p l i c a t e l o t  28 o f the f o u r d i e t a r y t r e a t m e n t groups from the second  l o t of chicks  r e s p e c t i v e l y , were randomly  described e a r l i e r .  The f i f t e e n  removed  chicks  removed f r o m each d i e t a r y t r e a t m e n t group a t each s p e c i f i e d p e r i o d redistributed g r o u p was  randomly  into  groups of  b a t t e r y compartment w i t h r a i s e d w i r e s c r e e n  ventilated, of  with  f l o o r space  the compartments  was  a d j u s t e d a t each housing  the c h i c k s  were i n d i v i d u a l l y weighed  were kept f o r each p e r i o d . diets  The c h i c k s  Feathers,  required for Moisture  o f crude  f o o d and e x t r a n e o u s  Food c o n s u m p t i o n  Food was w i t h d r a w n  and  records  m a t e r i a l s were c a r e f u l l y  t o t r e a t m e n t and f r o z e n . i n screw-cap  picked  replicate  The f r o z e n  sample  jars  and  excreta stored  analysis.  d e t e r m i n a t i o n was  c a r r i e d o u t on a l l  t o be made on d r y w e i g h t  basis.  done u s i n g  K j e l d a h l macro-method  was  samples  to  permit  Assay f o r energy  content  P a r r O x y g e n Bomb P l a i n j a c k e t followed in the  determination  protein.  from each  of the weight of fat  a t t h e commencement  c o l l e c t i o n s from each  A t t h e end o f t h e e x p e r i m e n t , a l l chicks  commensurate  total  o f b o t h f o o d and e x c r e t a was Calorimeter.  period  The  and t e r m i n a t i o n o f t h e c o l l e c t i o n o f  l y o p h i l i z e d , g r o u n d and s t o r e d  calculations  well-  hours  group were pooled a c c o r d i n g  until  in a  18  f r o m t h e e x c r e t a and t h e t h r e e d a y s '  was  floors  w e r e c o n t i n u e d on t h e same e x p e r i -  f o r two and one h a l f d a y s .  t o t h e commencement  excreta.  each  requirement.  t e r m i n a t i o n o f e a c h p e r i o d l a s t i n g one week.  prior  and  t e m p e r a t u r e - c o n t r o l l e d c h i c k e n room i n t h e l a b o r a t o r y .  size  mental  five chicks  a s s i g n e d t o an e l e c t r i c a l l y - h e a t e d , t h e r m o s t a t i c a l l y - c o n t r o l l e d  adjustable  All  triplicate  were  t h e c h i c k s were k i l l e d  r e p l i c a t e g r o u p w e r e s e l e c t e d a t random f o r the abdominal  pad and t h a t a s s o c i a t e d  adipose  w i t h the  tissue  viscera.  which  and  three  determination  i n c l u d e d the  abdominal  0  29  3.1.3 Experiment 1  -  Results  Statistical  analysis  m a r i z e d i n T a b l e 2) t h e same  final  the source  grams,  values  per b i r d fed d i e t s respectively.  gains  Fig.  1,2,3  1 shows t h e c l o s e n e s s  among  made t h e p o o r e s t  e x c e p t i o n o f the f o u r t h week, w e e k l y body w e i g h t g a i n s  the source o f  body w e i g h t g a i n s .  among  the various  d i e t a r y groups  e f f i c i e n c y values  are presented  e f f i c i e n c y was b e s t on t h e l o w - f a t h i g h - p r o t e i n  protein  diet  e f f i c i e n c y values  (diet 4).  low-fat high-protein  Next  and  on w e e k l y signifiIn groups.  suppleWith  the  t h e r e w e r e no s i g n i f i c a n t d i f f e r e n c e s  W i t h t h e e x c e p t i o n o f t h e s e c o n d week i n w h i c h t h e f o o d  food conversion  weight  the d i e t a r y  week t o t h e t e r m i n a t i o n o f t h e e x p e r i m e n t i n t h e s e v e n t h The f o o d c o n v e r s i o n  body  r e v e a l e d no  s i g n i f i c a n t d i f f e r e n c e s o c c u r r e d among  ( d i e t 2)  1646  the d i f f e r e n t d i e t a r y groups.  f e d t h e l o w - p r o t e i n d i e t i n w h i c h f a t was  mentary energy  of  from the  in third  week. in Table  4.  conversion  d i e t (diet 3),  the  were o b t a i n e d w i t h the h i g h - f a t  in order of food conversion  of  body  1665,  The d a t a ( T a b l e 3)  subjected to s t a t i s t i c a l a n a l y s i s , trait  regardless  The a v e r a g e  and 4 w e r e 1 6 5 3 ,  the experimental p e r i o d .  cant differences in this the f i r s t week,  (sum-  shows t h a t t h e c h i c k e n s w e r e a b l e t o a t t a i n p r a c t i c a l l y  w e i g h t t o a p p r o x i m a t e l y s e v e n weeks o f a g e ,  throughout  body w e i g h t  Birds  body w e i g h t g a i n s  of dietary energy/fat or protein l e v e l .  weight gains 1704  a p p l i e d t o the t o t a l  best high-  e f f i c i e n c y was  d i e t , i n d i c a t i n g b e t t e r food conversion  the  e f f i c i e n c y on  30  T a b l e 2.  Effect of dietary in  D  I  E  f a t and p r o t e i n  l e v e l s on b o d y w e i q h t g a i n s  E x p e r i m e n t 1.  Mean  T  Initial  1  B o d y W e i g h t s i n Grams Final  Gain  No.  Fat  Protein  1  Low  Low  68  1721  1653a  0  £_  High  Low  68  1733  1665a  3  Low  High  67  1713  1646a  4  High  High  66  1770  1704a  2  Means w i t h i n a c o l u m n f o l l o w e d by d i f f e r e n t (P <  0.05)  B i r d s were 2 days o l d a t  initiation.  letters  differ  significantly  31  D I  •  LOW FAT LOW PROTEIN  D2 1500  2  HIGH FAT LOW PROTEIN  03  •  D  ^  4  •  LOW FAT HIGH PROTEIN HIGH FAT HIGH PROTEIN  1000  H X CD  UJ  >Q O oo  <  UJ  500  _L  0 0  1  2  3  4  5  6  AGE (WEEKS) FIG. I:  EFFECT  OF DIETARY  ON BODY WEIGHT .  FAT AND PROTEIN  LEVELS  32  T a b l e 3.  Effect of weight  D  I  E  dietary  f a t and p r o t e i n  l e v e l s on w e e k l y  body  gain.  Mean  T  1  Body W e i g h t G a i n s i n  Grams  Weeks No.  Fat-  Protein  1  1  Low  Low  93bc  162b  214a  2  High  Low  89c  167b  3  Low  High  99b  .4  High  High  107a  2  3  5  6  7  225b  277a  344a  338a  218a  224b  266a  360a  341a  169b  209a  222b  269a  344a  334a  178a  221a  253a  272a.  338a  334a  Means w i t h i n a c o l u m n f o l l o w e d by d i f f e r e n t (P < 0 . 0 5 ) .  4  letters  differ  significantly  33  Table 4.  D  I  E f f e c t o f d i e t a r y f a t and p r o t e i n l e v e l s on food efficiency^,2.  E  T  conversion  Weeks  No.  Fat  Protein  1  2  3  4  5  6  7  Overall  1  Low  Low  1.51  1 .48  1.71  1.75  2.15  2.21  2.42a  1.89a  2  High  Low  1.53  1 .46  1.73  1.74  2.16  2.16  2.45a  1.89a  3  Low  High  1.34  1 .32  1.74  1,58  2.02  2.14  2.25a  1.77b  4  High  High  1.24  1 .33  1.62  1.44  2.00  2.04  2.30a  1.71b  ^Units o f food consumed per u n i t o f body weight g a i n . 7  Values w i t h i n a column followed by the same l e t t e r s a r e n o t s i g n i f i c a n t l y d i f f e r e n t (P < 0.05).  34  the h i g h - p r o t e i n conversion  T h e r e was  gave c o n s i s t e n t l y  weekly periods  of the  T h e r e was of  birds  birds  there  criterion. diet  Birds  T h i s t r e n d was a l s o  Birds  same f o o d c o n v e r s i o n  values  fat  fat, high-protein  as  diet  consumed)  in the low-protein  those  diets.  fed diets  gave the g r e a t e s t case level  of  the basal  protein conversion  food conversion  of d i e t a r y f a t  category.  conversion  shown i n F i g .  2.  weight  f e d t h e two l o w - p r o t e i n d i e t s ,  b e t t e r t h a n t h a t o b t a i n e d by b i r d s containing  effic-  high-  e f f i c i e n c y (body  significantly Birds  is  f e d t h e two  fat levels  efficiency values.  e f f i c i e n c y , the source  in the l o w - p r o t e i n d i e t s  that  gave p r a c t i c a l l y t h e  fed the h i g h - f a t  d i e t a r y groups  by t h e b i r d s  to  e v i d e n c e d by t h e f a c t  ( d i e t 3)  T a b l e 5 shows t h a t t h e p r o t e i n c o n v e r s i o n  gain/protein  does n o t a p p e a r  The t r e n d f o r t h e c u m u l a t i v e f o o d  f o r the various  consis-  converted food w i t h equal  ( d i e t 2)  e f f i c i e n c y v a l u e as  (diet 4).  diets  conversion.  ( d i e t 1)  fed the a d d i t i o n a l  fed the basal  efficiency  fed the low-protein  in low-protein diets  dietary fat  birds  similar  i n t h e s e c o n d week a f t e r w h i c h t h e y showed a  the e f f i c i e n c y of food conversion  protein diet  shown by  ( d i e t 3) w h i c h had e x h i b i t e d a  e x p e r i m e n t a l week.  of dietary f a t  those  all  t h e f o u r t h week when  fed the basal  i e n c y as  during  fed d i e t 4 except during  d e c l i n e i n e f f i c i e n c y of food  influence  values  food  i n the second  The l e v e l  •  lower food conversion  in the e f f i c i e n c y of  fed the other h i g h - p r o t e i n  tent  f e d t h e two l o w - p r o t e i n d i e t s .  d e c l i n e w i t h age  in this  showed i m p r o v e m e n t  food  experiment.  a consistent  was an i m p r o v e m e n t  tendency  no d i f f e r e n c e i n t h e o v e r a l l  e f f i c i e n c y between t h e b i r d s  These b i r d s  conversion  diets.  high-protein  (diets As  1 and  noted i n  of d i e t a r y energy d i d not  was  influence  or the  3) the the  35  FIG. 2: EFFECT OF DIETARY FAT AND PROTEIN  LEVELS  ON FOOD CONVERSION EFFICIENCY (CUMULATIVE).  T a b l e 5.  D  i  Protein conversion  efficiency  E • j  Body W e i g h t G a i n s / P r o t e i n Consumed ( g g~^) . Weeks 3 4 5 6 7  No.  Fat  Protein  1  2  0-7  1  Low  Low  3,.63  3.72  3.22  3.15  2.56  2.49  2.27  3.01  2  High  Low  3..59  3.77  3.18  3.15  2.55  2.54  2.24  3.00  3  Low  High  3..41  3.45  2.61  2.89  2.26  2.13  2.03  2.68  4  High  High  3..69  3.44  2.81  3.16  2.28  2.24  1.98  2.80  CO CTl  37  u t i l i s a t i o n of dietary  p r o t e i n as  r e f l e c t e d in the lack of  b e t w e e n t h e two l o w - p r o t e i n d i e t s w h i c h d i f f e r e d o n l y supplementary similar diets  dietary  i n the source  energy  and f a t  level.  is  interesting  relationship  existed  between b i r d s  f e d t h e two  the source  supplementary  which d i f f e r e d also fat  level.  in  . It  of  difference of  to note t h a t a high-protein energy  and  38  •3.1.4 Experiment 1  -  Discussion  Although chickens fed the high-fat high-protein d i e t grew s i g n i f i c a n t l y heavier in the f i r s t , second and fourth weeks than those fed the other experimental d i e t s , the f i n a l body weight gain data (Table 2), the weekly body weight gain data (Table 3), and the closeness of data on o v e r a l l growth rate (Fig. 1) do not demonstrate the concept that has been established f o r turkeys that supplementary f a t promotes superior growth. The absence of a s i g n i f i c a n t d i f f e r e n c e in l a t e r weeks in the f i n a l body weights between chickens fed e i t h e r fat-based or carbohydrate-based d i e t s indicates that the influence of d i e t a r y f a t on growth rate would be exhibited in early rather than l a t e in the l i f e of the b i r d .  This obser-  vation i s in close agreement with the f i n d i n g of Touchburn and Naber (1966) who reported that the b e n e f i c i a l e f f e c t of supplementary f a t on the performance of turkeys became less apparent in the f i n a l i n t e r v a l , 12 to 14.5 weeks of age and that of Salmon (1972) who did not obtain a s i g n i f i c a n t d i f f e r e n c e in the f i n a l weights between turkeys fed a highf a t d i e t f o r the e n t i r e 24 week experimental period compared with others fed a high-fat d i e t from 16 to 24 weeks. The observation that no s i g n i f i c a n t differences existed in the f i n a l body weights and the o v e r a l l body weight gains among the d i f f e r e n t d i e t ary groups could be reconciled with two w e l l - e s t a b l i s h e d concepts.  It  has been documented that as d i e t a r y f a t increases, lipogenesis assumes r e l a t i v e l y less importance (Donaldson, 1966) and that dietary f a t has a sparing e f f e c t on amino acid conversion to f a t t y acids.  As Donaldson  (1966) e x p l a i n s , " i f the t o t a l energy a v a i l a b l e f o r t i s s u e synthesis were  39  similar chicks acids  for chicks  w o u l d have t h e a d v a n t a g e and t h u s  might  protein  synthesis".  percent  in the  lipogenesis the  f e d b o t h f a t and  have  ' f a t - f r e e ' d i e t s , the f a t - f e d  of not  having  to synthesize  r e l a t i v e l y more e n e r g y  The l e v e l  dietary fat  of dietary f a t of  level  of  six  p e r c e n t may have  The p r o t e i n e f f i c i e n c y r a t i o d a t a this  view.  Ratios  of units  p r o t e i n - i n g e s t e d were h i g h e r protein diets. March only  These  results  ( 1 9 5 4 ) and W a i b e l if  w i t h the d i e t a r y energy  are  significance This  containing  5000  as,the to  energy  was  provide evidence  which  per u n i t  of  high-  with those of B i e l y promotion  increased  in  is  accordance  the d i e t a r y energy  t h e same and s i n c e  to protein r a t i o is  supports  concen-  t h e r e was  a f a c t o r of  t h e s t a t e m e n t o f S c o t t e t al_. (1969)  as much as  35 t o 40 p e r c e n t f a t and 45 t o 50  o r no c a r b o h y d r a t e , and w i t h e n e r g y  k c a l ME/kg, w i l l  support  e x c e l l e n t growth  and achieved  between t h e d i e t a r y groups w i t h i n  p r o t e i n a n d amino a c i d l e v e l s  the  5)  i n agreement  Since  lipo-  i n the promotion o f growth than the source of d i e t a r y  protein^ with l i t t l e as  series,  adequate.  o f body w e i g h t g a i n  concentration.  i t appears  observation  "Diets  the other  ( 1 9 5 8 ) who f o u n d t h a t g r o w t h  d i f f e r e n c e i n growth  series,  In  ten  depress  f o r the l o w - p r o t e i n d i e t s than the  t r a t i o n w i t h i n the p r o t e i n s e r i e s  protein  (Table  p e r c e n t and enough t o  fatty  tissue  s i m i l a r l y depressed  the c o n c e n t r a t i o n of d i e t a r y p r o t e i n i s  significant  six  protein synthesis.  g e n e s i s w h i l e t h e p r o t e i n l e v e l s may h a v e been  supports  available for  l o w - p r o t e i n d i e t s may h a v e been h i g h  and i n d u c e t i s s u e  tissue  values  no the greater energy.  that, percent as  high  i n young c h i c k s , . a s  a r e m a i n t a i n e d a t t h e optimum  ratios  energy".  The l a c k o f s i g n i f i c a n t d i f f e r e n c e s  in overall  body w e i g h t  long  gain  40  among was  t h e d i f f e r e n t d i e t a r y g r o u p s seems t o s u g g e s t a l s o  a superfluous  diets.  The w i d e r r a t i o  t h e same g r o w t h as  supply  o f p r o t e i n and amino a c i d s  as  b e i n g more e f f i c i e n t as Poults  given  the narrower f a r as  a low l e v e l  energy.protein  imbalance than those  1974).  Chickens  c o u l d be c o n s i d e r e d •  concerned.  o f age and w e r e more s e n s i t i v e given  higher  involved in this  l e v e l s o f added  study  may have  a s i m i l a r manner t o t h e d i f f e r e n t d i e t a r y e n e r g y : p r o t e i n ticularly for  t h e w i d e r r a t i o i n t h e f i r s t f o u r weeks  the v a r i a t i o n i n growth  i n the p e r i o d under  The d a t a on body w e i g h t s  of birds  studied  t h e f i n d i n g o f V e r m e e r s c h and V a n s c h o u b r o e k fat  incorporated at l e v e l s  weight  gain,  of dietary  there is  does n o t  ranging  results  improve  par-  could  account  in this  (1968)  experiment  that, while  confirm  dietary  f r o m 2 t o 20 p e r c e n t i m p r o v e s  body  level  r e l a t i n g to e f f i c i e n c y of food u t i l i s a t i o n substituted  affects this  and V a n s c h o u b r o e k ,  and V a n s c h o u b r o e k  tween e n e r g y  1968;  e t al_., 1971,  t h a t when f a t r e p l a c e s a change  i s o c a l o r i c a l l y f o r corn  trait.  which appear to c o n t r a d i c t the f i n d i n g s  is  in  reference.  the e f f i c i e n c y o f food u t i l i s a t i o n .  show t h a t p r o t e i n l e v e l  there  reacted  no r e l a t i o n s h i p b e t w e e n body w e i g h t and  show t h a t c o r n o i l  Vermeersch  dietary  ratios,  and t h i s  to  fat.  The o v e r a l l ( T a b l e 4)  produced  o f added d i e t a r y f a t r e q u i r e d a n a r r o w e r  r a t i o t o f o u r weeks  (Salmon,  is  there  high-protein  having  r a t i o , 154:1,  protein level  energy:protein  fat  i n the  ( K c a l : p e r c e n t p r o t e i n ) , 186:1  response  that  rather  1970;  and N a b e r ,  Jensenet  n o t be l o s t o f t h e  results  1966; ,  1970  fact  s t a r c h g r a v i m e t r i c a l l y r a t h e r than i s o c a l o r i c a l l y  not only  and o t h e r  should  The r e s u l t s  i n t e r p r e t i n g these  of Touchburn  Herstad,  sight  In  starch  in calorie density  nutrients.  but a l s o  i n the r a t i o  be-  41  The l a c k o f s i g n i f i c a n t conversion and t h o s e  differences  between t h e c h i c k e n s f e d on t h e h i g h - f a t  l o w - p r o t e i n d i e t (2)  and t h e s u p e r i o r i t y  porating  high-protein  ing low-fat high-protein strate fats  again  should  (4)  the v a l i d i t y of  the suggestion  that diets  food conversion  high-protein  diet is  level  of protein  e f f i c i e n c y value. values  protein  is  ratio.  triglyceride relative supply  This  consistent  in  CoA f o r e n e r g y  A possible  fed  requirement or  and  the  satisfactory  f a t from the i n t e s t i n e ,  f a t t y acids  demon-  explanation  with a favourable  t h e e p i t h e l i u m and o f t r a n s p o r t  to the e f f i c i e n c y w i t h which  acetyl  of  contain-  achieve  w i t h the r e p o r t e d low energy  i n and t h e a b s o r p t i o n  resynthesis  in order to  d i e t c o n t a i n e d a more  concentration associated  incor-  incorporating  obtained with chickens  that this  (1)  duration  o v e r t h e g r o u p f e d on t h e d i e t s t a t i s t i c a l analysis  contain a concomitant  hydrolysis  the  o f t h e g r o u p f e d on t h e d i e t  m e t a b o l i s a b l e energy  fat  throughout  i n the o v e r a l l  the b e t t e r food conversion  high-fat  food  (3)  a satisfactory for  the e f f i c i e n c y o f  f e d on t h e l o w - f a t l o w - p r o t e i n d i e t  o f the experiment high-fat  in  and  calorie: cost  of  of deposition  carbohydrates  fat synthesis  (Annison,  1971).  42  3.2.1 Experiment 2  -  Results  The m e t a b o l i s a b l e energy v a l u e s are p r e s e n t e d i n T a b l e 6.  (ME) f o r the f o u r e x p e r i m e n t a l  diets  In the f i r s t week, b i r d s which were f e d the  l o w - f a t h i g h - p r o t e i n d i e t ( d i e t 3) m e t a b o l i s e d energy b e t t e r than b i r d s fed a l l o t h e r e x p e r i m e n t a l d i e t s .  significantly The d i f f e r e n c e s  between a l l o t h e r d i e t a r y t r e a t m e n t s d u r i n g the r e s t o f the e x p e r i m e n t a l p e r i o d s were not s t a t i s t i c a l l y s i g n i f i c a n t . n i f i c a n t d i f f e r e n c e i n the combined v a l u e s period.  The t r e n d observed  However, t h e r e was a s i g f o r the e n t i r e e x p e r i m e n t a l  i n the f i r s t week was repeated i n the o v e r a l l  m e t a b o l i s a b i 1 i t y o f the d i e t s w i t h the v a l u e f o r the b a s a l - f a t  high-  p r o t e i n d i e t s being s i g n i f i c a n t l y h i g h e r than the two l o w - p r o t e i n d i e t s . The added f a t appeared t o i n f l u e n c e m e t a b o l i s a b i 1 i t y o f the d i e t s  incor-  p o r a t i n g the low p r o t e i n l e v e l s as evidenced by the s i g n i f i c a n t l y  higher  ME v a l u e s f o r the l o w - p r o t e i n d i e t ( d i e t 2) which c o n t a i n e d f o u r p e r c e n t more f a t than the o t h e r . As shown i n T a b l e 7, no s i g n i f i c a n t d i f f e r e n c e s were observed a d i p o s e t i s s u e , among the f o u r d i e t a r y groups.  in  B i r d s f e d the l o w - p r o t e i n  d i e t i n which f a t r e p l a c e d s t a r c h ( d i e t 2) gave the h i g h e s t adipose weights each week throughout  the whole e x p e r i m e n t a l p e r i o d .  Birds  tissue fed  the h i g h - p r o t e i n d i e t i n which f a t r e p l a c e d s t a r c h ( d i e t 4) gave the second h i g h e s t  adipose t i s s u e weights.  The lowest adipose t i s s u e  weights  were o b t a i n e d i n b i r d s f e d the d i e t i n c o r p o r a t i n g the basal  level  d i e t a r y f a t and high l e v e l o f p r o t e i n ( d i e t 3 ) .  observable  variations  There were  w i t h i n the d i e t a r y groups d u r i n g each week.  of  43  T a b l e 6.  E f f e c t o f d i e t a r y f a t and p r o t e i n l e v e l s on m e t a b o l i s a b i l i t y of energy.  D  I  E  Calories  T  1  per grani o f food Weeks  No.  Fat  Protein  1  2  4  7  Overal1  1  Low  Low  3343a  3460a  3568a  3560a  3483a  2  High  Low  3270a  3482a  3530a  3516a  3450a  3  Low  High  3429b  3532a  3604a  3533a  3525b  4  High  High  3280a  3469a  3618a  3560a  3482a  Means w i t h i n a column f o l l o w e d by d i f f e r e n t l e t t e r s are different  (P <  0.05).  significantly  44  T a b l e 7.  E f f e c t o f f a t a n d p r o t e i n l e v e l s on -mean tissue  abdominal  adipose  weight.  Grams D  I  E  T Weeks  No.  Fat  Protein  1  Low  Low  1.57±0?07  4.87+0.84  15.30+0.72  22.76+4.84  2  High  Low  2.10+0.21  6.20 o.03 ±  17.67+1.23  32.67^-2.70  3  Low  High  1.60*0,06  4.80+TJ.33  13.07+1,39  19.03+1.36  4  High  High  1.60+0.17  6.17+0.50  13.07+0.83  27.00+1.31  1  S t a n d a r d e r r o r o f means.  2  4  7  45  The u t i l i s a t i o n o f m e t a b o l i s a b l e essentially A similar  t h e same f o r  relationship  f o r the second first  high l e v e l s  utilised parison  protein.  intake for  up t o t h e f o u r t h w e e k . groups d i d  not e x i s t  metabolisable  energy  t h e g r o u p t h a t was  fed the  energy  p e r gram o f  was  slight  dietary fourth  groups  energy  2,  intake  gain  difference  high-fat  and s i x t h weeks  8).  protein  diets  in  All  high-protein  birds  All  levels  two weeks  except  utilised  less  metabolisable  were 4,  occurred  and w e r e a t t r i b u t a b l e t o  gain  utilised  dietary  among t h e d i e t a r y  deaths  the losses  in  shown by a l l  Mortality  The r e s p e c t i v e  d i e t which  An i n c r e a s e  g a i n was  Com-  protein-level  groups of  high-protein  diet  body w e i g h t  t h e two  the  con-  with high-protein  between  week.  body w e i g h t  3 and 4 .  (Table  i n body w e i g h t .  p e r gram o f  fed the d i e t s  and s u b s e q u e n t w e e k s .  1,  fed the l o w - f a t  i n t h e f i r s t week.  and v a r i a b l e .  was  However,  w i t h t h e same e f f i c i e n c y i n t h e f i r s t  energy  in the f o u r t h  higher  the experiment.  for a unit  i n the seventh  metabolisable intake  Birds  chickens This  of  fed the  diets  gain  b e t w e e n t h e two g r o u p s f e d d i e t s  energy  the m e t a b o l i s a b l e  less  weeks  a difference of  f o r body w e i g h t  fed the low-protein  shown by c h i c k e n s  less metabolisable of  revealed  was  and t h e s e v e n t h  week t h e r e was  taining  chickens  energy  2,  perosis.  groups  1 and 3  between  groups  the  for  46  Metabolisable energy intake per b i r d per gram body weight gain  D  I . •E  T  No.  Fat  Protein  1  Low  Low  2  High  3  4  WEEKS  1  Factor  1  2  4  7  ME (kcal/kg d i e t ) Food intake (g)^ ME intake (kcal) . Weight gain (g) ME/Weight gain  3343 • 20.1 67.3 13.3 5.1  3460 34.2 118.5 23.2 5.1  3568 54.2 193.5 31.1 6.2  3560 117.0 416.4 48.3 8.6  Low  ME (kcal/kg d i e t ) Food intake (g) ME intake (kcal) Weight gain (g) ME/Weight gain  3270 19.5 63.6 12.7 5.0  3482 34.8 121.1 23.9 5.1  3530 55.2 194.8 31.6 6.2  3516 114.9 404.0 46.8 8.6  Low  High  ME (kcal/kg d i e t ) Food intake (g) ME intake (kcal) Weight gain (g) ME/Weight gain  3429 19.0 65.0 14.2 4.6  3532 31.9 112.7 24.1 4.7  3604 49.8 176.6 31.5 5.7  3533 107.3 379.0 47.7 7.9  High  High  ME (kcal/kg d i e t ) Food intake (g) ME intake (kcal) Weight gain (g) ME/Weight gain  3280 19.4 63.5 15.6 4.1  3469 32.6 113.1 24.6 4.6  3618 50.6 182.9 35.0 5.2  3560 110.3 392.6 47.9 8.2  The birds were 2 days old at the commencement of feeding experimental diets. Food intake per b i r d .  47  3.2.2 Experiment 2  -  Discussion  The r e s u l t s o f the m e t a b o l i s a b l e energy d e t e r m i n a t i o n s  (Table 6)  suggest the need f o r d i e t a r y c a r b o h y d r a t e c a l o r i e s e a r l y i n the o f the b r o i l e r c h i c k e n .  The f a c t t h a t the d i e t s i n c o r p o r a t i n g  life higher  f a t l e v e l s were more p o o r l y m e t a b o l i s e d makes i t r e a s o n a b l e t o assume t h a t high d i e t a r y f a t l e v e l depresses c h i c k s t o one week of age.  It  m e t a b o l i s a b i l i t y o f d i e t s i n young  i s known t h a t f a t s and o i l s have  a very high a v a i l a b i l i t y o f m e t a b o l i s a b l e energy 1969).  chicks  Sakurai,  (Whitehead and  Fisher,  I t has been e s t a b l i s h e d t h a t corn o i l i s r e a d i l y absorbed (Renner and H i l l ,  1960)  by  and t h a t the l e v e l o f a b s o r b a b i l i t y  the same up t o 8 weeks o f age. al.  and  However, the m e t a b o l i s a b l e energy c o n t e n t o f a f a t i s the product  o f i t s g r o s s energy c o n t e n t and i t s a b s o r b a b i l i t y 1975).  (Tasaki  normally  remains  More r e c e n t d e t e r m i n a t i o n s by Carew e_t  (1972) o f a b s o r b a b i l i t i e s o f corn o i l by c h i c k s i n d i c a t e t h a t the  newly hatched c h i c k t o 7 days o f age does not have f u l l capacity for fat absorption.  It  physiological  i s suspected t h a t the c h i c k s  i n t h i s study must have absorbed f a t at a s u b - o p t i m a l  involved  e f f i c i e n c y and t h i s  c o u l d have r e s u l t e d i n a lowered m e t a b o l i s a b l e energy i n t a k e i n the week.  I t i s d i f f i c u l t to e x p l a i n the d i s c r e p a n c y between the  first  observed  h i g h e r body weight g a i n s on the h i g h - f a t d i e t s i n the f i r s t week (Table 3) and the lower m e t a b o l i s a b l e energy v a l u e s on the same d i e t s i n the same period.  The h i g h e r a d i p o s e t i s s u e c o n t e n t o f the high f a t d i e t s may  have c o n t r i b u t e d t o the h i g h e r body w e i g h t s .  There i s evidence t h a t 10  t o 15 p e r c e n t more energy was d e p o s i t e d i n the c a r c a s s  of  chickens  48  r e c e i v i n g d i e t s c o n t a i n i n g 5 t o 10 p e r c e n t f a t compared w i t h s i m i l a r d i e t s low i n f a t and t h a t t h i s phenomenon o c c u r r e d even when m e t a b o l i s a b l e energy Forbes  i n t a k e from t h e two d i e t s was the same (Carew e t a l _ . , 1964).  and S w i f t  the a s s o c i a t i v e  (1944) observed t h i s phenomenon i n r a t s and termed i t dynamic a c t i o n o f f a t s .  The improvement  in  energetic  e f f i c i e n c y can be a t t r i b u t e d t o a lower m e t a b o l i c c o s t of u t i l i s i n g i n comparison  t o the o t h e r major source o f d i e t a r y energy  -  fats  carbohydrate.  The s u g g e s t i o n t h a t poor a b s o r b a b i l i t y may have c o n t r i b u t e d to the observed d e p r e s s i o n  i n m e t a b o l i s a b l e energy v a l u e s  seems v a l i d i n the l i g h t o f the observed b i l i t y of d i e t s i n c o r p o r a t i n g  improvement  diets  i n the m e t a b o l i s a -  high d i e t a r y f a t i n subsequent weeks  they had developed t h e i r p h y s i o l o g i c a l lack of s i g n i f i c a n t d i f f e r e n c e s d i e t s from two through  o f the h i g h - f a t  when  capacity for fat absorption.  i n the m e t a b o l i s a b l e energy v a l u e s  The o f the  seven weeks i s i n t e r e s t i n g from the p o i n t of view  of i t s economic i m p l i c a t i o n s .  In terms o f m e t a b o l i c i m p l i c a t i o n , i t  has  been r e p o r t e d t h a t p r o t e i n i s not the o n l y d i e t a r y f a c t o r t h a t must be a d j u s t e d commensurate w i t h d i e t a r y f a t l e v e l et_ a]_. , 1955).  ( A i t k e n et_ a l _ . , 1954;  The l e v e l s o f o t h e r n u t r i e n t s , n o t a b l y some v i t a m i n s ,  r e q u i r e adjustment  (March and B i e l y , 1955, 1956; Looi and Renner,  It f o l l o w s that the s u b s t i t u t i o n of f a t c a l o r i e s f o r starch w i t h o u t changing  Slinger  the p r o p o r t i o n s  of other d i e t a r y f a c t o r s ,  the m i c r o n u t r i e n t s , c r e a t e s an imbalance among n u t r i e n t s . on the h i g h - f a t d i e t s o f p e r o s i s ,  calories particularly The  incidence  a c o n d i t i o n a t t r i b u t a b l e to a d e f i c i e n c y  o f manganese c o u l d have been p r e c i p i t a t e d by n u t r i e n t imbalance. et al_. (1973) observed  1974a).  small d i f f e r e n c e s  i n metabol i s a b l e energy  Farrell values  comparable t o those being r e p o r t e d i n t h i s study and e x p l a i n e d the poor  49  growth r a t e o f b r o i l e r s f e d d i e t s o f v a r y i n g energy c o n c e n t r a t i o n s  on  the b a s i s of n u t r i e n t imbalance o r d e f i c i e n c y . Wide v a r i a b i l i t y o c c u r r e d w i t h i n the d i e t a r y groups and t h i s  could  have c o n t r i b u t e d t o the l a c k o f s i g n i f i c a n t d i f f e r e n c e s i n a d i p o s e  tissue  a c c u m u l a t i o n among the d i f f e r e n t t r e a t m e n t groups i n the f i r s t two weeks o f the e x p e r i m e n t a l p e r i o d . (2)  Chickens  f e d the h i g h - f a t l o w - p r o t e i n d i e t  showed a s i g n i f i c a n t l y h e a v i e r a d i p o s e t i s s u e weight i n the f o u r t h  and seventh weeks  (Table 7 ) .  It  i s i n t e r e s t i n g t o note t h a t the  periods  i n which the b i r d s f e d the h i g h - f a t l o w - p r o t e i n d i e t s d e p o s i t e d s i g n i f i c a n t l y more a d i p o s e t i s s u e c o i n c i d e d w i t h the p e r i o d s  i n which the group  i n q u e s t i o n gave the lowest m e t a b o l i s a b l e energy v a l u e s . f e r e n c e s i n the l a t t e r response nificance  (P < 0.05)  S i n c e the d i f -  c r i t e r i o n d i d not reach s t a t i s t i c a l  sig-  t h e r e was l i t t l e o r no b a s i s t o e x p l o r e the p o s s i b i l i t y  of a s t a t i s t i c a l r e l a t i o n s h i p .  The reasons f o r the d i f f e r e n c e s i n f a t  d e p o s i t i o n among the t r e a t m e n t groups are not immediately o b v i o u s . the h i g h e s t d e p o s i t i o n o f f a t o c c u r r e d i n b i r d s f e d the h i g h - f a t  Since low-  p r o t e i n d i e t , the p o s s i b i l i t y e x i s t s t h a t the 18 p e r c e n t p r o t e i n l e v e l adequate i n terms o f amino a c i d l e v e l s and b a l a n c e .  was  With an adequate  s u p p l y o f amino a c i d s and preformed f a t t y a c i d s , the magnitude of n u t r i e n t interconversions saving  would be c o m p a r a t i v e l y l e s s and t h i s would r e s u l t i n a  i n energy which would have been expended on b i o s y n t h e s i s  t h a t might be r e q u i r e d . into fat.  It  The " s u r p l u s "  nutrients  energy c o u l d have been c o n v e r t e d  i s noteworthy t h a t f a t d e p o s i t i o n i n b i r d s f e d the  h i g h - p r o t e i n d i e t was l e s s than t h a t i n b i r d s f e d the h i g h - f a t diet.  of  high-fat  low-protein  The p o s s i b i l i t y e x i s t s t h a t the energy saved as a r e s u l t o f the  s p e c i f i c dynamic e f f e c t o f f a t was d i r e c t e d towards u t i l i s i n g more p r o t e i n f o r muscle t i s s u e s .  T h i s view becomes more a t t r a c t i v e w h e n . i t i s  considered  50  t h a t b i r d s f e d the l o w - f a t h i g h - p r o t e i n d i e t , which was i s o c a l o r i c w i t h the o t h e r d i e t s , d e p o s i t e d the l e a s t amount o f adipose  tissue.  The r e s u l t s r e l a t i n g t o the e f f i c i e n c y o f m e t a b o l i s a b l e  energy  u t i l i s a t i o n u s i n g the number o f c a l o r i e s o f m e t a b o l i s a b l e energy per a gram o f body weight g a i n as a response  c r i t e r i o n (Table 8) were the same  f o r the d i e t s c o n t a i n i n g the low p r o t e i n l e v e l . shown between the h i g h - p r o t e i n d i e t s .  A . s i m i l a r e f f e c t was  The lower r a t i o s o b t a i n e d on the  d i e t s i n c o r p o r a t i n g h i g h e r p r o t e i n l e v e l s and which c o n t a i n e d a narrower c a l o r i e r p r o t e i n r a t i o , a g a i n emphasize the importance o f t h i s p r i n c i p l e w i t h r e g a r d t o the e f f i c i e n t metabolism o f d i e t a r y energy and n u t r i e n t s . The c o n c l u s i o n s  t o be drawn on t h e r e s u l t s o f t h i s study agree  w i t h those r e p o r t e d by Payne and Lewis Farrell  essentially  ( 1 9 6 4 ) , F a r r e l l ejt al_. ( 1 9 7 3 ) , and  ( 1 9 7 4 ) , i n t h a t t h e r e appears t o be an optimum energy  concentration  i n the d i e t beyond which performance of b i r d s does not appear t o improve and i n some cases a c t u a l l y d e t e r i o r a t e s .  Payne and Lewis  (1964)- found  t h a t growth r a t e o f b r o i l e r c h i c k e n s d i d not i n c r e a s e a t energy above 3.1  levels  Meal ME/kg and c a l o r i e s consumed per gram o f g a i n were the same  f o r d i e t s above 3.2 Meal ME/kg.  51  3.3  The E f f e c t o f Added C e l l u l o s e  on t h e P e r f o r m a n c e  of  Broiler  Chicks  3.3.1 Experiment  3  -  The d o m e s t i c Cellulose tal  has  diets.  In  Introduction  c h i c k e n has  been u s e d f r e q u e n t l y as a d d i t i o n to increasing  to a c c e l e r a t e the r a t e of strate-enzyme and a b s o r p t i o n  limited digestive  an i n e r t f i l l e r the bulk  p a s s a g e w h i c h means  c o n t a c t and a c o n s e q u e n t of n u t r i e n t s .  The p r e s e n c e  been i n v e s t i g a t e d  an a s s u m p t i o n  sufficiently.  that the presence  a shortened  compared w i t h t h o s e  chicken. of d i e t s  The r e s u l t s  older  t h a n one  d e v o i d o f added c e l l u l o s e  added c e l l u l o s e have  i n f o r m a t i o n as  2 justify to  life  of  the  metabolisabi1ity  chicks  i n d i c a t e d above  which  prompted the  t o be c o n d u c t e d w i t h t h e o b j e c t i v e o f e v a l u a t i n g  o f a d d e d c e l l u l o s e on g r o w t h isability  involved  on  has  ingredient  in the e a r l y  published  sub-  cellulose  Experiment  included that  known  were  week.  The p a u c i t y o f experiment  of  experimen-  food  o f c e l l u l o s e m u s t have c o n t r i b u t e d  U n f o r t u n a t e l y , most o f t h e . p a p e r s incorporating  of.added  of  important problem t h a t  the poorer m e t a b o l i s a b i l i t y of the d i e t s which as  is  time f o r  in digestion  and l e v e l  foods.  i n many p o u l t r y  of food, c e l l u l o s e  reduction  i n p o u l t r y d i e t s , t h e r e f o r e , imposes a v e r y not  capacity for fibrous  of energy  and f a t  r a t e , food conversion deposition.  following  the e f f e c t  e f f i c i e n c y , metabol-  52  3.3.2  Experiment  3  -  Day-old six  chicks  Materials  and  Methods  b r o i l e r c h i c k s w e r e r a n d o m l y d i s t r i b u t e d i n t o 12 g r o u p s  each.  A l l g r o u p s were p l a c e d i n a s i x - t i e r b a t t e r y  equipped with wire f l o o r s  groups tively, in  per treatment. as d i e t s  T a b l e 9.  1,  Diets  The t r e a t m e n t s w e r e f o u r d i e t s  2,  3 and 4 .  3 and 4 i n c o n t a i n i n g  individual  treatments,  designated,  c o r n s t a r c h as  contained corn o i l  s i x weeks. body w e i g h t s .  as  was  Records  fed i t s  shown  source  1 and 2 d i f f e r e d f r o m of supplementary  of supplementary  diets  energy.  energy.  e x p e r i m e n t a l d i e t and w a t e r ad  were kept o f w e e k l y food consumption  Food c o n v e r s i o n  e x c r e t a were c o l l e c t e d a t 24-hour each e x p e r i m e n t a l week.  the  the source  from the weekly food consumption  e f f i c i e n c y values  and body w e i g h t g a i n  were  data.  i n t e r v a l s on t h e l a s t  and  computed  Samples  t h r e e days  of  of  The d a i l y c o l l e c t i o n s w e r e i m m e d i a t e l y f r o z e n  and t h e t h r e e - d a y c o l l e c t i o n s f o r e a c h g r o u p w e r e p o o l e d t o g e t h e r , lized,  three  respec-  The c o m p o s i t i o n o f t h e d i e t s a r e  added c e l l u l o s e D i e t s  Each group o f c h i c k e n s 1ibiturn f o r  units.  1 and 3 w e r e d e v o i d o f a d d e d c e l l u l o s e w h i l e 2 and 4  each c o n t a i n e d 11.2 p a r t s  The l a t t e r  brooder  and t h e r m o s t a t i c a l l y - c o n t r o l l e d h e a t i n g  The g r o u p s w e r e a s s i g n e d a t random t o f o u r e x p e r i m e n t a l  of  f i n e l y g r o u n d and k e p t i n s c r e w - c a p p e d  glass jars  for  lyophi-  various  analyses. Moisture of  nitrogen  was d e t e r m i n e d a c c o r d i n g t o A . O . A . C . m e t h o d .  c o n t e n t o f t h e d i e t and f a e c a l  samples  was  c o n d u c t e d by  Kj e l d a h l m e t h o d and g r o s s e n e r g y  by bomb c a l o r i m e t r y u s i n g  jacket  The s u b s t a n c e  o x y g e n bomb c a l o r i m e t e r .  u s e d as  Determination  Parr  an i n d e x  the  plain for  53  T a b l e 9.  .Composition  of diets  fed in Experiment  3.  D I E T Ingredient  1  2  3  4  weight H e r r i n g meal  21.3  21.3  21.3  21.3  Ground wheat  53.0  53.0  53.0  53.0  Corn  19.2  19.2  3.0  3.0  11.0  11.0  1.5  1.5  1.5  1.5  Limestone  1.0  1.0  1.0  1.0  Salt  0.5  0.5  0.5  0.5  0.5  0.5  0.5  0.5  starch  Corn o i l Calcium  Premix  phosphate  1  •-  Cel1ulose  Total  weight  Calculated analysis  100.0  Protein ME  111.2  ME: CP  Micronutrients  as  11.2  88.8  100.0  24.7  21.9  %  21.9  (kcal/kg)  -  11.2  chemical  -  -  19.8  3382  3046  3814  3385  154  154  154  154  in Table  1.  54  digestibility is  c o e f f i c i e n t was 4N HC1  essentially  t h e one d e s c r i b e d  and e x c r e t a , a p p r o x i m a t e l y were used.  The s a m p l e s  4N HC1  f o r 30 m i n u t e s .  filter  paper,  drops  of  were h y d r o l y s e d The h y d r o l y s a t e s  tested with litmus  were ashed  were d e t e r m i n e d u s i n g  The m e t h o d  e_t a l _ . ( 1 9 7 5 ) .  by means o f b o i l i n g were f i l t e r e d  a t 600°C  paper).  f o r a minimum o f s i x  values  the f o l l o w i n g  in  free of  food  samples  through  The f i l t e r  used  For  10 and 5 grams r e s p e c t i v e l y o f d r y  The m e t a b o l i s a b l e e n e r g y  MEd  by Vogtmann  ash.  and w a s h e d w i t h d i s t i l l e d w a t e r u n t i l  filtrate  hydrolysates  insoluble  100 ml  of  ashless  acid'(final  papers  with  the  hours.  c o r r e c t e d to nitrogen  equilibrium  equation:  =  CEd - CEe X-.-j^j- - 8 . 2 2  ( N d - Ne X ^  )  MEd  =  Metabolisable  CEd  =  Combustible  energy  p e r gram o f  diet  CEe  =  Combustible  energy  p e r gram o f  excreta  Ad  =  Ash  p e r gram o f  diet  Ae  =  Ash  p e r gram o f  excreta  Nd  =  Nitrogen  8.22  =  Combustible  where, energy  p e r gram o f energy  The d a t a w e r e a n a l y s e d  This continued  weeks  m i x i n g o f a second of  time.  diet  excreta acid (kcal/g  s t a t i s t i c a l l y using m u l t i p l e range  of  N)  the a n a l y s i s  tests  of  variance  w e r e u s e d t o t e s t means  different.  e x p e r i m e n t was to s i x  k i l o - c a l o r i e s p e r gram o f  of uric  and t h e Student-Newman-Keuls which are s i g n i f i c a n t l y  in  originally  before  i t was  batch of d i e t s  designed  to l a s t  terminated.  a t f o u r weeks  t h r e e weeks  This  but i t  necessitated  f o r the extended  the  period  was  55  3.3.3 Experiment 3  -  Results  A summary o f the e f f e c t o f t h e d i e t a r y t r e a t m e n t s on t o t a l weight g a i n i s p r e s e n t e d i n T a b l e 10.  body  Average body weight g a i n  obtained  w i t h the l o w - f a t c e l l u l o s e - a d d e d d i e t was s i g n i f i c a n t l y lower than t h a t o b t a i n e d w i t h the h i g h - f a t c e l l u l o s e - e x c l u d e d d i e t . source o f d i e t a r y energy,  higher t o t a l  On the b a s i s o f  body weight g a i n s were o b t a i n e d  w i t h the f a t - b a s e d than w i t h the s t a r c h - b a s e d  diets.  W i t h i n the s e t  r e l a t i n g t o energy s o u r c e , h i g h e r body weight g a i n s were o b t a i n e d w i t h the d i e t s which d i d not i n c o r p o r a t e c e l l u l o s e . weight g a i n were a n a l y s e d on weekly b a s i s  When the data on body  (Table 1 1 ) , i t was shown t h a t  the b i r d s f e d the d i e t s w i t h o u t added c e l l u l o s e were g e n e r a l l y  slightly  h e a v i e r than those fed the d i e t s i n c o r p o r a t i n g added c e l l u l o s e . progressive  increases  The  i n body weight g a i n on the " c e l l u l o s e - f r e e " d i e t s  were r e f l e c t e d i n s i g n i f i c a n t d i f f e r e n c e s i n mean weekly body weight g a i n s among the d i e t a r y groups i n the t h i r d and s i x t h weeks o f the e x p e r i m e n t a l period.  F i g . 3 shows the t r e n d o f growth, among the d i f f e r e n t d i e t a r y  groups. The a d d i t i o n o f f a t r e s u l t e d i n improved e f f i c i e n c y o f food i n the f i r s t t h r e e weeks.  conversion  B i r d s f e d the d i e t s i n c o r p o r a t i n g added  l u l o s e made poorer c o n v e r s i o n o f f o o d .  The poorest food  cel-  conversion  e f f i c i e n c y v a l u e s were o b t a i n e d c o n s i s t e n t l y w i t h the b i r d s fed the l o w f a t c e l l u l o s e - i n c l u d e d d i e t (Table 12).  The r e l a t i o n s h i p e x i s t i n g  the determined food c o n v e r s i o n e f f i c i e n c y v a l u e s as p l o t t e d a g a i n s t weekly p e r i o d o f time i s markedly a l t e r e d when the a d j u s t e d food s i o n e f f i c i e n c y v a l u e s are s i m i l a r l y p l o t t e d .  among each  conver-  As shown i n F i g . 4, the  56  T  a  b  1  e  1 0  -  E f f e c t of source  of supplementary  c e l l u l o s e on t o t a l  D No.  I Starch  E  T Fat  1  +  Basal  2  +  Basal  3  -  4  -  2  body w e i g h t  d i e t a r y energy  gain.  Mean b o d y Cel1ulose  Initial  1  weight^ Final  (+)>  (-)>  in  grams Gain  33  1227  1194ab  +  33  1170  1137b  +  -  32  1327  1295a  +  +  32  1286  1254ab  Means w i t h i n a c o l u m n f o l l o w e d by d i f f e r e n t l e t t e r s a r e different  and  (P <  signifies  0.05). present,  absent,  respectively.  significantly  57  T  a  b  1  e  1  T  '  E f f e c t of source of supplementary d i e t a r y cellulose  D  I  E  on w e e k l y body w e i g h t  T  energy  and  gains.  Mean  body w e i g h t p a i n s  in  grams  Weeks No.  Starch  1  Fat  Cellulose  Basal  _2  Initial  1  (33)  55a  138a  2  3  4  5  203ab  233a  261a  306ab  6  2  +  Basal  +  (33)  55a  127a  .188b  229a  272a  267b  .3  -  +  -  (32)  61a  135a  221a  252a  295a  331a  4  -  +  +  (32)  64a  139a  221a  240a  292a  297ab  Means i n a c o l u m n f o l l o w e d by d i f f e r e n t different (+)•>  (-),  (P <  letters  are  0.05).  s i g n i f i e s , present, absent,  respectively.  significantly  58  1500 r -* 3 % OIL, NO ADDED CELLULOSE  DI  3 % OIL, 11.2% ADDED CELLULOSE  D2 D3 D4 ^  -  • 1I%0IL, NO ADDED CELLULOSE ||%0IL,II.2% ADDED CELLULOSE//  1000 X CD  UJ  >-  o o  GO  < Ul 2  500  0  2  3 AGE  FIG.3  4  (WEEKS)  EFFECT OF SOURCE OF SUPPLEMENTARY DIETARY ENERGY AND CELLULOSE ON FOOD CONVERSION EFFICIECY.  59  differences  among t h e t r e a t m e n t g r o u p s a r e v i r t u a l l y e l i m i n a t e d o r  non-existent conversion  i n the adjusted values  e f f i c i e n c y values  The r e s u l t s are presented energy  (Table  compared t o t h e d e t e r m i n e d  i n T a b l e 13.  Severe  occurred  in the f i r s t  m e t a b o l i s a b l e energy  values  food  12a).  of the d e t e r m i n a t i o n s of m e t a b o l i s a b l e energy depression  was o b s e r v e d w i t h t h e d i e t s  depression  as  of metabolisabi1ity  incorporating cellulose.  week.  values  For the f i r s t  were p r o g r e s s i v e l y  higher  The  of greatest  t h r e e weeks for all  the  diets.  The i n t r o d u c t i o n o f a s e c o n d m i x o f d i e t was a t t e n d e d w i t h a d e c r e a s e m e t a b o l i s a b l e energy  values  m e t a b o l i s a b i 1 i t y o f energy A comparison (Table  13)  (Table  14),  i n t h e f o u r t h week. i n the subsequent  and t h e c o r r e s p o n d i n g  in  weeks. values  a d j u s t e d m e t a b o l i s a b l e energy  values  shows c l e a r l y t h e e f f e c t o f t h e a d d e d c e l l u l o s e on t h e  mined v a l u e s  is  The r e l a t i o n s h i p e x i s t i n g among  the  c o m p a r e d t o t h a t e x i s t i n g among t h e a d j u s t e d  effic-  deter-  values  5). The mean a d i p o s e  dietary  source  in this  experiment.  source as  a rise  between t h e d e t e r m i n e d m e t a b o l i s a b l e energy  iency of energy metabolism.  (Fig.  T h e r e was  in  of energy  of energy  appeared  Although  laid  the major source  the values  t i s s u e weights  are presented  the b i r d s  f e d d i e t s w i t h f a t as  this  a r e c o m p a r e d on t h e b a s i s  fed d i e t s with  d i f f e r e n c e becomes  of c e l l u l o s e l e v e l .  tissue  than those  fed diets  The  deposition the major carbohydrate  negligible  when  The b i r d s  w e r e f e d d i e t s w h i c h d i d n o t c o n t a i n a d d e d c e l l u l o s e had t h e adipose  15.  t o h a v e no i n f l u e n c e on f a t  down more f a t t h a n t h o s e  of energy,  in Table  heavier  c o n t a i n i n g added c e l l u l o s e .  which  60  Tabl e 12.  E f f e c t o f source o f supplementary energy  and c e l l u l o s e  on f o o d c o n v e r s i o n e f f i c i e n c y .  Units D No.  I  E  food per u n i t o f  T  Starch  Fat  1  +  Basal  2  +  Basal  3  -  4  -  Values  of  Weeks Cel 1 u l o s e  0-1  0-2  0-3  0-4  0-5  0-6  OveralT  1.24  1.28  1.47  1.52  1.67  1.81  1.50  a  +2  1.50  1.55  1.61  1.74  1.90  2.01  1.72  c  +  -  1.18  1.23  1.24  1.36  1.50  1.58  1.35  b  +  +2  1.21  1.37  1.38  1.53  1.73  1.91  1.52  a  w i t h i n a c o l u m n f o l l o w e d by t h e same l e t t e r  (P <  gain  0.05).  do n o t d i f f e r  significantly  61  e  12(a). E f f e c t of source of  supplementary d i e t a r y  c o m p o n e n t on f o o d c o n v e r s i o n on t h e b a s i s  efficiency calculated  o f i n g r e d i e n t s o t h e r than added c e l l u l o s e .  Adjusted units" of food 1  D No..  I  E  Starch  T Fat  Cellulose  +  Basal  -  2  +  Basal  +  3  -  + +  Values  per u n i t of  2  0.1  0.2  0.3  0.4  0.5  0.6  Overal1  1.24  1.28  1.47  1.52  1.67  1.81  1.50  a  1.35  1.39  1.45  1.56  1.71  1.81  1.55  a  1.23  . 1.24  1.36  1.50  1.58  1.35  b  1.22  1.23  .1.37  1.36  b  1.18 +  1.07  2  w i t h i n a c o l u m n f o l l o w e d by t h e same l e t t e r  nificantly  gain  Weeks  1  4  energy  (P <  0.05).  The a d d e d c e l l u l o s e was n o t u s e d  in c a l c u l a t i o n .  1.54 .  1.71  do n o t d i f f e r  sig-  62  1.8  1.6 h  DATA  ADJUSTED  FOR CELLULOSE  i cn  1.4 < CD  X (D  1.2  LU  >~ Q  O  1.0  CD  Lu O  DI —  D 2« D3 • LU Q_  D4 2.0 r  -  3 % OIL, NO ADDED CELLULOSE  •-  3 % OIL , 11.2 % ADDED CELLULOSE  -  1.1% OIL, NO ADDED CELLULOSE 11% OIL, 11.2% ADDED CELLULOSE  Q LU LU  CO r-  1  2  3  4  5  6  AGE ( W E E K S ) FIG. 4 :  EFFECT  OF SOURCE  OF SUPPLEMENTARY DIETARY ENERGY  AND CELLULOSE ON FOOD CONVERSION EFFICIENCY.  63  E f f e c t o f source o f supplementary d i e t a r y cellulose  on m e t a b o l i s a b l e e n e r g y  Calories D No.  1  I  E  Starch  2 +  2 3  T Cellulose  2  Basal  -  +  + +  4  +  Means i n a c o l u m n f o l l o w e d different (+)»  (-)»  values.  p e r gram o f  diet  Weeks  Fat  Basal  e n e r g y and  (P <  signifies  1  2  3  4  6  3349  3652  3777  3608  3608 c  2966  3148  3444  3177  3264 a  3252  3867  3933  3651  3863 d  2591  3268  3556  2972  3349 a  by d i f f e r e n t  letters  are  0.05). present, absent,  respectively.  significantly  Table  14.  Effect of energy  dietary  values  source  of supplementary  c a l c u l a t e d on t h e b a s i s  of  d i e t a r y energy ingredients  on  metabolisable  other  than  added  cellulose.  •  n  No.  r  T u  1  Starch  T  L  1  Fat  3  4  6  overal1  3608  3608  3596a  +  3298  3500  3830  3532  3630  3558a  +  -  3252  3867  3933  3651  3863  3713b  +  +  2917  3680  4004  3346  3771  3544a  2  +  Basal  3 4  (-),  2  3777  Basal  (+),  _2  1  1  3652  +  ^Means i n a c o l u m n (P<. 0.05).  Cellulose  values in diet  3349  1  2  Adjusted energy calories/g of Weeks  f o l l o w e d by d i f f e r e n t  signifies  present,  absent,  l e t t e r s are s i g n i f i c a n t l y  respectively.  different  65  DATA ADJUSTED FOR ADDED CELLULOSE 4000 *-..\  3500  UJ Q  3000  D <  D  ce o cc ui  3 % OIL, NO ADDED CELLULOSE 2  -  - 3 % OIL, 11.2% ADDED CELLULOSE  D3 • D 4  • 11% OIL, NO ADDED CELLULOSE  ».  _ ||% OIL, 11.2% ADDED CELLULOSE  CL  CO UJ  4000 r-  DC O -J <  o  ORIGINAL DATA.  3500  3000  2500  _i_  2  3  4  AGE (WEEKS) FIG. 5:  EFFECT OF SOURCE OF SUPPLEMENTARY DIETARY ENERGY AND CELLULOSE ON FOOD CONVERSION EFFICIENCY.  66  Table  15.  E f f e c t of source of supplementary d i e t a r y energy cellulose  Q No.  j  £  Starch  Fat  Cellulose  Basal  -  +  2  +  Basal  3  _  +  4  -  +  Standard (+)»  (-)>  (six-week)  adipose  tissue  Grams o f mean a b d o m i n a l  j  1  2  on f i n a l  •  (six-week)  25.72 ±  2.72  +  18.33  ±  1.95  _  31.79  ±  4.55  +  19.68  ±  2.89  2  e r r o r o f t h e mean. signifies  present, absent,  respectively.  1  and  weights.  fat  67  3.3.4 Experiment 3  -  The h i g h e r cellulose indicate weight  Morris  body w e i g h t g a i n s o f c h i c k e n s  i n comparison  (Table 10).  This  i n the l i t e r a t u r e .  e t al_. ( 1 9 3 2 ) ,  (1959),  to those  fed diets  finding is However,  t h a t f e e d i n g m o d e r a t e amounts  g r o w t h and i m p r o v e t h e u t i l i s a t i o n o f fibre  basal  diet.  tween t h e c h i c k e n s  the l o w - f a t ( c a r b o h y d r a t e - b a s e d ) , in  adverse  added  cellulose  e f f e c t s on  is  body  at variance with those  ( 1 9 4 7 , 1 9 4 8 ) , and S a i t o of fibrous  of  increase  f o o d a b o v e t h a t o b t a i n e d on t h e  body w e i g h t g a i n  c e l l u l o s e - a d d e d d i e t , appears (1961)  to  depression  high  ingredients lised  should  contain a high  f o r growth o r p r o d u c t i o n .  to suggest t h a t d i e t s  in  Corn o i l  the much-needed  chickens  fed the corn o i l - r i c h d i e t s  is  superior  to starch  f a t t y a c i d s w h i l e s t a r c h does n o t . had t h e a d v a n t a g e  i n body w e i g h t o f b i r d s  c e l l u l o s e - i n c l u d e d d i e t over diet, 12)  is  are  of high  understandable.  of u t i l i s i n g  those  w h i c h were f e d t h e  fed the starch-based  The d a t a on f o o d c o n v e r s i o n  fibrous  ingredients  to chicken diets  utiit  Therefore  for  the growth.  fat-based  cellulose-included  efficiency  i n l i n e w i t h t h e c o n c e p t as m e n t i o n e d e a r l i e r t h a t t h e levels of  fibrous  in that  e n e r g y w h i c h w o u l d have been expended i n f a t t y a c i d b i o s y n t h e s i s increase  a  p r o p o r t i o n o f e n e r g y w h i c h c o u l d be  contains  Hence,  fed  t h a t the major e f f e c t o f e n e r g y was  appears  be-  confirm  c e l l u l o s e when i n c l u d e d i n t h e d i e t w i t h o u t s u p p l e m e n t a r y This  low  c e l l u l o s e - e x c l u d e d d i e t and t h o s e  p r i n c i p l e t h e s t a t e m e n t made by B e g i n  in growth.  of  e t al_.  m a t e r i a l s may  The s i g n i f i c a n t d i f f e r e n c e i n t o t a l fed the h i g h - f a t  devoid of  i n a c c o r d w i t h a l a r g e body  it  D a v i s and B r i g g s  fed d i e t s  i n c o r p o r a t i n g added  t h a t 11 p e r c e n t a d d e d c e l l u l o s e has  gain  evidence  Discussion  depresses  (Table  addition the  68  efficiency series diets  of food u t i l i s a t i o n .  The e v i d e n c e shows t h a t w i t h i n t h e  r e l a t i n g to the source of d i e t a r y energy,  the birds  fed the  i n c o r p o r a t i n g a d d e d c e l l u l o s e u t i l i s e d more f o o d f o r a u n i t  body w e i g h t g a i n  i n comparison w i t h those  added c e l l u l o s e .  fed the d i e t s  of  containing  no  The f a c t t h a t t h e d i f f e r e n c e s e x i s t e d b e t w e e n t h e two  mean w e e k l y v a l u e s  w i t h i n the starch-based  or fat-based s e r i e s ,  markedly reduced or p r a c t i c a l l y n o n - e x i s t e n t  (Table  12a)  becomes  when t h e  values  a r e c a l c u l a t e d t o remove t h e e f f e c t s a t t r i b u t a b l e t o t h e a d d e d c e l l u l o s e , demonstrates  t h e i n f l u e n c e o f added c e l l u l o s e ( F i g .  The mucosa o f t h e g a s t r o i n t e s t i n a l t r a c t the e n t r y  i n t o t h e body o f  u t i l i s e d (White et a l _ . , 1973).  that  high  of energy o b t a i n e d w i t h b i r d s shown by F i g .  5,  H a l l s w o r t h and C o a t e s  severe depression  fed the d i e t s  ( T a b l e 13)  14) mean m e t a b o l i s a b l e e n e r g y  provides  S i b b a l d and S l i n g e r  This  finding is  (Table for  the  depressed  c o n t r a r y to those  ( 1 9 6 0 ) , P o t t e r e t al_. ( 1 9 6 0 ) , and B e g i n  of  (1961)  i t s e f f e c t on m e t a b o l -  values.  T h a t a d d e d d i e t a r y c e l l u l o s e has tissue  signifi-  and t h e a d j u s t e d  a d d i t i o n a l support  who r e p o r t e d c e l l u l o s e t o be i n e r t i n r e s p e c t o f i s a b l e energy  This  of m e t a b o l i s a b i l i t y  v i e w t h a t , a t h i g h e r d i e t a r y l e v e l s added d i e t a r y c e l l u l o s e of energy.  reported  cells.  the r e d u c t i o n i n magnitude or e l i m i n a t i o n of  values,  not  i n c o r p o r a t i n g added c e l l u l o s e .  c a n t d i f f e r e n c e s between t h e o b s e r v e d  metabolisability  against  (1962)  caused g r e a t e r d e s t r u c t i o n o f mucosal  a c t i o n may e x p l a i n t h e o b s e r v e d  As  a c t s as a b a r r i e r  large molecules, which, i f absorbed, are  well  fibre diets  4).  deposition is  a depressing  effect  on  shown by t h e d a t a p r e s e n t e d i n T a b l e 1 5 .  explanation f o r the observed  higher  values  o f mean a d i p o s e  adipose A  tissue  possible weight  69  obtained with birds series  f e d d i e t s d e v o i d o f added c e l l u l o s e w i t h i n  r e l a t i n g to supplementary  lowered energy  intake.  Hainan  energy  appears  (1930),. R o b e r t s o n  (1963) a t t r i b u t e d a s i m i l a r o b s e r v a t i o n limitation  source,  on t h e i n t a k e o f d i g e s t i b l e  t o be a  e t al_. (1948),  to the imposition of nutrients.  the possible and  Wells  physical  70  3.4  The E f f e c t o f R e s i d u a l  Yolk on the Performance o f C h i c k s  3.4.1  Experiments 4 and 5  3.4.1.1  Introduction  There i s a wide v a r i a t i o n among m e t a b o l i s a b l e energy v a l u e s assayed w i t h c h i c k s up t o t h r e e weeks o f age.  S i b b a l d e t al_. (1960) c o n s i d e r e d  the i n f l u e n c e o f age on the m e t a b o l i s a b l e energy v a l u e o f corn to be small and n e g l i g i b l e f o r p r a c t i c a l  purposes.  Bayley et al_. (1974)  r e p o r t e d the m e t a b o l i s a b l e energy v a l u e s o f t e n samples o f rapeseed meal determined w i t h both c h i c k s and mature r o o s t e r s to be e q u a l . On the o t h e r hand, t h e r e are r e p o r t s t h a t i n d i c a t e t h a t the metabo l i s a b l e energy v a l u e s f o r some f e e d i n g r e d i e n t s and d i e t s a r e h i g h e r . f o r mature b i r d s than f o r c h i c k s  ( B a l d i n i , 1961; Young, 1961; Carew  e t a l _ . , 1963; Z e l e n k a , 1968; Lodhi e t a l _ . , 1 969; March e t a l _ . , 1973). An a t t r a c t i v e t h e o r y used to e x p l a i n the d i s c r e p a n c y among r e p o r t e d m e t a b o l i s a b l e energy v a l u e s o f d i e t s determined w i t h c h i c k s i s the one i m p l i c a t i n g the r e s i d u a l y o l k .  A v a i l a b l e evidence i n d i c a t e s that  absor-  p t i o n of the y o l k sac c o n t i n u e s u n t i l about the 14th day i n the l i f e the c h i c k ( Z e l e n k a , 1968).  S i b b a l d and S T i n g e r  of  (1963) suggested t h a t  the r e s i d u a l y o l k might f u r n i s h the c h i c k w i t h a s i g n i f i c a n t s u p p l y n u t r i e n t s f o r p e r i o d s up to 10 days p o s t - h a t c h i n g .  A significant  of  supply  o f n u t r i e n t s from the r e s i d u a l y o l k would i n d i c a t e t h a t the m e t a b o l i s a b l e energy v a l u e s determined d u r i n g t h i s p e r i o d would be i n f l u e n c e d i n a c c o r dance w i t h the magnitude o f c o n t r i b u t i o n of n u t r i e n t s by the r e s i d u a l yolk.  Z e l e n k a (1968) t e s t e d t h i s h y p o t h e s i s and p u b l i s h e d r e s u l t s  that  i n d i c a t e changes i n the m e t a b o l i s a b l e energy v a l u e s o f d i e t s w i t h i n the  71  f i r s t 14 days o f the c h i c k ' s  life.  As the e f f i c i e n c y o f u t i l i s a t i o n of m e t a b o l i s a b l e energy i s  the  prime concern o f t h i s phase of the s t u d y , two experiments were conducted to i n v e s t i g a t e the e f f e c t o f r e s i d u a l y o l k on the m e t a b o l i s a b l e energy v a l u e s of a p r a c t i c a l d i e t and on the s u r v i v a l of c h i c k e n s .  72  3.4.1 Experiment 4  -  M a t e r i a l s and Methods  D a y - o l d b r o i l e r s were d i s t r i b u t e d a t random i n t o t h r e e groups o f t w e l v e c h i c k s each a c c o r d i n g to t r e a t m e n t s which were c o n t r o l , shamo p e r a t e d and s u r g i c a l l y - a l t e r e d .  The sham-operated c h i c k s had t h e i r  y o l k sacs brought o u t s i d e the body c a v i t i e s , m a n i p u l a t e d and r e t u r n e d t o p o s i t i o n i n t a c t w h i l e the s u r g i c a l l y - a l t e r e d c h i c k s had t h e i r y o l k a b l a t e d through the f o l l o w i n g t e c h n i q u e .  sacs  A p p r o x i m a t e l y 0.2 ml of p e n t o -  b a r b i t o n e (nembutal a t a c o n c e n t r a t i o n o f 60 mg/ml) was i n j e c t e d i n t r a venously  i n t o each c h i c k .  The a n a e s t h e t i z e d c h i c k was p l a c e d back  downwards w i t h the vent towards the o p e r a t e d and was f a s t e n e d t o an o p e r a t i n g board by i t s l e g s and wings w i t h e l a s t i c bands.  After plucking  the down on the abdomen, the c h i c k was washed w i t h an a n t i s e p t i c s o l u t i o n . The y o l k sac was reached through an i n c i s i o n made i n t o the s k i n and the u n d e r l y i n g muscles t o the l e f t o f the c e n t r e l i n e o f the abdomen.  The  y o l k sac was brought out w i t h f o r c e p s and was l i g a t e d a t the s t a l k b e f o r e section.  The y o l k sacs o f sham-operated c h i c k s were brought o u t , handled  and pushed back.  The abdominal w a l l s o f both the y o l k s a c - a b l a t e d and  sham-operated c h i c k s ' ' w e r e c l o s e d by c o t t o n s u t u r e s each p a s s i n g the s k i n and the muscle l a y e r s . to the s u t u r e d a r e a .  through  A t o p i c a l a n t i b i o t i c d r e s s i n g was a p p l i e d  The o p e r a t e d c h i c k s were put i n a b a t t e r y brooder  and no s p e c i a l t r e a t m e n t was n e c e s s a r y a f t e r complete r e c o v e r y from the a n a e s t h e t i c which l a s t e d a p p r o x i m a t e l y two hours.  73  The t h r e e groups o f . i n t a c t and o p e r a t e d c h i c k s were housed,  accor-  d i n g to t r e a t m e n t s , i n e l e c t r i c a l l y - h e a t e d , t h e r m o s t a t i c a l l y - c o n t r o l l e d b a t t e r y brooders w i t h r a i s e d w i r e screen f l o o r s , i n a w e l l - v e n t i l a t e d , t e m p e r a t u r e - c o n t r o l l e d b r o o d i n g room. two r e p l i c a t e s o f s i x c h i c k s each.  One t r e a t m e n t group c o n s i s t e d o f  A l l were f e d the same e x p e r i m e n t a l  d i e t , the c o m p o s i t i o n of which i s shown in T a b l e 16.  Food and water  were p r o v i d e d ad l i b i t u m .  Records were kept on body weight and food c o n -  sumption on weekly b a s i s .  Both food and e x c r e t a samples were a n a l y s e d  f o r m o i s t u r e , n i t r o g e n and c o m b u s t i b l e energy a c c o r d i n g to methods d e s c r i b e d f o r Experiment 3.  as  T a b l e 16.  Composition  of  experimental  diet -  Ingredients  H e r r i n g meal  Experiment  Percent  (72%  CP; 3197  k c a l ME/kg)  21.3  Ground wheat  53.0  Corn  19.2  starch  Corn o i l  3.0  Limestone  1.0  Calcium phosphate  1.5  Premix  0.5  1  Iodized  salt  Microingredients  0.5  as  described  in Table  1.  4  75  3.4.2 Experiment 4  -  Results  For the p e r i o d of differences  1-21  days p o s t h a t c h i n g ,  t h e r e w e r e no  i n body w e i g h t g a i n s b e t w e e n t h e t r e a t m e n t g r o u p s .  17 shows t h a t i n t h e f i r s t week t h e c h i c k s w i t h o u t y o l k slightly  more w e i g h t t h a n b o t h c h i c k s  groups but t h i s body w e i g h t s groups. growth  significant  f e a t u r e was  i n the c o n t r o l  sacs  gained  and t h e  n o t shown i n t h e s e c o n d w e e k .  sham-operated  The  do n o t show any s i g n i f i c a n t d i f f e r e n c e s b e t w e e n  Fig.  6 gives  the g r a p h i c a l  Table  final  treatment  r e p r e s e n t a t i o n of the trends  in  rate.  T h e r e was a s i g n i f i c a n t d i f f e r e n c e i n t h e o v e r a l l e f f i c i e n c y o f food conversion  between t h e c o n t r o l  hand and t h e g r o u p w i t h y o l k Throughout  sacs  and s h a m - o p e r a t e d  g r o u p s on t h e  r e m o v e d on t h e o t h e r  (Table  or the sham-operated  chicks.  Fig.  7 shows t h e t r e n d s  r e l a t i n g to  t h e d i e t a r e p r e s e n t e d i n T a b l e 19.  obtained with birds  The s l i g h t l y  to metabolise  t h a t the surgery  birds  yolks  provides  p e r se d i d n o t a f f e c t t h e c h i c k s  ability  energy.  An i n t e r e s t i n g p o i n t b r o u g h t higher  of  higher  without residual  compared w i t h t h o s e o b t a i n e d w i t h the sham-operated evidence  values  The t r e a t m e n t s e m p l o y e d had no  a p p a r e n t e f f e c t on m e t a b o l i s a b i l i t y o f t h e d i e t . values  effi-  the t h r e e treatment groups.  D a t a on t h e e f f e c t o f t r e a t m e n t on t h e m e t a b o l i s a b l e e n e r g y  m e t a b o l i s a b l e energy  yolk  i n body w e i g h t t h a n e i t h e r t h e c o n t r o l  c i e n c y o f f o o d u t i l i s a t i o n t h a t e x i s t e d among  clear  18).  the experimental period, the chicks without residual  u t i l i z e d more f o o d . p e r u n i t g a i n  one  apparent  retention value  the b i r d s w i t h o u t r e s i d u a l y o l k  o u t by t h e d a t a ( F i g .  (2.53  g/100  g of diet)  compared t o the 2.18  8).  is  the  obtained  and 2 . 1 3  with  g/100  g  76  T a b l e 17.  E f f e c t o f r e s i d u a l y o l k on weekly body weights and t o t a l body w e i g h t g a i n .  Mean  body w e i g h t and w e i g h t g a i n s Weeks  Treatment  .  (g)  3  , , Total Gain  225a  426a  393a  90a  226a  437a  404a  93a  224a  427a  396a  Initial  1  Control  33a  89a  Sham-operated  34a  Y o l k sac removed  32a  2  x  Means w i t h i n a column f o l l o w e d by the same l e t t e r do n o t d i f f e r cantly  (P < 0 . 0 5 ) .  signifi-  77  AGE ( WEEKS) FIG. 6 : EFFECT OF RESIDUAL YOLK SAC ON TOTAL BODY WEIGHT.  78  T a b l e 18.  E f f e c t of r e s i d u a l  Units  y o l k on food c o n v e r s i o n  efficiency.  o f food per u n i t o f body weight  gain  Weeks Treatment  1  2  3  Overall  Control  1 .24a  1 .28a  1 .47a  1 .33a  Sham-operated  1 .18a  1 .31a  1 40a  1 .29a  Y o l k sac  1 .37a  1 .49b'  1 .54a  1 .46b  Values  removed  f  f o l l o w e d by d i f f e r e n t l e t t e r s are s i g n i f i c a n t l y d i f f e r e n t  (P <  0.05).  79  .8 r  < O  YOLK SAC REMOVED. _ .  U_  O  h;  or  UJ D_  Q O O  INTACT  u. o  SHAM-OPERATED  CO  1.0 0  2  I AGE  FIG. 7:  EFFECT  OF RESIDUAL  FOOD CONVERSION  (WEEKS) YOLK ON CUMULATIVE  EFFICIENCY.  80  T a b l e 19.  E f f e c t o f r e s i d u a l y o l k on m e t a b o l i s a b l e energy v a l u e s .  Mean  1  ME" v a l u e s  (kcal/kg)  Weeks Treatment  1  2  3  Control  3402a  3673a  3788a  Sham-operated  3348a  3625a  3776a  Yolk sac removed  3396a  3635a  3776a  Means w i t h i n a column f o l l o w e d by the same l e t t e r are not s i g n i f i c a n t l y different  (P < 0 . 0 5 ) .  ME : M e t a b o l i s a b l e energy.  81  w i t h the sham-operated b i r d s p r o v i d e s c l e a r e v i d e n c e t h a t the  surgery  per se d i d not a f f e c t the c h i c k s a b i l i t y to m e t a b o l i s e energy. An i n t e r e s t i n g p o i n t brought out by the d a t a on apparent n i t r o g e n r e t e n t i o n i s the h i g h e r apparent r e t e n t i o n v a l u e (2.53 g/100 g o f d i e t ) o b t a i n e d w i t h the b i r d s w i t h o u t r e s i d u a l y o l k compared to the 2.18 and 2.13 g/100 g o b t a i n e d w i t h the i n t a c t and t h e sham-operated b i r d s ,  res-  p e c t i v e l y , i n the f i r s t week and the d r a m a t i c drop to p r a c t i c a l l y the same l e v e l  (2.39 g/100 g o f d i e t ) as t h a t o f the sham-operated b i r d s  i n the second week ( F i g . 8 ) .  The v a l u e f o r the b i r d s w i t h o u t r e s i d u a l  y o l k s rose as s h a r p l y as i t had dipped r e a c h i n g a l e v e l  o f 2.68 g/100 g  o f d i e t , the h i g h e s t o f the t h r e e v a l u e s i n the t h i r d week.  Both the  i n t a c t and t h e sham-operated b i r d s showed a g r a d u a l r i s e i n apparent n i t r o g e n r e t e n t i o n from the second week and by the t h i r d week, both groups had reached the same l e v e l o f apparent n i t r o g e n r e t e n t i o n .  82  ±0.03 /  /  h-  2.6  / ±0.02  LU  YOLK SAC REMOVED  Li_ O  ±0.04 v s  .-'•±0.02 ± 0  ^  o> O O CC LU  a.  2 4  o LU  h-  LU  CC  2  2.2  SHAM-OPERATED  JL  2.0 0  J  1  2  AGE  3  (WEEKS)  FIG. 8 : EFFECT OF RESIDUAL YOLK ON APPARENT NITROGEN RETENTION  83  3.4.3 Experiment 4  -  Discussion  The data on body weight g a i n r e p o r t e d here (Table 17)  indicate  c l e a r l y t h a t r e s i d u a l ' y o l k has no e f f e c t on the growth r a t e o f to 21 days o f age.  chickens  S i n c e the h i g h e r mean body w e i q h t g a i n o f the c h i c k s  w i t h o u t y o l k sacs d i d not d i f f e r s i g n i f i c a n t l y from the mean body w e i g h t g a i n s o f the o t h e r t r e a t m e n t s i n the f i r s t week and s i n c e the l e a d i n weight g a i n was l o s t i n subsequent weeks, f u r t h e r d i s c u s s i o n o b s e r v a t i o n does not appear w a r r a n t e d .  on t h i s  The l a c k o f s i g n i f i c a n t  differ-  ences i n mean o v e r a l l body w e i g h t g a i n j u s t i f i e s the above c o n c l u s i o n . The c l o s e n e s s  o f the mean body weight v a l u e s o f each o f the t h r e e  t r e a t m e n t groups i s i l l u s t r a t e d i n F i g . 6.  R e s i d u a l y o l k appears  to  have e f f e c t on the e f f i c i e n c y o f food c o n v e r s i o n as demonstrated by the c o n s i s t e n t l y poorer food c o n v e r s i o n v a l u e s o b t a i n e d w i t h b i r d s w i t h o u t r e s i d u a l y o l k s and the c o n s i s t e n t l a c k o f s i g n i f i c a n t d i f f e r e n c e s between the i n t a c t and the sham-operated b i r d s , the y o l k sacs o f which groups were not removed.  It  is surprising  t h a t the d i f f e r e n c e s i n food c o n -  v e r s i o n e f f i c i e n c y among the t r e a t m e n t groups i n the f i r s t week d i d not reach the f i v e p e r c e n t s t a t i s t i c a l s i g n i f i c a n c e l e v e l .  There i s no  o b v i o u s e x p l a n a t i o n f o r t h e b e t t e r food c o n v e r s i o n e f f i c i e n c y v a l u e s o b t a i n e d w i t h the sham-operated c h i c k e n s over those of the i n t a c t However, i t appears  the s u r g i c a l  growth i n the f i r s t week.  groups.  t r e a t m e n t must have s t i m u l a t e d some  Evidence to support t h i s s u g g e s t i o n  is  pro-  v i d e d by the f a c t t h a t t h e b i r d s which had undergone s u r g i c a l  treatment  gained a s l i g h t l y -higher average w e i g h t than the i n t a c t b i r d s  (Table  17).  84  T h i s s t i m u l a t e d growth which can l o g i c a l l y be expected to be compens a t o r y i n n a t u r e must have been accompanied by a r a p i d t u r n o v e r o f n u t r i e n t s i n the f i r s t week,  t h e sham-operated, w i t h o u t l o s s o f  tissue  compared to those w i t h y o l k sacs removed, under such s t i m u l a t i o n may have u t i l i s e d food more e f f i c i e n t l y .  A s i m i l a r response c o u l d have  been shown by the b i r d s w i t h y o l k sacs removed but the l o s s o f  tissue  would m i l i t a t e a g a i n s t a c h i e v i n g the same r a t i o o b t a i n e d by the shamo p e r a t e d group.  The narrowing o f the gap i n food c o n v e r s i o n  ratios  between the b i r d s w i t h y o l k sacs removed and the i n t a c t b i r d s appears to i n d i c a t e a t r e n d towards  " n o r m a l i s a t i o n " of  (Fig.  7)  physiological  processes. The observed h i g h e r apparent n i t r o g e n r e t e n t i o n v a l u e ( F i g .  8)  o b t a i n e d w i t h the group of c h i c k s w i t h o u t r e s i d u a l y o l k s and which a l s o had the h i g h e s t body w e i g h t g a i n i n the f i r s t week i s c o n s i s t e n t w i t h the f a c t t h a t t h e r e i s a p o s i t i v e c o r r e l a t i o n between r a p i d growth r a t e and n i t r o g e n r e t e n t i o n .  The d i f f e r e n c e i n the apparent n i t r o g e n r e t e n -  t i o n between the i n t a c t b i r d s and those w i t h y o l k sacs- removed c o u l d p r o b a b l y be e x p l a i n e d on the f o l l o w i n g b a s i s .  There i s e v i d e n c e t h a t  a l t h o u g h the y o l k sac i s connected d i r e c t l y w i t h the i n t e s t i n e , t h e r e  is  l i t t l e o r no movement of m a t e r i a l v i a t h i s r o u t e even a f t e r h a t c h i n g and t h a t the r e s i d u a l y o l k i s absorbed through the y o l k sac membrane and t r a n s p o r t e d to the t i s s u e s 1961).  by the omphalomesenteric v e s s e l s  (Fritz,  The r e s i d u a l y o l k i s r a p i d l y u t i l i s e d by the b i r d w i t h i n f i v e  days (Freeman, 1965).  In the absence o f i n f o r m a t i o n on the u t i l i s a t i o n  o f n u t r i e n t s d e r i v a b l e from the r e s i d u a l y o l k q u a l i t a t i v e l y and q u a n t i t a t i v e l y , the p o s s i b i l i t y should be c o n s i d e r e d t h a t the e n d - p r o d u c t s may  85  be h i g h l y n i t r o g e n o u s nitrogenous  i n n a t u r e and t h i s c o u l d add to the normal  e x c r e t i o n to b r i n g down, the v a l u e o f apparent  nitrogen  retention. Z e l e n k a (1968) found the m e t a b o l i s a b l e energy v a l u e s o f the d i e t to i n c r e a s e r a p i d l y d u r i n g the f i r s t days a f t e r h a t c h i n g , about one week o f age and i n c r e a s e a g a i n u n t i l  stabilise  two weeks o f age; a  f i n d i n g which the data o f t h i s experiment (Table 1.9) would g e n e r a l l y tend t o s u p p o r t .  However, i t does not agree w i t h the o b s e r v a t i o n o f  S i b b a l d e t al_. (1960) who, a f t e r a s e r i e s of experiments d e s i g n e d to p r o v i d e f u r t h e r i n f o r m a t i o n on the age of b i r d s on m e t a b o l i s a b l e energy v a l u e s o f c o r n , concluded t h a t t h e r e were no s i g n i f i c a n t d i f f e r e n c e s between, ages (2 weeks to 16 months) w i t h i n d i e t s and suggested t h a t i f age d i f f e r e n c e s e x i s t , they a r e n e g l i g i b l e f o r a l l p r a c t i c a l It  purposes.  i s worthy o f note t h a t t h e i r d e t e r m i n a t i o n s d i d not cover the metab-  o l i s a b l e energy v a l u e s f o r one w e e k ' p o s t - h a t c h i n g .  Removal a t h a t c h i n g  o f the r e s i d u a l y o l k d i d not have any s i g n i f i c a n t e f f e c t on the c h i c k s a b i l i t y to m e t a b o l i z e energy, an i m p o r t a n t o b s e r v a t i o n  i n view of the  fact that discrepancies  i n the f i r s t  i n m e t a b o l i s a b l e energy v a l u e s  seven to t e n days p o s t - h a t c h i n g have been e x p l a i n e d on the  assumption  t h a t the r e s i d u a l y o l k s u p p l i e s n u t r i e n t s i n amounts s i g n i f i c a n t enough to a f f e c t m e t a b o l i s a b l e energy v a l u e s Z e l e n k a , 1968).  ( S i b b a l d and S l i n g e r ,  1963; and  86  3.5  E f f e c t of R e s i d u a l  Y o l k on S u r v i v a l  of Chicks  3.5.1 Experiment 5  -  Introduction  The purpose of t h i s experiment was to t e s t the h y p o t h e s i s  t h a t the  r e s i d u a l y o l k f u r n i s h e s c h i c k s w i t h a s i g n i f i c a n t amount o f n u t r i e n t s f o r a p e r i o d as much as 10 days a f t e r h a t c h i n g .  If  t h i s assumption were  t r u e , c h i c k s whose y o l k sacs had been removed w i t h i n a day o f h a t c h i n g and w i t h o u t a c c e s s  to f o o d , would be expected to d i e i n a s i g n i f i c a n t l y  s h o r t e r t i m e as compared t o t h o s e w i t h i n t a c t y o l k sacs but a l s o d e p r i v e d food.  3.5.2 M a t e r i a l s and Methods The e x p e r i m e n t a l procedure was the same as i n Experiment 4.  The  o n l y d i f f e r e n c e s were t h a t White Leghorn males were used and t h a t t h e c h i c k s were not f e d throughout the t e s t which l a s t e d e i g h t days. c h i c k s had access to water a t a l l  A l l the  times.  3.5.3 Results Ta'ble 20 summarizes the r e s u l t s o f t h e e f f e c t o f y o l k sac on the l i v a b i l i t y of starved c h i c k s .  There was no m o r t a l i t y i n the i n t a c t  c o n t r o l group i n the f i r s t f i v e days o f t h e e x p e r i m e n t a l p e r i o d . t h i r d s o f the c o n t r o l group d i e d on the seventh day. the e i g h t h day.  The r e s t d i e d on  Most o f the m o r t a l i t y among the sham-operated  o c c u r r e d on the s i x t h day when 23 out o f a t o t a l  Two-  o f 32 d i e d .  group The  longest  p e r i o d reached by c h i c k s f o r t h i s group was 8 days as i t o c c u r r e d i n the  87  T a b l e 20.  E f f e c t o f y o l k sac on the s u r v i v a l  of c h i c k s .  Days m o r t a l i t y o c c u r r e d Treatment  1 2  1  Control  no. o f b i r d s  Sham-operated  no. o f b i r d s  Yol k sac removed no. o f b i r d s  Total  2  3  2  2  number o f c h i c k s on each t r e a t m e n t :  Control  - 24  Sham-operated - 32 Y o l k sac removed - 28  4  5  6  7  8  3  1 6 5  1  2  23  5  1  -  3  17  2  -  88  case of the c o n t r o l mortality for  chicks.  o c c u r r e d on e a c h d a y f o r t h e s e v e n  the group w i t h o u t y o l k  without yolk Fig. groups.  With the exception of the f o u r t h  sacs.  Seventeen  s a c s d i e d on t h e s i x t h  9 represents  days  day,  t h a t v/as t h e  of the t o t a l  of  28  duration chicks  day.  t h e t r e n d o f m o r t a l i t y among  the three  treatment  FIG. 9=  EFFECT OF RESIDUAL YOLK ON THE LI VABILITY OF STARVED CHICKS .  89  FIG. 9=  EFFECT OF RESIDUAL YOLK ON THE LIVABILITY OF STARVED CHICKS .  90  3.5.4 Experiment 4  -  Discussion  The o b s e r v a t i o n days  against  significant  a major r o l e f o r the r e s i d u a l  amounts  The o b s e r v e d  of n u t r i e n t s  for the surgically-altered birds  present  surgery.  It  observation yolk  sac  kcal  of  of  Zelenka  had l o s t energy  13.1  s i x t h and  upon an. o b s e r v e d week.  kcal  subsequent  nutrient  is  supplying  (the  fifth  be a s s o c i a t e d in  to  a b o u t 85 p e r c e n t o f  f l u c t u a t i o n i n m e t a b o l i s a b l e energy  values  the  its  yolk  t h e e a r l y d a y s has  of studies  15.4  supplies  been in  based the  on n u t r i e n t u t i l i s a t i o n  to take i n t o account the f a c t t h a t  a b i l i t y to d i g e s t  food  is  at  n o t f u l l y d e v e l o p e d and '  development of the a b i l i t y to d i g e s t  f o o d and  absorb  l a r g e l y a c c o u n t a b l e f o r t h e r i s e and s t a b i l i s a t i o n  u t i l i s a t i o n f r o m t h e s e c o n d week  onwards.  the  the  day p o s t - h a t c h i n g  The c o n c e p t t h a t t h e r e s i d u a l  of nutrients during  with  chicks with a s i g n i f i -  t h e f i r s t week a f t e r h a t c h i n g  representing  has  hatching.  to r e c o n c i l e the f i n d i n g  does n o t f u r n i s h  Interpretation of results  hatch the chicks  in  9) m i g h t  ( 1 9 6 8 ) t h a t by t h e f i f t h  the newly-hatched chick  nutrients  yolk  yolk  seventh  respectively  on t h e same d a y  (Fig.  difficult  during  at hatch.  s i g n i f i c a n t amounts  that  is  paper t h a t r e s i d u a l  c a n t amount o f n u t r i e n t s  in  on t h e  i n the f i r s t few days a f t e r  heaviest mortality occurring  the e f f e c t of  first  severest  f o r t h e s u r g i c a l l y - m a n i p u l a t e d and t h e i n t a c t b i r d s  argues  day)  t h a t m o r t a l i t y was  of  91  3. PART 2 THE AVIAN CAECA AND EFFICIENCY OF UTILISATION OF DIETARY ENERGY AND PROTEIN  3.6  The Role o f the Caeca i n Energy and P r o t e i n  Metabolism  3.6.1 Experiment 6  -  Introduction  The presence of a l a r g e b a c t e r i a l p o p u l a t i o n i n the a v i a n caeca and e x t r a p o l a t i o n o f the f e a t u r e s a s s o c i a t e d w i t h b a c t e r i a - h o s t  symbiosis  i n ruminants and o t h e r a n i m a l s to the domestic c h i c k e n c o n t i n u e to prompt sporadic  investigations  i n t o the r o l e o f the a v i a n caeca i n the  a t i o n of d i e t a r y n u t r i e n t s .  These i n v e s t i g a t i o n s  utilis-  have f a i l e d to e s t a b -  l i s h a c h a r a c t e r i s t i c f u n c t i o n f o r the caeca o f the domestic c h i c k e n . There i s s t r o n g e r e v i d e n c e to s u p p o r t the h y p o t h e s i s o f c e l l u l o l y t i c p r o t e o l y t i c f u n c t i o n s f o r w i l d b i r d s than t h e r e i s f o r domestic Recent s t u d i e s  or  chickens.  by Thompson and Boag (1975) o f the u t i l i s a t i o n o f d i e t a r y  energy by i n t a c t and c a e c e c t o m i z e d Japanese q u a i l showed t h a t the caeca c o n t r i b u t e d 5.7% o f the d a i l y energy r e q u i r e m e n t .  In a p r e v i o u s  s t u d y , Fenna and Boag (1974) concluded t h a t the major f u n c t i o n o f the caeca i s to r e t a i n n u t r i e n t - r i c h i n g e s t a f o r f u r t h e r d i g e s t i o n and a b s o r p t i o n w h i l e a l l o w i n g the b u l k i e r c e l l u l o s e m a t e r i a l to be e x c r e t e d more r a p i d l y from the g u t . The t h e o r y which suggests t h a t microorganisms  i n the caeca of the  domestic c h i c k e n are a source o f c e l l u l o l y t i c . enzymes which would e n a b l e t h e c h i c k e n to o b t a i n some n u t r i t i o n a l v a l u e from d i e t a r y f i b r e and A l u m o t , 1963; Thornburn and Kh'll.cox, 1964)  (Nitsan  has not gained wide  92  acceptance.  McNab (1973) doubts whether such a p r o c e s s ,  if it  would be o f any n u t r i t i o n a l s i g n i f i c a n c e t o t h e c h i c k e n . Alumot  (1963) r e p o r t e d t h a t c a e c a l p r o t e o l y s i s  degree f o r i n h i b i t e d p r o t e o l y s i s  i n the small  fed.  Mitsan  compensated  and  i n some  i n t e s t i n e when raw soy-  bean meal was f e d to i n t a c t and c a e c e c t o m i z e d b i r d s . f e r e n c e , however,  occurs,  There was no d i f -  i n n i t r o g e n u t i l i s a t i o n when heated soybean meal was  Caecectomy d i d not appear to a f f e c t the n i t r o g e n e x c r e t e d i n the  experiments o f N i t s a n and Alumot  (1963).  Barnes and Impey (1972,  have r e p o r t e d t h a t many d i f f e r e n t types o f c a e c a l anaerobes o f b r e a k i n g down u r i c a c i d . o f the b i r d i s  are  capable  What t h i s may have on the n i t r o g e n  economy  unknown.  The absence o f a w e l l - e s t a b l i s h e d f u n c t i o n f o r the caeca o f domestic c h i c k e n u n d e r l i n e s absurd,  the need f o r r e s e a r c h  the  in t h i s area as i t  is  from t h e t e l e o l o g i c a l v i e w p o i n t , f o r the domestic c h i c k e n to  possess an organ o f t h i s T h i s view supports against  1974)  s i z e t h a t has no c h a r a c t e r i s t i c f u n c t i o n .  Mattocks'  (1971) c o n t e n t i o n t h a t s e l e c t i o n  pressure  p o s s e s s i o n o f an organ w i t h no f u n c t i o n might be expected to  cause the o r g a n ' s e x t i n c t i o n and t h a t an organ w i t h a b l i n d end such as the caecum would be p a r t i c u l a r l y s u s c e p t i b l e to p a r a s i t i c resulting  in a f a t a l  invasion  peritonitis.  The p a u c i t y o f i n f o r m a t i o n as i n d i c a t e d above and the r e l e v a n c e  of  the c o n c e p t o f c a e c a - m e d i a t e d n u t r i e n t u t i l i s a t i o n to t h e t o p i c under investigation  prompted t h e f o l l o w i n g experiment u s i n g i n t a c t and c a e c e c -  tomized c h i c k e n s  to i n v e s t i g a t e  the e f f e c t of the e x c i s i o n o f the caeca  on the u t i l i s a t i o n o f d i e t a r y energy and p r o t e i n .  93  3.6.1 Experiment  6  -  Materials  Nine-week-old  New H a m p s h i r e  were c a e c e c t o m i z e d . the o p e r a t i o n . straps gical  so t h a t  its  was  i t was  anaesthetic.  chickens  withdrawn  each w e i g h i n g  t i e d to the o p e r a t i o n  p a r t was  0.4  ml o f  pointed  (60 mg/ml)  lost  l a s t e d about  t h e amount o f  t h e head o f  showed  signs  of  was  slowly  Surand  18-gauge  p a r a l l e l to the  c o t t o n wool  t h e c h i c k e n f o r a few s e c o n d s u n t i l  the  a  wing  per  a d m i n i s t e r e d was used as  before  injected  twenty minutes  Nembutal  ether-soaked  The  inade-  standby  was  placed  chicken  sedation.  .  The c a e c a w e r e r e a c h e d  through  a 2.5  cm-long  longitudinal  incision  2 made i n t o a d e p l u m e d a r e a inal  wall  muscles  in  (about  the l e f t  cm f r o m ' t h e m i d l i n e and 2 . 5 was  torn with forceps  5 cm ) o f  c a r e f u l l y brought  whereupon  the c e r v i x of  cm a n t e r i o r  outside  and  into the  (postventer)  to the vent.  p o r t i o n of the  The  abdom-  region  2.5  peritoneum  intestine with  t h e body c a v i t y w i t h a b l u n t  e a c h caecum was  was made w i t h  the skin  ventral-lateral  and t h e d i s t a l  c a e c a was  before excision  g  elastic  (Nembutal)  consciousness.  l e n g t h o f t i m e , t h e r e f o r e e t h e r was  around  board w i t h  sodium  t o w a r d t h e body and n e a r l y  A bottle containing  18 h o u r s  up a n d t o w a r d t h e o p e r a t o r .  Nembutal  The o p e r a t i o n  a p p r o x i m a t e l y 800  f r o m them a t l e a s t  induced w i t h p e n t o b a r b i t o l  i n some c a s e s  this  Methods  until the chicken  inserted.  c h i c k e n and quate f o r  of  vein  n e e d l e u s e d was as  ventral  An a v e r a g e  i n t o the wing  Food was  The c h i c k e n was  anaesthesia  ether.  and  scissors  l i g a t e d and h e l d w i t h a  the  probe haemostat  at the i l e o - c o l i c j u n c t i o n  leaving  94  a 5 mm stump sutured  for suturing.  One c a e c u m was  b e f o r e t h e o t h e r was  o f t h e stump u s i n g  r o u n d body s u r g i c a l  The n e e d l e was  s u t u r e was  a surgical  needle.  the c i r c u l a r opening  stump  touched.  A modified purse-string opening  e x c i s e d and t h e  used  silk  to close  (No.  4/0)  The s u t u r e was p a s s e d  a n d t h e two ends  t h e n drawn back  through  of  the c i r c u l a r and a 3/8  circle  i n and out  around  t h e s u t u r e was drawn  tight.  t h e stump and t h e t h r e a d  was  wrapped a few t i m e s around  i t b e f o r e t h e n e e d l e was d r i v e n t h r o u g h  more f o r a s u r g i c a l  k n o t t o be made.  i n t e s t i n e was antibiotic  square  then put back  i n p l a c e and t h e wound was  preparation, V-Sporin*  manufactured  The c a e c a l p a r t o f  once  the  sprayed with  an  ( t r a d e name f o r a t o p i c a l a n t i b i o t i c  by W e l l c o m e D i v i s i o n  of Agrco  Pharmacy  Ltd.,  Lasalle,  P.Q.). The l a y e r s mattress  suture  was c o n t i n u o u s l y  of muscles using  a 1/2  suture  The two e d g e s  c l i p p e d w i t h 18 mm wound c l i p s . sprayed w i t h V - S p o r i n * and g i v e n  the necessary  removed seven removal  was  cutting surgical  and f o r t h t h r o u g h  necessitated  purse-string  by t h e d i g e s t a .  circle  a p p l i e d back  The m o d i f i c a t i o n was the s t r a i g h t  w e r e s t i t c h e d by a m e t h o d s i m i l a r t o  both edges  by an o b s e r v a t i o n t o r e o f f as  needle.  before the chickens  of  the  a r e s u l t of pressure together  t h e m u s c l e and s k i n  were put back  post-operative care.  The  suture wound.  made p r e v i o u s l y  o f t h e s k i n were b r o u g h t The wound o f  the  in their  The s u t u r e c l i p s  d a y s a f t e r t h e o p e r a t i o n , e x c e p t i n two c a s e s  exerted and was cages  were  where  e f f e c t e d t e n days a f t e r t h e o p e r a t i o n .  C a e c e c t o m i z e d and protein diet for  intact control  the ensuing  11 w e e k s .  b i r d s w e r e m a i n t a i n e d on a 17% The a b i l i t y o f  the b i r d s  that  to  95  utilize  nutrients  composition corn  of  starch.  the d i e t s Diet  in place of corn Diet  1.  during  Each d i e t was  voided  shown i n T a b l e  and was  by t h e 1,  3,  4,  5 and 6.  d e t e r m i n e d f o r each week.  and 1 1 . 2 %  ground  and  absorption  and u r i c  acid  Total  nitrogen  was  the the  t h e one o f  f e e d i n g a n d c o l l e c t i o n o f e x c r e t a and bomb c a l o r i m e t r y .  flasks.  The f l a s k s  mixed t h o r o u g h l y . f o r about uric  d e t e r m i n e d by t h e m a c r o - K j e l d a h l  method.  and 0 . 2 5  (1965).  f i n e l y ground i n a 250 ml  Faecal  M glycine  0.25  acid  a c i d c o n c e n t r a t i o n was 1800).  10 ml o f  ml o f  t h e e x t r a c t was  excreta  volumetric  the supernatant  centrifuged  was a n a l y z e d  using a m o d i f i c a t i o n of the procedure  t o 2.75  SP  method  and  plasma,  ( U n i c a m model  l i t h i u m carbonate,  the  The  w e r e t h e n made t o 250 ml w i t h d i s t i l l e d w a t e r Approximately  A uric  nitrogen  the  used i n s t e a d o f  liter»pH9.3).  utilis-  shaking of  acid concentration  m l , 0.1  0.5%  Samples o f  a t room t e m p e r a t u r e w i t h c o n s t a n t  ten minutes  by P r a c t o r i o u s  quantitative  nitrogen r e t e n t i o n , apparent  by P u d e l k i e w i c z e_t a l _ . ( 1 9 6 8 ) .  f o r 30 m i n u t e s  diets  excretion.  w e r e e x t r a c t e d w i t h 50 ml o f flask  last  Protein  p r o c e d u r e f o r u r i c a c i d d e t e r m i n a t i o n was a m o d i f i c a t i o n o f described  birds  total  during  M e t a b o l i s a b i l i t y of  The m e t h o d u s e d i s  a t i o n was e v a l u a t e d by m e a s u r i n g  with  caecectomized  were measured  19.2%  cellulose  isonitrogenous  Feed c o n s u m p t i o n  birds  The  Diet 1 contained  i n t a c t and s i x  periods.  individual  then determined.  21.  i s o c a l o r i c and  fed to s i x  three-week  t h r e e d a y s o f weeks was  is  2 c o n t a i n e d 8% c o r n o i l  starch  successive  excreta  f r o m two d i f f e r e n t d i e t s was  e x t r a c t o b t a i n e d as  ml o f  buffer  supernatant  (8.06  standard  r e a d a t 292  was  of  for  described  d e s c r i b e d above t h e e x t r a c t was  g g l y c i n e + 14.2  g sodium  added hydroxide  i n c l u d e d to check a c c u r a c y .  my on an u l t r a v i o l e t  was  Uric  spectrophotometer  per  96  T a b l e 21.  Composition o f d i e t s fed to i n t a c t and cacecectomized chickens.  DIET Ingredient  1  2  % H e r r i n g meal  21.,3  21 .,3  Ground wheat  53.,0  53..0 .  Corn o i l Corn  3..0  starch  19.,2  V •.2  Ground c e l l u l o s e Bonemeal Limestone Iodized  .  salt  Micronutrients  n . ,0  1  % Protein  M i c r o n u t r i e n t s as l i s t e d i n T a b l e 1.  1..5  I..5  .0  l . .0  0..5  0..5  0..5  0..5  100..0  100..0  2'4..0  24..0  ' !•  97  Considering bial  the f a c t t h a t the caeca are areas  a c t i v i t y , i t was o f  interest  of  high  to a s c e r t a i n whether  micro-  there  was  a n y d i f f e r e n c e b e t w e e n t h e i n t a c t and- t h e c a e c e c t o m i z e d c h i c k e n s the p r o p o r t i o n tive,  o f t h e e x c r e t a due t o b a c t e r i a .  t h e b a c t e r i a were s e p a r a t e d m e c h a n i c a l l y  procedure. thoroughly  Freshly  m i x e d , a n d an a v e r a g e  of  0.5  tube.  was a d d e d a n d t h e s a m p l e was  thoroughly  was  C e n t r i f u g e a t maximum s p e e d  r e m o v e d a n d t h e s e d i m e n t was  about  60 ml d i s t i l l e d w a t e r .  were shaken f o r 1 hour through filtrate was  four layers (about  removed  using the  voided excreta from i n d i v i d u a l  p l a c e d i n a 50 ml c e n t r i f u g e  Angle  To a c h i e v e  Glass  of c h e e s e c l o t h onto spun as  and t h e r e m a i n i n g  following was  collected,  m i x e d a n d s p u n i n an The  The m i x t u r e was  solids  containing bottles  filtered  a 50 ml c e n t r i f u g e earlier.  MSE  supernatant  in a d i l u t i o n b o t t l e  mentioned  and  ml o f d i s t i l l e d w a t e r  b e a d s w e r e a d d e d and t h e  on an a g i t a t o r .  40 m l ) was  49.5  ten minutes.  placed  objec-  g o f s a m p l e was w e i g h e d  To t h i s  for  birds  this  The  tube.  which c o n s t i t u t e a crude  bacteria  and d r i e d i n a vacuum d r y e r .  bacteria  a p r e - d r i e d e x c r e t a sample  then c a l c u l a t e d .  of  The  supernatant  c o n t e n t of t h e e x c r e t a were weighed c o n t e n t as a p e r c e n t a g e  in  was  The  98  3.6.2  Results  The m e t a b o l i s a b l e energy v a l u e s o b t a i n e d f o r the d i e t s when they were f e d t o the i n t a c t and c a e c e c t o m i z e d b i r d s are g i v e n i n T a b l e 22. These v a l u e s  have been c o r r e c t e d f o r n i t r o g e n r e t e n t i o n .  D i e t 1 was  u t i l i z e d w i t h p r a c t i c a l l y the same e f f i c i e n c y by both groups o f  birds.  A s i m i l a r p i c t u r e emerges f o r D i e t 2 which c o n t a i n e d added c e l l u l o s e , higher f a t l e v e l  and no corn s t a r c h .  bol i s a b l e energy v a l u e s  between D i e t  S i g n i f i c a n t d i f f e r e n c e s i n meta1 and D i e t 2 were n o t e d .  m e t a b o l i s a b l e energy v a l u e s were o b t a i n e d on D i e t 2.  Higher  The ME v a l u e s  o b t a i n e d w i t h i n t a c t c h i c k e n s were always s l i g h t l y h i g h e r than  those  of c a e c e c t o m i z e d c h i c k e n s on both d i e t s but t h e d i f f e r e n c e s were not statistically  significant.  T a b l e 23 summarizes  the r e s u l t o f u r i c a c i d e x c r e t i o n (as  by u r i c a c i d c o n c e n t r a t i o n ) i n the f a e c e s . D i e t 1 were v a r i a b l e .  The r e s u l t s  measured  in respect of  In the f i r s t week the i n t a c t b i r d s e x c r e t e d more  u r i c a c i d than the c a e c e c t o m i z e d b i r d s but t h i s s i t u a t i o n changed i n the t h i r d week.  The r e s u l t s f o r D i e t 2 were more c o n s i s t e n t .  b i r d s e x c r e t e d more u r i c a c i d than the c a e c e c t o m i z e d b i r d s . ences, however, were not s t a t i s t i c a l l y s i g n i f i c a n t .  The i n t a c t The d i f f e r -  The percentage o f  i n g e s t e d n i t r o g e n as u r i c a c i d (Table 23) a l s o f o l l o w e d a p a t t e r n s i m i l a r to t h a t o f t h e u r i c a c i d c o n c e n t r a t i o n . The n i t r o g e n b a l a n c e s o f the c h i c k e n s f o r the p e r i o d over which c o l l e c t i o n was made are p r e s e n t e d i n T a b l e 24.  With t h e e x c e p t i o n o f the  t h i r d week, the n i t r o g e n r e t e n t i o n i n the c a e c e c t o m i z e d c h i c k e n was s l i g h t l y h i g h e r than t h a t o f the i n t a c t c h i c k e n s as was the case f o r u r i c  99  Table  22.  Metabolisable (corrected  fo r  energy  values  1  of  diets.  nitrogen-retention)  ' Age o f chickens i n weeks  Intact kcal/kg  Caecectomized kcal/kg  21  3345a  3325a  23  3350a  3305 a  &  24  3535b  3530b  Cel1ulose)  25  3520b  3515b  26  3520b  3510b  Diet  1 (Cornstarch)  2 (Corn  oil  Values  not  f o l l o w e d by t h e same l e t t e r s  differ  significantly  (P<  0.05)  TOO  Table 23.  Uric acid concentration caecectomized  Intact  Caecectomized  %  2  1 (Cornstarch)  and  chickens.  Age o f chickens i n weeks  Diet  i n e x c r e t a by i n t a c t  1?  X  2  21  8.4  22.0a  7.7  20.0a  23  13.7  36.2b  14.3  38.0b  &  24  8.4  28.8c  7.8  25.0c  Cellulose)  25  10.3  33.7d  10.0  32.6d  26  10.7  34.9d  9.5  31 . I d  2 (Corn  oil  % in e x c r e t a , dry matter 2  % of  ingested  basis.  N e x c r e t e d as  uric  acid.  3 comparisons and v a l u e s  (P<  0.05)  a r e between  i n t a c t and c a e c e c t o m i z e d groups w i t h i n  f o l l o w e d by t h e same l e t t e r s  do n o t d i f f e r  diets  significantly  101  T a b l e 24.  Apparent Nitrogen of nitrogen  absorption  ingested)  by i n t a c t  Intact Diet  Age o f chickens i n weeks  1 (Cornstarch)  %  absorption  64.3  ±  3.42  23  66.9  ±  (Corn o i l &  24  70.2  Cellulose)  25 26  Standard  as  1  percentage  and c a e c e c t o m i z e d c h i c k e n s .  %  absorption  63.5  ±  2.13  1.89  65.6  ±  1.17  ±  0.47  69.0  ±  3.14  65.9  ±  2.63  68.4  ±  5.90  70.9  ±  3.24  69.2  ±  0.81  e r r o r o f t h e means.  a  Caecectomized  21  1  (expressed  102  showed no c l e a r t r e n d as T a b l e 24 s h o w s . out that the birds  were s t i l l  The i n t a c t b i r d s (P^O.Ol)  ranged  weight  from Table 26,  i n t e r e s t i n g to  (Table  t h e r a n g e was  to 19.00  (mean:13.6).  point  25). significantly  than d i d the caecectomized  the i n t a c t b i r d s , w h i l e the values from 9.87  is  voided faeces which contained  more b a c t e r i a l r e s i d u e  As c a n be s e e n among  gaining  It  from 15.6  f o r the b i r d s  birds.  to 30.5 without  (mean:22.5) caeca  T  a  b  1  e  -  2 5  l  n  I  a  Body, weight gains of i n d i v i d u a l c h i c k e n s .  c  Caecectomized  t  9  % gain  551  19.3  11  9  1  .  • % gain  398  16.8  .0.4  408  16.3  739  32.1  531  24.0  310  11.2  424  17.7  187  -7.4  388  14.6  264  10.5  368  17.2  Mean 344  13.7  420  17.7  D i f f e r e n c e s , b e t w e e n body w e i g h t s  at.21  and 26 weeks o f  age.  104  Table  26.  Bacterial  content  of excreta of  p e r c e n t on a d r y m a t t e r  1  Caecectomized  17.9  13.7  22.8  9.9  30.5  19.0  25.9  11.2  15.6  14.3  22.5a  13.6b  Mean v a l u e  chickens,  basis.  Intact  Mean  individual  f o l l o w e d by d i f f e r e n t l e t t e r s  differ  significantly  (P<  0.05)  105  3.6.3  Discussion  The m e t a b o l i s a b l e  energy  b i l i t y o f n e i t h e r d i e t was  values  (Table  is  d e r i v e d from carbohydrate  pectin),  and p r o t e i n c o m p o n e n t s  t r a c t without the caeca of digestion  is  testine.  and a b s o r p t i o n  w h i c h means t h a t  p r o l i f e r a t i o n and  Jayne-Williams  microorganisms of the  intestinal wall  small  intestine.  chickens this  and/or  between  support  on a m y l a s e (Lepkovsky  by R a d e f f  Even  is if  (1971)  premise less  is  The  digestive  out the  processes will  t h e c a e c a may  cause  in the small  in-  suggested that the presence causes  increased  in the absorptive  efficiently.  of  thickness  e f f i c i e n c y of  the r e s u l t s  significant  of  difference  in respect of t h e i r a b i l i t y evidence which provides  t h a t the presence  a c t i v i t i e s in d i f f e r e n t sites  the  caecectomized  However,  The l a c k o f  an e x p e r i m e n t a l  to the f i n d i n g  of  one w o u l d e x p e c t t h e  do n o t show t h a t .  amylo-  of the caeca  of microorganisms  i n t a c t and c a e c e c t o m i z e d c h i c k e n s  The r e s u l t s  there  and F u l l e r  to u t i l i s e nutrients  indirect  tract  increase  the absence  required  and  food.  to carry  The a b s e n c e  and a r e d u c t i o n  m e t a b o l i z e d i e t a r y energy  effect  attribute.  amylose  ingested  t h e i r metabolic products  On t h i s  investigation  of the  metabolisa-  The e n e r g y  (mainly  a n a t o m i c a l l y endowed  not s i g n i f i c a n t l y a l t e r t h i s an a b n o r m a l  show t h a t  a l t e r e d by c a e c e c t o m y .  by t h e c h i c k e n lipid  22)  to an  o f a m i c r o f l o r a has  in the f o w l ' s  little  alimentary  et_ a l _ . , 1 9 6 4 ) . of t h i s  ( 1 9 2 8 ) , Henning  experiment are not  i n agreement  ( 1 9 2 9 ) and T h o r n b u r n  microbial digestion  w i t h those  and W i l l c o x  (1965)  that  o f f i b r e i n t h e caecum o f t h e d o m e s t i c  some b a c t e r i a l d i g e s t i o n  occurs  i n the caecum,  i t probably  obtained  chicken. plays  an  106  insignificant  part i n the metabolism of the host  that occurring  i n t h e c a e c a o f t h e w i l d b i r d where  the d a i l y energy  requirement  (Thompson  The h i g h e r m e t a b o l i s a b l e e n e r g y contained corn o i l with values hydrate  as  and B o a g ,  values  the major source  1964, Dror  1966;  e t a l _ . , 1957;  et^ a l _ . , 1 9 7 3 ) .  The o b s e r v e d  Diet  2 can a l s o  be e x p l a i n e d on t h e b a s i s  fed,  t h e age o f t h e c h i c k e n s  uric acid is  in the avian caeca might data  species, increase  group  expressed  in this  study  the primary nitrogenous  higher  t h e amount o f n i t r o g e n  for was  tracts  uric  of  uric acid.  e x c r e t e d was c a l c u l a t e d as  This  acid  formed the The  no a p p r e c i a b l e e f f e c t o f  the  was  true  a percentage of the excreta  ingested.  The v a l u e s  of the e x c r e t a  a s a p e r c e n t a g e o f t h e n i t r o g e n consumed  by t h e c o n t r o l  ( 2 0 - 3 6 % , mean 31%)  are analogous  level  p r o t e i n to chicks  ingested  nitrogen  and S c h o l z ,  t h e two m e a n s .  diet  excretory product  e x c r e t e d as  a similar  (Featherston  values  t h e p o s s i b i l i t y was c o n s i d e r e d t h a t r e m o v a l  r e p o r t e d by F e a t h e r s t o n and S c h o l z  percentage of  carbo-  digesta.  mean 23%)  of  agree  for  of b a c t e r i a i n h a b i t i n g the caeca u t i l i z e  o r r e l a t i v e t o t h e amount o f n i t r o g e n nitrogen  2)  Rand ejt a l _ . , 1 9 5 8 ;  o f t h e c a e c a on t h e amount o f u r i c a c i d e x c r e t e d .  w h e t h e r t h e amount  of  which  had i n c r e a s e d and t h a t t h e i r d i g e s t i v e  shown i n T a b l e 23 show t h a t t h e r e was  removal  (Diet  t h a t by t h e t i m e t h i s  had been more d e v e l o p e d t o c o p e w i t h b u l k y Many o f t h e t y p e s  obtained f o r the d i e t  Donaldson  1964;  5.7%  1975).  who s u b s t i t u t e d c o r n o i l  C a r e w and H i l l ,  to  i t represents  of d i e t a r y energy  r e p o r t e d by o t h e r w o r k e r s  (Donaldson,  and s i n c e  c h i c k e n compared  1968)  to those  (20-25%,  ( 1 9 6 8 ) who f e d a d i e t  containi  f r o m d a y - o l d t o 10 d a y s o f a g e .  e x c r e t e d as  uric acid increases  with  The age  and t h i s may e x p l a i n t h e d i f f e r e n c e b e t w e e n  In T a b l e 24 t h e a p p a r e n t  absorption  of nitrogen  has  been  107  e s t i m a t e d as  t h e sum o f u r i c a c i d n i t r o g e n  will  t h a t t h e r e was  be s e e n  caecectomized chickens Although test in  the chickens  (Table 25).  and r e t a i n e d n i t r o g e n .  no d i f f e r e n c e b e t w e e n t h e i n t a c t and  in the apparent w e r e 20 weeks  absorption  of age,  The s i g n i f i c a n t l y r e d u c e d a v e r a g e  teria  Since  t h e r e was  less  i n t h e c a e c e c t o m i z e d , i t was  increase  i n the loss  of  nutrients  loss  logical  nitrogen  t h a n do c o n v e n t i o n a l  (Table  26)  of n u t r i e n t s to expect  via other route.  been shown t o o c c u r . the  The r e v e r s e  Under t h e d i e t a r y c o n d i t i o n s  c a e c a d i d n o t a p p e a r t o be e s s e n t i a l  and p r o t e i n .  If  c a e c a , t h e y must is  w o u l d show l e s s  animals.  t h e r e are advantages have  appears  the  bacteria to  be  via excreted  bac-  some.compensatory Similar results animals.  excretion of  have  It  might  faecal  s i t u a t i o n , however, of the present  f o r maximum u t i l i s a t i o n o f  energy  been c o u n t e r - b a l a n c e d w i t h some d i s a d v a n t a g e s .  e n o u s p r o t e i n and a m i n o a c i d s w i t h l i t t l e  is  b e t w e e n b a c t e r i a l and  e f f e c t on a b s o r p t i o n  of  has  experiment,  associated with the presence of  t e n t a t i v e l y suggested that the balance  nutrients.  nitrogen.  percentage of  been o b t a i n e d w i t h g e r m - f r e e c o m p a r e d w i t h c o n v e n t i o n a l be e x p e c t e d t h a t g e r m - f r e e a n i m a l s  the  they gained weight during  the e x c r e t a from the caecectomized chickens  of consequence.  of d i e t a r y  It  the It  endogingested  108  3.7  REGROWTH OF THE AVIAN CAECA FOLLOWING CAECECTOMY  3.7.1 Experiment 7  -  Introduction  Caecectomy has been employed e x t e n s i v e l y as a means o f s t u d y i n g r o l e the caeca may p l a y i n the n u t r i t i o n and p h y s i o l o g y l a r l y t h e domestic c h i c k e n (Sunde e t a l _ . , 1950;  of b i r d s , p a r t i c u -  B e a t t i e and  Shrimpton,  1958; Nelson and N o r r i s ,  1961; N i t s a n and Alumot, 1963; F i s h e r  G r i m i n g e r , 1966;  1972;  Kese and March, 1975).  and  Although  several  a r t i c l e s appear i n the l i t e r a t u r e c o n c e r n i n g the measurement o f  various  physiological  Barnes,  the  parameters a f t e r caecectomy, r e l a t i v e l y few d i s c u s s  a t i v e procedure and post-mortem o b s e r v a t i o n s .  Surgical  oper-  a b l a t i o n of the  a v i a n caeca i s a t t e n d e d by some problems not the l e a s t of which i s of c e r t a i n t y of completeness o f the e x t i r p a t i v e p r o c e d u r e . of d e s c r i p t i v e of the s u r g i c a l  Tlie o m i s s i o n  p r o c e s s , p a r t i c u l a r l y t h e completeness  caecectomy does not a l l o w one a common base f o r v a l i d comparison surgical  that  of  of  t r e a t m e n t and d a t a .  Internal  organs r e a c t d i f f e r e n t l y to removal o f d i f f e r e n t amounts  of t h e i r t i s s u e  ( L i o z n e r , 1974).  S t u d i e s on a d u l t developmental  p o i n t to a remarkable a b i l i t y o f animals o r organs removed by s u r g e r y .  to r e p l a c e p o r t i o n s o f  There are no t i s s u e s  i n the bodies  processes tissues of  warm-blooded v e r t e b r a t e s which are not c a p a b l e of r e p a i r i n g l o c a l i z e d i n j u r i e s and i n some cases ( e . g . f r a c t u r e h e a l i n g , f e a t h e r and h a i r r e g e n e r a t i o n , or the r e s t i t u t i o n o f the u r i n a r y b l a d d e r ) , the may i n v o l v e high degrees Adaptive morphological  of h i s t o l o g i c a l morphogenesis  response  (Goss, 1965).  and f u n c t i o n a l changes f o l l o w i n g r e s e c t i o n of  parts  109  of the a l i m e n t a r y t r a c t are w e l l documented i n s u r g i c a l and medical literature  (Wickborn e t a l _ . , 1 975; McDermott and Roudnew,  1976).  The f i n d i n g s , c i t e d p r e v i o u s l y , u n d e r l i n e the need f o r s t u d i e s i n v o l v i n g b i o p s y and autopsy o f c a e c e c t o m i z e d b i r d s .  T h i s s e c t i o n of  the study i s concerned w i t h the major g r o s s and m i c r o s c o p i c anatomy observed on a u t o p s y .  no  3.7.2  M a t e r i a l s and Methods  The m a t e r i a l s and methods are e s s e n t i a l l y as d e s c r i b e d f o r e x p e r i ment 6 because the c h i c k e n s i n v o l v e d i n t h i s study are the same c h i c k e n s used t o study the r o l e o f the a v i a n caeca i n the u t i l i s a t i o n o f d i e t a r y energy and p r o t e i n .  3.7.3  Results  The b i r d s were a u t o p s i e d 85 weeks a f t e r caecectomy and the a l i m e n t a r y t r a c t was examined.  As shown i n F i g s .  10 and 1 1 , the f o u r  surviving  c a e c e c t o m i z e d b i r d s had regrown t h e i r caeca t o v a r y i n g l e n g t h s .  The  regrowth ranged from 17 t o o v e r 40 p e r c e n t o f t h e l e n g t h o f t h e caeca i n the unoperated c h i c k e n s  (Table 2 7 ) .  Trunk s e c t i o n s from the midzone  o f each caecum o f both the c a e c e c t o m i z e d and unoperated c h i c k e n s  showed,  on h i s t o l o g i c a l e x a m i n a t i o n , t h a t r e g e n e r a t i o n o f the caeca had o c c u r r e d as e v i d e n c e d by the presence o f most o f the elements t h a t c o n s t i t u t e the b a s i c s t r u c t u r e o f the caecum, namely, the s e r o s a , t h e m u s c u l a r i s e x t e r n a , the submucosa,  the m u s c u l a r i s mucosae, and some glands ( F i g .  12).  Ill  10.  Regrown caeca from 85-week-old c h i c k e n s c a e c e c t o m i z e d a t 9 weeks o f age and caeca from unoperated c h i c k e n s of the same age. -  F i r s t t h r e e on the l e f t - c a e c e c t o m i z e d ; the next  unoperated.  five  112  F i g . 11.  (Left) Regrown caecum from caecectomized chicken, and ( r i g h t ) caecum from unoperated chicken.  113  Table  27.  Length of  intact  and  regrown  caeca.  Control Bird  Caecectomized cm  1  21.6  4.0  2  23.4  4.1  3  23.7  8.6  4  24.1  10.5  5  24.5  114  Fig. 12.  Transverse section through the mid-caecum,  top: regrown caecum;  bottom: i n t a c t caecum.  115  3.7.4  Discussion  Studies  on the r o l e of the caeca i n a v i a n n u t r i t i o n or  physiology  have, so f a r , f a i l e d t o e s t a b l i s h a f u n c t i o n f o r t h i s organ. l i g h t o f the f a c t t h a t r e g e n e r a t i o n o f t i s s u e s phenomenon,  the  or organs i s not a r a r e  i t i s p e r t i n e n t to make the f o l l o w i n g comments  to e x p l a i n what c o u l d cause some o f the d i s c r e p a n c i e s  i n an attempt  e x i s t i n g i n the  l i t e r a t u r e on the performance o f c a e c e c t o m i z e d c h i c k e n s . o f p r e c i s e d e s c r i p t i o n s of e x c i s i o n methods  In  The absence  i n experiments  involving  caecectomy a l l o w s f o r v a r i a t i o n i n methods, p a r t i c u l a r l y w i t h r e g a r d to the amount o f r e s i d u a l  tissue.  The presence o r absence o f r e s i d u a l  t i s s u e i s l i k e l y to i n f l u e n c e the h e a l i n g o f the s u r g i c a l r e g e n e r a t i o n of the organ. i n t h i s study  wound o r the  The observed regrowth of the f i v e m i l l i m e t e r s stump  (Table 27) u n d e r l i n e s  the importance of t h i s p o i n t .  Figs.  10 and 11 i n d i c a t e c l e a r l y t h a t a p i e c e o f t i s s u e or organ i n a d v e r t e n t l y or purposely l e f t  i n s i t u i s l i k e l y to s t i m u l a t e some form o f  or r e p a r a t i v e r e g e n e r a t i o n .  regrowth  Such a s i t u a t i o n i s l i k e l y to d i s t o r t  results. A b i l i t y to r e g e n e r a t e l o s t organs has been r e p o r t e d to d e c l i n e w i t h age.  Compensatory  do o c c u r , w i l l morphological  regrowth o r r e g e n e r a t i o n o f an o r g a n ,  be f a s t e r i n younger  than i n o l d e r c h i c k e n s .  and f u n c t i o n a l changes w i l l  than i n o l d e r ones.  This  raises  if  they  Adaptive  be q u i c k e r i n younger  chickens  the q u e s t i o n r e g a r d i n g t h e age a t which  the o c c l u s i o n of an organ w i l l make the most s i g n i f i c a n t impact.  When  an organ i s removed very e a r l y i n l i f e ,  to .  p r o b a b l y b e f o r e i t begins  function e f f e c t i v e l y , i t is l i k e l y that i t s  (possible)  function w i l l  be  116  taken over  by an o r g a n o f  the organ  is  removed  homologous t i s s u e s .  later  in l i f e ,  r e s u l t w o u l d be p r o d u c e d .  Comparing  c a e c e c t o m i z e d a t d i f f e r e n t ages probable  source  of  variation  in  In  t h e phenomenon  i n one month  were s t i l l  very  associated  with tissue  In  are  developmental  quail,  1974)  the rates  o f food consumption  increases It did  t h a t changes  volumes  in caecal  is  unfortunate  In role(s)  of this  conclusion,  hyperplasia  regeneration  bear  which  takes  1958).  (Table  the  and t h e i r  the developmental  processes  adjustment i t has  stage,  the  t o meet f u n c t i o n a l been w e l l  cells  avian requirements.  documented  a t t r i b u t e s of  (Fenna  f o o d and  i n changes o f the morphology  ingested  p e r day  produced  age  represents  25)  in the a d u l t  resulted  place. be  Nine weeks,  in of  the  significant  of  of observing  the experiment the onset  being  criteria  existing  reported  and t h e r a t e  Such i n f o r m a t i o n would h e l p e l u c i d a t e  in response  tomized chickens  all  that the design  of the caeca.  or d i f f e r e n c e s  to  lengths.  not o f f e r the o p p o r t u n i t y  regrowth  important  o f f u n c t i o n a l i t y may  i n some p h y s i c a l  of food  birds  s t u d y were c a e c e c t o m i z e d ,  Even  f o r example,  is  and/or  i n a c t i v e growth  regrowth.  and B o a g ,  Larger  in this  of  t h e r e f o r e t o be a  r e p a i r or  v e r s a t i l e t o undergo  the Japanese  caeca.  hypertrophy  hand,  that a different  indices  It  and r e s t o r a t i o n  involved  at which the birds  c a e c a may u n d e r g o  appears  ( B e a t t i e and S h r i m p t o n ,  at which the chickens a stage  life  on t h e o t h e r  probable  physiologic  of tissue  the c h i c k e n , regeneration  complete  is  in the r e s u l t s .  i n mind the r a p i d i t y w i t h which characterize  it  If,  between t h e  of  similarities  i n t a c t and  caecec-  study.  i t must  be r e s t a t e d t h a t p r o o f  f o r the caeca of the domestic  chicken  has  of a  physiological  been e l u s i v e  for  the  117  following a)  reasons:  Difference failure  b)  in experimental to ascertain  Possibility functional  c)  Variation  of  occurrence  restoration  shifts  i n age o f  methods  or absence  of function  to c e l l s birds  - v a r i a b i l i t y in excision of  - sharing  regrowth, of  o f homologous t i s s u e s ,  involved  methods;  in the d i f f e r e n t  functional and studies.  load;  .118  4.  GENERAL SUMMARY AND CONCLUSIONS  The  r e s e a r c h w h i c h forms  considered source  of energy of  for b r o i l e r chickens. f a t for carbohydrate  been e v a l u a t e d i n  efficiency,  terms  of  Hypotheses  t h e t o p i c under  The f i r s t s e v e n weeks  in  a r e most c r i t i c a l responses this  (Scott  to s t i m u l i  period.  These  by,  (1969)  results  f i c i a l ' or deleterious  o f energy et  protein  food  for balanced  This  It  finding  (Begin, of  e f f e c t was  1969;  levels,  conversion abdominal treatment  tested.  is  p r o t e i n and o t h e r reasonable  to expect  that  associated  Breed d i f f e r e n c e s  have  i n the  i n agreement w i t h a  found t o improve and N a b e r ,  been n o t e d among  of  Begin  w h i c h he s t u d i e d  the f i n d i n g of t h i s  diet  number  1974).  used  bene-  with the replacement  (Touchburn  during  or the u t i l i s a t i o n  V e l u and B a k e r ,  a  nutrients  e f f i c i e n c y and t h a t no  i n w h i c h d i e t a r y f a t p_er se_ was  u t i l i s a t i o n by t u r k e y s .  is  of,  the t h r e e breeds  However,  the  of a b r o i l e r chicken represent  c a l o r i e s w i t h equal  by f a t c a l o r i e s .  al_., 1972).  f a t and  p e r t i n e n t t o an i n - d e p t h  e f f e c t on t h e g r o w t h  on c h i c k e n s  f a t and c a r b o h y d r a t e  from others  supplementary  show t h a t t h e i n c o r p o r a t i o n o f f a t  reported that chickens  carbohydrate  performance,  e_t a l _ . , 1 9 6 9 ) .  b r o i l e r chickens.  of other reports  at varying  has  i n d u c e d by d i e t a r y t r e a t m e n t s w o u l d be m a x i m a l  d i d n o t h a v e any s p e c i a l energy  a  of dietary  were d e v e l o p e d and/or  the l i f e  p e r i o d i n which the requirements  f a t as  and n u t r i e n t u t i l i s a t i o n and  considered  investigation  The l e v e l  calories  growth  m e t a b o l i s a b l e energy  fat deposition. of  dissertation  many i m p l i c a t i o n s o f t h e u s e o f d i e t a r y  substitution have  the subject of t h i s  study  of differs  the e f f i c i e n c y  1966; chickens  Halloran in  the  119  efficiency  of nitrogen  of calories difference  (Begin,  and e n e r g y  1969)  a n d , as S a l m o n  is  pointed out,  to consider  consider  Factors  and b a l a n c e between amino a c i d s  energy  as  ing not only the l e v e l  such as  d i e t a r y energy  are probably  o f energy  been e m p h a s i z e d  (1955), S c o t t e t al.. (1969).  It  has  but a l s o  and W a l k e r , depression  1970;  concentration  the c a l o r i e to p r o t e i n  by B i e l y and M a r c h  far  (1954),  considerratio  Donaldson e t a l .  Another f a c t o r , o t h e r than the l e v e l  1961); excess  (Almquist,  M a r c h and B i e l y , 1972)  i n food i n t a k e .  its  The i m p o r t a n c e o f  of  the balancebetween  been d e m o n s t r a t e d t h a t an i m b a l a n c e  F i s h e r and S h a p i r o ,  important  i n t h e f o r e f r o n t as  o r p r o t e i n o r t h e r a t i o between them, i s  acids.  carbohydrate  one o f t h e m o s t  food i n t a k e - l i m i t i n g f a c t o r s are concerned.  energy  species  i n t h e e v a l u a t i o n o f n u t r i e n t s on a c c o u n t o f  i n f l u e n c e on f o o d i n t a k e .  o f a d i e t has  a  source  conceivable.  Summers e t a l _ . ( 1 9 6 4 )  as  (1972)  of the  i n the r e l a t i v e e f f i c i e n c y of u t i l i s a t i o n of  and f a t e n e r g y  factors  u t i l i s a t i o n regardless  1954)  ( H a r p e r and K u m t a , or deficiency  i n amino a c i d s  An e a r l i e r O b s e r v a t i o n  amino  results  1959;  (March in  marked  t h a t the d e t r i m e n t a l  e f f e c t o f i n c o r r e c t e n e r g y - . p r o t e i n r e l a t i o n s h i p c o u l d be a l l e v i a t e d by improving  t h e b a l a n c e o f amino a c i d s  established  the importance o f energy  t i o n of nutrients or It  is  the present  and a m i n o a c i d b a l a n c e  important to p o i n t out t h a t i n study  congnizance  p r o v i d e a good s u p p l y  and Dansky, in the  1950) evalua-  diets.  should  was t h e p r i n c i p a l s o u r c e o f p r o t e i n .  constant  in the d i e t ( H i l l  of essential  i n t e r p r e t i n g the r e s u l t s  be t a k e n o f t h e f a c t t h a t f i s h meal As s u c h i t was p o s s i b l e  amino a c i d s  b a l a n c e between amino a c i d s  of  as  but a l s o  not only  to maintain a  the p r o t e i n l e v e l  increased.  to  120  Lipogenesis acetyl  CoA t o f a t t y a c i d s  pyruvate rise  i n the domestic  CoA i n  where  the m i t o c h o n d r i a .  t o be t r a n s p o r t e d t h r o u g h  it  is  necessitates  the expenditure o f energy.  biosynthetic  activity, this  proportions.  substrate  Quite apart  f a t has  the supply  w i t h o u t added d i e t a r y and J e n s e n acids  mostly with turkeys,  has  efficiency several However,  fatty acids.  by t u r k e y  of  others  reported in  consume s u f f i c i e n t e n e r g y  is  1974).  cytoplasm  of  increased  significant extra-caloric  the b e n e f i c i a l a consequence  doubtful  of  i n terms  whether the  o f Touchburn  of  diets  and Naber  i n meeting  the e s s e n t i a l  3 demonstate  t h a t added  e f f e c t on m e t a b o l i s a b i 1 i t y This observation  is  the l i t e r a t u r e ( P e n q u i t e ,  inclusion of cellulose study  It  citrate  (1966)  fatty  broilers.  food u t i l i s a t i o n .  used i n the p r e s e n t  largely  the s t u d i e s  in Experiment  a deleterious  as  (Pearce,  from the f a c t t h a t the s o - c a l l e d  f a t used i n  The d a t a p r e s e n t e d cellulose  CoA  into  lipogenesis  membrane  e x p e n d i t u r e may r e a c h  e_t a l _ . ( 1 9 7 0 ) w e r e a d e q u a t e  requirement  for  w i t h o u t a d d e d f a t may n o t be a d e q u a t e  of e s s e n t i a l  gives  CoA c a n n o t d i f f u s e  Under c o n d i t i o n s  a t t r i b u t a b l e t o added d i e t a r y f a t i s  the  the b i r d ,  from the m i t o c h o n d r i a t o the  energy  been o b s e r v e d  the f a c t t h a t d i e t s  in  the mitochondrial  of  effect  Acetyl  of  1971), but  with requirement  The s h u n t i n g  effect of  (Annison,  c o n v e r t e d t o o x a l o a c e t a t e and a c e t y l this  the conversion  a major f a t precursor  the c y t o p l a s m a t a r a t e commensurate and has  involves  in the cytoplasm  formed from g l u c o s e ,  to acetyl  chicken  of diets  with  1976,  1963).  Wells,  higher  i n t e r f e r e with the b i r d s '  f o r t h e i r requirements  and  i n agreement  i n the d i e t a t a l e v e l  did not  dietary  (Sibbald  than  that  ability  to  e t al_., 1960).  121  The d i f f e r e n c e b e t w e e n t h e f i n d i n g o f t h e p r e s e n t e x p e r i m e n t and t h e under  r e f e r e n c e may be e x p l a i n e d on t h e b a s i s  and g r o w t h  r a t e of the b i r d s  physiological time.  conditions,  involved  high  of differences  i n t h e two s t u d i e s .  d i e t a r y f i b r e may s h o r t e n  The i n c r e a s e d b u l k o f n o n - a s s i m i l a b l e  material  in  strain  Under  normal  ingesta  i n the  one  transit  alimentary  t r a c t o f t h e c h i c k e n may p r e c i p i t a t e p h y s i c o - c h e m i c a l  reactions  may a f f e c t p r o c e s s e s  and w a t e r - f a c i 1 i t a t e d  s u c h as  movement o f n u t r i e n t s As  Southgate  undoubtedly  enzyme-substrate  towards  and t h r o u g h  binding  the absorbing  mucosal  a f f e c t the r e s u l t s erosion  of  of balance studies  the mucosal observed  surface.  Piekarska  and c o n s e q u e n t l y  decreased apparent p r o t e i n d i g e s t i b i l i t y in  Similar findings  containing high and P a z o u r e k , Contrary i s a b l e energy  levels  bation,  of  have  fibre  faecal nitrogen  10-20  result and  Rao  excretion rats  percent f i b r e or  Vlcek,  fed  crystalline  been o b t a i n e d w i t h c h i c k e n s  ( K i b e e t a j _ . , 1964;  will  fed  1968;  diets Vlcek  1970). to popular b e l i e f , the y o l k values yolk  of nutrients  influences  few d a y s p o s t h a t c h i n g , measured  containing  a  (1964)  (1970)  semi-purified casein diets  increased  may o c c u r as  and S u n d e r a v a l l i  the r e s i d u a l  surface.  (1973) e x p l a i n e d , l o s s e s o f endogenous m a t e r i a l w h i c h  of mechanical  cellulose.  which  i n the e a r l y days p o s t h a t c h i n g .  the performance of the c h i c k  i t must  by body w e i g h t s  sac does n o t i n f l u e n c e m e t a b o l -  be a p a r a m e t e r ( s )  in  to a near depletion l e v e l .  first  o t h e r than growth  and m e t a b o l i s a b i 1 i t y o f n u t r i e n t s .  t h e embryo u t i l i z e s a l l  the  If  During  n u t r i e n t s , with the exception of  T h r o u g h some unknown m e c h a n i s m ,  as incu-  protein,  there is  a  122  noticeable (Romanoff  increase  i n the c o n c e n t r a t i o n o f t o t a l  and R o m a n o f f ,  1967)  and t h e y o l k  sac  proteins  (Rol'nick,  t o t h e amount a t t h e m i d p o i n t o f embryo d e v e l o p m e n t . several  nitrogenous  amino a c i d s  compounds  are present  amount o f n i t r o g e n o u s t h e baby c h i c k . of nitrogen  the  compounds  and.Romanoff,  imposes  1967).  additional  This  hypothesis  addition,  The  increased  physiological  load  retention values  of this  lower  obtained with chicks with intact yolk  e x p e r i m e n t , i t has  yolk.  Under  been shown t h a t n o t o n l y  does  but  p r e s e n c e may i n t e r f e r e w i t h t h e u t i l i s a t i o n o r t h e e x c r e t i o n o f  the  products  not provide n u t r i e n t s  without residual  i n s i g n i f i c a n t amounts,  waste  yolk  i n P a r t 2 i n d i c a t e t h a t energy  by m e t a b o l i s a b l e e n e r g y  o r absence o f the caeca. McBee  (1971)  cellulolysis of  Fisher  values  is  The d a t a s u p p o r t  the avian caeca.  and G r i m i n g e r  (1966)  n o t i n f l u e n c e d by t h e the observations  concerted process  closely  The d a t a a l s o  (1955),  the c l a i m of  The a s s i m i l a t i o n o f p r o t e i n s  r e g u l a t e d by n e u r a l  b a l a n c e method as  r e t e n t i o n i n t h e body  of Scott  tend to support  and h o r m o n a l  r a t h e r than a r e s u l t of c l e a r l y d e f i n e d i n d i v i d u a l The u s e o f n i t r o g e n  presence  the  finding  t h a t t h e a v i a n c a e c a do n o t p l a y a s i g n i f i -  cant r o l e in protein u t i l i s a t i o n .  nitrogen  u t i l i s a t i o n as  and McNab ( 1 9 7 3 ) among o t h e r s , who d i s p u t e in  its  of n u t r i e n t s , p a r t i c u l a r l y those of p r o t e i n .  The d a t a p r e s e n t e d measured  on  rate  would e x p l a i n the observed  compared t o t h o s e o b t a i n e d w i t h c h i c k s  residual  compared  i n c l u d i n g r i b o n u c l e i c a c i d and some t w e n t y  (Romanoff  excretion.  the c o n d i t i o n s  1970)  yolk  The i m p l i c a t i o n seems t o be a s t e p p i n g up o f t h e  apparent nitrogen sac  In  in the  is  steps  is  the  mechanisms  (Gitler,  1964).  a c r i t e r i o n f o r the e s t i m a t i o n  a s e n s i t i v e m e t h o d , so  sensitive  of  that  123  the balance w i l l  vary  very  rapidly with shifts  responding  to a l t e r a t i o n s in d i e t s , endocrine  of various  kinds.  responsible values  secretions  One o r more o f t h e a b o v e - m e n t i o n e d  f o r the observed  variations  in  of dietary nitrogen nitrogen  (1964)  through  from the l u n g s .  have  abnormalities  f a c t o r s c o u l d be  the apparent n i t r o g e n  reported losses  some u n s u s p e c t e d  retention  resulting  in the loss  of nitrogen  a c i d n i t r o g e n was u s e d as  apparent nitrogen underestimates arriving  the t o t a l  at a conclusion  apparent nitrogen The v i e w i s actively w h i c h has  absorption  in  of sizeable  route, possibly  N e s h e i m and C a r p e n t e r  t i o n o f p r o t e i n and p e p t i d e s w h i c h e s c a p e  (1967)  breakdown  is  in  situations  The f a c t  f o r the e s t i m a t i o n of  excreted should  on t h e p r o t e i n u t i l i s a t i o n as m e a s u r e d  by  or retention.  h e l d by some r e s e a r c h e r s  t h a t t h e c a e c a may  and/or a b s o r p t i o n  in  function protein  the upper gut.  If  this  t o e x p e c t t h i s m e c h a n i s m t o be f u l l y o p e r a t i o n a l  of p r o t e i n inadequacy or d e f i c i e n c y .  i n the body.  The l e v e l  a n d t h i s may a f f e c t t h e  The t e s t i n g o f t h i s  t h a t t h e c a e c a may r e c y c l e p r o t e i n i n c a s e s o f y i e l d valuable  R e c y c l i n g may  o f p r o t e i n used i n t h i s  low enough to evoke s u c h a mechanism.  - will  that  the  in  t h e amount o f p r o t e i n e x c r e t o r y p r o d u c t s of nitrogen  caeca  be c o n s i d e r e d  absorption  logical  gaseous  and t h e f a c t t h a t u r i c a c i d d e t e r m i n a t i o n  nitrogen  escaped d i g e s t i o n  true, i t  amounts  and e n t e r t h e  t h e f o r m o f ammonia.  a component  as  Costa  reported fermenta-  i n t r a p p i n g p r o t e i n o f endogenous o r i g i n o r d i e t a r y  is  level  and  states,  w i t h i n t r e a t m e n t g r o u p s and t h e f l u c t u a t i o n s w i t h i n p e r i o d s .  ( 1 9 6 0 ) , A l l i s o n and B i r d  uric  in physiological  information.  reduce balance  s t u d y was hypothesis  inadequate d i e t a r y  not -  protein  124  Finally, influencing should related  i n view o f  the' i n t e g r a t e d n a t u r e o f the n u t r i t i o n a l  the e x p r e s s i o n  o f any p h y s i o l o g i c  response,  further  factors  research  i n v o l v e t h e i n v e s t i g a t i o n o f t h e b r o a d i m p l i c a t i o n s o f as many f a c t o r s as  possible.  The s t u d y  a t t e m p t t o a c h i e v e s u c h an o b j e c t i v e .  described herein  represents  an  125  REFERENCES  Ahrens,  R.A.,  J.E.  storage  from d i e t s  amino a c i d s Aitken,  J.R.,  source Akester,  Wilson,  o f energy R.S.  Allison,  8:  acsein.-J. Nutr.,  Anderson,  K.J.  of urine  Hill  and J . W . C .  Bird.  1969.  bolites  and  Nutrition H.J.  ketogenesis  52:  1971.  pp.  J.T.  J.T. of  (H.N.  Br.  A Poult.  New Y o r k ,  from  the  Munro a n d J . B .  Allison,  London.  fed "carbohydrate-free"  by c h i c k s .  l i v e r metadiets.  Arch.  of  1961.  a n d H.R.  storage.  the Domestic  321-337.  10th  during  f a t e x t r a c t a b i 1 i t y and p r o t e i n J . Agr.  Food Chem. 4 :  " L i p i d and A c e t a t e M e t a b o l i s m " . Fowl.  (D.J.  Academic P r e s s ,  Agricultural  Bell  London,  Chemists.  E d i t i o n , Washington,  J.  Biochem.  In:  1965.  638-639.  Physiology  and B.M.  New  digesti-  Poultry Sci.  Rosenberg.  1955.  t h e d i e t on t h e m e t h i o n i n e  and  Freeman,  York. O f f i c a l Methods  of  D.C.  The e f f e c t o f d i e t a r y d e f i c i e n c y on t h e e n e r g y  bolism of the chick.  level  1967.  between t h e c o n c e n t r a t i o n o f  in chicks  Changes i n  of O f f i c i a l  Analysis.  Baldini,  fowl.  Abs.  197-202.  i n f i s h meal  Biochemistry  Baldini,  1038.  Osbaldiston,  U t i l i s a t i o n o f amino a c i d s  1956.  E.F.  Association  33:  a  101-108.  1954.  H.J.  eds.),  Poultry Sci.  Protein Metabolism.  Relationships  99:  Biophys.  Annison,  of  t a l l o w as  Elimination of nitrogen  pp. 4 8 3 - 5 1 2 . Academic P r e s s ,  J.B.  Mammalian  1964.  eds.),  bility  Beef  flow i n the domestic  In:  Almquist,  a mixture  209-  J.B.  Almquist,  nitrogen  219-224.  1954.  a n d G.W.  body.  AlTred,  C a l o r i e and versus  88:  Hunsaker.  in b r o i l e r rations.  study  1966.  p u r i f i e d casein  L i n d b l a d and W.G.  radiographic Sci.  containing  simulating  G.S.  A.R.,  J r . and M. Womack.  40:  meta-  1177-1183.  The e f f e c t o f p r o d u c t i v e requirement of the c h i c k .  energy Poultry  126  S c i . 34: Barnes,  E.M.  1301-1307. 1972. The a v i a n i n t e s t i n a l f l o r a w i t h p a r t i c u l a r r e f e r e n c e t o  the p o s s i b l e  ecological  s i g n i f i c a n c e o f the c a e c a l a n a e r o b i c  bacteria.  Am. J . o f C l i n . N u t r . 25: 1475-1479. Barnes,  E.M.  and C.S.  Impey. 1970. The i s o l a t i o n and p r o p e r t i e s o f the p r e -  dominant a n a e r o b i c  b a c t e r i a i n the caeca o f c h i c k e n s  and t u r k e y s .  Br.  P o u l t . S c i . 11: 467-481. Barnes,  E.M.  and C.S.  a c i d decomposing 37: Barnes,  The o c c u r r e n c e and p r o p e r t i e s o f u r i c  a n a e r o b i c b a c t e r i a i n the a v i a n caecum. J . A p p l .  E.M.  and C.S.  E.M.  Impey. 1972.  Some p r o p e r t i e s o f the  non-sporing  from p o u l t r y c a e c a . J . A p p l . B a c t . 35: 241-251.  and D.H.  Shrimpton.  1957. A s u r g i c a l  and chemical  technique  f o r the study o f the m e t a b o l i c a c t i v i t y o f the gut f l o r a i n v i v o . Int. Barnes,  Bact.  393-409.  anaerobes Barnes,  Impey. 1974.  Congr. N u t r .  E.M.,  ( P a r i s ) , Abs.  G.C. Mead, D.A.  p.  Fourth  72.  Barnum and E.G. H a r r y .  1972. The i n t e s t i n a l  f l o r a o f the c h i c k e n d u r i n g the p e r i o d 2 to 6 weeks o f age w i t h  par-  t i c u l a r r e f e r e n c e to the a n a e r o b i c  13:  b a c t e r i a . B r i t . Poult-  Sci.  311-326. Barnes,  R.H.  and E. Kwong.  1964.  Methionine absorption  soybean p r o t e i n and the e f f e c t o f soybean t r y p s i n  and u t i l i s a t i o n from i n h i b i t o r - A study  o f amino a c i d a v a i l a b i l i t y . In: The Role o f the G a s t r o i n t e s t i n a l i n P r o t e i n Metabolism. Bartov,  I.,  S.  (H.N. Munro, ed.) B l a c k w e l l . pp. 41-80.  B o r n s t e i n and B. L i p s t e i n . 1974.  t e i n r a t i o on the degree o f f a t n e s s B r . P o u l t . S c i . 15:  Tract  107-117.  E f f e c t of c a l o r i e to pro-  i n b r o i l e r s f e d on p r a c t i c a l  diets.  127  B a y l e y , H.S.,  S . J . S l i n g e r , J . D . Summers and G.C. A s h t o n .  1974.  Factors  i n f l u e n c i n g the m e t a b o l i s a b l e energy v a l u e of rapeseed meal: l e v e l  in  d i e t , e f f e c t s of s t e a m - p e l l e t i n g , age o f c h i c k , l e n g t h o f time on d i e t , v a r i e t y o f rapeseed and o i l e x t r a c t i o n p r o c e d u r e . Can. J . Anim. S c i . 54:  465-480.  B e a t t i e , J . and D.H. S h r i m p t o n . 1958. S u r g i c a l  and chemical t e c h n i q u e s  for  i n v i v o s t u d i e s of the metabolism o f the i n t e s t i n a l m i c r o f l o r a of dome s t i c f o w l s . Q u a r t . J . Exp. P h y s i o l . 43: 399-407. B e g i n , J . J . 1961. The e f f e c t o f c e l l u l o s e w i t h and w i t h o u t supplemental energy i n c h i c k d i e t s . P o u l t r y S c i . 40:  892-900.  B e g i n , J . J . 1969. The e f f e c t of d i e t and breed of c h i c k e n on the m e t a b o l i c e f f i c i e n c y of n i t r o g e n and energy u t i l i z a t i o n . B i e l y , J . and B.E.  March. 1954.  Fat s t u d i e s  P o u l t r y S c i . 48: 48-54.  i n p o u l t r y . 2. Fat  supplements  i n c h i c k and p o u l t r a t i o n s . P o u l t r y S c i . 33: 1220-1227. B i e l y , J . , B.E.  March and H.L.A. T a r r . 1951. The n u t r i t i v e v a l u e o f  meal and condensed f i s h s o l u b l e s .  III.  and h e x a n e - e x t r a c t e d meal. P r o g r e s s Res.  Bd. (Canada)  No. 89:  fish  E f f e c t of heating f a t - c o n t a i n i n g  R e p o r t , P a c i f i c Coast S t a .  Fish.  79-81.  Boge, G . I 9 6 0 . Amino a c i d c o m p o s i t i o n o f h e r r i n g (Clupea harengus) and h e r r i n g m e a l . D e s t r u c t i o n o f amino a c i d s d u r i n g p r o c e s s i n g . J . Sc. Food Agr. 11: 362-365. Carew, L.B.  J r . and F.W.. H i l l .  1964.  E f f e c t of corn o i l on m e t a b o l i c  e f f i c i e n c y of energy u t i l i z a t i o n by c h i c k s . J . N u t r i t i o n 83: 293-299. Carew, L.B.  J r . , D.T.  Hopkins and M.C. Nesheim. 1964.  I n f l u e n c e o f amount  and type of f a t on m e t a b o l i c e f f i c i e n c y o f energy u t i l i z a t i o n by the c h i c k . J . N u t r i t i o n 83:  300-306.  128  Carew, L.B.  J r . , M.C.  Nesheim and F.W.  d i e t a r y energy l e v e l and d e n s i t y f a t s . P o u l t r y S c i . 42: Carew, L.B.  J r . , R.H.  absorption C a r r i c k , C.W.  Hill.  1963. The r e l a t i o n s h i p  to the growth response o f c h i c k s  Machemer,  J r . , R.W.  Sharp and D,C.  Roberts.  1947a. S t u d i e s  C a r r i c k , C.W. and R.E.  Fat  738-742.  in chick  rations.  111-117. Roberts.  1947b. S t u d i e s  r e l a t i v e e f f i c i e n c y o f corn and oats 27:  Foss. 1972.  on feed e f f i c i e n c y , 1. The  r e l a t i v e e f f i c i e n c y o f corn and wheat p r o d u c t s P o u l t r y S c i . 27:  to  710-718.  by the very young c h i c k . P o u l t r y S c i . 51:  and R.E.  of  on feed e f f i c i e n c y , I I .  in chick rations.  Poultry  The  Sci.  213-218.  Combs, G . F . ,  E.H.  B o s a r d , G.R.  protein level and c a r c a s s C o s t a , G. 1960.  C h i l d s and D.L.  Blamberg.  1964.  and amino a c i d balance on v o l u n t a r y energy  composition.  P o u l t r y S c i . 43: 1309.  E f f e c t of consumption  Abs.  H y p o t h e t i c a l pathway o f n i t r o g e n m e t a b o l i s m . Nature  188:  549-552. C u l l e n , M.P.,  O.G. Ramussen and O.H.M. W i l d e r . 1962. M e t a b o l i z a b l e  energy  v a l u e and u t i l i z a t i o n o f d i f f e r e n t types and grades of f a t by the c h i c k . P o u l t r y S c i . 41: Davidson,  J . , J . Mathieson,  animal  360-367. R.B.  W i l l i a m s and A.W. Boyne.  1964.  Effects  of  f a t and o f low r a t i o s o f p r o t e i n to m e t a b o l i z a b l e energy on the  u t i l i z a t i o n o f d i e t a r y energy by medium- and f a s t - g r o w i n g p o u l t r y . J . S c i . Fd. A g r i c .  15:  i n p u r i f i e d d i e t s f o r c h i c k s . J . N u t r i t i o n 15:  S c i . 27:  117-118.  of  316-325.  D a v i s , F. and G.M. B r i g g s . 1947. The growth promoting a c t i o n of  D a v i s , F. and G.M. B r i g g s . 1948.  strains  cellulose  383-395.  Sawdust i n p u r i f i e d c h i c k r a t i o n s .  Poultry  129  DeGroote, G., N. Reyntens and J . A m i c h - G a l i . 1971. Fat s t u d i e s . M e t a b o l i c e f f i c i e n c y of enerqy u t i l i z a t i o n of g l u c o s e , and d i f f e r e n t animal f a t s by growing Donaldson,  W.E.  1962. The response o f c h i c k s  and o l d e n v i r o n m e n t s . Donaldson,  W.E.  P o u l t r y S c i . 41:  W.E. 1966.  P o u l t r y S c i . 50:  W.E.,  to d i e t a r y animal f a t i n new 1106-1108.  Influence  o f d i e t a r y f a t on l i p o g e n e s i s  World's  P o u l t r y Congr. P r o c . 13:  G.F. Combs and G.L. Romoser. 1956.  in poultry rations.  Studies  Donaldson,  W.E.,  levels  source.  and f a t t y 196-199.  on energy  of  chicks.  1100-1105.  G.F. Combs and G.L. Romoser. 1958.  in p o u l t r y r a t i o n s .  Studies  on the  Donaldson,  W.E.,  G.F. Combs, G.L. Romoser and W.C. Supplee.  c o n d i t i o n o f growing  W.E.,  abs.  in poultry rations.  H.F.  Sassoon, J . J . Watson, D.O.  1957.  2. T o l e r a n c e o f growing  d i e t a r y f a t . P o u l t r y S c i . 36: 807-815. Dror, Y.,  Body  c h i c k s as i n f l u e n c e d by the c a l o r i e / p r o t e i n r a t i o  G.F. Combs, G.L. Romoser and W.C. Supplee.  levels  1955.  i n t a k e , feed e f f i c i e n c y , growth r a t e and f e a t h e r  o f the r a t i o n . P o u l t r y S c i . 34; 1190,  on energy  Poultry  614-619.  c o m p o s i t i o n , energy  Donaldson,  energy  3. E f f e c t o f c a l o r i e - p r o t e i n r a t i o on  growth, n u t r i e n t u t i l i s a t i o n and body c o m p o s i t i o n o f p o u l t s . S c i . 37:  levels  1. The e f f e c t of c a l o r i e - p r o t e i n r a t i o of the  r a t i o n on growth, n u t r i e n t u t i l i s a t i o n and c o m p o s i t i o n P o u l t r y S c i . 35:  808-819.  115-120.  acid interconversion. Donaldson,  soybean o i l  1964. A d a p t a t i o n o f the c h i c k to d i e t a r y energy  J . N u t r i t i o n 82: Donaldson,  chicks.  2.  Studies chicks  to  -  Mack and B.C.  Johnson.  1973.  versus s u c r o s e as the non p r o t e i n c a l o r i e p o r t i o n o f the d i e t of  Fat rats.  130  J . N u t r i t i o n 103:  342-346.  Dukes, H.H. 1955. The P h y s i o l o g y C o . , New York,  o f Domestic A n i m a l s . Comstock  Publishing  N.Y.  Edwards, H.M. and P. H a r t . 1971. Carcass  c o m p o s i t i o n of c h i c k e n s f e d c a r b o -  hydrate-free diets containing various  l i p i d energy s o u r c e s . J . N u t r .  101: 989-996. El-Lakany.  1972.  Storage changes  i n n a t u r a l and model 1 i p i d - p r o t e i n  systems.  Ph.D. T h e s i s , U n i v . B r i t . C o l . F a r r e l l , D . J . 1972. The e f f i c i e n c y of u t i l i s a t i o n o f energy by b r o i l e r c h i c k e n s on d i e t s w i t h a range o f energy c o n c e n t r a t i o n s . P r o c . Stock Fd. M f r s . Ass. F a r r e l l , D.J. 1974.  Aust.  A u s t . Meat Fedn. 155-159.  E f f e c t s of d i e t a r y energy c o n c e n t r a t i o n on u t i l i s a t i o n  o f energy b y . b r o i l e r c h i c k e n s and on body c o m p o s i t i o n determined by carcass a n a l y s i s F a r r e l l , D . J . , R.B.  and p r e d i c t e d u s i n g t r i t i u m . Br. P o u l t r y S c i . 15:  25-41.  Cumming and J . B . Hardaker. 1973. The e f f e c t s o f d i e t a r y  energy c o n c e n t r a t i o n on growth r a t e and c o n v e r s i o n o f energy to weight g a i n i n b r o i l e r c h i c k e n s . Br. P o u l t . S c i . 14: F e a t h e r s t o n , W.R. and R.W.  329-340.  S c h o l z . 1968. Changes i n l i v e r x a n t h i n e d e h y d r o -  genase and u r i c a c i d e x c r e t i o n i n c h i c k s d u r i n g a d a p t a t i o n to a high p r o t e i n d i e t . J . N u t r i t i o n 95: Fenner, L. and D.A. spruce grouse  393-398.  Boag. 1974. A d a p t i v e s i g n i f i c a n c e i n Japanese q u a i l and ( G a l l i f o r m e s ) . Can. J . Z o o l . 52:  1577-1584.  F i s h e r , H. and P. G r i m i n g e r . 1966. Raw soybean u t i l i s a t i o n by c a e c e c t o m i z e d c h i c k s . P o u l t r y S c i . 45: 848-849. F i s h e r , H. and R. S h a p i r o .  1961. Amino a c i d imbalance: R a t i o n s  low i n  t r y p t o p h a n e , m e t h i o n i n e or l y s i n e and the e f f i c i e n c y o f u t i l i s a t i o n  131  of nitrogen Forbes,  E.B.  in imbalanced r a t i o n s .  and R.W.  395-401.  S w i f t , w i t h the t e c h n i c a l c o l l a b o r a t i o n of  Greenwood-Buckman, • ••  J . N u t r i t i o n 75:  J.E.  Schopfer  and M.T.  Davenport.  1944.  A. Associative  d y n a m i c e f f e c t s o f p r o t e i n , c a r b o h y d r a t e and f a t . J . N u t r i t i o n  27:  453-468. Forbes,  E.B.,  R.W.  S w i f t , R.F.  f a t t o economy o f Nutrition Fraps,  G.S.  31:  1943.  G.S.  1946.  rations. Freeman,  B.M.  food u t i l i z a t i o n .  6:  of chickens.  Composition Exp.  and p r o d u c t i v e e n e r g y Sta.  the r a t i o n s  to  and  678. consumption, chick.  body, t e m Br.  Poult.  Swift.  1948.  F u r t h e r e x p e r i m e n t s on  Dotterresorption  und h i s t o l o g i s c h e  n a c h dem s c h l u p f e n  1971.  Org.,  153:  des  kOkens.  York.  Low p r o t e i n  intake.  Relationship  Protein digestion (H.N.  verclnderungen  W i l h e l m Roux*  des  Arch.  93-119. of energy,  phosphorus  t o g r o w t h and f o o d e f f i c i e n c y . B r .  1964.  3.  the  83-88.  Protein Metabolism. New  of  albino rat. J .  of p o u l t r y feeds  o f f a t t o economy o f f o o d . u t i l i z a t i o n .  E.E.  C.  Bull.  of  i n t h e h a t c h i n g and y o u n g  B l a c k and R.W.  Entwickl.-Mech.  Gitler,  Relation  421-424.  The r e l a t i o n s h i p b e t w e e n o x y g e n  dottersacks  chicken  22:  1965.  1961.  Gardiner,  Poultry Sci.  Agr.  N u t r i t i o n 35: E.  By t h e g r o w i n g  Texas  A.  relation  Fritz,  1946.  67-72.  French, C.E.,  J.  I.  R e l a t i o n o f p r o t e i n , f a t and e n e r g y  p e r a t u r e and s u r f a c e a r e a Sci.  and W.H. J a m e s .  203-212.  the composition Fraps,  Elliott  Poult. Sci.  and a b s o r p t i o n  Munro a n d J . B .  and b r e e d 12:  31-39.  in nonruminants.  A l l i s o n , eds.).  of  Mammalian  Academic  Press,  132  Goodridge, A.G. 1968. Metabolism of glucose U-  C in v i t r o in adipose  t i s s u e from embryonic and growing c h i c k s . Am. J . P h y s i o l . 214: 897-901. Goss, R.J. 1965. Mammalian regeneration and i t s phylogenetic r e l a t i o n s h i p . Proc. Regeneration in Animals. N o r t h - H o l l . Publ. Co., Amsterdam. Griminger, P. 1957. On the vitamin K requirement of turkey poults. Poultry S c i . 36: 1227-1235. Halloran, H.R.,  J.B. Lyle and W.T. Trana'. 1972. "Extra c a l o r i c " e f f e c t of  a blended animal and vegetable feeding f a t . Poultry S c i . 51: 1814. Abs. Hallsworth, E.G. and J . I . Coates. 1962. The growth of the alimentary t r a c t of the fowl and the goose. J . Agr. S c i . 58: 153-163. Hainan, E.T. 1930. The r o l e of f i b r e in poultry feeding. Proc. Fourth World's Poultry Congress, 221-228. Hainan, E.T. 1949. The a r c h i t e c t u r e of the avian gut and tolerance of crude f i b r e . B r i t . J . N u t r i t i o n 3: 245-253. Harper, A.E. and U.S. ment. Fed.  Kumta. 1959. Amino acid balance and protein r e q u i r e Proc. 18: 1136-1142.  Henning, H. 1929. Die v e r d a u l i c h k e i t der Rohfaser beis Huhn. Landurn. Vers Stnen 108: 253. Cited by McNab.  1973.  Herstad, 0. 1970. Effekt av f e i t t - t i l s k o t t t i l b r o i l e r f o r . ( E f f e c t of f a t supplements in b r o i l e r feed). Meldinger f r a Norges  Landbrukshogskole  49: 1-55. Cited by Salmon, 1972. Heuser, G.F., L.C. N o r r i s , H.T. Peeler and M.L. Scott. 1945. Further studies on the apparent e f f e c t of d i g e s t i b i l i t y upon growth, weightmaintenance and egg production. Poultry S c i . 24: 142-145. H i l l , F.W. and L.M. Dansky. 1950. Studies on the protein requirements of chicks and i t s r e l a t i o n to dietary energy l e v e l . Poultry S c i . 29: 763. Abs.  133  Hill,  F.W.  and  L.M.  chickens.  F.W.  1954.  Studies  of  the energy  1. The e f f e c t o f d i e t a r y e n e r g y  consumption. Hill,  Dansky.  Poultry  and S.  Sci.  Brambila.  free fatty acids.  33:  1955.  Fed..  level  requirements  on g r o w t h  and  of  feed  112-119. Properties  of  high  lipid  diets  Proc.  based  24.  on  Abs.  2066. Hill,  F.W.  and S.  Brambila.  triglycerides 24: Horani,  Abs. F.  1965.  f o r the c h i c k .  and N . J .  Poultry Sci.  Daghir.  54:  physiology  Bull. Isaaks,  1975. as  of caecal  R.E.  (M.E.) v a l u e s  determined with chicks  pouches  Hogan. of  1930.  turkeys.  caeca. Univ.  Davies,  R.  e f f e c t s of high  of  and l a y i n g  hens.  Studies  on p a t h o l o g y  and  2.  U t i l i s a t i o n of  Missouri  Agric.  Exp.  food  Sta.  by  Res.  Reiser  levels  and C R .  Couch.  of vegetable  oils.  1963.  Growth  J . Am. O i l  stimuChem.  Soc.  747-749.  Jayne-Wi11iams,  D.J.  a n d R.  Fuller.  m i c r o f l o r a on n u t r i t i o n . I n : Fowl.  (D.J.  L.S.,  Bell  G.W.  and B.M.  Schumaier  ratio. B.F.  Poultry and J . E .  Sci. Ivey.  49:  1971.  The  Physiology  Freeman,  and J . D .  of d i e t a r y f a t f o r d e v e l o p i n g  Kaupp,  energy  136.  lating  Jensen,  reconstituted  Proc.  Metabolisable  and A . G .  with ablated  R.E.,  40:  of  1886-1889.  J . E . , A . J . Durant  turkeys  Fed.  properties  2067.  t h r e e p r o t e i n supplements  Hunter,  Nutritional  i n f l u e n c e of  and B i o c h e m i s t r y  eds.),  Latshaw.  turkeys  the  as  Academic 1970.  Press,  "Extra  intestinal of  the  Domestic  New Y o r k ,  caloric"  effect  i n f l u e n c e d by c a l o r i e : p r o t e i n  1697-1704.  1922.  Digestible  N.Y.  nutrients  of p o u l t r y feeds  as  134  d e t e r m i n e d by l a b o r a t o r y Kese,  A.G.  and B . E .  March.  protein metabolism. Kibe,  K.,  I.  value of  Tasaki  and  Neue M e t h o d e  B.D.  composition  L o t t , J.W.  of chicks  1958.  solubles Agr.  and  Sci.  Lea, C H .  51:  and r e d u c i n g  L.J.  Leeson,  S.,  energy Br.  as  Hannan. sugars  1781.  i n energy  o f f i b r e on t h e  in stored  proteases,  35:  biological  detailed in  51:  development  159-166.  Stickstoffs  in  organischen  A.O.A.C.  F r e e c e and J . O .  Poultry Sci.  heated h e r r i n g  Studies  the " d r y "  K.J.  May.  1972.  temperature  Body and  517-522.  meal, chick  herring  experiments.  K.J.  D.  J.  and c o n v e n t i o n a l  5:  1958.  Nature of  Carpenter. meal.  Lewis  Br.  12:  Chemical  J . Nutr.  and D.H.  14:  and  nutritional  297-312. and n u t r i t i o n a l  91-113.  Shrimpton.  metabolisable  protein  433-454.  Chemical  1960.  the  proteins  energy  1974.  Metabolisable  of d i e t a r y  ingredients.  183-189.  M. W a g n e r , F. amylase  111.  Acta  Carpenter.  herring  15:  t h e r e a c t i o n between  state.  Biophys.  with turkeys:  Sci.  of  herring meal. Br. J . Nutr.  Boorman,  studies  S.,  des  Sc.  i n f l u e n c e d by e n v i r o n m e n t a l  Biochem.  P a r r and  K.N.  Jap. J . Zootech.  F.N.  and  Abs.  Effects  3 6 6 - 3 8 2 . As  1950.  in  P a r r and  L.J.  Poult.  Lepkovsky,  1-9.  164-176.  changes i n s t o r e d  changes  2:  P r o t e i n v a l u e and a m i n o a c i d b a l a n c e o f c o n d e n s e d  groups r e a c t i n g .  Lea, C.H.,  1964.  Deaton,  spontaneously  a n d R.S.  Lea, C.H.,  54:  z u r Bestimmung  Chem. 2 2 :  selected dietary factors. B.  Poultry Sci.  r o l e of the avian caeca  Poultry'Sci.  and M. S a i t o .  Z. A n a l .  L.F.,  Laksevela,  The  organs of c h i c k s .  J . 1883.  Ktirpern. Kubena,  1975.  tests.  t r u e 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 and on t h e  internal  Kjeldahl,  feeding  and  Furuta, lipase  chickens.  K.  Ozone  of the  Poultry  and T .  Koike.  1964.  i n t e s t i n a l contents  Sci.  43:  722-726.  of  The germfree  135  L i o z n e r , L.D.  1974.  Organ R e g e n e r a t i o n :  A Study o f Developmental  i n Mammals. (B.M. C a r l s o n , e d . ) , C o n s u l t a n t s L o d h i , G.N., R. Renner and D.R.  C l a n d i n i n . 1969.  Biology  Bureau, New York, Studies  N.Y.  on the m e t a b o l -  i z a b l e energy of rapeseed meal f o r growing c h i c k s and l a y i n g  hens.  P o u l t r y S c i . 48: 964-970. L o o i , S.H.  and R. Renner.  on the c h i c k ' s L o o i , S.H.  Maas, W. 1934. Abstr. Mangold;,  requirement f o r v i t a m i n B-12.  and R. Renner.  on the c h i c k ' s  1974a. E f f e c t o f f e e d i n g " c a r b o h y d r a t e - f r e e " J . N u t r i t i o n 104:  E. 1934.  394-399.  1974b. E f f e c t o f f e e d i n g " c a r b o h y d r a t e - f r e e "  requirement f o r m e t h i o n i n e . J . N u t r i t i o n 104:  Metabolism experiments on f o w l s w i t h a r t i f i c i a l  Rev. 3:  diets  diets  400-404.  anus.  Nutr.  949.  Digestion  and u t i l i s a t i o n o f crude f i b r e .  Nutr.  Abstr.  Rev. 3: 647-656. March, B.E.  and J . B i e l y . 1955.  Fat s t u d i e s  i n p o u l t r y . 3. F o l i c a c i d and  f a t t o l e r a n c e i n t h e c h i c k . P o u l t r y S c i . 34: March, B.E.  and J . B i e l y . 1956.  Fat s t u d i e s  39-44.  i n p o u l t r y . 5. The e f f e c t o f  d i e t a r y f a t l e v e l on the c h o l i n e requirement o f the c h i c k . P o u l t r y 35:  545-549.  March, B.E.  and J . B i e l y . 1972. The e f f e c t o f energy  and from environment v  Sci.  of dietary lysine.  March, B.E.  and R.O.  head on the response o f c h i c k s to d i f f e r e n t  P o u l t r y S c i . 21 ( 5 1 ) :  March, B.E.,  levels  665-668.  Walker. 1970. The e f f e c t o f s h i f t s  a c i d p a t t e r n on feed consumption Pharmacol. 48:  s u p p l i e d from the d i e t  i n the d i e t a r y  i n the c h i c k . Can. J .  amino  PhysioT.  265-268.  J . B i e l y , C. G o u d i e , F.E.  e f f e c t of s t o r a g e  C l a g g e t t and H.L.A. T a r r .  1961.  The  temperature and a n t i o x i d a n t t r e a t m e n t on the chemical  136  and n u t r i t i v e c h a r a c t e r i s t i c s o f h e r r i n g m e a l . J . Amer. Chem. Soc.  33:  80-84. March, B.E.,  T. Smith and S. E l - L a k a n y .  1973. V a r i a t i o n s  in estimates  of  m e t a b o l i z a b l e energy v a l u e o f rapeseed meal determined w i t h c h i c k e n s  of  d i f f e r e n t ages. P o u l t r y S c i . 52: 614-618. M a r i o n , J . E . and H.M.  Edwards, J r . 1963.  E f f e c t o f d i e t on the uptake o f  c a r b o n - 1 4 - l a b e l l e d a c e t a t e , g l u c o s e and l e u c i n e i n t o l i p i d s o f the c h i c k . J . N u t r i t i o n 8 1 : 55-59. Masson, M . J . 1954. M i c r o s c o p i c special  studies  o f the gut f l o r a o f the hen w i t h  r e f e r e n c e to the breakdown o f s t a r c h e s .  P o u l t r y Congress, Edinburgh,  P r o c . 10th  World's  105-111.-  M a t t o c k s , J . G . 1971. Goose f e e d i n g and c e l l u l o s e d i g e s t i o n . W i l d f o w l 22:  107.  M a t t s o n , F.H. 1967. D i e t a r y c o m p o s i t i o n , as r e l a t e d t o the f a t e o f d i e t a r y lipids.  P r o c . 1967 D e v e l . Conf. on L i p i d s on the Fate o f D i e t a r y  (G. C o w g i l l and L.W.  K i n s e l l , e d s . ) . U.S.  Lipids.  Govt. P r i n t i n g O f f i c e ,  Washington. Maumus, J . 1902. 15:  Les caecums des o i s e a u x . Ann. S c i . N a t l . V I I I S e r .  1.  Maumus, J . and L. Launoy. Mus.  1901. La d i g e s t i o n c a e c a l e chez l e s o i s e a u x .  Natn. H i s t . N a t . , P a r i s , 7:  McBee, R.M. Rev.  Zool.  Bull.  361.  1971. S i g n i f i c a n c e o f i n t e s t i n a l m i c r o f l o r a i n h e r b i v o r y .  Annu.  E c o l . S y s t . 2: 165-176.  McDermott, F.T.  and B. Roundness. 1976.  Ileal  crypt c e l l  a f t e r 40% small bowel r e s e c t i o n . G a s t r o e n t e r o l o g y McNab, J . M . 1973. The a v i a n c a e c a : A r e v i e w . W o r l d ' s 251-263.  population  kinetics  70: 707-711.  P o u l t . S c i . J . 29:  137  Mead, G.C. and B.W. Adams. 1975.  Some o b s e r v a t i o n s  on the c a e c a l m i c r o f l o r a  o f the c h i c k d u r i n g the f i r s t two weeks o f l i f e .  Br. P o u l t . S c i .  16:  169-176. M i l l e r , D.S. 18: Morris,  1955. The n u t r i t i v e v a l u e o f f i s h p r o t e i n s . Chem. & Ind.  501-502. L.,  R.B.  rations. Mraz, F.R.,  Thompson and V.G. H e l l e r . 1932.  P o u l t r y S c i . IT:  R.V.  Crude f i b r e i n c h i c k e n  219-225.  Boucher and M.G. McCartney.  1956. The i n f l u e n c e o f d i e t a r y  p r o d u c t i v e energy and f i b r e on growth response i n c h i c k e n s . 35:  (Lond.)  Poultry  Sci.  1335-1340.  Munro, H.N. and T.W. Wikramanayake.  1954. Absence o f a time f a c t o r i n the  r e l a t i o n s h i p between l e v e l o f energy  i n t a k e and p r o t e i n m e t a b o l i s m .  J . N u t r i t i o n 52: 99-114. Munro, H.N.,  J . G . B l a c k and W.S.J. Thomson. 1959. The mode o f a c t i o n o f  d i e t a r y c a r b o h y d r a t e on p r o t e i n m e t a b o l i s m . B r i t . J . N u t r . 13: 475-485. N e l s o n , T.S.  and L.C.  Norris.  1961.  Studies  on the v i t a m i n K requirement  of  the c h i c k . P o u l t r y S c i . 40: 392-395. Nesheim, M.C. ceedings  1965. Amino a c i d a v a i l a b i l i t y i n processed  proteins.  Pro-  1965 C o r n e l l N u t r i t i o n Conference f o r feed m a n u f a c t u r e r s ,  pp.  112-118. Nesheim, M.C. and K . J . C a r p e n t e r .  1967. The d i g e s t i o n o f heat damaged p r o t e i n  B r . J . N u t r . 21: 399-411. N i t s a n , Z. and E. Alumot. 1963. The r o l e o f the caecum i n the u t i l i s a t i o n o f raw soybean i n c h i c k s . J . N u t r i t i o n 80: 2 9 9 - 3 0 4 . '  1  Nowland, W . J . , R.A.E. Pym and P . J . McMahon. 1971. The 1971 random b r o i l e r t e s t . P o u l t r y N o t e s , pp. 6-11 C i t e d by D.J.  F a r r e l l , 1974.  N.S.W. Department o f  Br. P o u l t . S c i . 15:  25-41.  sample  Agriculture.  138  O ' D e l l , B.L.,  W.D. Woods, O.A.  L a e r d a l , A.M. J e f f a y and J . E . Savage.  D i s t r i b u t i o n o f the major nitrogenous, compounds  1960.  and amino a c i d s  in  c h i c k e n u r i n e . P o u l t r y S c i . 39: 426-432. O'Hea, E.K.  and G.A. L e v e i l l e . 1969.  Lipid biosynthesis  domestic c h i c k ( G a l l u s d o m e s t i c u s ) . Olsson,  and t r a n s p o r t i n the  Comp. Biochem. P h y s i o l . 30:  N. 1948. The r o l e o f ' f i b r e i n the food o f hens and c h i c k s .  Eighth World's  149-159.  Proc.  P o u l t r y C o n g r e s s , 162-167. •  Panda, J . N . and G.F. Combs. 1950.  Studies  on the energy r e q u i r e m e n t s of the  c h i c k f o r r a p i d growth. P o u l t r y S c i . 29: 774-775. Payne, G.C. and D. L e w i s . 1964, P o u l t . Congr. Payne, W.L.,  R.R.  Kiev,  World's  182-186.  K i f e r , D.G.  tein digestion  N u t r i e n t d e n s i t y i n c h i c k d i e t s . 13th  Snyder and G.F. Combs. 1971. S t u d i e s  i n the c h i c k e n . 1. I n v e s t i g a t i o n  of pro-  o f apparent amino a c i d  d i g e s t i b i l i t y o f f i s h meal p r o t e i n u s i n g c a e c e c t o m i z e d , a d u l t male chickens.  P o u l t r y S c i . 50:  143-150.  P e a r c e , J . 1974. The i n t e r r e l a t i o n s h i p s o f c a r b o h y d r a t e and l i p i d m e t a b o l i s m . World's  P o u l t r y S c i . 30:  115-128.  P e n q u i t e , R. 1936. Over 10 p e r c e n t f i b r e a p p a r e n t l y i s u n d e s i r a b l e . Agr.  Exp. S t a . Annual  P e t e r s o n , D.W.,  CR.  Report,  Grau and N.F,  Oklahoma  156-157. Peek. 1954.  Growth and food  consumption  i n r e l a t i o n t o d i e t a r y l e v e l s o f p r o t e i n and f i b r o u s b u l k . J . N u t r i t i o n 52: 241-257. P i e k a r s k a , J . 1964.  E f f e c t o f chemical c o m p o s i t i o n o f crude f i b r e on some  f u n c t i o n and weight of the d i g e s t i v e t r a c t . Rocz. Pantstowowego.  Zakl.  H i g . 15: 471-480 ( N u t r . Abs. Rev. 35: 3845). P o t t e r , L.M.,  L.D.  1960. S t u d i e s  M a t t e r s o n , A,W. A r n o l d , W.J. P u d e l k i e w i c z and E.P.  Singsen.  i n e v a l u a t i n g energy c o n t e n t o f feeds f o r the c h i c k .  1.  139  The e v a l u a t i o n o f the m e t a b o l i s a b l e and p r o d u c t i v e energy o f a l p h a c e l l u l o s e . P o u l t r y S c i . 39: 1166-1177. P r a c t o r i u s , E. 1965. U r i c a c i d . In: Methods Bermeyer, e d . ) . Academic P r e s s ,  o f enzymatic a n a l y s i s .  New Y o r k , N.Y.  P u d e l k i e w i c z , W . J . , M.W. S t u t z and L.D.  Matterson.  (H.W.  pp. 500-501. 1968. D e t e r m i n a t i o n o f  u r i c a c i d i n a v i a n e x c r e t a by the use o f u r i c a s e and d i f f e r e n t i a l s p e c t r o p h o t o m e t r y . P o u l t r y S c i . 47:  1274-1277.  R a d e f f , T. 1928. Uber d i e Rohfaserverdaureng B l i n d d a r m zukommende Bedeutung. Rand, N.T. , F.A.  beim Huhm und d i e h i e r b e i dem  Biochem. Z. 193:  192-196.  Kummerow and H.M. Scott-. 1957. The r e l a t i o n s h i p o f d i e t a r y  p r o t e i n , f a t and energy on the amount, c o m p o s i t i o n and o r i g i n o f fat.  P o u l t r y S c i . 36: 1151-1152.  Rand, N.T.,  H.M. S c o t t and F.A.  Abs.  Kummerow. 1958.  o f the growing c h i c k . P o u l t r y S c i . 37: Rao, M.N. and O.E. utilisation.  Sunderavalli.  1970.  carcass  D i e t a r y f a t i n the n u t r i t i o n  1075-1085.  Extraneous  c e l l u l o s e : e f f e c t on p r o t e i n  S t u d i e s w i t h w e a n l i n g r a t s . J . Am. D i e t e t i c A s s o c .  57:  517-519. R e c o r d , P.R.  1943. A f a c t o r i n oat h u l l s e s s e n t i a l  Iowa Research B u i . Renner, R. 1964.  f o r growth o f  chicks.  312.  F a c t o r s a f f e c t i n g the u t i l i z a t i o n o f  "carbohydrate-free"  d i e t s by the c h i c k . 1. L e v e l o f p r o t e i n . J . N u t r i t i o n 84: Renner, R. and A.M. Elcombe. 1964.  322-326.  F a c t o r s a f f e c t i n g the u t i l i s a t i o n o f  " c a r b o h y d r a t e - f r e e " d i e t s by the c h i c k . 2. L e v e l o f g l y c e r o l . J . N u t r i t i o n 84:  327-330.  Renner, R. and F.W. H i l l .  1960. The u t i l i z a t i o n o f corn o i l , l a r d and t a l l o w  by c h i c k e n s o f v a r i o u s  ages. P o u l t r y S c i . 39: 849-854,  140  R i c h a r d s o n , C . E . , A . B . Watts and E.A.  Epps.  b r o i l e r s : The e f f e c t o f u s i n g v a r i o u s  1956. Energy s t u d i e s w i t h f i b r o u s f e e d s t u f f s w i t h and  w i t h o u t added f a t i n a p r a c t i c a l b r o i l e r r a t i o n . P o u l t r y S c i . 35:  1167-  1168. R o b e r t s o n , E.I.,  R.F.  M i l l e r and G.F. Heuser.  1948. The r e l a t i o n o f  t o f i b r e i n c h i c k r a t i o n s . P o u l t r y S c i . 27: R o l ' n i k , V.V. 1970.  energy  736-741.  "Withdrawal o f the y o l k sac and i t s importance i n  embryonic d e v e l o p m e n t " . In:  B i r d Embryology,  pp. 98-99.  Israel  post-  Program  f o r S c i e n t i f i c T r a n s l a t i o n s , J e r u s a l e m , 1970. Romanoff, A . L . and A . J . Romanoff. p o r t i o n s o f the e g g " .  In:  1967.  B i o c h e m i s t r y o f the A v i a n Embryo. John W i l e y  and Sons, New Y o r k , London, Sydney, S a i t o , M. I.  " C h e m i s t r y o f the nonembryonic  p.  187.  T a s a k i , K. K i h e , H. Yamada and T.  Igarashi.  1959. E f f e c t o f  v a r i o u s c e l l u l o s e l e v e l s i n the d i e t on the c h i c k growth. P o u l t r y S c i . 38:  373-376.  Salmon, R.E.  1972. The e f f e c t o f d i e t a r y f a t on the p e r f o r m a n c e ,  carcass  q u a l i t y , f a t t y a c i d c o m p o s i t i o n and s t o r a g e s t a b i l i t y o f t u r k e y s . T h e s i s , U n i v . o f Saskatchewan, Salmon, R.E.  1974.  Ph.D.  Canada.  E f f e c t o f d i e t a r y f a t c o n c e n t r a t i o n and energy t o p r o t e i n  r a t i o on the p e r f o r m a n c e , y i e l d o f c a r c a s s components and c o m p o s i t i o n o f s k i n and meat o f t u r k e y s as r e l a t e d t o age. Br. P o u l t . S c i . 1.5: 543-560. S a l t e r , D.N.  and M.E. C o a t e s . 1971. The i n f l u e n c e o f the m i c r o f l o r a o f the  a l i m e n t a r y t r a c t on p r o t e i n d i g e s t i o n i n the c h i c k . Br. J . N u t r .  26:  55-69. S c h w a r t z , H.G., M.W. T a y l o r and H. F i s h e r . 1958. The e f f e c t o f d i e t a r y energy c o n c e n t r a t i o n and age on the l y s i n e r e q u i r e m e n t o f growing c h i c k s . J . N u t r i t i o n 65:  25-37.  141  S c o t t , H.M.  1955.  V i t a m i n K as r e l a t e d t o the haemorrhagic  Feed Age 5, No. 3: S c o t t , H.M.,  L.D.  condition.  40.  M a t t e r s o n and E.P.  S i n g s e n . 1947.  Nutritional  factors  i n f l u e n c i n g growth and feed e f f i c i e n c y . 1. E f f e c t o f the source carbohydrate. S c o t t , M.L., p.50. Shapiro,  P o u l t r y S c i . 26: 554.  Abs.  M.C. Nesheim and R . J . Young. 1969.  M.L.  S.K.  Scott & Associates,  and W.B. S a r l e s .  of normal c h i c k e n s . Sheeny, E . J . 1939.  of  N u t r i t i o n o f the C h i c k e n ,  I t h a c a , New York.  1949. M i c r o o r g a n i s m s i n the i n t e s t i n a l  J . B a c t . 58:  531-544.  E f f e c t o f f i b r e and bulk i n the d i e t o f c h i c k e n s on t h e i r  growth and on the p r e v e n t i o n o f f e a t h e r p i c k i n g and c a n n i b a l i s m . Seventh W o r l d ' s Sibbald,  I.R.  tract  Proc. ,  P o u l t r y C o n g r e s s , 205-209.  and S . J . S l i n g e r .  1960. The m e t a b o l i z a b l e energy c o n t e n t of a  c h i c k s t a r t e r d i e t d i l u t e d w i t h c e l l u l o s e and k a o l i n . P o u l t r y S c i . 1294. Sibbald,  Abs.  I.R.  energy  and S . J . S l i n g e r .  1963. A b i o l o g i c a l assay f o r m e t a b o l i z a b l e  i n p o u l t r y feed i n g r e d i e n t s  together with findings  which demon-  s t r a t e some o f the problems a s s o c i a t e d w i t h the e v a l u a t i o n o f P o u l t r y S c i . 42: Sibbald,  39:  I.R.,  fats.  313-325.  J . D . Summers and S . J . S l i n g e r .  1960.  F a c t o r s a f f e c t i n g the  m e t a b o l i z a b l e energy c o n t e n t o f p o u l t r y f e e d s . P o u l t r y S c i . 39: 544-556. Slinger,  S.J.,  I.R.  S i b b a l d and W.F. Pepper. 1964. The r e l a t i v e a b i l i t i e s  o f two breeds o f c h i c k e n s and two v a r i e t i e s o f t u r k e y s  to metabolizable  d i e t a r y energy and d i e t a r y n i t r o g e n . P o u l t r y S c i . 43: 329-333. Slinger,  S . J . , J . D . McConnachie  fat for different strains 794.  and W.F. Pepper. 1955. The v a l u e of- animal and c r o s s e s o f b r o i l e r s . P o u l t r y S c i . 34:  789-  142  Southgate, D.A.T. 1973. Fibre and the other unavailable carbohydrates and t h e i r e f f e c t s on the energy value of d i e t s . Proc. Nutr. Soc. 32: 131-136. Spring, J . L . and W.G. Wilkinson. 1957. The influence of d i e t a r y protein and energy level on body composition of b r o i l e r s . Poultry S c i . 36: 1159. Abs. Stansby, M.E. 1948. Report on f a t in f i s h meal. J . Assoc. O f f i c . Agr. Chem. 31: 606-610. Sugden, L.G. 1974. Energy metabolized by bantam chickens and blue-winged t e a l . Poultry S c i . 53: 2227-2228. Summers, J.D., S.J. Slinger and G.C. Ashton. 1965. The e f f e c t of d i e t a r y energy and protein on carcass composition with a note on a method for estimating carcass composition. Poultry S c i . 44: 501-509. Summers, J.D., S.J. S l i n g e r , J.R. Sibbald and W.F. Pepper. 1964.  Influence  of protein and energy on growth and protein u t i l i z a t i o n in the growing chicken. J . of N u t r i t i o n 82: 463-468. Sunde, M.L., W.W. Cravens, C A . Elvehjem and J.G. Hal p i n . 1950. The e f f e c t of d i e t and caecectomy on the i n t e s t i n a l synthesis of b i o t i n in the mature f o w l . Poultry S c i . 29: 10-14. Supplee, W.C. 1960. The e f f e c t of a n t i b i o t i c supplementation on the response of poults to d i e t a r y corn o i l . Poultry S c i . 39: 227-229. S w i f t , R.W. and A. Black. 1949. Fats in r e l a t i o n to c a l o r i c e f f i c i e n c y . J . Am. O i l Chem. Soc. 26: 171-176. Tasaki, I. and H. Sakurai. 1969. Studies on the energy metabolism in the fowl. Mem. Lab. Anim. Nutr., Nagoya Univ., 4. Cited by F a r r e l l et a l . (1973) Br. Poult. S c i . 14: 329-340. Thomas, O.P. and P.V. Twining. 1971. B r o i l e r n u t r i t i o n during the w i t h drawal period (7-8% weeks). Proc. Md. Nutr. Conf.,  87-90.  143  Thompson,  D.C.  and D.A.  Boag.  1975. Role o f the caeca i n Japanese q u a i l  e n e r g e t i c s . Can. J . Zoology 53: Thomson, W.S.T. and H.N. Munro.  166-170.  1955. The r e l a t i o n s h i p o f  metabolism t o p r o t e i n m e t a b o l i s m . IV.  The e f f e c t o f s u b s t i t u t i n g  f o r d i e t a r y c a r b o h y d r a t e . J . N u t r . 56: Thornburn, C C .  and J . S .  carbohydrate  139-150.  W i l l c o x . 1964. The caeca o f the domestic fowl and  d i g e s t i o n o f the crude f i b r e complex. 11. Experiments f i s t u l a t e d b i r d s , and the a r t i f i c i a l B r i t . Poult. Thornburn, C C  fat  S c i . 5:  in vivo with  and i s o l a t e d caecum i n v i t r o .  33-43.  and J . S . W i l c o x . 1965a. The caeca o f the d o m e s t i c fowl  and  d i g e s t i o n o f t h e crude f i b r e complex. 1. D i g e s t i b i l i t y t r i a l s w i t h normal and c a e c e c t o m i z e d b i r d s . B r i t . P o u l t . S c i . 6: Thornburn, C C .  and J . S .  W i l c o x . 1965b. The caeca o f the domestic fowl and  d i g e s t i o n of the crude f i b r e complex. I I . f i s t u l a t e d b i r d s and the a r t i f i c i a l B r i t . P o u l t S c i . 6: Touchburn, S.P. turkeys. Vanschoubroek,  and E . C  Experiments  in vivo with  and i s o l a t e d caecum i n v i t r o .  33-43. Naber. 1966. The energy v a l u e o f f a t s f o r  P r o c . 13th W o r l d ' s F.,  23-31.  growing  P o u l t r y Congress. 190-195.  G. Vermeersch and R. De S c h r i j v e r . 1971. A comparison  of e f f e c t o f l a r d and soyabean o i l on food and water i n t a k e , body w e i g h t , food c o n v e r s i o n e f f i c i e n c y and m o r t a l i t y of b r o i l e r c h i c k s . P o u l t r y S c i . 50: V e l u , J . G . and D.H.  495-501.  Baker.  1974.  Body c o m p o s i t i o n and p r o t e i n u t i l i s a t i o n  o f c h i c k s f e d graded l e v e l s o f f a t . P o u l t r y S c i . 53: Vermeersch, G. and F. Vanschoubroek. of i n c r e a s i n g l e v e l s of various  1831-1838.  1968. The q u a n t i f i c a t i o n of the e f f e c t f a t s on body weight g a i n , e f f i c i e n c y o f  food c o n v e r s i o n and food i n t a k e o f growing c h i c k s . B r i t . P o u l t .  Sci.  144  9:  13-30.  V l c e k , A. 1968.  Influence  o f i n c r e a s e d amounts of crude f i b r e i n feeds on  w e i g h t g a i n s and consumption Vyzk.  Ustavukrmivar  o f feeds by b r o i l e r s . Sborn.  P o h o r e l i c e 7: 87-96. ( N u t r . Abs.  ved.  & Rev.  Praci  1970:  6444). V l c e k , A. and M. Pazourek.  1970.  Influence  o f amount and q u a l i t y of  f i b r e i n feeds f o r c o c k e r e l s and p u l l e t s on N b a l a n c e and o f f e e d s . S b o r n i k Ved. P r a c i Vyz. Ustav.u V y z i v y Z o i r a t . 8: 169-183. ( N u t r . Abs. Vogtmann,  H., H.P.  Rev. 42:  P f i r t e r and A . L .  crude  digestibility  Pohorelice,  10025).  P r a b u c k i . 1975. A new method  of  d e t e r m i n i n g m e t a b o l i s a b i l i t y o f energy and d i g e s t i b i l i t y o f f a t t y i n b r o i l e r d i e t s . Br. P o u l t . S c i . 16: V o h r a , P. 1972.  W a i b e l , P.E.  531-534.  E v a l u a t i o n o f m e t a b o l i z a b l e energy f o r p o u l t r y .  P o u l t r y S c i . J . 29: 1958.  Effectiveness  o f unknown growth f a c t o r s ,  Whitehead, C.C. and C. F i s h e r .  P o u l t r y S c i . 37:  1144-1149.  Br. P o u l t . S c i . 4:  1975. The u t i l i s a t i o n o f v a r i o u s  o f d i f f e r e n t ages. Br. P o u l t . S c i . 16:  W h i t e , A . , P. Handler and E.L. e d . ) , McGraw-Hill  S m i t h . 1973.  c a n i n e g a s t r i c o u t p u t and serum g a s t r i n  and J . C . Hammond.  1940.  fats  by  481-485. (5th  N.Y.  Bushkin and J . E . McHuiqan.  i n t e s t i n e r e s e c t i o n . Gastroenterology  161-168.  P r i n c i p l e s of B i o c h e m i s t r y  Book Company, New York,  Wickbom, G . , J . H . L a n d o r . F . L .  W i l c k e , H.L.  antibiotics,  1963. The r e l a t i o n s h i p between d i e t a r y energy l e v e l , food c o n -  sumption and growth i n b r o i l e r c h i c k s .  turkeys  World's  204-214.  and animal f a t i n t u r k e y p o u l t r a t i o n s . W e l l s , R.G.  acids  1975. Changes i n  l e v e l s f o l l o w i n g massive s m a l l  60: 448-452.  F e a t h e r i n g , g r o w t h , feed  consumption  145  and rachi-togenesis in chicks as influenced by kinds of grain in the d i e t . J . Agr. Research 61: 369-380. Yacowitz, H., R.D. Carter, J . Wyne and M.G. McCartney. 1956. E f f e c t s of varying protein and f a t l e v e l s in a f i n i s h i n g r a t i o n for turkey b r o i l e r s . Poultry S c i . 35: 227-229. Yoshida, M. and H. Morimoto. 1970a. I n t e r r e l a t i o n s h i p between d i e t a r y prot e i n level and carcass composition of c h i c k s . A g r i c . B i o l . Chem. 34: 414-422. Yoshida, M. and H. Morimoto. 1970b. P e r i o d i c a l change in the carcass comp o s i t i o n of chicks a f t e r switching over the d i e t to lipogenic or l i p o l y t i c d i e t . A g r i c . B i o l . Chem. 34:  423-431.  Yoshida, M., H. Hoshii and H. Morimoto. 1966. L i p o l y t i c d i e t to control ' carcass f a t deposition of growing c h i c k s . World's Poultry Congr. Proc. 13: 200-202. Yoshida, M., H. Hoshii and H. Morimoto. 1970. L y p o l y t i c d i e t to control carcass f a t deposition of growing c h i c k s . Abs. Nutr. Abs. & Revs. (1971) 41: 8622. Young, R.J. 1961. The energy value of f a t s and f a t t y acids for c h i c k s .  I.  Metabolizable energy. Poultry S c i . 40: 1225-1233. Young, R.J., R.L. Garrett and M. G r i f f i t h . 1963. Factors a f f e c t i n g the a b s o r b a b i l i t y of f a t t y acid mixtures high in saturated f a t t y a c i d s . Poultry S c i . 42: 1146-1154. Zelenka, J . 1968. Influence of age of chicken on the metabolizable energy value of poultry d i e t s . B r i t . P o u l t .  S c i . 9: 135-142.  

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