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Nutrient availability of wheat feed screenings in broiler diet Wolde-Tsadick, Maheteme Selassie 1982

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NUTRIENT AVAILABILITY OF WHEAT FEED SCREENINGS IN BROILER DIET by. Maheteme S e l a s s i e jWolde-Tsadick B . S c , H a i l e S e l a s s i e I U n i v e r s i t y , 1962 M.Sc, Oklahoma State U n i v e r s i t y , 1970 M.Sc, U n i v e r s i t y of B r i t i s h Columbia, 1978 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY i n THE FACULTY OF GRADUATE STUDIES Department of P o u l t r y Science We accept t h i s t h e s i s as conforming to the re q u i r e d standard THE UNIVERSITY OF BRITISH COLUMBIA May 1981 © Maheteme S e l a s s i e Wolde-Tsadick. In presenting t h i s thesis i n p a r t i a l f u l f i l m e n t of the requirements for an advanced degree at the University of B r i t i s h Columbia, I agree that the Library s h a l l make i t f r e e l y available for reference and study. I further agree that permission for extensive copying of t h i s thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. I t i s understood that copying or publication of t h i s thesis for f i n a n c i a l gain s h a l l not be allowed without my written permission. Department of Poultry Science  The University of B r i t i s h Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3 Date Apr i l 15, 1982 DE-6 (3/81) ABSTRACT Content and a v a i l a b i l i t y o f n u t r i e n t s i n t e n wheat f e e d s c r e e n i n g samples were determined u s i n g day o l d b r o i l e r c h i c k s . The m e t a b o l i z a b l e energy (ME) v a l u e of wheat f e e d s c r e e n i n g s (WFS)in a b a l a n c e d d i e t was s i g n i f i c a n t l y (P > 0.05) h i g h e r than wheat which was used as a c o n t r o l d i e t . Growth performance o f a l l WFS samples were h i g h e r than c o n t r o l d i e t . D i e t s one, two, f o u r , seven, t e n and e l e v e n had f e e d e f f i c i e n c y r a t i p s w h i c h were s i g n i f i c a n t l y (P > 0.05) h i g h e r than the c o n t r o l d i e t . The t o t a l average a v a i l a b i l i t y o f s i x t e e n amino a c i d s i n these f e e d s t u f f s ranged from 66% ( c o n t r o l ) t o 84% ( d i e t t h r e e ) . Among l i m i t i n g e s s e n t i a l amino a c i d s , l y s i n e was s i g n i f i c a n t l y (P > 0.05) h i g h e r (83%) i n a v a i l a b i l i t y f o l l o w e d by t h r e o n i n e (67%) and m e t h i o n i n e ( 6 4 % ) . The average a v a i l a b i l i t y o f the s t u d i e d c h e m i c a l elements (Ca, P, Mg, Mn, Cu, Zn) ranged from 59% (Zn) to 84% (Cu). Among the c h e m i c a l n u t r i e n t s t e s t e d , copper (84.28%) was the h i g h e s t t o be f o l l o w e d by manganese (76.57%) and phosphorus (74.14%) and the l e a s t was z i n c (59%) i n a v a i l a b i l i t y v a l u e . i i i The r e s u l t s o f these s t u d i e s i n d i c a t e d t h a t WFS has an a c c e p t a b l e p o t e n t i a l to r e p l a c e wheat w i t h r e a s o n a b l e margin of p r o f i t to the p r o d u c e r . iv TABLE OF CONTENTS Page ABSTRACT ii TABLE OF CONTENTS iv LIST OF TABLES vii LIST OF APPENDIX TABLES — ix ACKNOWLEDGEMENTS x INTRODUCTION 1 I. LITERATURE REVIEW 4 1. Wheat 4 A. P r o t e i n 5 B. M e t a b o l i z a b l e Energy 13 C. Chemical - Elements \-j 2. Rapeseed 19 A. P r o t e i n 22 B. M e t a b o l i z a b l e Energy _ — 27 C. Chemical Element.. 30 D. T o x i c i t y 3 4 (a) G l u c o s i n o l a t e s 1 34 V Page (b) Tannins 39 (c) E r u c i c a c i d 41 (d) Gums 42 •(e) P h y t a t e 43 E. - S a f e t y L e v e l 43 F. P r o c e s s i n g 47 3. Buckwheat 50 A. P r o t e i n 52 B. E f f e c t o f P r o c e s s i n g 56 4. Weed Seeds 58 I I . MATERIALS AND METHODS 60 A. Amino A c i d A v a i l a b i l i t y Study 60 B. M e t a b o l i z a b l e . Energy Study 63 C. Che m i c a l Element Study 63 D. Fe e d i n g T r i a l 67 I I I . RESULTS AND DISCUSSION 68 A B o t a n i c a l C o m p o s i t i o n 68 B Chemical A n a l y s i s 70 C M e t a b o l i z a b l e Energy 72 D Body Weight Ga i n 76 T Chemical Element."'-: 81 vi Page F Chemical Element A v a i l a b i l i t y 86 1-.. C a l c i u m • 88 2. Phosphorus 88 3. Magnesium 91 4. Manganese 91 5. Copper 92 '-6. Z i n c 93 .G- Amino A c i d A v a i l a b i l i t y o f Wheat Feed S c r e e n i n g s 94 Economic E v a l u a t i o n o f Wheat Feed S c r e e n i n g s 104 IV. SUMMARY AND CONCLUSION -. 112 V. BIBLIOGRAPHY 115 VI . APPENDIX TABLES 137 LIST OF TABLES Table Page 1 C o m p o s i t i o n o£ s y n t h e t i c ( p u r i f i e d ) d i e t — 62 2 C o m p o s i t i o n o f e x p e r i m e n t a l d i e t 64 3 B o t a n i c a l c o m p o s i t i o n o f wheat f e e d 69 s c r e e n i n g s (%) 4 Chemical a n a l y s i s o f wheat f e e d s c r e e n i n g s 71 5 Chemical a n a l y s i s o f e x p e r i m e n t a l d i e t 73 6 Gross and m e t a b o l i z a b l e energy o f e x p e r i m e n t a l d i e t 75 7 Average body weight f e e d consumption and f e e d e f f i c i e n c y o f b r o i l e r c h i c k s at f o u r weeks o f age ----- •? •- 77 8 Content of six chemical elements presentv,in .wheat feed-screenings 82 9 Content of s i x . chemical elements present in . experimental diet 85 10 Chemical e l e m e n t a v a i l a b i l i t y o f e x p e r i m e n t a l d i e t 87 11 Amino a c i d c o m p o s i t i o n o f experimental diets 96 12 Amino a c i d c o m p o s i t i o n o f wheat feed screenings 97 v i i i Page 13 Amino acid a v a i l a b i l i t y of experimental d iet fed to chicks 98 14 Wholesale price l i s t of d iet ingredients as based on March 27, 1981 price • 107 15 Average feed consumption, feed conversion,, feed cost per kg gain and mortal i ty of b ro i l e r fed diets based on wheat and wheat feed scree-nings to 4 weeks of age • 108 ix LIST OF APPENDIX TABLES Appendix Page 1 A n a l y s i s o f v a r i a n c e f o r f e e d consump-t i o n o f wheat f e e d s c r e e n i n g s __ 137 2 A n a l y s i s o f v a r i a n c e f o r m e t a b o l i z a b l e energy o f wheat f e e d s c r e e n i n g s 138 3 A n a l y s i s o f v a r i a n c e f o r f e e d e f f i c i e n c y o f wheat f e e d s c r e e n i n g s 139 4 A n a l y s i s o f v a r i a n c e f o r body weight g a i n o f wheat f e e d s c r e e n i n g s 140 5 A n a l y s i s o f v a r i a n c e f o r amino a c i d a v a i l a b i l i t y o f wheat f e e d s c r e e n i n g s 141 6 A n a l y s i s o f v a r i a n c e f o r c h e m i c a l elem e n t 1 a v a i l a b i l i t y o f wheat f e e d s c r e e n i n g s 142 X ACKNOWLEDGEMENTS I would f i r s t l i k e t o ex p r e s s my s i n c e r e and deep-e s t a p p r e c i a t i o n t o myvmajor p r o f e s s o r , Dr. D.B. Bragg, whose a t t e n t i o n t o d e t a i l , c o u p l e d w i t h h i s e n t h u s i a s t i c a t t i t u d e and t o l e r a n c e f o r the many time demanding p r o j e c t s i n w hich I was engaged, p u t s me s o l i d l y i n h i s debt. I c o u l d not have had b e t t e r g u i d a n c e , a d v i c e or b r e a d t h o f o p p o r t u n i t y and I am so g r a t e f u l . H i s u n d e r s t a n d i n g and u n s u r p a s s i n g : k i n d n e s s are s t r o n g l y admired and w i l l be l o n g remembered. I am a l s o i n d e b t e d t o the members o f my Graduate S t u d i e s Committee f o r t h e i r a d v i c e and s u g g e s t i o n s i n the p r e p a r a t i o n o f the m a n u s c r i p t : Dr. W.D. K i t t s , Department of A n i m a l S c i e n c e , Dr. R.C. F i t z s i m m o n s , Department o f P o u l t r y S c i e n c e and Dr. J . V a n d e r s t o e p , Department of Food S c i e n c e . I would l i k e t o thank a l l t e c h n i c i a n s , farm w o r k e r s , graduate and g r a d u a t i n g s t u d e n t s o f the Department o f P o u l t r y S c i e n c e f o r t h e i r s t i m u l a t i o n , i n f o r m a t i o n and h e l p they p r o v i d e d as w e l l as the sheer p l e a s u r e of t h e i r company. A note o f a p p r e c i a t i o n i s due to the Department of P o u l t r y S c i e n c e f o r the space and f a c i l i t i e s w hich have g r e a t l y enhanced the n a t u r e of the stu d y . Moreover, the Department seemed t o r e a l i z e t h a t i t was the s t u d e n t h i m s e l f , r a t h e r than c r e d i t s , and p r o j e c t s t h a t was the end p r o d u c t xi of a graduate program. T h i s a t t i t u d e has made my time a t U.B.C. not o n l y a f r u i t f u l e d u c a t i o n a l adventure but y e a r s of- hard work f o r the purpose of establishing an academic treasure. I am v e r y g r a t e f u l t o the governments o f E t h i o p i a and Canada whose c o l l a b o r a t e d e f f o r t s made t h i s s tudy p o s s i -b l e . I am i n d e b t e d t o the Department of P o u l t r y S c i e n c e once a g a i n f o r the c r u c i a l f i n a n c i a l a s s i s t a n c e p r o v i d e d t h r o u g h f e l l o w s h i p s and t e a c h i n g a s s i s t a n t s h i p s t o b r i n g t h i s p r o j e c t i n t o s u c c e s s f u l c o m p l e t i o n . M. S. Wolde-Tsadick INTRODUCTION In the p a s t s e v e r a l decades, the a v a i l a b i l i t y o f more a r a b l e l a n d , the abundance o f r e s o u r c e s , the low c o s t o f p r o d u c t i o n , the l e s s g l o b a l p o p u l a t i o n e t c . have been the cause o f easy and pr o s p e r o u s l i f e f o r mankind. However, as time winds-up n a t u r e i s t a k i n g away i t s g e n e r o s i t y , p a r t l y o f man's f a i l u r e n e s s i n p r o p e r c o n s e r v a -t i o n and severe e x p l o i t a t i o n o f n a t u r a l r e s o u r c e s . C o n s e q u e n t l y , the e x h a u s t i o n o f r e s o u r c e s i s becoming a phenomenal problem to mankind. T h e r e f o r e , the human i n t e l l e c t must d e c i d e t o c h a l l e n g e the c r y s t a l i z i n g problem t h r o u g h r e p a i r i n g the damage and i n s t a l l i n g the pr o p e r c o n s e r v a t i o n measures i n a c o l l a b o r a t e d e f f o r t b e f o r e i t i s too l a t e . The c o s t o f f e e d i n the p o u l t r y p r o d u c t i o n i n d u s t r y r e p r e s e n t s 65-70% o f the t o t a l c o s t and a t p r e s e n t , c e r e a l s comprise about 75% o f the d i e t . To c h a l l e n g e the i n c r e a s i n g t h r e a t o f i n f l a t i o n and t o i n c r e a s e the margin o f the p r o d u c e r ' s p r o f i t as w e l l as t o enable consumers to c o n t i n u e e n j o y i n g the f l a v o u r o f the i n d u s t r y ' s p r o d u c t a t a r e a s o n a b l e p r i c e , i t i s c o n s i d e r e d to be one o f the major concerns o f the p o u l t r y n u t r i t i o n i s t s t o f i n d ways and means to c u t down the c o s t o f p r o d u c t i o n . 2. Wheat f e e d s c r e e n i n g s o b t a i n e d i n the p r o c e s s o f c l e a n i n g wheat g r a i n s c o n s i s t l a r g e l y o f b r o k e n and shrunken wheat k e r n e l s . The remainders are composed of c r a c k e d b a r l e y , r a p e s e e d , f l a x seed, o a t , w i l d buckwheat and farm weeds and dust ( B i e l y and Pomeranz, 1975). The Canada Feeds A c t (1967) c l a s s i f i e d the wheat f e e d s c r e e n i n g s i n t o f o u r major c l a s s i f i c a t i o n s which were m a i n l y based on the p e r c e n t a g e o f b o t a n i c a l c o m p o s i t i o n . Weed seeds o c c u r i n s i g n i f i c a n t amount i n g r a i n . Western Canadian g r a i n c o n t a i n s weed seeds a t l e v e l s : r a n g i n g from 0.5% to 6%. These l e v e l s are e q u i v a l e n t to an annual weed seed p r o d u c t i o n o f a p p r o x i m a t e l y 20 m i l l i o n b u s h e l s (Tkachuk and M e l l i s h , 1977). In s p i t e o f the a v a i l a b i l i t y o f such l a r g e q u a n t i t i e s o f weed seeds, l i t t l e p r a c t i c a l use i s made of them. R e l a t i v e l y l i t t l e i n f o r m a -t i o n has been a v a i l a b l e to a n i m a l n u t r i t i o n a l i s t s t o p r o v i d e g u i d e l i n e s f o r e f f i c i e n t u t i l i z a t i o n o f t h e s e m a t e r i a l s . T h i s l a c k o f i n f o r m a t i o n was emphasized i n a r e c e n t c a t a l o g u i n g o f the c o m p o s i t i o n o f weed and c r o p seeds (Schroeder ejt a l . , 1974) i n which much o f the d a t a c o n c e r n i n g weed seeds were t a k e n from M o r r i s o n (1959). WFS have changed i n b o t a n i c a l c o m p o s i t i o n i n Canada d u r i n g the l a s t decade due to the i n f l u e n c e o f rapeseed c o n t a m i n a t i o n d u r i n g h a r v e s t , s t o r a g e and 3. t r a n s p o r t a t i o n ; a l s o the r e v i e w of l i t e r a t u r e i n d i c a t e d l i m i t e d i n f o r m a t i o n on n u t r i t i o n v a l u e o f WFS. T h e r e f o r e , the i n d i v i d u a l i n g r e d i e n t s p r e s e n t i n WFS are d i s c u s s e d i n the f o l l o w i n g l i t e r a t u r e r e v i e w . T h i s s t u d y was d e s i g n e d t o i n v e s t i g a t e the n u t r i e n t a v a i l a b i l i t y and p r o v i d e c o m p o s i t i o n a l i n f o r m a t i o n f o r use i n m a x i m i z i n g the e f f i c i e n c y o f u t i l i z a t i o n o f wheat f e e d s c r e e n i n g s and a l s o a p o t e n t i a l c e r e a l c rop r e p l a c e r i n p o u l t r y r a t i o n . 4. I . LITERATURE REVIEW Wheat f e e d s c r e e n i n g s are a b y - p r o d u c t used by the f e e d m a n u f a c t u r i n g company and are a m a t e r i a l which v a r i e s i n c o m p o s i t i o n from sample to sample. O b s e r v a t i o n o f h i g h q u a l i t y s c r e e n i n g s i n d i c a t e s t h a t t hey may v a r y from more th a n 601 whole ( t h i n or shrunken) g r a i n to a p p r o x i m a t e l y 90% weed seeds. High q u a l i t y g r a i n s c r e e n i n g s c o n t a i n m i n i m a l amounts o f d i r t , s t r a w , c h a f f and o t h e r u n d e s i r a b l e m a t e r i a l ( H a r o l d e_t al_ . , 1980) . T r a d i t i o n a l d i s p o s a l o f the s c r e e n i n g s (dockage) a t the l o c a l l e v e l has been by b u r n i n g or by f i n e g r i n d i n g to d e s t r o y seed v i a b i l i t y and i n c o r p o r a t i o n as a p o r t i o n o f l i v e s t o c k r a t i o n s ( M o r r i s o n , 1959; S c o t t e_t a l _ . , 1969). R e l a t i v e l y l i t t l e i n f o r m a t i o n has been a v a i l a b l e to p o u l t r y or a n i m a l n u t r i t i o n i s t s t o p r o v i d e g u i d e l i n e s f o r e f f i c i e n t f o r m u l a t i o n o f t h e s e m a t e r i a l s . The p o t e n t i a l advantage o f wheat s c r e e n i n g s i s t h a t o f lower c o s t t o the f e e d m a n u f a c t u r e r s and i n t u r n , to the p o u l t r y p r o d u c e r . 1. Wheat Wheat i s one o f the p r i n c i p a l c e r e a l s i n the b r o i l e r d i e t . The major n u t r i t i o n a l c o n t r i b u t i o n s o f wheat 5 . are p r o t e i n and energy. The range o f i t s energy c o n t e n t i s between 2800-3120 k e a l / k g (NRC, 1976) depending on the v a r i e t y . A. P r o t e i n Johnson e_t a_l. (1970) showed t h a t the p r o t e i n c o n t e n t o f wheats from the World C o l l e c t i o n v a r i e d from 6% t o 22%, w i t h the h i g h e s t f r e q u e n c y d i s t r i b u t i o n between 13% t o 14%. I t has been shown t h a t the p r o p o r t i o n o f some e s s e n t i a l amino a c i d s r i n p r o t e i n i n c r e a s e d w i t h the d e c r e a s i n g c o n t e n t o f crude p r o t e i n i n the wheat (Ivan and F a r r e l l , 1975; Shoup e_t al _ . , 1966). Ivan and F a r r e l l (1975) a l s o s t a t e d i n t h e i r r e p o r t t h a t a s i m i l a r r e s u l t was o b t a i n e d by o t h e r s as w e l l . In s t u d i e s w i t h r a t s , Ivan and F a r r e l l (1975) found t h a t the sequence of l i m i t i n g amino a c i d s i n a 13% crude p r o t e i n (CP) wheat was l y s i n e , t h r e o n i n e , and m e t h i o n i n e , whereas w i t h 10% CP l y s i n e , t h r e o n i n e , v a l i n e and m e t h i o n i n e were l i m i t i n g f o r maximum growth and f e e d c o n v e r s i o n ratio:. (FCR) and a f u r t h e r f o u r amino a c i d s ( i s o l e u c i n e , h i s t i d i n e , t r y p o t o p h a n and t y r o s i n e ) f o r FCR o n l y . I t has been suggested by the same a u t h o r s t h a t i n f o r m a t i o n on the p a t t e r n o f e s s e n t i a l amino a c i d s i n the p r o t e i n o f a low crude p r o t e i n wheat w i l l not 6. n e c e s s a r i l y a p p l y to a medium or h i g h crude p r o t e i n wheat. P r o l i n e was found to be an e x c e p t i o n i n t h a t i t was ~ a p p r e c i a b l y h i g h e r i n wheat c o n t a i n i n g 15.9% p r o t e i n . However, i n low p r o t e i n (8.5 - 11.7%) wheat samples amino a c i d s such as l y s i n e , a r g i n i n e and h i s t i d i n e were a l l h i g h e r (March and B i e l y , 1973). P r o l i n e , g l u t a m i c a c i d and p h e n y a l a n i n e have a l l been r e p o r t e d to i n c r e a s e w i t h i n c r e a s i n g l e v e l o f p r o t e i n i n h a r d wheat (Hepburn and B r a d l e y , 1965). Data p u b l i s h e d by a number o f workers i n d i c a t e a g e n e r a l u n i f o r m i t y i n the p r o p o r t i o n o f amino a c i d s i n t h e ; p r o t e i n o f wheat over a v a r i e t y o f sample t y p e s . Thus, l y s i n e p e r c e n t a g e tends t o r i s e as t h e p r o t e i n c o n t e n t i s l owered (Pomeranz, 1971). T h i s i n v e r s e r e l a t i o n seems to h o l d o n l y a t p r o t e i n l e v e l s l e s s t h a n 13.5% (N x 5.7) (Lawrence et al_. , 1958) . A r g i n i n e and some o t h e r amino a c i d s show s i m i l a r i n v e r s e c o r r e l a t i o n s w i t h p r o t e i n . G l u t a m i c a c i d , p h e n y a l a n i n e and p r o l i n e have been r e p o r t e d p o s i t i v e l y c o r r e l a t e d w i t h p r o t e i n c o n t e n t (Hepburn and B r a d l e y , 1965) . S i n c e l y s i n e i s the most l i m i t i n g amino a c i d from a n u t r i t i o n a l s t a n d p o i n t , and i t i n c r e a s e s r e l a t i v e to p r o t e i n c o n t e n t d e c r e a s e s , the net o v e r a l l e f f e c t i s t h a t a l l wheats now b e i n g produced are e s s e n t i a l l y e q u i v a l e n t on a n u t r i t i o n a l b a s i s (Pomeranz, 1971). The c o n t e n t s o f l y s i n e , a r g i n i n e , t r y p t o p h a n , v a l i n e , t h r e o n i n e , h i s t i d i n e and a s p a r t i c a c i d are a l l i n the a l e u r o n e p r o t e i n than i n the f l o u r y endosperm p r o -t e i n s ; g l u t a m i c a c i d and p r o l i n e show a r e v e r s e r e l a t i o n . As i n the case o f s h o r t s , b r a n p r o t e i n i s l a r g e l y a l e u r o n e c e l l p r o t e i n and shows a s i m i l a r amino a c i d p a t t e r n . Wheat germ compared to o t h e r p a r t s o f wheat k e r n e l i s the r i c h e s t i n e s s e n t i a l amino a c i d s (Lawrence e_t al_. , 1958) . The f i r s t - l i m i t i n g amino a c i d o f b o t h whole wheat and f l o u r i s l y s i n e . The s e c o n d - l i m i t i n g amino a c i d i s t h r e o n i n e and i s o l e u c i n e the t h i r d . In the cases o f wheat germ and wheat p r o t e i n c o n c e n t r a t e the amount o f amino a c i d s t o the amount o f e s s e n t i a l amino a c i d s (A/E) v a l u e s show a much b e t t e r b a l a n c e , the o n l y l i m i t i n g amino a c i d b e i n g i s o l e u c i n e (Pomeranz, 1971). R e s u l t s o f s t u d i e s by Ivan and F a r r e l l (1975) suggest t h a t the e q u a l i z i n g o f d i e t s on an a v a i l a b l e r a t h e r than t o t a l l y s i n e b a s i s , would g i v e s i m i l a r r a t e s o f g a i n and f e e d c o n v e r s i o n r a t i o i n the growing p i g when d i e t s c o n t a i n p r o t e i n from d i f f e r e n t s o u r c e s . T h i s i s i n agree-ment w i t h o t h e r o b s e r v a t i o n s (Jones e t a l . , 1965; Lynch and O'Grady, 1971; O s t r o w s k i e t a l . , 1971). However, i t was emphasized by the same a u t h o r s t h a t t h i s a p p l i e s o n l y when none o f the o t h e r e s s e n t i a l amino a c i d s are l i m i t i n g . D i f f e r e n c e s between a n i m a l s p e c i e s have a marked i n f l u e n c e on the a v a i l a b i l i t y o f amino a c i d s from the same p r o t e i n s o u r c e (Sarwar and Bowland, 1975) . 8. High p r o t e i n l e v e l does not n e c e s s a r i l y c o r r e l a t e w i t h h i g h p r o t e i n q u a l i t y as shown by Salmon and Dunkelgod (1974) . These workers used d i f f e r e n t wheat c u l t i v a r s w i t h v a r y i n g p r o t e i n l e v e l s and c h i c k s as e x p e r i m e n t a l a n i m a l . The growth r a t e o f c h i c k s i n c r e a s e d as the p r o t e i n l e v e l o f wheat d e c r e a s e d i n o r d e r of c u l t i v a r s Chinook, I n d i a 66, G l e n l e a and Lemhi 53. In t h e i r r e p o r t , they mentioned t h a t the growth response o f c h i c k s l e d d i e t s c o n t a i n i n g wheat of lower p r o t e i n l e v e l may be a t t r i b u t e d i n p a r t to improved amino a c i d b a l a n c e o f t h e i r lower p r o t e i n wheats. I t may a l s o be r e l a t e d t o the i n c r e a s e d p r o p o r t i o n o f soybean meal t h a t was r e q u i r e d to b a l a n c e the d i e t w i t h a r e s u l t a n t improvement i n amino a c i d b a l a n c e . The r e s u l t o f t h i s experiment i s i n agreement w i t h p r e v i o u s l y r e p o r t e d o b s e r v a -t i o n s ( S o s u l s k i e_t a l _ . , 1963; Hepburn and B r a d l e y , 1965). As i t was mentioned e a r l i e r , the wheat crop v a r i e s w i d e l y i n crude p r o t e i n c o n t e n t . T h i s wide v a r i a t i o n i n p r o t e i n c o n t e n t i s a s c r i b e d to c u l t i v a r and c u l t u r a l f a c t o r s . There i s e v i d e n c e o f v a r i a t i o n i n n u t r i e n t c o n t e n t between c u l t i v a r s i n a d d i t i o n to v a r i a t i o n w i t h i n a s i n g l e c u l t i v a r . S o s u l s k i e t a l _ . (1963) r e p o r t e d t h a t the r e l a t i v e l e v e l s o f n i n e amino a c i d s were s i g n i f i c a n t l y c o r r e l a t e d w i t h changes i n the p r o t e i n l e v e l o f T h a t c h e r wheat grown under c o n t r o l l e d environment c o n d i t i o n s . McDermott and Pace 9. (1960) a t t r i b u t e d the r e l a t i v e l y h i g h e r l y s i n e and a r g i n i n e l e v e l s i n lower p r o t e i n wheats t o a lower p r o p o r t i o n o f the p r o t e i n f r a c t i o n s g l i a d i n and g l u t e n i n i n the endosperm o f t h e s e wheats. In comparison between s o f t w h i t e wheat and h a r d r e d wheat, Moran's (1971) r e p o r t s t a t e s t h a t s o f t w h i t e wheat c o n t a i n s a more d e s i r a b l e amino a c i d b a l a n c e f o r the c h i c k than h a r d r e d wheat. March e t aJL. (1961) a l s o observed t h a t d i e t s con-t a i n i n g wheat o f h i g h e r p r o t e i n c o n t e n t , supplemented w i t h f i s h m eal, reduced the growth r a t e and f e e d e f f i c i e n c y o f c h i c k s i n comparison w i t h d i e t s c o n t a i n i n g wheat o f lower p r o t e i n c o n t e n t . However, March and B i e l y (1973) found no c o n s i s t e n t d i f f e r e n c e i n the n u t r i t i o n a l q u a l i t y o f p r o t e i n from wheats c o n t a i n i n g d i f f e r e n t l e v e l s o f p r o t e i n . T h e r e f o r e , based on the r e p o r t o f Salmon and Dunkelgod (1974) d i e t s based on lower p r o t e i n wheat and b a l a n c e d w i t h s u i t a b l e p r o t e i n c o n c e n t r a t e s may produce b e t t e r growth performance i n comparison w i t h h i g h e r p r o t e i n wheat. The lower p r o t e i n q u a l i t y c u l t i v a r s appeared to have b e t t e r amino a c i d b a l a n c e than h i g h e r p r o t e i n wheats. I t has been suggested by some workers ( Y o s h i d a et a l . , 1966) t h a t the l i m i t i n g amino a c i d i n an imbalanced d i e t i s used as e f f i c i e n t l y as i n the c o n t r o l d i e t , p r o v i d e d the food i n t a k e can be m a i n t a i n e d . From the a s p e c t o f 10. n i t r o g e n u t i l i z a t i o n , a d e f i c i e n c y o f a s i n g l e amino a c i d i s analogous i n e f f e c t , t o an excess o f the o t h e r amino a c i d s a t the l e v e l o f the l i m i t i n g one (March, B i e l y and T o n z e t i c h , 1950). However, more d e t a i l e d s t u d i e s a re s t i l l l a c k i n g i n o r d e r to e l u c i d a t e the mechanism o f some o f these changes. The d i g e s t i b i l i t y of a n u t r i e n t i s d e f i n e d as the p r o p o r t i o n o f the n u t r i e n t absorbed (McNab and Shannon, 1974) . A l t h o u g h i t has been argued t h a t a b s o r p t i o n o f a n u t r i e n t does not n e c e s s a r i l y i m p l y t h a t i t i s u t i l i z e d (Calhoun et a l . , 1960 ; Ford ejt aJL_. , 1967), i t must be a c c e p t e d t h a t an unabsorbed n u t r i e n t i s l o s t t o the meta-b o l i c p r o c e s s e s . The d e f i n i t i o n has been f u r t h e r c r i t i c i z e d (McNab and Shannon, 1974) because o f the p o s s i b i l i t y o f m i c r o f l o r a l d e s t r u c t i o n o f some unabsorbed n u t r i e n t o r i t s a l t e r a t i o n to a b s o r b a b l e compounds ( e . g . , ammonia), of no n u t r i t i o n a l importance (Ousterhout ejt a_l. , 1959; Nesheim and C a r p e n t e r , 1967; S a f e r and C o a t e s , 1971). However, i n l a t e r s t u d i e s w i t h b i r d s (Bragg et_ a l . , 1965) the v a l u e s o b t a i n e d c o r r e s p o n d e d to b i o l o g i c a l v a l u e s or e f f i c i e n c y w i t h which i n g e s t e d n u t r i e n t s are u t i l i z e d . F u r t h e r m o r e , the d e a m i n a t i n g or o t h e r r e a c t i o n s o f the m i c r o f l o r a do not a f f e c t the 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 (McNab and Shannon, 1974). 11. R e s u l t s o f s t u d i e s by McNab and Shannon (1974) i n d i c a t e d t h a t the t r u e d i g e s t i b i l i t y o f the n i t r o g e n c o n t e n t o f wheat (84.7%) was c l o s e l y comparable to b a r l e y , maize and o a t s . However, i n the amino a c i d the d i g e s t i b i l i t y o f l y s i n e was found t o be s l i g h t l y h i g h e r ( 8 0 . 8 % ) , a l t h o u g h i t was lower than the crude p r o t e i n . Under no c i r c u m s t a n c e s w i l l an improvement i n p r o t e i n q u a l i t y be o f any s i g n i f i c a n c e u n l e s s c a l o r i e i n t a k e i s s u f f i c i e n t t o meet energy demands. In most f o o d s , the b i o l o g i c a l a v a i l a b i l i t y o f the amino a c i d s i s p r i m a r i l y d e t e r m i n e d by the o v e r a l l d i g e s -t i b i l i t y o f the p r o t e i n . However, t h e r e are c r i t i c i s m s o f t h i s method among r e s e a r c h e r s because o f the assumption t h a t t h e r e may be d i f f e r e n c e s i n d i g e s t i b i l i t y between amino a c i d s w i t h i n a p r o t e i n and the measurement o f i n d i v i d u a l amino a c i d d i g e s t i b i l i t i e s may t h e r e f o r e be j u s t i f i e d . In c o n s i d e r i n g the n u t r i t i o n a l q u a l i t y o f p r o t e i n s the main i n t e r e s t w i l l be the amounts and b i o l o g i c a l a v a i l a b i l i t i e s o f s p e c i f i c amino a c i d s . T h i s i s c o n s i d e r e d as a v e r y i m p o r t a n t a r e a . Achinewhu and H e w i t t (1979) conducted an experiment u s i n g d i f f e r e n t p l a n t s o u r c e s t o s u p p l y the d i e t a r y p r o t e i n s . As a c o n c l u s i o n o f t h e i r s t u d i e s , they s t a t e d t h a t d i g e s t i b i l i t y was the main f a c t o r d e t e r m i n i n g the a v a i l a b i l i t y o f l y s i n e and t h r e o n i n e i n the u n t r e a t e d 12. and u n a u t o c l a v e d s o y a - b e a n - p r o t e i n i s o l a t e . However, upon t r e a t m e n t w i t h heat the d e c r e a s e i n the d i g e s t i b i l i t y o f l y s i n e d i d not f u l l y account f o r the r e d u c t i o n i n a v a i l -a b i l i t y . The t e c h n i q u e used i n t h e i r e x p eriments was known as " i l e a l " ( d i s s e c t i n g out the i l e u m from Meckel's d i v e r t i c u l u m to 40mm p r o x i m a l to the i l e o - c a e c a l j u n c t i o n and r e t a i n c o n t e n t s f o r a n a l y s i s ) . R e g a r d l e s s o f the s i t u a t i o n , the o v e r r i d i n g demand o f the body i s f o r c a l o r i e s . U n l e s s the energy i n t a k e i s adequate, the i n d i v i d u a l w i l l be i n a n e g a t i v e n i t r o g e n b a l a n c e r e g a r d l e s s o f the amount o f p r o t e i n i n the d i e t or i t s b i o l o g i c a l v a l u e . The importance o f the c a l o r i c v a l u e o f the d i e t even d u r i n g r e h a b i l i t a t i o n from a p r o t r a c t e d p e r i o d o f s e m i s t a r v a t i o n was emphasized by the r e s u l t s o f the M i n n e s o t a S t a r v a t i o n Study (Keys e_t a l . , 1950). Wheat and wheat p r o d u c t s c o n t a i n p r o t e a s e i n h i b i -t o r s (Creek and V a s a i t i s , 1962; Shyamala and Lyman, 1964), but t h e r e do not appear t o be p r e s e n t i n q u a n t i t i e s l a r g e enough t o have a s i g n i f i c a n t e f f e c t on p r o t e i n u t i l i z a t i o n . Wheat germ c o n t a i n s a t h e r m o l a b i l e i n h i b i t o r w h i c h must be d e s t r o y e d i f good u t i l i z a t i o n o f wheat germ n u t r i e n t s i s to be o b t a i n e d by p o u l t r y ( A t t i a and Creek, 1965; Moran et a l . , 1968) . 13. S e v e r a l workers ( M i l n e r and C a r p e n t e r , 1969; K o h l e r , 1964; H u t c h i n s o n et_ al_. , 1964) have shown t h a t m i l d c o o k i n g t r e a t m e n t s improve the n u t r i t i o n a l v a l u e o f wheat or f l o u r . M i l d heat i n the pr e s e n c e o f r e l a t i v e l y h i g h l e v e l s o f w a t e r , g e n e r a l l y improve the n u t r i t i o n a l v a l u e o f wheat. However, h i g h t e m p e r a t u r e s w i t h l i m i t e d m o i s t u r e reduce p r o t e i n q u a l i t y o f wheat and wheat p r o d u c t s (Pomeranz, 1962; Hepburn e_t a l . , 1966). The most i m p o r t a n t l o s s d u r i n g p r o c e s s i n g i s o f l y s i n e (10-20%). The l o s s o c c u r s m a i n l y i n the c r u s t and i s a p p a r e n t l y r e l a t e d t o nonenzymatic browning ( e . g . , r e a c t i o n o f f r e e amino groups w i t h r e d u c i n g s u g a r s ) (Pomeranz, 1971). S e v e r a l i n v e s t i g a t o r s (Gray e_t a l . , 1960; M o r r i s o n ejt a l . , 1961; Ivan and F a r r e l l , 1975) have r e p o r t e d t h a t i t i s not o n l y by n a t u r a l l i m i t a t i o n , o r due t o p r o c e s s i n g nor i n h i b i t o r y f a c t o r s t h a t e s s e n t i a l amino a c i d shows a d e f i c i e n c y on a g i v e n f e e d or d i e t , but even a f t e r b e i n g a v a i l a b l e a t a r e q u i r e d l e v e l i n the d i e t , d e f i c i e n c y can be shown due to i n t e r a c t i o n . L y s i n e and t h r e o n i n e are the two e s s e n t i a l amino a c i d s which are w e l l i d e n t i f i e d i n t h i s r e s p e c t . 14. B. M e t a b o l i z a b l e Energy (ME) For most p u r p o s e s , net energy i s the measure o f g r e a t e s t u t i l i t y . There are two p o p u l a r p r o c e d u r e s f o r ME d e t e r m i n a t i o n , v i z , i n d i c a t o r method and t o t a l c o l l e c t i o n method. The l a t t e r p r o c e d u r e demands the a c c u r a t e measure-ment o f f e e d consumed and e x c r e t a v o i d e d . T h i s i s e x t r e m e l y d i f f i c u l t t o p e r f o r m s i n c e c h i c k s have a tendency t o s p i l l f e e d and some e x c r e t a tends t o be r e t a i n e d on the w i r e -mesh f l o o r s o f the cages. F u r t h e r , t o t a l c o l l e c t i o n i n v o l v e s the h a n d l i n g and s t o r a g e o f r e l a t i v e l y l a r g e q u a n t i t i e s o f e x c r e t a , an u n n e c e s s a r y p r o c e d u r e when an i n d i c a t o r i s employed. In f a v o u r o f the i n d i c a t o r i s the f a c t t h a t e x c r e t a samples f r e e from c o n t a m i n a t i o n w i t h f e e d may be r e a d i l y o b t a i n e d . I t i s t r u e t h a t the i n d i c a t o r t e c h n i q u e i n v o l v e s a d d i t i o n a l c h e m i c a l a n a l y s e s . However, i n a comparison o f the two p r o c e d u r e s S i b b a l d et_ a l . (1960) found the i n d i c a t o r t e c h n i q u e t o be more p r e c i s e than the t o t a l c o l l e c t i o n method. Based on the s e f a c t s , the i n d i c a t o r method was employed i n d e t e r m i n i n g the ME o f feeds used i n t h i s p r o j e c t . For the purpose o f h a v i n g a r e l a t i v e l y a c c u r a t e knowledge o f the wheat ME v a l u e , e l e v e n d i f f e r e n t wheat v a r i e t i e s which were drawn from the same l o t s had been d i s t r i b u t e d t o t h r e e d i f f e r e n t l a b o r a t o r i e s - v i z , A n i m a l Resources I n s t i t u t e - A g r i c u l t u r e Canada 15. (Agr. Can.), U n i v e r s i t y o f Guelph (U.G.) and U n i v e r s i t y o f B r i t i s h Columbia (U.B.C.) ( S i b b a l d , 1975). The U.B.C. ME v a l u e s , o b t a i n e d w i t h c h i c k s , have a lower o v e r a l l mean than do the U.G. c h i c k v a l u e s , 3.19 vs 3.48 k c a l / g DM. A p a i r e d t - t e s t o f the mean v a l u e s , r e v e a l s s i g n i f i c a n t (P £ 0.05) d i f f e r e n c e s between the two l a b o r a t o r i e s . Much o f the d i f f e r e n c e i s a t t r i b u t a b l e to the v a l u e s f o r Neepawa, P i t i c and S t e w a rt wheats ( S i b b a l d , 1975) . The most i m p o r t a n t d i f f e r e n c e between the assays i s t h a t U.G. used chromium s e s q u i o x i d e as an i n d i c a t o r , whereas U.B.C. r e l i e d on t o t a l c o l l e c t i o n o f e x c r e t a w i t h 24-h p e r i o d s o f s t a r v a t i o n b e f o r e and a f t e r f e e d i n g t h e t e s t d i e t s . The o v e r a l l mean of U.B.C. v a l u e s are l o wer than from U.G. The p o s s i b i l e e x p l a n a t i o n g i v e n by S i b b a l d (1975) r e f e r r i n g to G u i l l a u m and Summer's (1970) work i s t h a t n u t r i e n t i n t a k e s below the maintenance r e q u i r e -ment depress ME v a l u e s when s t a r v a t i o n i s i n v o l v e d i n ME a s s a y . A p a r t from the s l i g h t d i f f e r e n c e s t h a t o c c u r r e d i n ME v a l u e s among e l e v e n t e s t e d wheat v a r i e t i e s the r e s u l t o f t h i s b i o l o g i c a l assay and o t h e r s show t h a t wheat v a r i e t i e s are n o t s i g n i f i c a n t l y v a r i a b l e i n ME v a l u e ( S i b b a l d , 1975). 16. Wheat m i l l i n g b y - p r o d u c t s are r e l a t i v e l y low i n m e t a b o l i z a b l e energy and h i g h i n f i b e r ( D i n 'et al_. , 1979) . The n u t r i t i o n a l v a l u e o f the s e f e e d s t u f f s has been r e v i e w e d i n d e t a i l by many workers (Cave e t al_. , 1965; Moran and Summers, 1970). I t has been c l e a r l y demonstrated t h a t h i g h p r e s s u r e steam p e l l e t i n g o f r a t i o n s c o n t a i n i n g up t o 501 wheat b y - p r o d u c t s improved growth and f e e d e f f i c i e n c y f o r c h i c k s . A p a r t from p r o c e s s i n g , A s i a and Netke (1971) have r e p o r t e d t h a t p u l l e t s grew s a t i s f a c t o r i l y on a d i e t composed o f 60% wheat bra n and 30.9% groundnut meal when a d e q u a t e l y supplemented w i t h m i n e r a l s and v i t a m i n s . C h i u and Pomeranz (1967) have s t u d i e d the r e l a t i o n s h i p between wheat k e r n e l s i z e and c h e m i c a l c o m p o s i t i o n . In t h e i r r e p o r t they s t a t e d t h a t a t w o - f o l d i n c r e a s e i n the we i g h t o f the k e r n e l was accompanied by a s m a l l d e c r e a s e i n the p e r c e n t a g e o f p r o t e i n and by a s u b s t a n t i a l d e c r e a s e i n the p e r c e n t a g e o f ash p r e s e n t . C o n c e n t r a t i o n s o f f r e e and bound l i p i d s were, on the o t h e r hand, h i g h e r i n s m a l l than i n l a r g e k e r n e l s ; and the l e v e l o f f a t was h i g h e r i n the b r a n ( i n c l u d i n g a l e u r o n e ) and germ p o r t i o n s o f the k e r n e l than i n the endosperm. Cookson and Coppock (1956) , from a s u r v e y o f v a l u e s o b t a i n e d i n d i f f e r e n t l a b o r a t o r i e s employing v a r i o u s methods o f 17. e x t r a c t i o n , c o n c l u d e d t h a t the approximate average l e v e l s o f f a t were 4.5% i n b r a n , 10% i n germ, and 1.2% i n endosperm. S h o l l e n b e r g e r e_t al_ . (1949) i n a comprehensive s u r v e y o f samples o f known o r i g i n showed t h a t the f a t c o n t e n t o f wheat depends more on the c u l t i v a r t han upon the e n v i r o n -mental c o n d i t i o n s under which i t i s grown. The o b s e r v a t i o n s o f March and B i e l y (1973) i n d i c a t e t h a t f a t c o n t e n t was i n v e r s e l y r e l a t e d to k e r n e l w e i g h t . K e r n e l s u r f a c e a r e a was, t h e r e f o r e , i n a c c o r d w i t h the g r e a t e r c o n c e n t r a t i o n s o f l i p i d s i n the b r a n and germ p o r t i o n s s i n c e these p o r t i o n s c o n s t i t u t e d a h i g h e r p r o p o r t i o n o f the t o t a l w eight i n s m a l l e r k e r n e l s . The r e p o r t o f Salmon ^arid Dunkelod (1974) i n d i c a t e s , t h a t the wheat t h a t has t r a d i t i o n a l l y been a v a i l a b l e f o r f e e d use i s ~ t h a t w hich has f a i l e d t o meet the q u a l i t y s t a n d a r d s f o r h a r d r e d s p r i n g wheat, and may be l e s s d e s i r a b l e f o r f e e d i n g purposes t h a n c u l t i v a r s i n t e n d e d s p e c i f i c a l l y as f e e d wheat. Feed e f f i c i e n c y s t u d i e s have been r e p o r t e d u s i n g s e v e r a l wheat v a r i e t i e s (Chinook, I n i a 66, G l e n l e a , Lemhi 53 and P i t i c 6 2). The P i t i c 62 v a r i e t y was shown to have a h i g h e r m e t a b o l i z a b l e energy (ME) v a l u e than a l l t h e r e s t . However, s i m i l a r work w h i c h was done by G a r d i n e r (1973) has shown no d i f f e r e n c e i n f e e d c o n v e r s i o n r a t i o between 18. d i e t s c o n t a i n i n g P i t i c 62 v s . o t h e r wheats or c o r n . A c c o r d i n g t o an assessment by Salmon and Dunkelgod (1974), the e f f i c i e n c y o f f e e d c o n v e r s i o n a l o n e may not be a r e l i a b l e i n d i c a t o r o f ME i n the absence of c a r c a s s composi-t i o n d a t a . March and B i e l y (1973) a l s o r e p o r t e d a con-s i d e r a b l e v a r i a t i o n i n ME v a l u e among t h r e e samples o f P i t i c 62, a l t h o u g h t h e i r average o f ME v a l u e s was near t h a t o f 30 o t h e r samples t e s t e d . C. Chemical Elements The s t u d i e s o f Lorenz and Loewe (1977) have shown t h a t h a r d wheats were h i g h e r t h a n s o f t wheats i n Fe and Zn, w h i l e s o f t wheats c o n t a i n e d s i g n i f i c a n t l y more K. T h e i r s t u d i e s a l s o showed a s i g n i f i c a n t p o s i t i v e c o r r e l a -t i o n between the p r o t e i n c o n t e n t o f h a r d wheats and h a r d wheat b l e n d s and Ca, Fe, K, and Cu c o n t e n t and between ash c o n t e n t o f those wheats and Ca, Mg, Na, K, Mn and Cu. In s o f t wheat and s o f t wheat b l e n d , a s i g n i f i c a n t p o s i t i v e c o r r e l a t i o n was found between p e r c e n t p r o t e i n and Ca and Zn c o n t e n t s . S o f t wheat ash was a l s o s i g n i f i c a n t l y c o r r e l a t e d w i t h Zn, Mn, and Cu c o n t e n t i n s o f t wheat (Lorenz and Loewe, 1977). Combining a l l c l a s s e s o f wheat, i t can be seen from the d a t a o f Lorenz and Loewe (1977) t h a t wheat p r o t e i n i s s i g n i f i c a n t l y c o r r e l a t e d w i t h Ca, Zn, Fe and K c o n t e n t . Aw-Yong (1980) has done c o n s i d e r a b l e work on c o n c e n t r a t i o n and a v a i l a b i l i t y o f s i x m i n e r a l s (Ca, P, Mg, Mn, Cu and Zn) from a s e r i e s o f c e r e a l g r a i n s i n c l u d i n g wheat. I t was found t h a t the c o n c e n t r a t i o n o f phosphorus and magnesium from a l l the c e r e a l g r a i n s was h i g h , whereas, the c o n c e n t r a t i o n o f c a l c i u m , manganese, z i n c and copper was g e n e r a l l y low. F u r t h e r m o r e , i t appears t h a t the a v a i l a b i l i t y o f copper ( 7 8 . 5 % ) , c a l c i u m ( 7 1 . 0 % ) , and phosphorus (67.4%) from wheat and t r i t i c a l e samples ranged from moderate t o h i g h f o r the b r o i l e r c h i c k s . However, magnesium ( 5 3 . 5 % ) , z i n c (49.6%) and manganese (48.4%) were low i n a v a i l a b i l i t y . S i g n i f i c a n t v a r i a t i o n among wheat and c o r n samples was o b s e r v e d . Aw-Yong (1980) has shown t h a t a v a i l a b i l i t y v a l u e s o f m i n e r a l s were s i g n i f i c a n t l y d i f f e r e n t when v a r i o u s l e v e l s o f the f e e d i n g r e d i e n t were t e s t e d . In t h i s p a r t o f h i s e x p e r i m e n t , r e s u l t s show t h a t a v a i l a b i l i t y o f m i n e r a l s i n c r e a s e s w i t h lower l e v e l s o f the f e e d i n g r e d i e n t , a l t h o u g h , the r e l a t i o n s h i p s between m i n e r a l a v a i l a b i l i t y and f e e d -s t u f f l e v e l s i s not l i n e a r . The g r e a t e r a b s o r p t i o n and r e t e n t i o n a t lower l e v e l s may be due to the improvement of d i g e s t i b i l i t y and l e s s c o m p e t i t i o n f o r the b i n d i n g s i t e s by p r o t e i n l i g a n d s f o r m i n e r a l t r a n s p o r t s i n the gut. 20. 2. Rapeseed Among t e n d i f f e r e n t samples o f wheat s c r e e n i n g s used i n t h i s s t u d y , wheat i s the major component and rape-seed i s the t h i r d ' major component. Rapeseed grown i n Canada c o n s i s t s o f two s p e c i e s , B r a s s i c a napus L. and B. C a m p e s t r i s L. They are commonly r e f e r r e d to as the " A r g e n t i n e t y p e " and the " P o l i s h t y p e " , r e s p e c t i v e l y . Meals produced from the two s p e c i e s are s i m i l a r i n c h e m i c a l c o m p o s i t i o n , e s p e c i a l l y i n t h e i r p r o t e i n and g l u c o s i n o l a t e l e v e l s ( t h i o g l u c o s i d e c o n t e n t s as per Rapeseed A s s o c i a t i o n o f Canada, 1972). Canada i s the w o r l d ' s l a r g e s t p r o d u c e r o f rape-seed (Downey et_ a_l. , 1974) . The i n c r e a s i n g s c a r c i t y and h i g h p r i c e o f p r o t e i n i n g r e d i e n t s f o r a n i m a l f e e d n e c e s s i t a t e c o n s i d e r a t i o n o f o t h e r p r o t e i n s o u r c e s i n p o u l t r y r a t i o n f o r m u l a t i o n . In a d d i t i o n to b e i n g e c o n o m i c a l t o produce i n Canada, ra p e s e e d p r o v i d e s an e x c e l l e n t s o u r c e o f p r o t e i n . Thus, commercial r a t i o n s i n Canada f o r b r o i l e r c h i c k e n s may c o n t a i n rapeseed meal as a p r o t e i n supplement a t l e v e l s up t o 15% (Steedman et a l . , 1979 a ) . Steedman et_ al_. (1979a) conducted an experiment t o determine whether rapeseed meal (RSM) has any i n f l u e n c e o r not on the e a t i n g q u a l i t y o f b r o i l e r c h i c k e n s f e d c o m m e r c i a l - t y p e r a t i o n s c o n t a i n i n g RSM. The r e s u l t o f t h e i r s t u d y has shown t h a t c h i c k e n s f e d RSM are a c c e p t a b l e 21. i n q u a l i t y . In another t r i a l , Steedman et al_ (1979b) a l s o r e p o r t e d t h a t the i n c l u s i o n o f 151 Span RSM i n b r o i l e r r a t i o n s may have caused a s l i g h t d e c r ease i n e a t i n g q u a l i t y . I t was a l s o s t a t e d i n the r e p o r t t h a t some d i f f e r e n c e s i n the q u a l i t y c h a r a c t e r i s t i c s o f c h i c k e n s a t t r i b u t a b l e to f r o z e n s t o r a g e have been n o t e d , g e n e r a l l y the s t o r a g e t r e a t m e n t s i n v e s t i g a t e d d i d not i n f l u e n c e the e a t i n g q u a l i t y o f the b r o i l e r s . Rapeseed i s grown f o r o i l e x t r a c t i o n w i t h the r e s i d u e b e i n g used i n a n i m a l f e e d s . The use o f the meal i n p r a c t i c a l d i e t s has been l i m i t e d by i t s low c o n c e n t r a t i o n o f a v a i l a b l e energy and by the presence of t o x i n s such as g l u c o s i n o l a t e s and g o i t r i n . P l a n t b r e e d e r s are making c o n s i d e r a b l e p r o g r e s s towards r e d u c i n g t o x i n l e v e l s , but the low c o n c e n t r a t i o n o f a v a i l a b l e energy c o n t i n u e s t o i n h i b i t u t i l i z a t i o n o f the meal i n d i e t s f o r m o n o g a s t r i c s . R e a l i z i n g t h i s problem Jones and S i b b a l d (1979) have a p p l i e d s e v e r a l methods o f p r o c e s s i n g i n o r d e r to i n c r e a s e the l e v e l o f a v a i l a b l e energy. In the r e p o r t o f t h e i r i n v e s t i g a t i o n , t hey s t a t e d t h a t f r a c t i o n a t i o n p e r m i t t e d the p r o d u c t i o n o f meals of c o m p a r a t i v e l y h i g h t r u e meta-b o l i z a b l e energy (TME) v a l u e s , but i n most i n s t a n c e s the TME r e c o v e r e d was not s u b s t a n t i a l l y g r e a t e r than the TME i n p u t . B o i l i n g whole seed w i t h water f o r 20 min. appeared 22 to cause an improvement, as d i d hot water e x t r a c t i o n o f whole seed. The most c o n s i s t e n t b e n e f i t r e s u l t e d from hexane e x t r a c t i o n o f o i l s . Jones and S i b b a l d (1979) presume t h a t the p h y s i c a l t r e a t m e n t i n c r e a s e d the amount o f o i l a v a i l a b l e f o r d i g e s t i o n and a b s o r p t i o n . T h e r e f o r e , r a p e s e e d - i s i m p o r t a n t not o n l y f o r i t s p o t e n t i a l i n the p r o d u c t i o n o f e d i b l e and i n d u s t r i a l o i l s but a l s o i n the manufacture o f h i g h p r o t e i n meals s u i t a b l e f o r s u p p l e m e n t i n g a n i m a l d i e t s . Rapeseed i s now f i r m l y e s t a b l i s h e d as Canada's t h i r d most v a l u a b l e g r a i n c r o p f o l l o w i n g wheat and b a r l e y (Downey e_t al_ . , 1974) . A. P r o t e i n The u l t i m a t e importance o f p r o t e i n i s i t s r o l e i n b i o l o g i c a l f u n c t i o n s . The amount of p r o t e i n consumed, d i g e s t e d and made a v a i l a b l e f o r body use beyond t h a t r e q u i r e d f o r immediate m e t a b o l i c p r o c e s s e s i s known as " r e t a i n e d " o r " s t o r e d " p r o t e i n (Cho and B a y l e y , 1970) . These workers found t h a t c h i c k e n s s t o r e d from 84-104 mg p r o t e i n per gram o f RSM d i e t consumed compared w i t h a v a l u e o f 96 mg p r o t e i n per gram soybean meal d i e t . In v i t r o s t u d i e s i n d i c a t e d t h a t the d i g e s t i b i l i o f RSM p r o t e i n i s reduced when the meal i s h eated i n the p r e s e nce o f w a t e r . T h i s r e d u c t i o n i s y e t more pronounced 23. when the meal i s heated i n the pr e s e n c e o f c a r b o h y d r a t e . P r o t e i n d i g e s t i b i l i t y was enhanced i n wh i c h had been d e t o x i f i e d . D i g e s t i b i l i t y o f p r o t e i n does not appear to be l i m i t e d by the r e l a t i v e l y h i g h e r f i b e r c o n t e n t o f the meal (March and S a d i q , 1974). F u r t h e r i n t h e i r r e p o r t , March and S a d i q (1974) have mentioned t h a t the r e s u l t o f t h e i r i n v i v o s t u d i e s i n d i c a t e d p r e - f e e d i n g c h i c k s a h i g h f i b e r d i e t d i d not improve energy u t i l i z a t i o n by t h e s e c h i c k s when they were f e d a RSM - c o n t a i n i n g d i e t . Heat t r e a t m e n t o f RSM r e s u l t e d i n a d e p r e s s i o n i n c h i c k growth which was o n l y p a r t i a l l y overcome by l y s i n e s u p p l e m e n t a t i o n . However, heat t r e a t m e n t o f RSM has no e f f e c t on the ME v a l u e o f the meal. Whil e d i g e s t i b i l i t y o f the p r o t e i n used i n a d i e t i s an i m p o r t a n t a s p e c t , the p r o p o r t i o n o f the d i g e s t e d p r o t e i n t h a t i s r e t a i n e d i s a l s o i m p o r t a n t . The r e t e n t i o n o f p r o t e i n or s t o r a g e i n the development o f new t i s s u e s r e f l e c t s the n u t r i t i o n a l b a l a n c e and the a v a i l a b i l i t y o f the amino a c i d s i n the p r o t e i n . Cho and B a y l e y (1970) found t h a t the amino a c i d s o f t h e p r o t e i n i n a p r e - p r e s s e d , s o l v e n t - e x t r a c t e d B.  c a m p e s t r i s , RSM were from 2-14% l e s s a v a i l a b l e t o p i g s than the amino a c i d s o f a s i m i l a r d i e t c o n t a i n i n g soybeam meal. Regarding the amino a c i d c o m p o s i t i o n , i t has been p o i n t e d out by s e v e r a l workers t h a t t h e r e i s no o b v i o u s 24. d i f f e r e n c e s among the meals f o r any p a r t i c u l a r amino a c i d (Rapeseed A s s o c i a t i o n o f Canada, 1972). A major s t o r a g e p r o t e i n e x t r a c t e d from commercial r a p e s e e d meal (B. c a m p e s t r i s L. v a r . Span) was c h a r a c t e r i z e d b o t h c h e m i c a l l y and u l t r a s t r u c t u r a l l y . The 12S g l y c o p r o -t e i n was found t o c o n t a i n 12.9% (w/w) c a r b o h y d r a t e c o n s i s t -i n g o f a r a b i n o s e , g a l a c t o s e , g l u c o s e , i n o s i t o l , g l u c o s a m i n e , and manose. The rap e s e e d a l e u r o n e g r a i n s c o n t a i n g l o b o i d b o d i e s which suggest the pr e s e n c e o f p h y t i c a c i d . The amino a c i d p r o f i l e o f the 12S g l o b u l i n was dominated by the a c i d i c amino a c i d s , g l u t a m i c and a s p a r t i c which i s t y p i c a l f o r an o i l seed a l e u r i n . There was a s c a r c i t y o f the s u l f u r -c o n t a i n i n g amino a c i d s c y s t i n e and m e t h i o n i n e . Tryptophan was not d e t e c t e d from a p t o l u e n e s u l f o n i c a c i d h y d r o l y z a t e o f p r o t e i n ( G i l l and Tung, 1978). A s i g n i f i c a n t i n t e r a c t i o n between l y s i n e and a r g i n i n e i n RSM d i e t s has been r e p o r t e d by s e v e r a l w o r k e r s . Summers (1976) has conducted a st u d y t o e v a l u a t e e f f e c t s or a r g i n i n e , l y s i n e , m e t h i o n i n e , p o t a s s i u m a c e t a t e or p o l y -v i n y l p y r r o l i d i n e (PVP) s u p p l e m e n t a t i o n o f RSM on performance o f c h i c k s and l a y i n g hens. As the auth o r s t a t e d , the purpose o f p o t a s s i u m a c c e t a t e i n c l u d e d i n the st u d y was to i n v e s t i g a t e i t s e f f e c t on a r g i n i n e - l y s i n e imbalance and s u p p l e m e n t a t i o n w i t h PVP was d e s i g n e d to g a i n i n f o r m a t i o n about t h e growth d e p r e s s i n g e f f e c t s o f t a n n i c a c i d . A c c o r d i n g to Summers' (1976) r e p o r t , a s i g n i f i c a n t i n t e r a c t i o n between a r g i n i n e and f e e d source was n o t e d . The a d d i t i o n o f l y s i n e r e s u l t e d i n a marked d e c r e a s e i n wei g h t g a i n and f e e d consumption. The d e p r e s s i o n was c o m p l e t e l y overcome by s u p p l e m e n t a t i o n w i t h a r g i n i n e . A r g i n i n e f a i l e d t o show a response when added t o the RSM d i e t . P o t a s s i u m a c e t a t e a l l e v i a t e d but d i d not overcome the d e p r e s s i o n i n performance n o t e d w i t h l y s i n e supplementa-t i o n . PVP had no e f f e c t on performance. T h i s would suggest t h a t the t a n n i c a c i d i s not a c a u s a t i v e f a c t o r i n the reduced performance encountered w i t h RSM d i e t s . L e s l i e and Summers (1975) i n t h e i r s t u d y o f amino a c i d b a l a n c e of RSM found t h a t the a d d i t i o n o f i s o l e u c i n e and p h e n y a l a n i n e , amino a c i d s which a re c a l c u l a t e d t o be f i r s t l i m i t i n g i n RSM, f a i l e d t o g i v e a response i n weight g a i n . However, s u p p l e m e n t a t i o n o f RSM w i t h a r g i n i n e and m e t h i o n i n e r e s u l t e d i n enhanced performance w h i l e the a d d i t i o n o f l y s i n e r e s u l t e d i n a marked d e p r e s s i o n i n weight g a i n . The p r o b a b l e e x p l a n a t i o n o f such r e s u l t s g i v e n by the a u t h o r s was due t o amino a c i d imbalance o r f a c t o r s w h i c h might a f f e c t the me t a b o l i s m o f amino a c i d s r a t h e r t h a n j u s t l o o k i n g at amino a c i d adequacy as such. 26. I t i s w e l l known t h a t excess l y s i n e can r e s u l t i n an i n c r e a s e i n the r e q u i r e m e n t f o r a r g i n i n e (Lewis e_t a l . 1963; Jones e t al_. , 1966; Dean and S c o t t , 1968). Such a response has been demo n s t r a t e d , f o r the most p a r t on c a s e i n d i e t s where the r a t i o o f l y s i n e to a r g i n i n e i s a p p r o x i m a t e l y 2:1. However, l o o k i n g a t the l e v e l s o f t h e s e amino a c i d s i n RSM, i t may be noted t h a t t h e i r r a t i o i s a p p r o x i m a t e l y 1:1. Hence, w i t h such l e v e l s o f a r g i n i n e and l y s i n e , one would not expect t o see the l y s i n e , a r g i n i n e antagonism n o t e d f o r d i e t s h i g h i n c a s e i n ( L e s l i e and Summers, 1975). Rapeseed meal c o n t a i n s a p p r o x i m a t e l y 3% t a n n i n s ( L e s l i e and Summers, 1975) and t h e r e i s work i n d i c a t i n g t h a t a r g i n i n e may p l a y a r o l e i n t a n n i n e x c r e t i o n ( F u l l e r e t a l . , 1967). I f t h i s were t r u e , the r a t i o o f " a v a i l a b l e a r g i n i n e " to l y s i n e i n c a s e i n (which c o u l d be used by the b i r d f o r normal m e t a b o l i c p r o c e s s e s ) , may be c l o s e r to 2:1. I t has a l s o been r e p o r t e d t h a t one o f the t a n n i n e x c r e t o r y p r o d u c t s i s 4-0 m e t h y l g a l l i c a c i d (Booth et_ a l . , 1961; K a d i r v e l e_t a_l. , 1970). Thus met h y l groups from c h o l i n e o r m e t h i o n i n e may a l s o be used i n the e x c r e t i o n p r o c e s s . A c c o r d i n g t o Nwokolo e t a l . (197 7) the amino a c i d a v a i l a b i l i t y o f RSM ranges from 78.4% t o 95.9% w i t h 27 . an average o f 91.9%. W i t h the e x c e p t i o n o f m e t h i o n i n e w h i c h was 78.4% a v a i l a b l e , the e s s e n t i a l amino a c i d s showed r e l a t i v e l y h i g h a v a i l a b i l i t y . However, most were s i g n i -f i c a n t l y lower than f o r soybean meal which was one o f the p r o t e i n s o u r c e s used f o r comparison. Tao e t al_ . (1971) u s i n g c o l o s t o m i z e d b r o i l e r c h i c k s showed t h a t t r u 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 f o r 16 amino a c i d s o f RSM v a r i e d from 63% to 80%. However, Bragg e t a l . (1969) showed t h a t normal c h i c k s p r o v i d e d h i g h e r v a l u e s w i t h g r e a t e r r e p r o -d u c i b i l i t y t h a n c o l o s t o m i z e d c h i c k s . Sarwar e_t al_ . (1975) used b a l a n c e t r i a l s t o show amino a c i d a v a i l a b i l i t y o f 83% t o 92% f o r RSM. Commenting on the e f f e c t o f u s i n g d i f f e r e n t p r o c e d u r e s , Nwokolo ejt a l . (1977) s t a t e d t h a t d i g e s t i b i l i t y t r i a l s do not i n c l u d e a method f o r measuring endogenous amino a c i d s . T h e r e f o r e , an endogenous c o r r e c -t i o n i s not u t i l i z e d i n c a l c u a l t i n g the apparent d i g e s t ! - : : b i l i t y r e s u l t i n g i n a lower v a l u e compared to the a v a i l -a b i l i t y p r o c e d u r e . F u r t h e r i n t h e i r comment, the a u t h o r s a l s o s t a t e d t h a t s u c c e s s f u l methods o f d e t o x i f i c a t i o n o f RSM have been d e v e l o p e d . The p r o d u c t p r o v i d e s a good source o f e s s e n t i a l amino a c i d s and a r e l a t i v e l y h i g h l e v e l o f a v a i l a b i l i t y . T h e r e f o r e , RSM can be i n c o r p o r a t e d as a major p r o t e i n s o u r c e i n the d i e t o f growing a n i m a l s . 28. B e l l and G i o v a n e t t i (1973) have suggested t h a t whenever a need a r i s e s t o s u b s t i t u t e soybean meal f o r RSM, adjustment s h o u l d be made to keep d i e t s i s o c a l o r i c as w e l l as i s o n i t r o g e n o u s . T h i s i s because the d i g e s t i b i l i t y o f p r o t e i n i n RSM i s l ower (average 75.9%) than i s t h a t f o r soybean meal (89.2%) and t h i s w i l l i n f l u e n c e a v a i l -a b i l i t y o f p r o t e i n and presumably of i n d i v i d u a l amino a c i d s . B. M e t a b o l i z a b l e Energy A major c o n c e r n i n u s i n g RSM i n the p o u l t r y d i e t has been the low m e t a b o l i z a b l e energy (ME). However, v a r i o u s p r o c e s s i n g methods have been a p p l i e d (removing the h u l l ) w hich r e s u l t s i n improved v a l u e s . N e v e r t h e l e s s , p l a n t g e n e t i c i s t s are t r y i n g to improve the ME v a l u e o f RSM by l o w e r i n g the f i b e r c o n t e n t o f r a p e s e e d . Energy e v a l u a t i o n o f d i e t s c o n t a i n i n g the RSM s t u d i e d by McDonald (1969) and B e l l (1969) showed t h a t the d i g e s t i b l e energy i n t a k e by p i g s (McDonald, 1969) and mice" ('Bell,. 1969) was s i g n i f i c a n t l y lower than t h a t o f d i e t s c o n t a i n i n g soybean meal (SBM). However, t h e r e was no s t a t i s t i c a l d i f f e r e n c e between the d i g e s t i b l e energy r e s u l t i n g from the v a r i o u s rapeseed meals. In a p r e l i m i n a r y s t u d y by B a y l e y (1969) w i t h barrow p i g s , 29. t h e r e was a 10% i n c r e a s e i n d i g e s t i b l e energy v a l u e s f o r RSM when the d i g e s t i b i l i t y o f crude f i b e r o f RSM was i n c r e a s e d from 38 to 57% by s t e a m - p e l l e t i n g . In the assessment o f ME f o r t e s t RSM, B a y l e y (1969) i n v e s t i g a t e d f a c t o r s known to a f f e c t ME v a l u e such as : (a) p o s s i b l e l e v e l s o f s u b s t i t u t i o n o f RSM i n the b a s a l d i e t o f c h i c k e n s w i t h o u t impairment o f d i g e s t i o n and a b s o r p t i o n by crude f i b e r c o n t e n t , (b) age o f the c h i c k e n and l e n g t h o f time and d i e t was f e d to g i v e r e l i a b l e v a l u e s , and (c) e f f e c t o f s t e a m - p e l l e t i n g and r e g r i n d i n g the RSM. I t was found t h a t ME v a l u e s (a) were r e l i a b l e when RSM was s u b s t i t u t e d a t the 40% l e v e l , (b) i n c r e a s e d w i t h age w i t h a maximum a t 4 weeks o f age ( v a l u e s i m i l a r t o t h a t o f mature r o o s t e r s ) , (c) were s l i g h t l y r educed when s o l v e n t and p r e - p r e s s s o l v e n t meals were s t e a m - p e l l e t e d and reground and (d) were s l i g h t l y i n c r e a s e d when e x p e l l e r p r o c e s s e d meals were s t e a m - p e l l e t e d and reg r o u n d (Rapeseed A s s o c i a t i o n o f Canada, 1972). C l a n d i n i n (1969), however, found t h a t ME" v a l u e s f o r RSM d i e t s consumed by c h i c k e n s 4 weeks o l d were s i g n i f i c a n t l y lower (p <_ 0.05) than v a l u e s d e t e r m i n e d when c h i c k e n s were 6 weeks o l d . 30. ME v a l u e d i f f e r e n c e s e x i s t between rapeseed samples but they a re not s i g n i f i c a n t except perhaps i n the case o f c h i c k e n s . Most c o n s i s t e n t l y , d i e t s c o n t a i n i n g e x p e l l e r - p r o c e s s e d RSMs, produced the h i g h e s t ME v a l u e s r e g a r d l e s s o f whether c h i c k e n s , mice or p i g s were f e d the v a r i o u s l e v e l s o f RSMs. Lowest ME v a l u e s u s u a l l y c o i n c i d e d w i t h RSMs h a v i n g the h i g h e s t crude f i b e r c o n t e n t . In many i n s t a n c e s , however, the d i f f e r e n c e s i n ME v a l u e s a p p a r e n t l y r e f l e c t e d the l e v e l o f r e s i d u a l o i l i n the RSMs (Rapeseed A s s o c i a t i o n o f Canada, 1972). A c c o r d i n g t o .the r e s u l t o f v a r i o u s s t u d i e s o f the Rapeseed U t i l i z a t i o n A s s i s t a n c e Program (1968-1969), B a y l e y (1969) and C l a n d i n i n (1969) i n d i c a t e d t h a t s a t i s -f a c t o r y meals may be o b t a i n e d from any v a r i e t y o f ra p e s e e d . T h i s i n d i c a t e s t h a t the v a r i o u s methods f o r e v a l u a t i n g the meals b i o l o g i c a l l y d i d not c o n s i s t e n t l y i n d i c a t e a h i g h e r r a n k i n g o f one v a r i e t y over a n o t h e r . E v i d e n c e o f the t r a i l s s u g g e sts t h a t the r a n k i n g ,of i n d i v i d u a l RSMs was i n f l u e n c e d more by the o t h e r i n g r e d i e n t s making up the t o t a l d i e t than by s p e c i e s and v a r i e t y o f rapeseed or by method o f p r o c e s s i n g the meals. 31. C. Chemical Elements Holmes and R o b e r t s (1963) r e p o r t e d t h a t the i n c l u s i o n o f RSM at the 30% l e v e l i n the d i e t o f growing c h i c k e n s caused an i n c r e a s e d i n c i d e n c e o f p e r o s i s . S i n c e C l a n d i n i n and Heard (1968) have r e p o r t e d t h a t RSM c o n t a i n s about 3% t a n n i n s and t a n n i n s have been shown by J u r d and Geissman (1956) to form complexes w i t h m e t a l i o n s i t seemed r e a s o n a b l e to p o s t u l a t e t h a t perhaps the h i g h e r i n c i d e n c e o f p e r o s i s n o t e d by Holmes and R o b e r t s (1963) i n c h i c k e n s on RSM c o n t a i n i n g d i e t s was due t o p a r t i a l d e f i c i e n c y o f manganese. S u p p o r t i n g the h y p o t h e s i s o f Holmes and Roberts (1963), r e s u l t s o f Seth and C l a n d i n i n (1973) showed t h a t when b r o i l e r - t y p e c h i c k e n s were f e d r a t i o n s i n which soybean meal or a c o m b i n a t i o n o f RSM and SBM s e r v e d as the s u p p l e -mentary s o u r c e s o f p r o t e i n a:" s i g n i f i c a n t l y h i g h e r i n c i d e n c e o f p e r o s i s was n o t e d i n the c h i c k s f e d the l a t t e r r a t i o n . I n c r e a s i n g the l e v e l o f manganese .in the RSM c o n t a i n i n g r a t i o n d i d not appear t o l o w e r the i n c i d e n c e o f p e r o s i s . R e s u l t s o f the s t u d y by Nwokolo e_t a l _ . (1976) i n d i c a t e d t h a t manganese a v a i l a b i l i t y was 56.7% f o r RSM. T h i s was the l o w e s t compared to the o t h e r m i n e r a l s under stu d y (Ca-71.7%, P-74.8%, Mg-61.1%, Zn-57.6%, Cu-62.2%). These f i n d i n g s s u p p o r t the r e s u l t s o f Seth and C l a n d i n i n 32. (1973) a l t h o u g h , the i n c i d e n c e o f p e r o s i s was not r e p o r t e d . P a r t o f the phosphorus i n p l a n t m a t e r i a l s e x i s t s as p h y t i n , the calcium-magnesium s a l t o f i n o s i t o l hexa-p h o s p h o r i c a c i d , w h i c h c h e l a t e s m i n e r a l s ( N e l s o n 'e_t a l . , 1968). A v a i l a b i l i t y o f phosphorus i n f e e d s t u f f s o f p l a n t o r i g i n i s c o n s i d e r e d low due t o the i n f l u e n c e o f the p h y t i c a c i d p r e s e n t . P u b l i s h e d r e s u l t s show a v a i l a b l e phosphorus v a l u e s f o r p l a n t f e e d s t u f f s o f between 30 and 40% ( T a y l o r , 1965). However, the r e c e n t f i n d i n g s o f Nwokolo et_ a l . (1977) c o n t r a d i c t t h o s e o f T a y l o r (1965). The major c o n t r a d i c t i o n might be due t o d i f f e r e n c e o f methodology. A c c o r d i n g t o Nwokolo and Bragg (1977) , the -c o n t e n t o f p h y t i c a c i d and crude f i b e r i n RSM was 1.92% and 12.0%, r e s p e c t i v e l y . The r e s u l t s o f t h e i r s t u d i e s have shown t h a t the r e t e n t i o n o f a l l m i n e r a l s (Ca, P, Mg, Mn, Cu and Zn) was a d v e r s e l y a f f e c t e d by e i t h e r p h y t i c a c i d or crude f i b e r . I t was a l s o s t a t e d i n t h e i r r e p o r t t h a t s e v e r a l m i n e r a l s showed s i g n i f i c a n t i n v e r s e r e l a t i o n s h i p to b o t h p h y t i c a c i d and crude f i b e r . Bragg (1974) has i n v e s t i g a t e d the c o n t e n t o f the t r a c e m i n e r a l s o f RSM i n comparison t o SBM. H i s r e s u l t s showed a c o n s i d e r a b l e v a r i a t i o n i n the c o n t e n t among RSMs t e s t e d . However, w i t h the e x c e p t i o n o f copper,, the l e v e l s o f the o t h e r m i n e r a l s (Ca, P, Fe, Mg, Mn, Zn 33. and Se) were h i g h e r i n RSM than the c o r r e s p o n d i n g v a l u e s n o r m a l l y c i t e d f o r SBM. The a u t h o r has suggested t h a t on the b a s i s o f c o n t e n t a l o n e , i t would appear t h a t RSM i s a b e t t e r s o u r c e o f t h e s e m a t e r i a l s than i s SBM. Rapeseed meal has g r e a t e r z i n c b i n d i n g c a p a c i t y than SBM and z i n c b i n d i n g c a p a c i t y o f RSM appears t o be r e l a t e d to i t s c o n t e n t o f bound t a n n i n s (Seth e t a l . , 1976). A l o n g the same l i n e , Nwokolo and Bragg (1977) found t h a t RSM and r apeseed p r o t e i n c o n c e n t r a t e b i n d z i n c , making i t l e s s a v a i l a b l e . A c c o r d i n g to the a u t h o r s a s s u m p t i o n s , p h y t i n and f i b e r appear to be the f a c t o r s i n v o l v e d i n r e d u c i n g the a v a i l a b i l i t y not o n l y o f z i n c but a l s o o f P, Ca, Mg, Mn and Cu as w e l l . As i t i s s t a t e d above, h i g h e r i n c i d e n c e o f l e g a b n o r m a l i t i e s ( p e r o s i s , s h o r t e r and t h i c k e r l o n g bones) i n c h i c k s f e d d i e t s w i t h RSM t h a n i n b i r d s f e d SBM has been o b s e r v e d . I t has been shown t h a t p h y t a t e s i n the d i e t o f c h i c k s and o t h e r s p e c i e s d e c rease z i n c a v a i l a b i l i t y w hich i s r e q u i r e d f o r normal bone f o r m a t i o n as w e l l as growth. I t i s b e l i e v e d t h a t RSM c o n t a i n s about t w i c e as much p h y t i n as SBM which may c o n t r i b u t e to l ower growth and bone a b n o r m a l i t i e s i n c h i c k s (Motzok, 1976). Motzok (1976) has conducted a number o f s t u d i e s to i n v e s t i g a t e the problem. In h i s r e p o r t , he s t a t e d t h a t 34. a l t h o u g h z i n c s u p p l e m e n t a t i o n o f SBM d i e t s had no apparent e f f e c t on the growth o f c h i c k s , the d a t a i n d i c a t e t h a t a d d i t i o n a l z i n c i s r e q u i r e d w i t h RSM f o r maximum growth. F u r t h e r i n h i s r e p o r t he a l s o mentioned t h a t s u p p l e m e n t a l z i n c and/or manganese had no apparent e f f e c t on l e g abnor-m a l i t i e s w h i c h were p r e v a l e n t t o about the same degree w i t h SBM and RSM d i e t s . However, the i n c i d e n c e o f p e r o s i s was a p p r e c i a b l y h i g h e r w i t h RSM than w i t h SBM d i e t s . In h i s c o n c l u s i o n , the auth o r a d m i t t e d t h a t h i s e x p e r i m e n t a l d a t a are inadequate to e x p l a i n the h i g h i n c i d e n c e o f l e g a b n o r m a l i t i e s . The Rapeseed A s s o c i a t i o n o f Canada (1972) has r e p o r t e d t h a t t h e r e i s c o n s i d e r a b l e m i n e r a l v a r i a t i o n among v a r i o u s RSMs. F u r t h e r , i t was p o i n t e d out t h a t the v a r i a -t i o n t h a t e x i s t e d was i n f l u e n c e d by the m i n e r a l c o n t e n t o f the s o i l s on w h i c h the rapeseed was grown. The type o f p r o c e s s i n g had no s i g n i f i c a n t e f f e c t on the amounts o f m i n e r a l s i n the meals. Most RSMs, however, c o n t a i n e d a h i g h e r c o n t e n t o f a l l m i n e r a l s e xcept copper and z i n c than d i d soybean meal. 35. D. T o x i c i t y (a) Gluco s i n o l a t e s The g l u c o s i n o l a t e s are a n i o n s and oc c u r i n p l a n t s as s a l t s . They are u s u a l l y r e g a r d e d as p o t a s s i u m s a l t s , a l t h o u g h , the complex o r g a n i c c a t i o n s i n a p i n e o c c u r s w i d e l y among C r u c i f e r s and i s the c a t i o n accompanying • p-hydroxybenzyl-GS ( s i n a l b i n ) as i t i s u s u a l l y i s o l a t e d ( K j a e r , 1960). G l u c o s i n o l a t e s o c c u r throughout a p l a n t i n c l u d i n g the r o o t , stem, l e a f , and seed. They are always accompanied by an enzyme system c a p a b l e o f h y d r o l y z i n g the g l u c o -s i n o l a t e s . However t h e r e i s ample e v i d e n c e t h a t the enzyme i s s e p a r a t e d from i t s g l u c o s i n o l a t e s u b s t r a t e i n the i n t a c t p l a n t (Tookey and W o l f f , 1970). In the e a r l y l i t e r a t u r e , t h e enzyme was c a l l e d m y r o s i n o r m y r o s i n a s e . E t t l i n g e r e t a l . (1961) c o i n e d the name g l u c o s i n o l a s e t o p a r a l l e l the name g l u c o s i n o l a t e . R e c e n t l y the I n t e r n a t i o n a l Union o f B i o c h e m i s t r y recommended the term t o be ' t h i o g l u c o s i d a s e ' ( F l o r k i n and S t o t z , 1965), E a r l y problems i n f e e d i n g RSM t o l i v e s t o c k were found t o be caused by g l u c o s i n o l a t e s , a f a m i l y o f compounds t h a t are found t o v a r y i n g l e v e l s i n rapeseed as w e l l as i n o t h e r c r o p s such as cabbage and mustard. When the seed 36. i s c r u s h e d i n the presence o f m o i s t u r e , the enzyme t h i o -g l u c o s i d a s e (myrosinase) h y d r o l y s e s the g l u c o s i n o l a t e s p r e s e n t t o r e l e a s e g l u c o s e , i n o r g a n i c s u l p h a t e and a group o f t o x i c o r g a n i c compounds. One o f t h e s e t o x i c compounds i s o x a z o l i d i n e t h i o n e and i s g o i t r o g e n i c i n t e r f e r i n g w i t h the p r o d u c t i o n of the m e t a b o l i c hormone t h y r o x i n e , r e s u l t i n g i n - i m p a i r e d growth and r e p r o d u c t i v e performance ( M i l l e r and B i e l y , 1978). Other g o i t r o g e n i c s u b stances may i n c l u d e i s o t h i o c y a n a t e , n i t r i l e and t h i o c y a n a t e depending on e n v i r o n m e n t a l c o n d i t i o n s . At l e a s t seven g l u c o s i n o l a t e s have been i d e n t i f i e d i n r a p e s e e d w h i c h range a p p r o x i m a t e l y from 10-12 mg/g RSM (Jo n e s , 1979). The number o f i d e n t i f i e d p l a n t g l u c o s i n o l a t e s i s now more than 70 ( K j a e r , 1973). Most o f t h e s e have been c h a r a c t e r i z e d by K j a e r and co-workers. A c c o r d i n g t o K j a e r (1966), a l l 300 examined s p e c i e s o f C r u f i c e r a e , c o n t a i n from one t o seven g l u c o s i n o l a t e s . N e a r l y a l l the s p e c i e s from the r e l a t e d f a m i l i e s C a p p a r i d a c e a e , M o r i h -gaceae, T o v a r i a c e a e , and Resedaceae, as w e l l a s , some s p e c i e s from u n r e l a t e d p l a n t f a m i l i e s c o n t a i n g l u c o s i n o -l a t e s ( K j a e r , 1973). As s t a t e d above g l u c o s i n o l a t e s are h y d r o l y z e d by an a s s o c i a t e d t h i o g l u c o s i d a s e enzyme system whenever wet, raw p l a n t m a t e r i a l i s c r u s h e d . G l u c o s e and a c i d 37. s u l f a t e i o n are always r e l e a s e d as p r o d u c t s . The o r g a n i c g l u c o n p o r t i o n may undergo an i n t r a m o l e c u l a r rearrangement f o l l o w i n g the h y d r o l y s i s t o g i v e an i s o t h i o c y a n a t e . Without such a rearrangement, the g l u c o n forms a n i t r i l e , o f t e n w i t h the l o s s o f s u l f u r . A l t e r n a t i v e l y , a rearrangement t o an o r g a n i c t h i o c y a n a t e may o c c u r . From some g l u c o s i n o l a t e s the e x p e c t e d i s o t h i o c y n a t e s are not formed. They may c y c l i z e t o form o x a z o l i d i n e - 2 - t h i o n e s ( L i e n e r , 1980). L a y e r d i e t s c o n t a i n i n g v a r i a b l e amounts o f i n t a c t g l u c o s i n o l a t e s and v a r i o u s g l u c o n e s i n d i c a t e d t h a t f e e d i n g RSM may cause l i v e r damage and m o r t a l i t y a t t r i b u t a b l e t o hemorrhagic l i v e r . I t was a l s o demonstrated t h a t m o r t a l i t y c o u l d be reduced markedly by adding v i t a m i n K to the f e e d or d r i n k i n g water (Papas e_t al_. , 1979) . Rapeseed meal, r a p e s e e d e x t r a c t s and compounds w i t h a c t i v e groups s i m i l a r t o those o f g l u c o n e s were used to s t u d y the e f f e c t o f g l u c o s i n o l a t e s on egg i o d i n e and t h y r o i d s t a t u s o f l a y i n g hens. R e d u c t i o n o f egg i o d i n e appeared to be more r e l a t e d to t h i o c y a n a t e i o n (SCN) than t o t o t a l g l u c o s i n o l a t e s . T h i s may be due to low g l u c o -s i n o l a t e RSM such as Tower caused a decrease s i m i l a r to or l a r g e r than Midas RSM or e x t r a c t s which c o n t a i n e d l a r g e l e v e l s o f t o t a l g l u c o s i n o l a t e . A d d i t i o n o f t h i o g l u c o s i d a s e to d i e t s c o n t a i n i n g i n t a c t g l u c o s i n o l a t e s i n c r e a s e d t h y r o i d 38 . s i z e ahoye g l u c o s i n o l a t e s a l o n e . T h y r o x i n e l e v e l s remained normal even when t h y r o i d s were g r e a t l y e n l a r g e d (Papas et a l . , 1979). The second f a c t o r which i s a d e t e r r e n t t o the use o f RSM i n m o n o g a s t r i c a n i m a l d i e t s i s i t s h i g h e r f i b e r c o n t e n t . Rapeseed has a d a r k , h a r d seed c o a t c o n t a i n i n g a condensed p o l y p h e n o l based complex which c o n t r i b u t e s a s u b s t a n t i a l amount o f f i b e r t o commercial RSM. T y p i c a l crude f i b e r c o n t e n t s o f commercial A r g e n t i n e and P o l i s h RSMs are u n a c c e p t a b l y h i g h ; i t ranges between 13-16% (Jones, 1979). Hobson-Frohock et_ al_. (1973) were the f i r s t t o show t h a t the f i s h y odor r e s u l t i n g from the i n c l u s i o n o f RSM i n the r a t i o n o f b r o w n - s h e l l e d egg l a y e r s was due to the p r e s ence o f t r i m e t h y l a m i n e (TMA). I t has been demonstrated t h a t the l e v e l o f RSM i n the l a y i n g r a t i o n o f b r o w n - s h e l l e d egg l a y e r s i n f l u e n c e d the degree o f f i s h y odor and a s u g g e s t i o n has been made t h a t the a b i l i t y o f the b i r d to m e t a b o l i z e TMA was g e n e t i c a l l y c o n t r o l l e d ( C l a n d i n i n and Robblee, 1978). B o l t o n ejt a l (1976) showed t h a t a p r e d i s p o s i t i o n to l a y i n g f i s h y eggs i s the p r e s e n c e o f a semi-dominant gene t h a t has v a r i a b l e e x p r e s s i o n depending on e n v i r o n m e n t a l f a c t o r s . T h e i r s t u d i e s showed t h a t brown egg l a y e r s , f e d a r a t i o n c o n t a i n i n g RSM, which 39. are kept i n f l o o r pens are more prone to l a y i n g f i s h y eggs than those m a i n t a i n e d i n l a y i n g b a t t e r i e s . R e c e n t l y , Hobson-Frohock e t a l . (1977) and C l a n d i n i n e t al_. (1977) have r e p o r t e d t h a t the source o f the TMA i n such eggs i s s i n a p i n e w h i c h i s p r e s e n t i n RSM a t a l e v e l o f about 1 to i i ? ±20. B e s i d e s " f i s h y eggs" the i n c i d e n c e o f " l i v e r hemorrhage" has a l s o been n o t i c e d by C l a n d i n i n e_t a l . (1976). In v i e w o f t h e i r f i n d i n g s , t h e y have recommended t h a t l e v e l s o f RSM i n excess o f 5% s h o u l d not be f e d to S i n g l e Comb White Leghorn hens and t h a t no RSM s h o u l d be i n c l u d e d i n the r a t i o n o f brown-egg l a y e r s . In a d d i t i o n , exogenous s o u r c e s o f t h i o g l u c o s i d a s e such as g r a i n con-t a m i n a t e d w i t h mustard seed or r a p e s e e d , s h o u l d n o t be p e r m i t t e d t o get i n t o r a t i o n s c o n t a i n i n g RSM. G o i t e r i s another c o n d i t i o n due to the i n c l u s i o n o f RSM i n the p o u l t r y d i e t . The g o i t r o g e n i c e f f e c t o f RSM has n ot been c o n s i d e r e d as a s e r i o u s problem when RSM i s i n c l u d e d i n r a t i o n a t recommended l e v e l s f o r v a r i o u s c l a s s e s o f l i v e s t o c k and p o u l t r y . I t has been o f some c o n c e r n , s i n c e even a t recommended l e v e l s o f i n c l u s i o n o f RSM, some t h y r o i d enlargement has been n o t e d . Low l e v e l s o f i o d i n e i n m i l k and eggs were obse r v e d by the i n c l u s i o n o f h i g h g l u c o s i n o l a t e (RSM) i n d a i r y and l a y e r s r a t i o n . ( P r o c e e d i n g s 40. (106) - 5th I n t e r . Rapeseed Conf. 2:210, 1978) and i n r a t i o n f o r cows ( I w a r s s o n , 1973 ; Iwarsson e_t al_. , 1973). I t has been i n d i c a t e d i n Sweden t h a t s u p p l e m e n t i n g r a t i o n s f o r d a i r y cows which c o n t a i n h i g h g l u c o s i n o l a t e RSM w i t h e x t r a i o d i n e r e s u l t s i n the p r o d u c t i o n o f m i l k w i t h h i g h e r i o d i n e c o n t e n t . There i s no s i m i l a r work r e p o r t e d on egg c o n t e n t . (b) Tannins Tannins a re p l a n t p o l y p h e n o l i c s u b s t a n c e s w i t h a m o l e c u l a r w e i g h t g r e a t e r than 500. Tan n i c a c i d i s the most common t a n n i n . Tannins a re found i n v a r i o u s p l a n t s such as spruce b a r k , oak acorns and rapeseed. Some d i e t a r y s u b s t a n c e s ( e . g . , i r o n and c a l c i u m s a l t s ) w i l l b i n d the t a n n i n and, t h e r e f o r e , p r e v e n t subsequent t o x i c i t y w h ich can produce l i v e r n e c r o s i s ( M i l l e r and B i e l y , 1978). Tannins are u s u a l l y c l a s s i f i e d i n t o h y d r o l y z a b l e and condensed c a t a g o r i e s on the b a s i s o f t h e i r s t r u c t u r a l d i f f e r e n c e s and d i v e r s e h y d r o l y t i c r e a c t i v i t i e s ( R i b e r e a u -Gayon, 1972) . Tannins have been e x t e n s i v e l y i n v e s t i g a t e d because o f t h e i r adverse e f f e c t s on (a) growth o f an i m a l s ( G l i c k and J o s l y n , 1970) and b i r d s (Chang and F u l l e r , 1964; Marquardt et_ a_l. , 1977) , (b) p r o t e i n u t i l i z a t i o n (Vohra et a l . , 1966) and (c) m e t a b o l i z a b l e energy v a l u e o f feeds (Yapar and C l a n d i n i n , 1972) . 41. C h i c k s are found t o be more s e n s i t i v e than r a t s to t a n n i n s i n t h e i r f e e d s . As l i t t l e as 1% o f t a n n i n s cause growth d e p r e s s i o n . T annin a l s o a d v e r s e l y a f f e c t s m e t a b o l i z a b l e energy and l e a d s to the e x c r e t i o n o f h i g h l e v e l s o f n i t r o g e n i n the f e c e s ( M i l l e r and B i e l y , 1978) . I t has been suggested by Yapar and C l a n d i n i n (1972) t h a t t a n n i n s i n RSM t e n d t o lower the ME v a l u e o f RSM and any i n c r e a s e i n the t a n n i n c o n t e n t o f the h i g h p r o t e i n - l o w h u l l f r a c t i o n ' would te n d to a d v e r s e l y a f f e c t s i t s ME v a l u e . A d d i t i o n o f a r g i n i n e t o a p o u l t r y d i e t seems to c o r r e c t the problem o f t a n n i n (Summers, 1974). However, s i n c e a r g i n i n e i s b e i n g used f o r the e x c r e t i o n o f t a n n i c a c i d , a r g i n i n e a v a i l a b i l i t y may be l o w e r e d . C l a n d i n i n and Heard (1968) r e p o r t e d t h a t RSM c o n t a i n s a p p r o x i m a t e l y 3% o f t a n n i n s . However, t h i s v a l u e has been shown by Fenwick and Hoggan (1976) to i n c l u d e s i n a p i n e . T h i s c h o l i n e e s t e r o f s i n a p i c a c i d c o n s t i t u t e s about 1.5% o f RSM ( M u e l l e r e t a l . , 1978). Hence, i t would appear t h a t RSM c o n t a i n s o n l y about 1.5% o f t a n n i n s . R e l a t i v e l y l i t t l e i s known about the c h e m i c a l n a t u r e o f t a n n i n s i n RSM. Based on t h e i r f i n d i n g s o f Leung et_ a l . (1979) the major p o r t i o n o f the condensed t a n n i n s o f r apeseed h u l l s cannot be e x t r a c t e d by common s o l v e n t s . Condensed t a n n i n s were e s t i m a t e d t o be..;0.1% of the h u l l s by w e i g h t . C y a n i d i n was d e t e c t e d as the p r i n c i p a l 42. d e g r a d a t i o n p r o d u c t o f the i s o l a t e d p o l y m e r i c f l a v a n o l s w h i c h i m p l i e s t h a t condensed t a n n i n s e x i s t s o l e l y as the polymers o f l e u c o c y a n i d i n s . In view o f the low e x t r a c t -a b i l i t y o f condensed t a n n i n s , i t appears t o e x i s t s o l e l y as the polymers o f l e u c o c y a n i d i n s i n RSM. In view o f the low e x t r a c t a b i l i t y o f condensed t a n n i n s from rapeseed h u l l s , a b s o r p t i o n o f these p o l y m e r i c compounds by the d i g e s t i v e system of the b i r d s and a n i m a l s would p r o b a b l y be i n s i g i f i c a n t . (c) E r u c i c A c i d The e x t r a c t e d o i l from rapeseed c o n t a i n s e r u c i c a c i d , w hich has been proven to reduce p r o d u c t i v e p e r f o r -mance o f v a r i o u s e x p e r i m e n t a l a n i m a l s when f e d a t h i g h l e v e l s . However, the c o n t e n t o f e r u c i c a c i d has been reduced from 45% i n p a s t c u l t i v a r s t o 1% i n modern c u l t i v a r s ( M i l l e r and B i e l y , 1978) . E r u c i c a c i d or c i s - 1 3 - d o c o s e n o i c a c i d i s a l o n g c h a i n u n s a t u r a t e d f a t t y a c i d t h a t e x i s t s i n g l y c e r i d e s i n rapeseed o i l . However, e r u c i c a c i d i s not commonly found i n a n i m a l l i p i d s ( M i l l e r and B i e l y , 1978). The e x p e r i m e n t a l e v i d e n c e r e p o r t e d by S l i n g e r (1973) showed t h a t rapeseed o i l s e x e r t e d a d e p r e s s i n g e f f e c t on egg p r o d u c t i o n , egg weight and h a t c h a b i l i t y . 43. The s u p p r e s s i o n o f r e p r o d u c t i v e performance was t h e r e f o r e due t o the pr e s e n c e o f e r u c i c a c i d . T h i s a u t h o r r e p o r t e d t h a t r apeseed o i l s were o f markedly lower ME and r e s u l t e d i n p o o r e r growth and f e e d e f f i c i e n c y than (a) an AV b l e n d (a commercial m i x t u r e o f an i m a l and v e g e t a b l e f a t con-t a i n i n g some rapeseed o i l ) , (b) rapeseed o i l foods ( a c i d u l a t e d soap s t o c k s from rapeseed o i l ) and (c) low e r u c i c a c i d r apeseed (LEAR) o i l . The e v i d e n c e a l s o i n d i c a t e s t h a t the removal o f the gums p r e s e n t i n the crude o i l s i s p a r t i a l l y r e s p o n s i b l e f o r the r e d u c t i o n i n the m e t a b o l i z a b l e energy v a l u e . (d) Gums Gums are one o f the c h e m i c a l components o f RSM. I t s c h e m i c a l n a t u r e i s not y e t w e l l d e f i n e d i n s p i t e o f m e t a b o l i c i n t e r a c t i o n . The e f f e c t o f rapeseed gums on l a y i n g b i r d m o r t a l i t y has been s t u d i e d by March e_t al_. (1978). The r e s u l t s o f t h e i r s t u d y show t h a t t h e r e was a s t r a i n d i f f e r e n c e i n the r a t e o f m o r t a l i t y and the b i r d s f e d RSM, the Midas gums had the h i g h e s t m o r t a l i t y . However, rapeseed gums are r e p o r t e d ( L a l l and S l i n g e r , 1974; March 1977) to be w e l l u t i l i z e d by growing b i r d s w i t h o u t adverse e f f e c t . The e a r l y s t u d i e s w i t h RSM i n d i c a t e d t h a t 44. g o i t r o g e n s and e r u c i c a c i d were r e s p o n s i b l e f o r h i g h m o r t a l i t y (March and Soong, 1976 ; V'ogt e_t a l . , 1969). (e) P h y t a t e Another c o n c e r n i n u s i n g r apeseed p r o t e i n con-c e n t r a t e i s the e f f e c t s o f the p h y t a t e c o n t e n t . As s t a t e d e a r l i e r , p h y t a t e i s a common component o f c e r e a l s and o i l s e e d s . P h y t a t e appears t o s e l e c t i v e l y b i n d z i n c i n foods ( J o n e s , 1979). I t was a l s o r e p o r t e d t h a t h i g h l y s t r e s s e d r a t s f e d rapeseed p r o t e i n as the o n l y p r o t e i n source r e s u l t e d i n a z i n c d e f i c i e n c y . T h i s d e f i c i e n c y was.overcome by sup p l e m e n t i n g the d i e t s o f pregnant r a t s w i t h z i n c i n amounts s u f f i c i e n t t o complex the p h y t i c a c i d p r e s e n t i n the p r o t e i n c o n c e n t r a t e . Nwokolo and Bragg (1977) have a l s o r e p o r t e d s i m i l a r r e s u l t s from t h e i r s t u d i e s . E. S a f e t y L e v e l There has been no, w e l l d e f i n e d s a f e t y l e v e l s u ggested i n the l i t e r a t u r e . One s h o u l d have to i d e n t i f y the type o f b i r d s ( l a y e r s or b r o i l e r s ) , t y pe o f a n i m a l s (ruminant o r m o n o g a s t r i c ) , type o f r a p e s e e d , n a t u r e o f the p r o c e s s i n g , and o t h e r components o f the r a t i o n b e f o r e making any d e c i s i o n on s p e c i f i c s a f e t y l e v e l o f RSM. 45. F u l l - f a t Tower rapeseed i s a h i g h energy, good q u a l i t y p r o t e i n p r o d u c t c o n t a i n i n g about 42% f a t and 22% p r o t e i n . I t s m e t a b o l i z a b l e energy v a l u e (4.65 K c a l / g ) as d e t e r m i n e d by the White Leghorn r o o s t e r s , was almost double the v a l u e f o r Tower meal. Tower rapeseed was i n c l u d e d i n b r o i l e r r a t i o n s up to 20% w i t h o u t any d e l e t e r i o u s e f f e c t s on growth, f e e d u t i l i z a t i o n and c a r c a s s q u a l i t y . However, t h y r o i d w e i g h t s o f the b i r d s i n c r e a s e d when 10% or more o f the seed was f e d . Cooking o f the f u l l - f a t Tower seed appeared t o have l i t t l e or no i n f l u e n c e on i t s n u t r i t i v e v a l u e . The performance o f s t a r t i n g - g r o w i n g t u r k e y p o u l t s f e d d i e t s c o n t a i n i n g 21.5% o f the a u t o c l a v e d f u l l - f a t Tower rapeseed was e q u i v a l e n t t o tho s e f e d soybean meal c o n t r o l . The good performance o f b r o i l e r c h i c k s and the t u r k e y p o u l t s on d i e t s c o n t a i n i n g the h i g h l e v e l s o f Tower rapeseed would suggest t h a t t h i s c u l t i v a r i s s u p e r i o r to h i g h g l u c o s i n o l a t e c u l t i v a r s . However, Tower rapeseed s t i l l produces some t h y r o i d enlargement (Rapeseed A s s o c . o f Canada, 1977). Summers (1974) r e p o r t e d t h a t u s i n g 20% o f RSM and 3% rapeseed o i l i n l a y e r s d i e t d i d not a f f e c t egg p r o d u c t i o n and egg q u a l i t y . Ten p e r c e n t rapeseed o i l reduced egg p r o d u c t i o n but had no adverse e f f e c t on egg q u a l i t y . In view o f Summers (1974) work, i t appears t h a t up t o 10% o f RSM can be used i n p r a c t i c a l l a y i n g 46. r a t i o n s c o n t a i n i n g 17% or p r o t e i n . A r e d u c t i o n i n egg p r o d u c t i o n was noted when 15% RSM was i n c l u d e d i n the l a y e r s d i e t . There was no i n d i c a t i o n t h a t performance c o u l d be improved by v a r i o u s amino a c i d a d d i t i o n s ( e s p e c i a l l y a r g i n i n e and m e t h i o n i n e ) to the d i e t (Summers, 1976). F u l l - f a t , cooked, Span rapeseed was i n c l u d e d i n l a y i n g r a t i o n s a t 5% w i t h o u t any d e l e t e r i o u s e f f e c t s . The l e v e l o f egg p r o d u c t i o n d e c r e a s e d and i n c i d e n c e o f hemorrhagic l i v e r syndrome i n c r e a s e d when the rap e s e e d was f e d a t h i g h e r l e v e l s (10-15%). However, the t r e a t m e n t s used had no e f f e c t on s i z e and p r o x i m a t e c o m p o s i t i o n o f the l i v e r s and h e a r t s o f the b i r d s . Egg q u a l i t y , f e e d c o n v e r s i o n and body w e i g h t s were not a f f e c t e d by any o f the t r e a t m e n t s , but a p r o g r e s s i v e i n c r e a s e i n t h y r o i d s i z e was noted as the l e v e l o f the rap e s e e d i n the r a t i o n was i n c r e a s e d (Rapeseed A s s o c . o f Canada, 1977). Rapeseed was f e d to s t a r t i n g and growing replacement p u l l e t s as the s o l e p r o t e i n supplement a t l e v e l s up t o 17% o f the d i e t w i t h o u t a d v e r s e l y a f f e c t i n g t h e subsequent r a t e o f egg p r o d u c t i o n or egg mass. An abrupt i n t r o d u c t i o n o f a h i g h l e v e l (19%) o f RSM i n the d i e t s o f l a y i n g b i r d s which had not p r e v i o u s l y been f e d the meal r e s u l t e d i n an immediate drop i n the r a t e o f egg p r o d u c t i o n . 47. F e e d i n g o f s i m i l a r d i e t s t o p u l l e t c h i c k s u n t i l s e x u a l m a t u r i t y demonstrated t h a t the t h y r o i d g l a n d i s permanently a f f e c t e d by e a r l y g o i t r o g e n i n t a k e but remains r e s p o n s i v e t o the t h y r o t r o p i n s t i m u l a t i o n (March, 1977) . The e f f e c t s o f f e e d i n g RSM on the t h y r o i d s i z e and h i s t o l o g y p e r s i s t e d a f t e r the b i r d s were s h i f t e d t o the soybean meal d i e t and f e d t h a t d i e t f o r 67 weeks. The l o n g term (91 weeks) f e e d i n g o f RSM a t h i g h l e v e l s (19.0-19.6%) r e s u l t e d i n c o n t i n u o u s i n c r e a s e i n the s i z e of the t h y r o i d g l a n d and d i s r u p t i o n o f the e p i t h e l i a l t i s s u e s . The t h y r o i d modi-f i c a t i o n o b s e r v e d i n the progency o f c h i c k e n s f e d the h i g h l e v e l o f RSM was r e l a t e d t o a low c o n c e n t r a t i o n o f i o d i n e i n the eggs. T h i s appears t o be caused by d i v e r s i o n o f a h i g h p r o p o r t i o n o f d i e t a r y i o d i n e i n t o the t h y r o i d g l a n d w i t h the r e s u l t t h a t amounts r e a c h i n g the d e v e l o p i n g ova were reduced (March and Leung, 1977). Span RSM was i n c l u d e d i n l a y i n g hen r a t i o n s a t l e v e l s up t o 7.5% w i t h o u t any adverse e f f e c t s on m o r t a l i t y o r r a t e o f egg p r o d u c t i o n . I n c r e a s i n g the d i e t a r y l e v e l o f Span RSM t o 10% had no e f f e c t s on the s i z e or g r o s s c o m p o s i t i o n o f l i v e r s and h e a r t s o f l a y i n g b i r d s , but d i d r e s u l t i n i n c r e a s e d t h y r o i d s i z e , and f e e d i n g f o r an extended time p e r i o d (6 months) produced changes i n the c o n n e c t i v e t i s s u e o f the l i v e r stroma such t h a t normal 48. i n t e g r i t y c o u l d not be m a i n t a i n e d and t h i s r e s u l t e d i n the f a m i l i a r hemorrhagic l i v e r syndrome. The i n c i d e n c e l e v e l o f l i v e r hemorrhage i n l a y i n g b i r d s was a s s o c i a t e d w i t h the d i e t a r y g l u c o s i n o l a t e c o n t e n t , the s t r a i n o f b i r d s u s e d , as w e l l as the p e r i o d o f time over which the meal was f e d . Tower RSM was f e d to l a y i n g hens a t l e v e l s up t o 12.7% w i t h o u t any d e l e t e r i o u s e f f e c t s on egg p r o d u c t i o n or m o r t a l i t y . T h i s may suggest t h a t the c u r r e n t recom-mended l e v e l o f 5% RSM i n the d i e t s f o r S i n g l e Comb White Leghorn hens c o u l d be d o u b l e d i n the case of Tower meal. However, t h e r e i s s t i l l a problem i n m a i n t a i n i n g egg s i z e when 10 t o 15% o f Tower meal i s i n c l u d e d i n l a y i n g hen d i e t s (Rapeseed A s s o c . o f Canada, 1977). F. P r o c e s s i n g The g l u c o s i n o l a t e s are o f p a r t i c u l a r i n t e r e s t i n the p r o c e s s i n g o f RSM f o r s e v e r a l reasons (Rapeseed As s o c . o f Canada, 1972): (1) I t i s i m p o r t a n t t o p r e v e n t the f o r m a t i o n o f u n d e s i r a b l e p r o d u c t s , o x a z o l i d i n e t h i o n e and i s o t h i o c y a n a t e s , from g l u c o s i n o l a t e s . T h i s i s 49. a c h i e v e d f b y the use o f heat t o d e s t r o y the enzyme, t h i o g l u c o s i d a s e , t h a t h y d r o l y s e s g l u c o s i n o l a t e s . (2) Gare must be t a k e n t h a t the te m p e r a t u r e s used (210°F-225°F) i n the p r o c e s s do not r e s u l t i n the c o m p l e x i n g o f p r o t e i n m o l e c u l e s t o o t h e r compounds, w i t h e v e n t u a l r e d u c t i o n i n the n u t r i t i o n a l a v a i l a b i l i t y o f amino a c i d s , e s p e c i a l l y l y s i n e . I t i s b e l i e v e d t h a t t h e s e f a c t o r s appear t o be more i m p o r t a n t t h a n the method used f o r o b t a i n i n g the o i l from the ra p e s e e d . D e s p i t e the r e c o g n i z e d d i f f e r e n c e s i n d i g e s t i b i l i t y and amino a c i d c o n t e n t , RSM supplemented t o p r a c t i c a l d i e t s has o f t e n r e s u l t e d i n performance e q u a l to t h a t o b t a i n e d w i t h soybean meal supplemented d i e t s , when the d i e t s were kept i s o n i t r o g e n o u s and i s o -c a l o r i c . T h i s r e q u i r e s a s l i g h t l y h i g h e r c o n t e n t o f RSM to meet the p r o t e i n l e v e l o f soybean meal, r e s u l t i n g i n h i g h e r crude f i b e r c o n t e n t and lower m e t a b o l i z a b l e energy v a l u e s . These drawbacks, may be o f f s e t by the i n c l u s i o n o f e x t r a f a t i n the d i e t o r by a p p r o p r i a t e s e l e c t i o n o f hi g h - e n e r g y c e r e a l g r a i n s (Rapeseed A s s o c . o f Canada, 1972). There i s e v i d e n c e t h a t i n t e s t i n a l m i c r o o r g a n i s m s can h y d r o l z e some o f the g l u c o s i n o l a t e s even though the 50. d i e t c o n t a i n s no t h i o g l u c o s i d a s e . T h e r e f o r e , i t i s o f utmost importance to p r e v e n t h y d r o l y s i s o f the g l u c o s i n o -l a t e s d u r i n g r a p e s e e d p r o c e s s i n g . As i t was s t u d i e d by Wetter and C r a i g (1959) the B. napus RSM i s d i s t i n g u i s h a b l e from the B. c a m p e s t r i s RSM by h i g h e r o x a z o l i d i n e t h i o n e c o n t e n t . P o l i s h - t y p e RSM c o n t a i n e d the h i g h e s t c o n t e n t o f the o t h e r g l u c o s i n o l a t e p r o d u c t . S o s u l s k i (1977) has attempted t o remove the g l u c o s i n o l a t e by d i l u t e a l k a l i e x t r a c t i o n s , u s i n g a s o l v e n t : seed r a t i o o f 3:1, i n two s t a g e s a t 80°C. F e e d i n g e x p e r i -ments w i t h r a t s r e v e a l e d t h a t the d i f f u s i o n e x t r a c t i o n had l i t t l e e f f e c t on the a v a i l a b i l i t y o f amino a c i d s i n Span meal, but i s o l a t i o n o f p r o t e i n s g e n e r a l l y improved the a v a i l a b i l i t y v a l u e by about 10%. G e n e t i c e n g i n e e r i n g i s another method which i s b e i n g u t i l i z e d to remove the u n d e s i r a b l e c h e m i c a l composi-t i o n o f RSM. In the German F e d e r a l R e p u b l i c , rapeseed v a r i e t i e s w i t h no e r u c i c a c i d have been de v e l o p e d t h r o u g h b r e e d i n g r e s e a r c h devoted to the removal o f t o x i c g l u c o -s i n o l a t e s . W i n t e r v a r i e t i e s w i t h l e s s t h a n 30 pmol/g d e f a t t e d seed may be a v a i l a b l e i n a few y e a r s . I t seems p o s s i b l e t h a t v a r i e t i e s r i c h i n p r o t e i n , o i l or b o t h may be produced and the f i b e r c o n t e n t may a l s o be d e c r e a s e d (Robbelem et a l . , 1980). 51. L a t e l y , Jones (1979) has developed the FRI-71 p r o c e s s i n g method wh i c h i s s i m i l a r t o a p r o c e s s by Ohlson (1973). He r e p o r t e d t h a t r apeseed p r o t e i n c o n c e n t r a t e s c o n t a i n i n g 65-70% p r o t e i n a re r e a d i l y o b t a i n e d when the f a t i s e f f i c i e n t l y e x t r a c t e d u s i n g t h i s method. T h i s water e x t r a c t i o n p r o c e s s removes over 90% o f the g l y c o -s i n o l a t e s and r e s u l t s i n a h i g h q u a l i t y p r o t e i n c o n c e n t r a t e . N u t r i t i o n a l e v a l u a t i o n work u s i n g the p r o t e i n e f f i c i e n c y r a t i o method has c o n s i s t e n t l y shown the rap e s e e d p r o t e i n c o n c e n t r a t e s t o be s u p e r i o r t o o t h e r o i l s e e d s and com-p a r a b l e or s u p e r i o r t o c a s e i n . 3. Buckwheat Buckwheat (Fagopyrum esculentum) i s not a c e r e a l (Gramineae) but a member o f the f a m i l y Polygonaceae. I t i s a summer a n n u a l , has a s h o r t growing season o f 10 to 12 weeks, and appears t o have a s p e c i a l c a p a c i t y t o grow i n c o o l c l i m a t e s under a wide range o f s o i l c o n d i t i o n s . I t can grow on s o i l s o f i n s u f f i c i e n t f e r t i l i t y w i t h economic y i e l d s ( F a r r e l l , 1976). L i k e the c e r e a l s , the g r a i n o f buckwheat i s a d r y f r u i t (Winton and Winton, 1947; M a r s h a l l , 1969). The b l a c k h u l l s o f the t r i a n g u l a r f r u i t are not s u i t e d - f o r m o n o g a s t r i c f e e d . S t r u c t u r a l l y , 52. .they have l i t t l e i n common w i t h b r a n c o a t s o f the c e r e a l s . The seed p r o p e r ( g r o a t ) i s s i m i l a r to t h a t o f c e r e a l s i n t h a t i t c o n s i s t s o f s t a r c h y endosperm and o i l y embryo (Pomeranz and R o b b i n s , 1972). A l t h o u g h more work i s r e q u i r e d to d etermine the most a p p r o p r i a t e supplement to buckwheat f o r optimum u t i l i -z a t i o n o f i t s p r o t e i n and energy by m o n o g a s t r i c a n i m a l s , i t does appear t o have p o t e n t i a l as b o t h a p r o t e i n and energy s o u r c e ( F a r r e l l , 1976). Buckwheat i s the second major component i n wheat s c r e e n i n g samples. A l t h o u g h buckwheat i s not c l a s s e d as a c e r e a l g r a i n , i t i s used i n t e r c h a n g e a b l y w i t h c e r e a l s i n l i v e s t o c k f e e d i n g programs. I t i s an e x c e l l e n t s o u r c e of l y s i n e (Lyman et a_l. , 1956) compared w i t h the c e r e a l g r a i n s . However, i t was s u g g ested by M o r r i s o n (1956) t h a t buckwheat i s w o r t h 10% l e s s than o a t s f o r l i v e s t o c k f e e d i n g v a l u e because o f i t s h i g h e r h u l l c o n t e n t . L i t t l e i n f o r m a t i o n i s a v a i l a b l e on the e f f e c t o f p r o c e s s i n g method on the n u t r i t i v e v a l u e o f buckwheat. M o r r i s o n (1956) r e p o r t e d t h a t i t s h o u l d be ground f o r a l l c l a s s e s o f s t o c k except p o u l t r y . There i s a s l i g h t l y problem n o t i c e d by c e r t a i n c l a s s o f a n i m a l when f e d buckwheat. M o r r i s o n (1949) r e p o r t e d t h a t o c c a s i o n a l l y , buckwheat g r a i n and the green 53. f o d d e r or s t r a w cause p e c u l i a r e r u p t i o n s and i n t e n s e i t c h i n g o f t h e s k i n . T h i s may be caused by the s k i n because o f p h o t o s e n s i t i z a t i o n caused by a f l u o r e s c e n t dye (McCollum et_ a_l. , 1939) . I t was a l s o r e p o r t e d t h a t o n l y the w h i t e or l i g h t - c o l o r e d p o r t i o n s o f the h i d e are a f f e c t e d . A. P r o t e i n The main o u t s t a n d i n g c h a r a c t e r i s t i c o f the buck-wheat p r o t e i n s i s the h i g h l y s i n e c o n t e n t (average o f 6.1%), which i s h i g h e r than i n any o f the c e r e a l g r a i n s . Among the c e r e a l s , oat p r o t e i n s are r i c h e s t i n l y s i n e a t 4.2% (Robbins e t al_. , 1973). Compared to c e r e a l g r a i n s , buckwheat p r o t e i n s c o n t a i n r e l a t i v e l y low c o n c e n t r a t i o n s o f g l u t a m i c a c i d and p r o l i n e , but are r i c h i n a r g i n i n e and a s p a r t i c a c i d . Assuming t h a t the source o f ammonia i s m a i n l y from g l u t a m i c and a s p a r t i c a c i d s , about 56% o f t hose amino a c i d s were i n the form o f amides; the c o r r e s -ponding v a l u e s were 85% i n wheat and 69% i n oat p r o t e i n s (Waggle et a l . , 1966; Robbins et_ al. , 1973). S t u d i e s o f Pomeranz and Robbins (1972) have shown t h a t none o f the amino a c i d s was s i g n i f i c a n t l y c o r r e l a t e d w i t h p r o t e i n c o n t e n t . Based on t h e i r f i n d i n g s Pomeranz and Robbins (1972) have s t a t e d t h a t i n c r e a s i n g p r o t e i n c o n t e n t p r o b a b l y does not i m p a i r the e x c e l l e n t amino a c i d p a t t e r n o f buckwheat p r o t e i n s , and t h a t p l a n t b r e e d i n g and c u l t u r a l p r a c t i c e s t o i n c r e a s e p r o t e i n c o n t e n t might not decrease the b i o l o g i c a l v a l u e o f buck-wheat. However, such d e c r e a s e s were obse r v e d i n wheat (Johnson e_t al_. , 1970) . B i e l y and Pomeranz (1975) have e v a l u a t e d the n u t r i t i v e v a l u e o f buckwheat u s i n g a l b i n o r a t s as an e x p e r i -mental a n i m a l . The r e s u l t o f t h e i r s t u d i e s have i n d i c a t e d t h a t buckwheat p r o v i d e d the b e s t source o f h i g h b i o l o g i c a l v a l u e p r o t e i n s i n the p l a n t kingdom (92.3% o f the v a l u e o f d r i e d n o n - f a t m i l k s o l i d s and 81.4% o f d r i e d whole egg). I t was a l s o r e p o r t e d t h a t buckwheat has enough l y s i n e f o r the growth o f c h i c k e n . Comparing the p r o t e i n q u a l i t y between the c u l t i v a t e d buckwheat and the w i l d buckwheat, i t was r e p o r t e d t h a t the l y s i n e c o n t e n t o f w i l d buckwheat was somewhat lower than t h a t o f the c u l t i v a t e d buckwheat. The d i f f e r e n c e s found w i t h the o t h e r e s s e n t i a l amino a c i d s i n p r o t e i n s o f w i l d and c u l t i v a t e d buckwheat were minor. F a r e l l (1976) a l s o d i d s i m i l a r work on buckwheat. H i s r e s u l t s have shown t h a t when buckwheat was f e d to r a t s w i t h o u t any p r o t e i n supplement, i t was always s u p e r i o r t o wheat and o a t s . The o n l y l i m i t i n g amino a c i d he has n o t i c e d was i s o l e u c i n e i n the growth o f w e a n l i n g r a t s . 55. In the case o f p i g s , buckwheat was not found t o be s u p e r i o r to wheat and f e e d c o n v e r s i o n r a t i o was s i g n i f i c a n t l y p o o r e r due to the lower d i g e s t i b l e energy c o n c e n t r a t i o n o f buckwheat. As i t i s s t a t e d e a r l i e r , i t i s the view o f s e v e r a l workers t h a t the p r o t e i n q u a l i t y o f buckwheat i s s u p e r i o r t o t h a t n o r m a l l y found i n the c e r e a l g r a i n s . However, the apparent d i g e s t i b i l i t y o f d r y m a t t e r n i t r o g e n and energy i s not as h i g h as found i n s e v e r a l o t h e r g r a i n s . T h i s can be e x p l a i n e d on the b a s i s o f f i b e r c o n t e n t , which i s p r o b a b l y a l a r g e component o f the h u l l s . N e v e r t h e l e s s , the p r o t e i n s o f buckwheat were shown to have e x c e l l e n t supplementary v a l u e to the c e r e a l g r a i n s ( S u r e , 1955; Wyld et al_. , 1958) . The c o n c e n t r a t i o n o f l y s i n e i n c r e a s e d as the c o n c e n t r a t i o n s o f h i s t i d i n e and a r g i n i n e i n c r e a s e d , and as g l u t a m i c a c i d d e c r e a s e d . H i s t i d i n e was p o s i t i v e l y c o r r e l a t e d w i t h a r g i n i n e and n e g a t i v e l y w i t h g l u t a m i c a c i d , i s o l e u c i n e , and l e u c i n e . N e g a t i v e c o r r e l a t i o n s were found between a r g i n i n e and a s p a r t i c a c i d , t h r e o n i n e , g l u t a m i c a c i d , g l y c i n e and a l a n i n e . C o n c e n t r a t i o n o f a s p a r t i c a c i d i n c r e a s e d as a l a n i n e i n c r e a s e d . T h r e o n i n e was c o r r e l a t e d p o s i t i v e l y w i t h s e r i n e , g l y c i n e , and a l a n i n e ; g l u t a m i c a c i d was c o r r e l a t e d w i t h g l y c i n e , a l a n i n e and p h e n y l a l a n i n e ; g l y c i n e was c o r r e l a t e d w i t h a l a n i n e and p h e n y l a l a n i n e ; and i s o l e u c i n e was c o r r e l a t e d w i t h l e u c i n e and v a l i n e (Pomeranz and R o b b i n s , 1972). C o r r e l a t i o n s among b a s i c amino a c i d s or among n e u t r a l and a c i d i c amino a c i d s were p o s i t i v e ; c o r r e l a t i o n s between b a s i c amino a c i d s , and a c i d i c or n e u t r a l amino a c i d s were n e g a t i v e . The r e s u l t s p o i n t to the p r e s e n c e of p r o t e i n s t h a t are c o n s i s t e n t l y r i c h i n amino a c i d s (Pomeranz and R o b b i n s , 1972). F u r t h e r m o r e , the g l u t a m i c a c i d c o n t e n t i n p r o t e i n s o f the wheat endosperm i s h i g h compared t o low l e v e l s i n the germ; the o p p o s i t e i s t r u e i n f r a c t i o n s o f buckwheat. The o n l y major s i m i l a r i t y between the germ o f wheat and buckwheat was t h a t b o t h c o n t a i n e d more a r g i n i n e t h a n the r e s p e c t i v e endosperms. The h i g h l y s i n e , r e l a t i v e l y low g l u t a m i c a c i d and p r o l i n e , and r e l a t i v e l y low ammonia c o n t e n t o f buckwheat h y d r o l y z a t e s c o n f i r m r e p o r t s on h i g h c o n c e n t r a t i o n s o f s o l u b l e p r o t e i n s . Such s o l u b l e p r o t e i n s are r i c h i n l y s i n e and may account f o r the e x c e l l e n t amino a c i d c o m p o s i t i o n o f buckwheat (Pomeranz and Ro b b i n s , 1972). Pomeranz and Robbins (1972) recommendations f o r m e a n i n g f u l and more r e l i a b l e method o f p r o t e i n e v a l u a -t i o n i s c a l c u l a t i n g the r a t i o o f s p e c i f i c e s s e n t i a l amino 57. a c i d s t o the sum o f the e s s e n t i a l amino a c i d s (A/TE). A comparison o f the A/TE r a t i o w i t h the e g g - r e f e r e n c e p a t t e r n y i e l d s a c h e m i c a l s c o r e which i n d i c a t e s the l i m i t i n g amino a c i d s ; the lower the v a l u e , the more l i m i t i n g the amino a c i d . Thus, i n wheat, l y s i n e , i s the f i r s t l i m i t i n g amino a c i d , the ne x t two are t h r e o n i n e and i s o l e u c i n e . In agreement w i t h f e e d i n g t e s t s o f Sure (1955) the c h e m i c a l amino a c i d assays o f Pomeranz and Robbins (1972) i n d i c a t e t h a t buckwheat has a b e t t e r b a l a n c e and b e t t e r p o t e n t i a l f o r s u p p l e m e n t i n g foods t h a n do c e r e a l g r a i n s . In c o n c l u s i o n , Pomeranz and Robbins (1972) do c r i t i c i z e the amino a c i d a n a l y s e s method f o r p r o t e i n q u a l i t y e v a l u a t i o n because t h i s method does not a s s e s s or measure one o f the most i m p o r t a n t parameters t h a t determine n u t r i t i v e v a l u e o f a f o o d , i t s d i g e s t i b i l i t y . "Chemical s c o r e s " s h o u l d be c o n s i d e r e d p r i m a r i l y as a p o w e r f u l and c o n v e n i e n t s c r e e n i n g t o o l . B. E f f e c t o f P r o c e s s i n g As d e b r a n n i n g o f c e r e a l g r a i n s (Pomeranz and MacMasters, 1970) d e h u l l i n g o f buckwheat i n c r e a s e d the p r o t e i n c o n t e n t . S i m i l a r l y , the dark f l o u r and buckwheat f e e d c o n t a i n e d more p r o t e i n , the l i g h t f l o u r l e s s , and 58 . h u l l s the l e a s t p r o t e i n among t h e m i l l i n g f r a c t i o n s (Pomeranz and Ro b b i n s , 1972). S i m i l a r r e s u l t s were a l s o r e p o r t e d by Coe (1931) . The amino a c i d p a t t e r n o f m i l l e d buckwheat f r a c t i o n s d i f f e r s from the p a t t e r n o f m i l l e d c e r e a l g r a i n s . In wheat, p r o t e i n s i n w h i t e f l o u r c o n t a i n sub-s t a n t i a l l y l e s s l y s i n e and i n dark f l o u r s l i g h t l y l e s s t han i n the whole k e r n e l . M i l l i n g wheat s h i f t s the c o n c e n t r a t i o n o f the main amino a c i d o f s t o r a g e p r o t e i n s . G l u t a m i c a c i d i n c r e a s e s from about 28.5% i n the whole k e r n e l t o 34.5% and 29.6% i n w h i t e and dark f l o u r s , r e s p e c t i v e l y . I t d e c r e a s e s t o 16.2% i n bran and to 14.0% i n germ. S i m i l a r changes t o those i n g l u t a m i c a c i d o c c u r i n p r o l i n e c o n t e n t o f wheat p r o d u c t s . However, m i l l e d buckwheat f r a c t i o n s d i f f e r e d l i t t l e i n amino a c i d composi-t i o n ; o n l y the h u l l s w hich are u n s u i t e d f o r m o n o g a s t r i c a n i m a l consumption d i f f e r e d i n amino a c i d c o m p o s i t i o n from t h a t i n the e d i b l e f r a c t i o n s . D e s p i t e i m p e r f e c t i o n s o f the m i l l i n g p r o c e s s , t h e r e are o n l y s m a l l d i f f e r e n c e s i n amino a c i d c o m p o s i t i o n o f p r o t e i n s among the t i s s u e s o f d e h u l l e d buckwheat g r o a t (Pomeranz and Robb i n s , 1972). 59. 4. Weed Seeds There i s l i t t l e work done r e g a r d i n g n u t r i t i o n a l e v a l u a t i o n o f weed seeds i n p o u l t r y d i e t nor i n any c l a s s o f l i v e s t o c k . R e g a r d i n g the p o t e n t i a l i t y o f weed seed to l i v e s t o c k f e e d H a r o l d and Nalewaja (1977) have s t a t e d t h a t i f weed seeds were removed from a l l s m a l l g r a i n s (as s c r e e n i n g s ) , t h i s would r e p r e s e n t o n l y 1% o f the c r o p h a r v e s t e d . There remains a c o n s i d e r a b l e p o t e n t i a l f o r the replacement o f g r a i n s i n l i v e s t o c k r a t i o n s and a l l o c a t i o n o f t h i s g r a i n t o a l t e r n a t e u s e s . Many weed seeds are i n a d v e r t e n t l y h a r v e s t e d d u r i n g the h a r v e s t o f s m a l l g r a i n c r o p s . T h i s contamina-t i o n o f g r a i n i s termed "dockage" and r e p r e s e n t s a p p r o x i -m a t e l y 1 t o 5% o f the g r a i n d e l i v e r e d t o c o u n t r y e l e v a t o r s ( H a r o l d and N a l e w a j a , 1977). Dockage l o s s e s i n Canada t o t a l l e d $43,000,000 i n 1954 and l o s s e s a s s o c i a t e d w i t h h a n d l i n g the dockage added another $6,000,000 ( C r a f t s and Robbi n s , 1962). Tkachuk and M e l l i s h (1976) have r e p o r t e d t h a t weed seeds a r e h i g h i n p r o t e i n and o i l c o n t e n t . F u r t h e r -more, i t was emphasized t h a t amino a c i d a n a l y s i s showed t h a t many weeds have an e x c e l l e n t e s s e n t i a l amino a c i d b a l a n c e and a h i g h e r c o n t e n t o f e s s e n t i a l amino a c i d s than do the commonly grown c e r e a l g r a i n s . 59a, Weed seeds most commonly p r e s e n t i n s c r e e n i n g s (dockage) from s m a l l g r a i n s i n most areas o f N o r t h America are w i l d buckwheat, green and y e l l o w f o x t a i l , and w i l d o a t s . Thus, the m i n e r a l and amino a c i d c o m p o s i t i o n o f t h e s e seeds are o f s i g n i f i c a n c e because o f t h e i r p r e -dominance i n s c r e e n i n g s ( H a r o l d and N a l e w a j a , 1977). A l t h o u g h weed seeds do c o n t a i n n u t r i t i o n a l l y v a l u a b l e n u t r i e n t s , some workers (Tkachuk and M e l l i s h , 1976) have i n d i c a t e d t h a t some weed seeds l i k e f l i x w e e d , s t i n k w e e d and f a l s e ragweed do c o n t a i n t o x i c s u b s t a n c e s and w i l l r e q u i r e p r o c e s s i n g b e f o r e they can be used f o r f o o d or f e e d . I I . MATERIALS AND METHODS Wheat f e e d s c r e e n i n g s s u b j e c t e d t o n u t r i t i o n a l e v a l u a t i o n were c o l l e c t e d from normal d e l i v e r i e s t o the l o c a l f e e d m a n u f a c t u r i n g i n d u s t r y d u r i n g a ten-week p e r i o d . D u p l i c a t e samples o f each wheat s c r e e n i n g were a n a l y z e d f o r gros s energy, crude p r o t e i n (% N x 6.25), e t h e r e x t r a c t , crude f i b e r , t o t a l ash and d r y m a t t e r c o n t e n t (A.O.A.C., 1965). A l l a n a l y t i c a l r e s u l t s were e x p r e s s e d on a d r y m a t t e r b a s i s . The e x p e r i m e n t a l arrangement i s d e s c r i b e d under each t r i a l l i s t e d below. Data were s u b j e c t e d t o a n a l y s i s of v a r i a n c e (Snedecor, 1956) and d i f f e r e n c e s among means de t e r m i n e d by m u l t i p l e range t e s t (Duncan, 1955) . A. Amino A c i d A v a i l a b i l i t y Study The b r o i l e r c h i c k s (3 weeks o l d ) u t i l i z e d f o r the amino a c i d a v a i l a b i l i t y s t u d y were u n i f o r m i n s i z e and were housed i n s t a i n l e s s s t e e l t h e r m o s t a t i c a l l y c o n t o T l e d m e t a b o l i s m cages. The e x p e r i m e n t a l arrangement was a c o m p l e t e l y randomized d e s i g n i n v o l v i n g e l e v e n e x p e r i m e n t a l d i e t s f e d t o f o u r r e p l i c a t e groups of f o u r c h i c k s each. The f e e d i n g t r i a l and a n a l y s i s were c a r r i e d out a c c o r d i n g to the p r o c e d u r e of Bragg e t a l _ . (1969) . The method i n c l u d e d a n a l y s i s of endogenous amino a c i d s e x c r e t e d by the c h i c k . The amount of endogenous amino a c i d s was s i g n i f i c a n t and c o r r e c t i o n f o r t h i s f a c t o r was n e c e s s a r y i n a v a i l a b i l i t y c a l c u l a t i o n s t o d i s t i n g u i s h c l e a r l y a v a i l a b i l i t y from apparent d i g e s t i b i l i t y . T e s t c h i c k s were f e d commercial s t a r t e r d i e t s t o t h r e e weeks of age. At the b e g i n n i n g of the t e s t , they were s u p p l i e d w i t h s t a r t e r f e e d c o n t a i n i n g 0.3% f e r r i c o x i d e marker f o r f o u r h o u r s , f a s t e d f o r s i x t e e n hours and f e d a s y n t h e t i c d i e t (Table 1) f o r a f o u r hour p e r i o d . They were s u b s e q u e n t l y f a s t e d f o r two hours and r e t u r n e d t o the s t a r t e r r a t i o n c o n t a i n i n g the marker. Feces from the c h i c k s s u b j e c t e d t o the s y n t h e t i c d i e t were c o l l e c t e d (Unmarked f e c e s ) . The n e x t day, the same pr o c e d u r e was r e p e a t e d , except t h a t the t e s t d i e t (Table 2) r e p l a c e d the s y n t h e t i c d i e t . Dry m a t t e r consumption and f e c a l d r y m a t t e r o u t p u t d u r i n g the experiment were r e c o r d e d . Amino a c i d s i n e l e v e n ( d i e t ) d i f f e r e n t wheat s c r e e n i n g samples ( i n c l u d i n g the c o n t r o l d i e t ) and f e c e s c o l l e c t e d from each sample under t e s t were determined by amino a c i d a n a l y s i s (Moore e t a l . , 1958) f o l l o w i n g h y d r o l y s i s w i t h 3N HC1 f o r f i f t e e n hours a t 121°C. Table 1. Composition of synthetic (purified) diet Ingredients g/kg (D. M.) Sucrose 810.17 Cellulose* 89.83 Corn oil 100.00 *Cel1u-f1 our , Nutritional Biochemical Corporation, Cleveland, Ohio. 63. B. Metabolizable Energy Study Metabolizable energy (ME) of wheat screenings was determined using three-week-old b r o i l e r c h i c k s . There were four r e p l i c a t e s of four c h i c k s each per treatment. The t e s t d i e t s contained wheat screening at a l e v e l of 61% i n s u b s t i t u t i o n f o r an equal amount of the d i e t a r y wheat (Table 2). The assay p e r i o d was f i v e days and sampling of the excreta and feed was i n the l a s t two days of the experiment. A l l samples of feed and feces were composited and subsampled f o r a n a l y s i s . Feed consumption and excreta output were determined by the a c i d i n s o l u b l e ash method of Vogtmann e_t al_. (1975) . Gross energy and n i t r o g e n content of feed and feces were determined (A.O.A.C., 1965). The excreta were frozen and l y o p h i l i z e d p r i o r to a n a l y s i s . Nitrogen r e t e n t i o n was determined and ME values were c a l c u l a t e d w i t h a c o r r e c t i o n of 8.22 Kcal/kg n i t r o g e n r e t a i n e d ( H i l l and Anderson, 1958). C. C h e m i c a l E l e m e n t S t u d y U t i l i z a t i o n of calcium, phosphorus, magnesium, manganese, zinc and copper from wheat feed screenings was studied with three-week-old b r o i l e r c h i c k s . There were four r e p l i c a t e s (four chicks each) per d i e t a r y treatment. Table 2. C o m p o s i t i o n o f e x p e r i m e n t a l d i e t I n g r e d i e n t s Wheat S c r e e n i n g s C o n t r o l % Wheat 61.0 -Wheat s c r e e n i n g s - 61.0 Soybean meal (48.5% p r o t e i n ) 25.0 25.0 Meat meal (501 p r o t e i n ) 6.5 6.5 An i m a l t a l l o w 6.0 6.0 Limestone 0 . 5 0.5 Premix* 1.0 1.0 1 - V i t a m i n p r emix s u p p l i e d p e r kg of d i e t : V i t a m i n A, 11,000 I.U.; V i t a m i n D 3, 880 I.C.U.; V i t a m i n E, 10 I.U.; V i t a m i n K, 2.2 mg;' V i t a m i n B -j 2 > 13.2 meg; . . R i b o f l a v i n , 6.6 mg; ICapantothenate, 24.2 mg; N i a c i n , 36.2 mg, B i o t i n , 0.04 mg; C h o l i n e C h l o r i d e , 500 mg. 2 - M i n e r a l premix s u p p l i e d p e r kg o f d i e t : N a C l , 3.52 g; Mn, 86 mg; Zn,.49 mg; Cu, 7.7 mg. T e s t b i r d s were f e d a s t a r t e r d i e t c o n t a i n i n g known n u t r i t i o n a l r e q u i r e m e n t s from one day to 21 days of age. C h i c k s were m a i n t a i n e d i n a b a t t e r y b r o o d e r d u r i n g the f i r s t 21 days and, t h e r e a f t e r , groups of f o u r b i r d s of:.u'niform s i z e were t r a n s f e r r e d t o me t a b o l i s m cages. On the 22nd day of age, a l l c h i c k s were s u p p l i e d w i t h f e e d ( s t a r t e r d i e t ) c o n t a i n i n g 0.3% f e r r i c o x i d e marker f o r f o u r h o u r s . A f t e r s i x t e e n hours of f a s t i n g , on the 23rd day, a s y n t h e t i c d i e t (Table 1) was f e d f o r f o u r h o u r s . Feces from c h i c k s on the s y n t h e t i c d i e t were c o l l e c t e d and the amount of f e e d consumed was r e c o r d e d . Once a g a i n , the s t a r t e r d i e t c o n t a i n i n g the marker was f e d f o r f o u r h o u r s . On the 24th day of age, the same p r o c e d u r e was r e p e a t e d except t h a t the t e s t f e e d (Table 2) r e p l a c e d the s y n t h e t i c d i e t . Feed consumption and f e c e s c o l l e c t i o n p r o c e d u r e were the same. T o t a l m a r k e r - f r e e f e c e s were c o l l e c t e d and the f e c e s were d r i e d a t 85°C f o r 24 h o u r s . The f o l l o w i n g samples were a n a l y z e d f o r t h e i r c h e m i c a l element c o n t e n t : the s y n t h e t i c d i e t , e x p e r i m e n t a l d i e t s , the wheat f e e d s c r e e n i n g s and the f e c e s from c h i c k s on the e x p e r i m e n t a l d i e t s . The d e t e r m i n a t i o n s were made u s i n g a t o m i c a b s o r p t i o n s p e c t r o p h o t o m e t r y f o l l o w i n g a low temperature d r y a s h i n g a t 450°C i n the m u f f l e f u r n a c e f o r 36 h o u r s . The phosphorus, as w e l l a s , o t h e r m i n e r a l s can 66. be d e t e r m i n e d from the ash sample. The a n a l y t i c a l method used i n t h i s s t u d y was as d e s c r i b e d i n "The a n a l y s i s o f A g r i c u l t u r a l M a t e r i a l s " ( M i n i s t r y o f A g r i c u l t u r e , F i s h e r i e s and Food, U.K., 1973). C a l c i u m , magnesium, manganese, z i n c and copper were de t e r m i n e d by the use o f a J a r r e l Ash atomic a b s o r p t i o n s p e c t r o p h o t o m e t e r . Lanthanium o x i d e (0.5% v/w) was r e q u i r e d i n the t e s t s o l u t i o n t o reduce the i n t e r -f e r e n c e from phosphorus when c a l c i u m and magnesium were a n a l y z e d . Phosphorus was det e r m i n e d by a Unicam SP1800 U l t r a v i o l e t S p e c t r o p h o t o m e t e r f o l l o w i n g c o l o r development w i t h ammonium molybdate. M i n e r a l c o n t e n t o f a l l samples was ex p r e s s e d on a d r y m a t t e r b a s i s . The f o l l o w i n g f o r m u l a was used to c a l c u l a t e the p e r c e n t m i n e r a l a v a i l a b i l i t y f o l l o w i n g a n a l y s i s o f f e e d and e x c r e t a : TCEI -" (TFCEE - EFME) P e r c e n t c h e m i c a l element a v a i l a b i l i t y = ------ „^„T J—: -— x 100 TCEI where TCEI = T o t a l Chemical Element Intake from ingredient (experimental diet) TFCEE. = T o t a l F e c a l Chemical Element Excreted EFME = Endogenous F e c a l Chemical Element Excreted (synthetic) or p u r i f i e d d i e t e x c r e t a ) . 67. D. r e e d i n g T r i a l The t r i a l arrangement was a c o m p l e t e l y randomized d e s i g n i n v o l v i n g e l e v e n e x p e r i m e n t a l d i e t s ( i n c l u d i n g c o n t r o l d i e t w hich was a s t a n d a r d wheat - Table 2 ) . Each d i e t was f e d t o t h r e e r e p l i c a t e groups o f t e n a day. old b r o i l e r c h i c k s . C h i c k s o f u n i f o r m s i z e were housed i n s t a i n l e s s s t e e l b a t t e r y b r o o d e r s . Feed and water were p r o v i d e d ad l i b i t u m i n s t a i n l e s s s t e e l f e e d e r s and w a t e r e r s . Test and c o n t r o l d i e t s were a p p r o x i m a t e l y i s o c a l o r i c and i s o n i t r o g e n o u s . Growth r a t e and f e e d c o n v e r s i o n r a t i o were c a l c u l a t e d and b i r d s were examined d a i l y f o r s i g n s o f i l l - h e a l t h . I I I . RESULTS AND DISCUSSION A. B o t a n i c a l C o m p o s i t i o n The n u t r i t i v e v a l u e o f wheat f e e d s c r e e n i n g s (WFS) was d e t e r m i n e d u s i n g t e n d i f f e r e n t samples. The b o t a n i c a l c o m p o s i t i o n o f the wheat f e e d s c r e e n i n g samples i s p r e s e n t e d i n T a b l e 3. The h i g h e s t p e r c e n t a g e among b o t a n i c a l components was wheat (Ave. 76%). The second h i g h e s t was w i l d buckwheat (Ave. 1 2 % ) ; whereas, the lowest were f l a x and oat h a v i n g an average o f 0.22% and 0.28%, r e s p e c t i v e l y . The n u t r i t i o n a l c o n t r i b u t i o n of both f l a x and o a t s w i t h such m i n i m a l amounts presumably would be small. The percent• botanical, c o m p o s i t i o n o f b a r l e y and rapeseed was the same.at about 4%. Farm weeds (1.5%) were the t h i r d l o w e s t i n the b o t a n i c a l c o m p o s i t i o n . Under the Canada Feeds A c t (1967), No. 1 f e e d s c r e e n i n g s s h a l l c o n t a i n : (a) hot l e s s than 35% broken or shrunken g r a i n or b o t h , (b) not more than 7% of crude f i b e r , (c) not more than 3% o f s m a l l weed seeds, c h a f f , h u l l s and d u s t , Table 3. B o t a n i c a l c o m p o s i t i o n of wheat f e e d s c r e e n i n g s ( P e r c e n t ) Sample Cracked ~-wheat Cracked b a r l e y Rapeseed F l a x seed Oats W i l d Buckwheat Farm weeds cl M i s c e l l a n e o u s 1 82.4 5.6 1.9 0.1 0.3 9.4 0 .1 0.3 2 72.0 6.9 5.2 - - 12.8 1.6 1.5 3 75.3 3.6 3.9 0.2 - 13.8 0.8 2.4 4 78.4 1.2 6.5 0.3 0.5 10.4 1.6 1.2 5 74.3 7 .1 1.4 0.1 0.4 14.1 1.7 0.9 6 76.9 - 7.2 0.2 0.3 11.1 2.5 1.8 7 73.9 3.1 5 .1 0.4 0.3 12 . 8 1.6 2 . 8 8 76.2 2.7 3.7 0.4 0.4 12.6 2.2 1.9 9 73.9 3.7 3.1 0.3 0.4 14.5 2.4 0.7 10 80.1 5.5 1.5 0.2 0.2 11.3 0.7 0.7 Means 76.3 3.9 4.0 0.2 0 . 3 12.3 1 .5 1 .4 Straw, seed c o a t s , r o c k s , dust,- e t c . (d) not more than 6% s m a l l weed seeds, c h a f f , h u l l s , d u s t , w i l d and domestic mustard, and r a p e s e e d , (e) not more than 8% w i l d o a t s , and ( f ) w i l d buckwheat and s m a l l p o r t i o n s o f o t h e r seeds of l e s s v a l u e . Based on the above s t a t e d grade d e f i n i t i o n , a l l t e n wheat f e e d s c r e e n i n g s samples which were u t i l i z e d i n t h i s p r o j e c t s a t i s f y the s t a n d a r d o f number one f e e d wheat s c r e e n i n g s . B. Chemical A n a l y s i s The c h e m i c a l a n a l y s i s o f f e e d wheat s c r e e n i n g s i s shown i n T a b l e 4. I t shows t h a t wheat f e e d s c r e e n i n g s have an average p r o t e i n c o n t e n t o f about 14% and 4431 c a l o r i e s per gram. R e g a r d i n g the p r o t e i n q u a l i t y , i t has been r e p o r t e d by Tkachuk and M e l l i s h (1977) t h a t many weeds have an e x c e l l e n t amino a c i d b a l a n c e and a l s o h i g h e r c o n t e n t o f e s s e n t i a l amino a c i d s than do commonly grown c e r e a l s . Based on t h i s i n f o r m a t i o n , w i l d buckwheat was the second major component o f s c r e e n i n g s (Table 3) assumed t o be a p o t e n t i a l c o n t r i b u t o r t o the improvement of the p r o t e i n q u a l i t y , d e s p i t e i t s h i g h e r f i b e r c o n t e n t . I t was a l s o r e p o r t e d by Sure (1955) t h a t buckwheat has a h i g h b i o l o g i c a l v a l u e f o r p r o t e i n s i n Table 4. Chemical a n a l y s i s of wheat f e e d s c r e e n i n g s (dry m atter b a s i s ) . S c r e e n i n g Dry Crude Crude E t h e r sample matter p r o t e i n f i b e r e x t r a c t Ash C a l o r i e s / g 1 85.0 13. 8 2.2 3.1 2.4 4332 2 85.2 14.1 2.5 5.2 2.9 4473 • 3 85. 2 13. 8 3.4 4.0 2.2 4433 4 85.1 13. 7 2.7 5.5 2.6 4496 5 84.4 14.1 3.3 3.7 2 . 2 4322 6 85.2 13.0 3.8 6.1 2.6 4464 7 84. 3 13. 8 2.7 5.7 3.0 4510 8 84.0 12.9 4.4 4.6 2.9 4458 9 84.1 14. 2 2.5 5.0 3.2 4434 10 84.1 13.7 4.2 3.3 2.1 4390 Means 84. 7 13. 7 3.2 4.6 2.6 4431 the p l a n t kingdom (92.3% o f the v a l u e o f d r i e d n o n - f a t m i l k s o l i d s and 81.4% o f d r i e d whole egg). R e s u l t s are s i m i l a r t o the work o f S t a p l e t o n e_t a l . (1980) i n which a c l o s e r e l a t i o n s h i p was shown between the e t h e r e x t r a c t and f i b e r c o n t e n t s i n most s c r e e n i n g : s a m p l e s . The ash c o n t e n t o f s c r e e n i n g s appears u n i f o r m among s c r e e n i n g samples w i t h the average b e i n g 2.6% (Table 4 ) . The ash c o n t e n t o f wheat i s 1.4% ( S t a p l e t o n e t al_. , 19 80) which i s c o n s i d e r a b l y lower t h a n s c r e e n i n g s . From the study o f H a r o l d and Nalewaja (1977) i t was shown t h a t weed seeds had a h i g h m i n e r a l c o n t e n t . T h e r e f o r e , the h i g h ash c o n t e n t o f s c r e e n i n g s (as compared to wheat) may be due, i n p a r t , to the weed seeds. C. M e t a b o l i z a b l e Energy The g r o s s energy and m e t a b o l i z a b l e energy (ME) v a l u e s o f the e x p e r i m e n t a l d i e t s are shown i n Table 6 and range from 5008 t o 5179 k c a l / k g and from 3197 t o 4065 k c a l / k g , r e s p e c t i v e l y . The ME v a l u e s o b t a i n e d w i t h a l l e x p e r i m e n t a l d i e t s are s i g n i f i c a n t l y h i g h e r (P > 0.05) than the c o n t r o l d i e t . D i e t 2 shows the h i g h e s t ME v a l u e o f any d i e t t e s t e d i n t h i s s t u d y . The h i g h ME v a l u e o f d i e t 2 i s a r e f l e c t i o n o f i t s h i g h e t h e r e x t r a c t , p r o t e i n and g r o s s energy v a l u e Table 5. Chemical a n a l y s i s of e x p e r i m e n t a l d i e t (dry m a t t e r b a s i s ) . Dry Crude Crude E t h e r D i e t m a tter p r o t e i n f i b e r e x t r a c t Ash 1 85.6 22.2 ,4.0 10.8 6.7 2 87.4 22.7 3.6 12.0 5.7 3 88.1 22.8 5.6 11 .4 6.6 4 85.8 22.7 4.0 12.3 5.6 5 86.4 23.2 4.5 10.9 5.9 6 87.5 22.1 4.1 12.1 5.6 7 86.0 23.0 4.1 11.2 6.1 8 86. 5 22.9 3.6 1 1 .0 5.2 9 87.1 22.5 4.2 10.8 5.7 10 88.1 23.5 4.0 10.4 6.0 11 * 85.1 21.0 4.7 10.1 5.7 Means-- ... .86,7 - 2 2.6 4.1 .11 • 1 5.9 * C o n t r o l d i e t (Table 5 ) . However, such a r e f l e c t i o n does not h o l d t r u e f o r d i e t 6. The h i g h e t h e r e x t r a c t and gross c a l o r i e v a l u e (Table 5) of d i e t 4 was a r e a s o n a b l e p a r a l l e l t o i t s h i g h ME v a l u e . D i e t 9 was the lo w e s t among e x p e r i m e n t a l d i e t s i n ME v a l u e f o l l o w e d by d i e t 1 i n d i c a t i n g lower a v a i l a b l e energy. A g a i n , the low ME v a l u e o f d i e t s 9 and 1 c o r r e s p o n d t o the low v a l u e s o f e t h e r e x t r a c t and g r o s s c a l o r i e s , e s p e c i a l l y i n the case of d i e t 1. There were p o s i t i v e r e l a t i o n s h i p ' between the gross energy and the m e t a b o l i z a b l e energy o f the e x p e r i m e n t a l d i e t s . However, an i n v e r s e r e l a t i o n s h i p between the crude f i b e r c o n t e n t ( T a b l e s 5 § 6) and m e t a b o l i z a b l e energy was observed. The c o n t e n t o f crude p r o t e i n appears t o improve gros s energy but a v a i l a b l e energy was v a r i a b l e among the h i g h e r p r o t e i n l e v e l s . T h e r e f o r e , i t appears t h a t energy components and crude f i b e r account f o r most of the d i f f e r e n c e s between the ME o f the e x p e r i m e n t a l d i e t s . P r e v i o u s workers ( C a r p e n t e r and C l e g g , 1956; Davidson e t i l l . , 1961) r e c o g n i z e d the need f o r a r a p i d assay c a p a b l e o f measuring a v a i l a b l e energy and d e r i v e d e q u a t i o n s f o r p r e d i c t i n g m e t a b o l i z a b l e energy from c h e m i c a l c o m p o s i t i o n o f f e e d s t u f f s . The e q u a t i o n of C a r p e n t e r and Clegg (1956), c o n f i r m e d by S i b b a l d e t a l . (1963) as c a p a b l e o f p r e d i c t i n g m e t a b o l i z a b l e energy w i t h s u f f i c i e n t p r e c i s i o n . However, Table 6. Gross and m e t a b o l i z a b l e energy of e x p e r i m e n t a l d i e t (dry m a t t e r b a s i s ) . D ^ e t s Gross energy M e t a b o l i z a b l e * ( k c a l / k g ) energy ( k c a l / k g ) 1 5070 3 2 3 9 d r 2 5152 4065 b 3 5171 cd 3 7 6 8 C Q 4 5171 3811 C 5 5008 3 5 4 3 d 6 5179 3626 d 7 5110 cd 3 4 7 3 C Q 8 5130 3 5 6 1 d 9 5153 3197 a 10 5178 3 6 7 8 c d 11 * * 4626 2525 e Average 5076 3485 * V a l u e s b e a r i n g the same l e t t e r are not s i g n i f i c a n t l y (P < 0.05); d i f f e r e n t ** C o n t r o l d i e t t h e i r ME p r e d i c t i n g e q u a t i o n does not seem t o be a r e l i a b l e t o o l f o r e v a l u a t i n g a l l f e e d s t u f f s . I t was r e p o r t e d by Nwokolo (1977) t h a t o n l y the ME of c o t t o n s e e d meal was p r e d i c t e d w i t h any degree o f a c c u r a c y compared t o soybean, c o t t o n s e e d and palm k e r n e l meals. Fu r t h e r m o r e , Nwokolo and Bragg (1977) d e v e l o p e d an e q u a t i o n f o r rapeseed meal a f t e r o b s e r v i n g l i m i t e d e f f e c t i v e n e s s o f a s i n g l e e q u a t i o n f o r many f e e d s t u f f s due t o v a r i a t i o n i n c h e m i c a l c o m p o s i t i o n . C a r p e n t e r and Clegg (1956) u t i l i z e d m a i n l y c e r e a l s and c e r e a l b y - p r o d u c t s i n d e r i v i n g t h e i r e q u a t i o n . These i n g r e d i e n t s have an e x t r e m e l y h i g h c o n t e n t o f s t a r c h and w i t h the e x c e p t i o n o f o a t s , a f a i r l y low c o n t e n t o f crude f i b e r as compared to most c e r e a l g r a i n s . Such a p r e d i c t i v e e q u a t i o n cannot be a p p l i e d t o a l l c l a s s e s o f f e e d i n g r e d i e n t s , e s p e c i a l l y t o compounded i n g r e d i e n t s (wheat f e e d s c r e e n i n g s ) , w i t h a r e s p e c t a b l e degree o f a c c u r a c y . T h e r e f o r e , a p r e d i c t i v e e q u a t i o n has not m a t e r i a l i z e d i n t h i s s t u d y . D. Body Weight Gai n The replacement o f wheat ( c o n t r o l d i e t ) w i t h wheat f e e d s c r e e n i n g s i n b r o i l e r r a t i o n s r e s u l t e d i n s t a t i s t i c a l l y s i g n i f i c a n t g a i n s i n body weight of the c h i c k s (Table 7 ) . E x c e p t i o n s were observed w i t h d i e t s 1 and 6, which were not 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) from the c o n t r o l d i e t Table 7. Average body weight f e e d consumption and f e e d e f f i c i e n c y o f b r o i l e r c h i c k s a t f o u r weeks of age. Body weight Feed e f f i c i e n c y D i e t g a i n p e r Feed consumption r a t i o ( f e e d b i r d (g) per b i r d (g) consumed/gain) 1 8 6 0 a b c 1 3 6 3 a b c 1 .58 a 2 8 8 5 b c 1 3 8 8 a b c d 1 .57 a 3 8 9 4 b c 14 85 cd 1 .61 b 4 87 7 b c 1 3 5 5 a b ' 1 .55 a 5 91 2 C 1 4 1 3 bed 1 .55 a 6 81 9 a b 1 3 3 0 a b 1 .62 b 7 9 0 5 c 1424 b c d 1 .57 a 8 he 8 8 6 D C 1432 : b t d 1 .62 b 9 be 8 7 2 D C 1419 b c d 1 .63 b 10 9 2 6 C 1 499 d "• 1 .57 a 11* 7 8 7 a 1 2 8 5 a 1 .63 b Average 875 1399 1 .59 Means w i t h i n columns w i t h d i f f e r e n t l e t t e r s are s t a t i s -t i c a l l y s i g n i f i c a n t l y d i f f e r e n t from one another (P < 0.0 5 ) . * C o n t r o l d i e t ( d i e t 11). The low f a t c o n t e n t of wheat f e e d s c r e e n i n g o f sample no. 1 (Table 4) was shown as p a r t of the e f f e c t on the lower body weight (Table 7 ) . In g e n e r a l , the body we i g h t was improved w i t h wheat s c r e e n i n g s which appears t o be a f f e c t e d by the h i g h e r ME v a l u e s o f these d i e t s . I t was observ e d e a r l i e r by S t a p l e t o n e t al_. , 1980, t h a t when d i e t s c o n t a i n i n g e i t h e r wheat or wheat f e e d s c r e e n i n g s were made t o c o n t a i n the same f a t l e v e l s , no s i g n i f i c a n t d i f f e r e n c e was observed i n f i n a l body w e i g h t s at f o u r weeks i n the f e e d e f f i c i e n c y r a t i o s . In f e e d consumption, t h e r e was no s t a t i s t i c a l l y s i g n i f i c a n t d i f f e r e n c e between d i e t s 1, 2, 4, 6 and the c o n t r o l d i e t (11) . A l l the r e s t of the e x p e r i m e n t a l d i e t s were s i g n i f i c a n t l y (P > 0.05) h i g h e r i n f e e d consumption than the c o n t r o l d i e t . A l t h o u g h d i e t s 1, 2, 4 and 6 were not s i g n i f i c a n t l y (P > 0.05) h i g h e r than the c o n t r o l d i e t , h i g h e r n u m e r i c a l v a l u e i n consumption was obs e r v e d ; o t h e r w i s e , the r e s t o f the d i e t s showed more or l e s s a u n i f o r m f e e d consumption (Table 7 ) . High f e e d consumption o f d i e t 10 does show a p a r a l l e l match t o h i g h f e e d e f f i c i e n c y r a t i o and h i g h body weight g a i n . Gross energy, as w e l l a s , m e t a b o l i z a b l e energy v a l u e s o f d i e t 10 were s i g n i f i c a n t l y (P > 0.05) h i g h e r i n comparison t o o t h e r d i e t s . D i e t 10 i n c l u d e s wheat f e e d s c r e e n i n g sample no. 10. There was no s p e c i f i c n u t r i e n t component s u p e r i o r i t y t h a t can be observed i n t h i s p a r t i c u l a r sample from the c h e m i c a l a n a l y s i s o f the wheat f e e d s c r e e n i n g s . In f a c t , the crude f i b e r c o n t e n t was the second h i g h e s t whereas the e t h e r e x t r a c t v a l u e was next t o the l o w e s t among wheat f e e d s c r e e n i n g samples t h a t were t e s t e d i n t h i s s t u d y (Table 4 ) . The b o t a n i c a l c o m p o s i t i o n o f wheat f e e d s c r e e n i n g s (Table 3) shows t h a t sample no. 10 has 80, 11 and 1 p e r c e n t o f wheat, w i l d buckwheat and r a p e s e e d , r e s p e c t i v e l y . Based on t h e s e f i g u r e s , i t i s o b v i o u s t h a t wheat i s the major energy s o u r c e . On the o t h e r hand, buckwheat i s b e l i e v e d t o be an e x c e l l e n t source o f l y s i n e i n which o t h e r i n g r e d i e n t s are d e f i c i e n t (Lynan, e t a l . , 1956). Robbins e t a l . (1973) r e p o r t the average c o n t e n t o f l y s i n e as 6.1%. Moreover, the r e s u l t o f s t u d i e s by B i e l y and Pomeranz (1975) i n d i c a t e d t h a t buckwheat p r o v i d e s the b e s t source o f high, b i o l o g i c a l v a l u e p r o t e i n s i n the p l a n t kingdom (92.3% o f the v a l u e o f d r i e d n o n - f a t m i l k s o l i d s and 81.4% o f d r i e d whole egg). In t h i s r e g a r d , buckwheat may p l a y an i m p o r t a n t r o l e i n p r o v i d i n g the c r u c i a l e s s e n t i a l amino a c i d ( l y s i n e ) at s a t i s f a c t o r y l e v e l s f o r e f f i c i e n t t i s s u e p r o t e i n s y n t h e s i s t o promote growth. W i t h . r e g a r d t o r a p e s e e d , the low l e v e l would c o n t r i b u t e a b e n e f i c i a l e f f e c t f o r e f f i c i e n t n u t r i e n t u t i l i z a t i o n . The type o f rapeseed p r e s e n t i n the samples was raw and u n p r o c e s s e d o f which the l e v e l o f g l u c o s i n o l a t e s (a f a m i l y compound) might be h i g h enough t o cause m e t a b o l i c d i s o r d e r . I t was r e p o r t e d by M i l l e r and B i e l y (1978) t h a t when the seed i s c r u s h e d i n the presence o f m o i s t u r e , the enzyme t h i o g l u c o s i d a s e h y d r o l y s e s the g l u c o s i n o l a t e s p r e s e n t t o r e l e a s e g l u c o s e , i n o r g a n i c s u l p h a t e and a group o f t o x i c o r g a n i c compounds. One o f the s e compounds, o x a z o l i d i n e t h i o n e , was found to be g o i t r o g e n i c , i n t e r f e r i n g w i t h the p r o d u c t i o n o f the m e t a b o l i c hormone t h y r o x i n e and r e s u l t i n g i n i m p a i r e d growth and r e p r o d u c t i v e performance. Such t o x i c c h e m i c a l s u b s t a n c e s ( o x a z o l i d i n e t h i o n e ) would have been p r e s e n t i n n e g l i g i b l e amounts t o cause a m e t a b o l i c d i s o r d e r due t o v e r y low amounts of rapeseed i n d i e t 10 which as a r e s u l t a t t r i b u t e d h i g h f e e d consumption f o r d i e t s 3, 5, 7, 8, 9 and 10. The h i g h f e e d consumption l e d t o i n c r e a s e d t o t a l p r o t e i n and energy i n t a k e and r e t e n t i o n ; t h e r e f o r e , t o h i g h e r average d a i l y g a i n . Moreover, d i e t 10 was h i g h e r (P * 0.05) i n f e e d e f f i c i e n c y r a t i o than the r e s t o f the d i e t s . The average f e e d e f f i c i e n c y showed an e x c e l l e n t f e e d c o n v e r s i o n r a t i o w i t h 1.59 gm o f f e e d per gram o f body w e i g h t . The f e e d e f f i c i e n c y r a t i o was g r e a t l y a f f e c t e d by the growth r a t e o f b i r d s f e d d i f f e r e n t wheat s c r e e n i n g d i e t s . 81. The c o n t r o l d i e t showed b o t h reduced growth and f e e d consumption; whereas, d i e t s 1, 2 and 4 p r o v i d e d adequate growth on s l i g h t l y l e s s f e e d . D i e t 6 showed the l e a s t growth and f e e d consumption among e x p e r i m e n t a l d i e t s and was s i g n i f i c a n t l y (P < 0.05) lower i n growth than d i e t s 5, 7 and 10. S i m i l a r e x p r e s s i o n has been shown w i t h f e e d e f f i c i e n c y w i t h the e x c e p t i o n o f d i e t s 3, 8 and 9. C o n t r a r y to the f i n d i n g s o f S t a p l e t o n e t a_l. (1980) , the replacement o f wheat f e e d s c r e e n i n g s w i t h wheat ( c o n t r o l d i e t ) i n b r o i l e r d i e t s r e s u l t e d i n s i g n i f i c a n t l y (P > 0.05) h i g h e r body weight g a i n s . The h i g h e r body weight g a i n h o l d s t r u e i n a l l s c r e e n i n g samples which are r e p o r t e d here (Table 7 ) . However, the body w e i g h t o f the c h i c k s was not d i r e c t l y r e l a t e d t o e i t h e r the f a t content, o f i n d i v i d u a l samples o f wheat s c r e e n i n g s or o f i n d i v i d u a l d i e t s . E. C h e m i c a l Elements The chemical elements of the wheat f e e d s c r e e n i n g s i s p r e s e n t e d i n T a b l e 8 and the m i n e r a l c o n t e n t o f the e x p e r i m e n t a l d i e t s i s p r e s e n t e d i n Table 9. The average c a l c i u m c o n t e n t o f the wheat f e e d s c r e e n i n g s was 0.15 p e r c e n t w i t h a range o f 0.13 p e r c e n t t o 0.18 p e r c e n t . Samples no. 2, 7, 8 and 9 were h i g h e r than average f o r the s c r e e n i n g s , Table 8. Content o f s i x c h e m i c a l elements p r e s e n t i n wheat f e e d s c r e e n i n g s * . Ca P Mg Mn Cu Zn S c r e e n i n g s Sample °'o ppm 1 0 . 13 0, .19 0. . 31 6 4 23 2 0. . 18 0, . 13 0. .31 9 2 40 3 0 , .14 0 .  11 0. .29 5 1 53 4 0 . 13 0 , .08 0. .24 4 2 36 5 0. . 13 0. .09 0. . 33 8 2 34 6 0. . 13 0. . 13 0 . 36 7 5 36 7 0 . 18 0, .17 0. .35 7 2 33 8 0 . 18 0. . 18 0 . 35 8 5 49 9 0. . 17 0. . 17 0 . 34 7 - 21 10 0. . 14 0. .08 0. ,29 5 2 20 Average/ 0 . 15 0. . 13 0. . 32 7 3 35 m i n e r a l * Dry ma t t e r b a s i s 83.-w h i l e the o t h e r s c r e e n i n g s were o f lower than average c a l c i u m c o n t e n t . Sample no. 1 was the h i g h e s t (.19%) i n phosphorus c o n t e n t f o l l o w e d by samples no. 8, 7 and 9 (.18%, .17% and .17%, r e s p e c t i v e l y ) . The l o w e s t phosphorus c o n t e n t was shown i n samples no. 4 and 10 w i t h a v a l u e o f 0.08%. The average phosphorus c o n t e n t o f the s c r e e n i n g s was 0.13%. The magnesium c o n t e n t o f the s c r e e n i n g s averaged 0.32% w i t h a range o f 0.29% t o 0.36%. A l t h o u g h s c r e e n i n g sample no. 6 showed the h i g h e s t and s c r e e n i n g samples no. 3 and 10 showed the l o w e s t magnesium c o n t e n t , i t appears the c o n t e n t o f t h i s m i n e r a l among s c r e e n i n g samples was f a i r l y even. In comparison w i t h c a l c i u m and phosphorus, the average magnesium c o n t e n t was h i g h e r (more than double) than the average o f b o t h c a l c i u m and phosphorus. Magnesium c o n t e n t was h i g h e r than any c h e m i c a l element examined i n t h i s p r o j e c t . L i k e magnesium, the c o n t e n t o f manganese i n s c r e e n i n g samples seems t o be f a i r l y c o n s t a n t w i t h the e x c e p t i o n o f samples no. 4, 3 and 10 which were r e l a t i v e l y low (4 ppm, 5 ppm, and 5 ppm, r e s p e c t i v e l y ) . Sample no. 2 has the h i g h e s t manganese c o n t e n t w i t h 9 ppm. The o v e r a l l average o f the manganese c o n t e n t o f the wheat f e e d s c r e e n i n g s samples was 7 ppm. 84. The average copper c o n t e n t (Table 8) o f s c r e e n i n g samples was 3 ppm. Copper was the l o w e s t i n amount compared to o t h e r m i n e r a l s . The copper c o n t e n t o f sample no. 9 was not w i t h i n d e t e c t a b l e l i m i t s . The copper c o n t e n t o f s c r e e n i n g sample no. 6 was h i g h e r than any o t h e r s c r e e n i n g sample. S i m i l a r t o manganese, magnesium and c a l c i u m , the c o n t e n t o f copper was r e l a t i v e l y c o n s t a n t w i t h the e x c e p t i o n o f samples no. 9 and 3. N e v e r t h e l e s s , the low c o n t e n t o f copper i n the s c r e e n i n g samples can be supplemented w i t h i n o r g a n i c copper to s u p p l y the c h i c k r e q u i r e m e n t and t h e r e i s no p o s s i b i l i t y o f t o x i c or adverse e f f e c t s from t h i s element. Z i n c was the t h i r d l o w e s t i n c o n t e n t of the s c r e e n i n g samples compared t o o t h e r m i n e r a l s h a v i n g an average o f 35 ppm o f the t e n d i f f e r e n t i n v e s t i g a t e d samples. The c o n t e n t o f z i n c ranges from 20 ppm to 53 ppm. Sample no. 3 was the h i g h e s t i n z i n c c o n t e n t w i t h 53 ppm and f o l l o w e d by sample no. 8 w i t h 49 ppm. Samples no. 10, 9 and 1 were found to be v e r y low i n z i n c w i t h 20, 21 and 23 ppm, r e s p e c t i v e l y . T a b l e 9. Content o f s i x c h e m i c a l elements p r e s e n t i n e x p e r i m e n t a l d i e t ( d r y m a t t e r b a s i s ) . Ca P Mg Mn Cu Zn D i e t % ppm 1 1.70 0.81 0.51 182 36 104 2 1.47 0.84 0.48 164 42 95 3 1.38 0.91 0.52 198 46 108 4 1.75 0.84 0.45 135 36 66 5 2.01 0 . 74 0.50 155 31 90 6 1/35 ' 0.74 0.51 159 39 105 7 1. 73 0.84 0.45 143 38 91 8 1.89 0.86 0.49 144 33 98 9 2.06 0.81 0.50 143 28 99 10 1.65 0.81 0.51 186 51 100 11* 1.55 0.84 0.45 162 33 98 Average/ 2.08 0.83 0.49 161 37 96 m i n e r a l * C o n t r o l d i e t F. C h e m i c a l E l e m e n t A v a i l a b i l i t y S e v e r a l f a c t o r s i n f l u e n c e the b i o a v a i l a b i l i t y of c h e m i c a l elements. One o f the most s i g n i f i c a n t f a c t o r s i s the p h y t i c a c i d ( i n o s i t o l h e x a p h o s p h o r i c a c i d ) which c h e l a t e s m i n e r a l e l e m e n t s , r e d u c i n g the a v a i l a b i l i t y t o the a n i m a l s ( N e l s o n e t al_. , 1968; Davies and N i g h t i n g a l , 1975). These workers suggest t h a t p h y t a t e p r o b a b l y c h e l a t e s p a r t of a l l c a t i o n s r e q u i r e d by a n i m a l s . P h y t a t e has a l s o been shown t o form s t a b l e complexes i n v i t r o w i t h Cu, Zn, ^ o , Mn, Fe and Ca ( O b e r l e a s , 1973). Other r e c o g n i z e d f a c t o r s a f f e c t i n g m i n e r a l a v a i l a b i l i t y are crude f i b e r , o x a l a t e , e t h y l e n e d i a m i n e t e t r a a c e t a t e (EDTA), p r o t e i n and amino a c i d s , v i t a m i n s , a n t i b i o t i c s and i n t e r a c t i o n between chemical"elements (Armstrong e t a l . , 1953; K r a t z e r e t a l . , 1959; O ' D e l l e t a l . , 1964; N i e l s o n e t a l . , 1966; K i r c h g e s s n e r e t a l . , 1961; M e i n t z e r and Steenbock, 1955 ; R i t c h i e e_t 'a!L. , 1963). P e r c e n t a v a i l a b i l i t i e s o f s i x d i f f e r e n t chemical "elements i n e x p e r i m e n t a l d i e t s are p r e s e n t e d i n Table 10. Average a v a i l a b i l i t y f o r a l l chemical elements varied from 59.1% (Zn) to 84.0% (Cu) . Of a l l s i x chemical elements tested for a v a i l a b i l i t y z i n c was the l o w e s t w h i l e copper was the h i g h e s t i n a v a i l a b i l i t y . C a l c i u m , magnesium and z i n c a v a i l a b i l i t y were Table 10. Chemical-element a v a i l a b i l i t y o f e x p e r i m e n t a l d i e t . Chemical-: Element Average/ D i e t s Ca p Mg Mn Cu Zn d i e t ab * 1 74.7 74.0 72.0 75.9 85.4 51.6 72.3 2 76.9 71.4 70.7 77.3 89.7 65.0 7 5 . 2 b c 3 75.3 75.6 67 . 2 78. 2 92.0 61.9 75. 0 b c 4 74.1:. 81. 1'-/ 66 . 5 74.5 89.2 57 .4 73. 8 a b c ah 5 68.6 72.2 66.1 73.9 85.9 52.1 6 9 . 8 d U 6 71. 9 78.7 .71.6 81.9 90 . 8 75 . 9 78.5 C 7 68.0 69.6 64.8 71.1 84.0 62.9 7 0 . 1 d U 8 66.5 71.9 65.1 71.4 86.3 46.9 6 8 . 0 a 9 70.0 70.9 63.4 77.4 70.9 57.6 68.4 a 10 75.8 70.8 72.2 77.8 85.2 57.3 7 3 . 2 a b c ab 1.1** 75.1 74 . 1 62.6 78. 7 69.6 61. 1 70 . 2 . Average 72.5 a 7 3 . 7 a b 6 7 . 5 C '76.2 b d 84.5 5 9 . l e 72.2 : * Means o f d i f f e r e n t s u p e r s c r i p t s are s i g n i f i c a n t l y d i f f e r e n t between d i e t s ( P < 0 . 0 5 ) . ** C o n t r o l d i e t . below the average (72.21 ) , each h a v i n g the a v a i l a b i l i t y v a l u e o f 72.51, 67.5% and 59.1%, r e s p e c t i v e l y . 1. C a l c i u m C a l c i u m a v a i l a b i l i t y ranged from 66.5% ( d i e t 8) t o 76.9% ( d i e t 2) w i t h an average o f 72.5%. E x p e r i m e n t a l d i e t 2 was the h i g h e s t i n c a l c i u m a v a i l a b i l i t y compared t o the r e m a i n i n g d i e t s . As i t was i n d i c a t e d e a r l i e r , f i b e r i s among s e v e r a l f a c t o r s which a f f e c t chemical element a v a i l a b i l i t y . The r e s u l t s o f these s t u d i e s are i n agreement w i t h the adverse e f f e c t o f crude f i b r e . Both i n c h e m i c a l a n a l y s i s o f wheat f e e d s c r e e n i n g s (Table 4) and e x p e r i m e n t a l d i e t s (Table 5 ) , the r e s u l t s showed t h a t the f i b e r c o n t e n t o f sample 2 was v e r y low, whereas, the ash c o n t e n t was h i g h . D i e t 8 showed the l o w e s t p e r c e n t a g e o f c a l c i u m a v a i l a b i l i t y (Table 10). A l s o , b o t h samples 2 and 8 had the h i g h e s t (0.18%) c a l c i u m c o n t e n t i n comparison w i t h o t h e r wheat f e e d s c r e e n i n g samples (Table 8 ) . The h i g h e r l e v e l of o r g a n i c c a l c i u m may account i n p a r t f o r lower Ca a v a i l a b i l i t y . T h i s r e s u l t i s i n agreement w i t h Nwokolo e t a_l. , 1977 and Aw-Yong, 1980. 2. Phosphorus Phosphorus a v a i l a b i l i t y was the t h i r d h i g h e s t o f a l l the c h e m i c a l elements t e s t e d w i t h 74.1% average (Table 10). 89. The v a l u e o f t h i s m i n e r a l a v a i l a b i l i t y ranges between 69.6% ( d i e t 7) and 81.1% ( d i e t 4 ) . Phosphorus o f p l a n t o r i g i n i s c o n s i d e r e d p o o r l y a v a i l a b l e due to the i n f l u e n c e o f p h y t a t e s . A v a i l a b l e phosphorus v a l u e s a p p l i e d to f e e d s t u f f s o f p l a n t o r i g i n a re between 30% and 40% ( T a y l o r , 1965). A s h t o n e t al_. (1960) observed t h a t f o u r week o l d c h i c k s r e t a i n e d a p p r o x i m a t e l y 20% o f p h y t a t e phosphorus w h i l e s i x week o l d c h i c k s r e t a i n e d 36% to 49% o f t h i s phosphorus. Temperton and C a s s i d y (1964), however, r e p o r t e d t h a t c h i c k s u t i l i z e d a p p r o x i m a t e l y 60% o f p h y t a t e phosphorus. The u t i l i z a t i o n o f phosphorus from v e g e t a b l e s o u r c e s i s h i g h as demonstrated by Salman and M c G i n n i s (1968). T h e i r r e p o r t i n d i c a t e d t h a t phosphorus u t i l i z a t i o n i n r a t i o n s c o n t a i n i n g 0.3% p l a n t phosphorus was not s i g n i f i c a n t l y d i f f e r e n t from i t s u t i l i z a t i o n i n r a t i o n s c o n t a i n i n g e i t h e r 0.6% p l a n t phosphorus or 0.3% p l a n t p l u s 0.3% i n o r g a n i c phosphorus. The r e s u l t s of the p r e s e n t study showed t h a t the a v a i l a b i l i t y o f phosphorus was s i g n i f i c a n t l y (P < 0.05) d i f f e r e n t from the r e s t o f the c h e m i c a l elements except c a l c i u m and manganese (Table 1 0 ) . R e s u l t s r e p o r t e d here are i n agreement w i t h r e s u l t s o f Nwokolo (1977). D i e t 4 showed the h i g h e s t phosphorus a v a i l a b i l i t y (81.1%) wh i c h i s p r o b a b l y r e l a t e d t o the l o w e s t c o n t e n t (0.08%) o f the wheat f e e d s c r e e n i n g s (Table 8 ) . However, the c o n t e n t o f phosphorus i n the e x p e r i m e n t a l t e s t was s l i g h t l y over the average (Table 9) which i n d i c a t e d t h a t most o f the phosphorus source was from the supplemented i n g r e d i e n t s i n the e x p e r i m e n t a l t e s t (Table 2 ) . On the o t h e r hand, the l o w e s t phosphorus a v a i l -a b i l i t y was d i e t 7 i n which the phosphorus c o n t e n t was i d e n t i c a l w i t h d i e t 4 (Table 9 ) . However, the wheat f e e d s c r e e n i n g s c h e m i c a l a n a l y s i s v a l u e showed the phosphorus c o n t e n t to be the t h i r d h i g h e s t (Table 8) i n comparison w i t h o t h e r samples. The r e s u l t o f t h i s s t u d y i n d i c a t e d t h a t phosphorus a v a i l a b i l i t y was s i g n i f i c a n t l y (P <_ 0.5) d i f f e r e n t from o t h e r c h e m i c a l elements w i t h the e x c e p t i o n of c a l c i u m . ° 5. Magnesium The a v a i l a b i l i t y o f magnesium of the e x p e r i m e n t a l d i e t ranges between 62.61 (diets 11 - c o n t r o l ) and 12.2% ( d i e t 10) w i t h the average of 67.5% (Table 10). Magnesium c o n t e n t o f the wheat f e e d s c r e e n i n g s was f a i r l y h i g h i n comparison o f the r e s t of the m i n e r a l s (Table 8 ) . However, the magnesium c o n t e n t o f the e x p e r i m e n t a l d i e t s was lower than c a l c i u m and phosphorus (Table 9 ) . Magnesium a v a i l a b i l i t y was s i g n i f i c a n t l y (P < 0.05) lower than Ca, Cu, Mn or P and s i g n i f i c a n t l y h i g h e r than Zn. 4. Manganese The c o n t e n t o f manganese was low i n the wheat f e e d s c r e e n i n g s (Table 8) whereas the c o n t e n t o f e x p e r i m e n t a l d i e t s was much h i g h e r (Table 9 ) . R e s u l t s o f the a v a i l a b i l i t y s t udy i n d i c a t e d t h a t manganese was next to the h i g h e s t on the average (76.2%) and r a n g i n g between 71.1% ( d i e t 7) and 81.9% ( d i e t 6) (Table 1 0 ) . R e s u l t s o f the a v a i l a b i l i t y t e s t i n d i c a t e t h a t manganese was s i g n i f i c a n t l y d i f f e r e n t from o t h e r c h e m i c a l elements except phosphorus (Table 10). I t was p o i n t e d out by G a l l u p and N o r r i s (1939a, b) and Wilgus and P a t t o n (1939) t h a t b i r d s had a h i g h requirement f o r manganese due t o poor a b s o r p t i o n o f the m i n e r a l from the d i e t . W h i l e the recommended manganese requirement i n p o u l t r y d i e t s i s 55 ppm (NAS - NRC, 1960), i t was r e p o r t e d by Nwokolo (197 7) t h a t the problem w i t h manganese seems t o be the low c o n t e n t i n p r o t e i n supplements r a t h e r than poor a v a i l a b i l i t y . T h i s work a l s o i n d i c a t e d t h a t at d i e t a r y l e v e l s o f p r o t e i n source n o r m a l l y used t o meet the p r o t e i n r e q u i r e m e n t s o f c h i c k s , a h i g h s u p p l e m e n t a l l e v e l o f manganese would be n e c e s s a r y i n most d i e t s , even though manganese from c e r e a l g r a i n s was e f f e c t i v e l y u t i l i z e d . 5. Copper There i s not much i n f o r m a t i o n i n the l i t e r a t u r e p e r t a i n i n g t o the c h e m i c a l n a t u r e or form i n which copper e x i s t s i n f o o d s . F a r r e r and M i s t i l i s (1967) have r e p o r t e d l a r g e v a r i a t i o n s i n copper a v a i l a b i l i t y . P h y t a t e has been r e p o r t e d by Da v i s 'et a_l (1962) t o reduce a b s o r p t i o n and a s s i m i l a t i o n o f copper. D e s p i t e the f i n d i n g s o f F a r r e r and M i s t i l i s (1967) , r e s u l t s o f t h i s s t u d y showed no l a r g e v a r i a t i o n s w i t h the e x c e p t i o n s o f d i e t 3 which showed the h i g h e s t a v a i l a b i l t i y (92.0%) and d i e t 11 ( c o n t r o l ) which showed the l o w e s t (69.6%) a v a i l a b i l i t y (Table 10). Average p e r c e n t a g e (84.5%) o f copper a v a i l a b i l i t y was s i g n i f i c a n t l y h i g h e r (P > 0.05) than o t h e r c h e m i c a l elements (Ca, P, Mg, Mn and Zn). T h i s would mean t h a t the i n t e r f e r e n c e o f p h y t a t e (Davis e t a_l. , 1962) and o t h e r u n i d e n t i f i e d f a c t o r s were m i n i m a l . 6. Z i n c R e g a r d i n g the a v a i l a b i l i t y o f z i n c , r e s u l t s o f t h i s s t u d y are i n agreement w i t h Nwokolo 'et a_l. (1977). F u r t h e r m o r e , i t has been r e p o r t e d t h a t p h y t a t e c o n t e n t o f v e g e t a b l e f e e d i n g r e d i e n t s has been i m p l i c a t e d i n r e d u c i n g z i n c a v a i l a b i l i t y (Lease e t a l . , 1960; L i k u s k i and F o r b e s , 1964; O ' D e l l e t a l . , 1972; Nwokolo e t a l . , 1977). S i n c e p h y t a t e was not i n c l u d e d i n t h i s s t u d y , i t i s d i f f i c u l t t o i d e n t i f y p h y t a t e as the o n l y r e s p o n s i b l e f a c t o r f o r low a v a i l a b i l i t y o f z i n c and o t h e r m i n e r a l s . However, p h y t a t e (as r e p o r t e d by s e v e r a l w o r k e rs) i s one f a c t o r w e l l i d e n t i f i e d t h a t i n t e r f e r e s w i t h m i n e r a l a v a i l a b i l i t y . T h e r e f o r e , i t i s assumed t h a t p h y t a t e and p o s s i b l y o t h e r f a c t o r s c o n t r i b u t e to the low a v a i l a b i l i t y v a l u e . The average z i n c a v a i l a b i l i t y was s i g n i f i c a n t l y (P < 0.05) lower than any o t h e r m i n e r a l i n c l u d e d i n t h i s s t u d y (Table 10). F i n d i n g s of t h i s s tudy p e r t a i n i n g t o m i n e r a l a v a i l a b i l i t y agree w i t h Aw-Yong (1980), i n t h a t , as the c o n c e n t r a t i o n o f a g i v e n m i n e r a l i n c r e a s e s the r a t e o f a v a i l a b i l i t y d e c r e a s e s and v i c e v e r s a . T h i s was s p e c i a l l y t r u e i n the case o f copper. Both the wheat f e e d s c r e e n i n g s m i n e r a l c o n t e n t and the e x p e r i m e n t a l d i e t , m i n e r a l c o n t e n t showed copper t o be the l o w e s t m i n e r a l component and y e t s i g n i f i c a n t l y (P > 0.05) h i g h e r i n a v a i l a b i l i t y than o t h e r m i n e r a l s . S i m i l a r t o o t h e r r e s e a r c h , the r e s u l t s o f t h i s s t udy i n d i c a t e d the e f f e c t o f f i b e r and m i n e r a l c o n c e n t r a t i o n on a v a i l a b i l i t y . G. Amino A c i d A v a i l a b i l i t y of Wheat Feed S c r e e n i n g s The amino a c i d c o m p o s i t i o n and a v a i l a b i l i t y o f e x p e r i m e n t a l d i e t s and wheat f e e d s c r e e n i n g s are d i s p l a y e d i n T a b l e s 11, 12 and 13, r e s p e c t i v e l y . There were d i f f e r e n c e s i n the amino a c i d a v a i l a b i l i t y (AAA) among e x p e r i m e n t a l d i e t s ( T able 13) and the same appeared t o be t r u e f o r the amino a c i d c o m p o s i t i o n o f wheat f e e d s c r e e n i n g samples (Table 11). The g e n e r a l p a t t e r n o f the amino a c i d a v a i l a b i l i t y r e s u l t s showed t h a t t h e r e was a s i g n i f i c a n t (P <, 0.05) d i f f e r e n c e among samples as wel l as among amino a c i d s (Table 1 3 ) . Amino a c i d s showing s i g n i f i c a n t l y h i g h e r a v a i l a b i l i t y v a l u e s were l y s i n e , h i s t i d i n e , a r g i n i n e , g l u t a m i c and p h e n y a l a n i n e . Those w i t h (P < 0.05) s i g n i f i c a n t l y lower a v a i l a b i l i t y were g l y c i n e and i s o l e u c i n e . C y s t i n e has been found t o undergo d e s t r u c t i o n d u r i n g d i r e c t HCL h y d r o l y s i s w i t h the amount o f d e s t r u c t i o n b e i n g e s s e n t i a l l y i n v e r s e l y p r o p o r t i o n a l t o the c o n c e n t r a t i o n of c y s t i n e i n the sample. T h e r e f o r e i t was not i n c l u d e d i n t h i s s t u d y . A l s o , some d e s t r u c t i o n may oc c u r i n g l y c i n e , i s o l e u c i n e and m e t h i o n i n e . A problem of the same n a t u r e has been e x p e r i e n c e d by M u z t a r and S l i n g e r (1980a). They r e p o r t e d t h a t c y s t i n e and m e t h i o n i n e are s u s c e p t i b l e t o d e s t r u c t i o n as a r e s u l t o f b a c t e r i a l a c t i o n i n the c h i c k e n e x c r e t a . F u r t h e r , i n t h e i r r e p o r t t hey s t a t e d t h a t e x c r e t a c o n t a i n e d much l e s s c y s t i n e than f e e d , the r e l a t i v e d e s t r u c t i o n o f t h i s amino a c i d i n e x c r e t a was g e n e r a l l y g r e a t e r . Thus, v a r i a b l e d e s t r u c t i o n of m e t h i o n i n e caused by HCL d u r i n g p r o t e i n h y d r o l y s a t e p r e p a r a t i o n and by b a c t e r i a i n e x c r e t a a re p o s s i b l e causes f o r some o f the s i g n i f i c a n t d i f f e r e n c e s i n the AAA v a l u e s . There were s i g n i f i c a n t d i f f e r e n c e s i n the AAA among d i e t s . D i e t s 3, 5 and 6 were s i g n i f i c a n t l y h i g h e r i n the t o t a l amino a c i d a v a i l a b i l i t y v a l u e . Whereas, d i e t s 9 and 11 were s i g n i f i c a n t l y l o w e r i n the t o t a l amino a c i d a v a i l a b i l i t y v a l u e compared t o the o t h e r d i e t s (Table 13). The h i g h average v a l u e s i n t o t a l AAA of d i e t s 3, 5 and 6 encompass the h i g h p r o t e i n q u a l i t y o f the t e s t i n g r e d i e n t s . The low e s t average v a l u e s i n t o t a l AAA o f d i e t s 9 and 11 ( b a s a l ) which encompass the low p r o t e i n q u a l i t y o f the t e s t i n g r e d i e n t s . T a b l e 11. Amino a c i d c o m p o s i t i o n o f e x p e r i m e n t a l d i e t s ( d r y m a t t e r b a s i s ) . I:xperiment;il Diets (o) Amino Acid Average amino ac i d 10 composition Lysine 1, .264 1. .059 1. .338 1, .136 1, .214 H i s t i d i n e 0. .549 0. .470 0, . 566 0. .505 0. .522 Arginine 1. .683 1, .378 1, .750 1, .479 .1, .598 Aspar t i c Acid 2. .301 1. .911 - 2, .403 2 .048 2 .254 Threonine 0, .904 0. ,743 0. .912 0, .796 0. .854 Serine 1. .228 1. .058 1. .280 1. .119 1, .182 Glutamic Acid 4. .664 4. .216 4. .655 4, .430 4. .416 Pr o l i n e 1. .825 1. .588 1, ,827 1. .632 1, .633 Glycine 1. .513 1. .248 1. .594 1. .305 1, .351 Alanine 1. .254 1, .043 1. .315 .1. ,098 1, .152 Valine 1. .115 • 0. , 939 1, .141 0, .992 1. .046 Methionine 0. .232 0. ,172 0. . 193 0. . 154 0. .167 1soleuc ine 0. .894 0. .753 0. .915 0, .796 0, .845 leucine 1. .734 1. .473 • 1. .761 1. ,572 L. .651 Tyrosine 0. .766 0. .648 0. .762 0, .698 0. .727 Phcnylalaninc 1. .118 0. .947 1. ,124 1. .021 1. .055 1. ,259 1, .181 1, .185 1. 229 1. .327 1, ,079 1.212 0. .551 0, .514 0, .526 0. 532 0. ,565 0. .474 0.529 1. ,619 1, .576 1 .575 1. 643 1. .754 1. .437 1.595 2, ,239 2. .140 2 .173 2. 260 2. .396 1. ,917 2.196 0, .589 0. .818 0. .812 0. 898 0, .913 0. .746 0.822 1. .213 1, .156 1. .172 1. 240 1. ,336 1. .069 1.194 4. .635 4. .414 4, .611 4. 590 4. ,681 4. .295 4.547 1. .736 1, .699 1, .713 1. 751 1. .873 1. ,750 1.745 1. .402 1. .400 1, .330 1. 413 1. ,567 1. ,494 1.296 1. .201 1. .165 1. .150 1. 199 1. ,303 1. ,167 1.889 1, .089 1. .035 1, .040 1. 086 1, ,169 0. ,963 1.060 0. .126 0. .211 0, .186 0. 188 0, .199 0. ,180 0.184 0. ,865 0, .832 0. .847 0. 877 0, ,933 0. .748 0.851 1. .700 1. .632 1, ,622 1. 709 1. .801 1. ,523 1.663 0, .740 0. ,715 0. .740 0. 792 0, .797 0. .698 0.741 1. .100 1. .046 1, .073 1. 094 1. ,151 0. . 967 1.071 *Basal d i e t Table 12. Amino a c i d c o m p o s i t i o n o f wheat feed screenings (dry ma t t e r b a s i s ) Wheat Feed Screenings Samples {%) Amino Acid 1 2 3 4 5 6 7 8 9 Lysine 0 .273 0. .386 0. .271 0 .327 0, .389 0, .499 0. .386 0. .415 0. ,365 0. ,365 0, .368 H i s t id ine 0, .206 0. .265 0. .187 0 .223 0, .275 0, .343 0. ,259 0, ,288 0. 234 0. ,272 0. .256 Arginine 0. .472 0. .663 0. .470 0 .545 0, .659 0, .845 0. ,593 0, .701 0. 566 0. ,561 0. ,607 Aspart ic Acid 0, .601 0. .723 0. .609 0 .841 0, .728 0, ,891 0. ,672 0. ,691 0. 636 0. ,694 0. ,709 Threonine 0. .295 0. .366 0. .296 0, .364 0, .376 0. ,472 0. 359 0. !349 0. 309 0. ,345 0. ,353 Serine 0. .485 0. .568 0. .456 0, .535 0. .595 0. ,727 0. 543 0. ,594 0. 492 0. ,577 0. ,567 Glutamic Acid 2. ,798 3. 184 2. ,568 2, .898 3, .376 4. ,026 3. 045 3. 356 3. 165 3. 460 3. ,188 Pro l ine 0. ,966 1. 042 0. 883 1. .041 1, ,102 1. ,503 0. 994 1. 322 1. 231 1. 250 1. 134 Glycine 0. 407 0. 509 0. 406 0, .486 0. ,534 0. 698 0. 504 0. 575 0. 502 0. 515 0. 514 Alanine 0. 399 0. 471 0. 395 0. .458 0. ,487 0. 632 0. 451 0. 521 0. 438 0. 465 0. 471 Va1i ne 0. 433 0. 515 0. 409 0. ,471 0. ,526 0. 650 0. 497 0. 529 0. 465 0. 521 o. 502 Methionine 0. 060 0. 093 0. 058 0. ,056 0. ,077 0. 109 0. 090 0. 087 0. 113 0. 053 0. 080 Isoleucine 0. 319 0. 413 0. 297 0. ,342 0. ,417 0. 505 0. 391 0. 428 0. 387 0. 416 0. 392 Leucine 0. 645 0. 831 0. 610 0. ,705 0. 864 1. 049 0. 802 0. 912 0. 795 0. 854 0. 807 Tyrosine 0. 291 0. 379 0. 275 0. 318 0. 389 0. 471 0. 343 0. 406 0. 321 0. 387 0. 358 Phenyl alanine 0. 450 0. 563 0. 420 0. 493 0. 591 0. 714 0. 541 0. 620 0. 507 0. 587 0. 548 Average amino 10 ac id composition Table 13. Amino acid a v a i l a b i l i t y of experimental diets fed to chicks. Experimental Diets(!) Amino Acid • Amino Acid 1 2 3 4 5 6 7 8 9 10 - 11** Mean Lysine 85 83 91 81 88 88 83 86 79 76 78 8 3 h i * • Histidine 83 81 90 79 87 88 79 84 75 80 76 82 h i Arginine 86 83 92 84 89 90 82 86 79 85 81 85 1 Aspartic Acid 72 65 83 71 79 79 66 71 60 67 63 7 0cde Threonine 69 65 81 69 77 66 61 68 56 65 61 6 7 c d Serine 71 70 83 72 81 80 67 73 63 71 68 72de£g Glutamic Acid' 83 83 90 86 89 89 79 85 73 79 79 83 h i Proline 76 76 86 78 85 84 72 77 66 73 75 7 7 f g h Glycine 55 54 74 - 66 65 - 52 - 52 - 60 b Alanine 70 69 85 74 80 80 68 71 55 67 67 7|.de£ Valine 74 70 87 77 82 81 71 74 64 70 12 7 4 e f g Methionine 67 62 77 66 74 57 65 61 47 67 60 64 c Isoleucine 57 51 72 56 67 66 55 55 49 50 48 57 b Leucine 78 75 86 78 83 83 74 78 68 76 74 7 7 f g h Tyrosine 75 72 85 71 60 82 69 75 65 73 77 7 2defg Phenyl alanine 79 76 87 80 84 85 75 80 70 77 77 7 9 g h i Average of total amino 7 4 c d 7lbc 84 e 7 0bc 7^ e 7 9de 67 b 74 c d 61 a 7 1bc 6 6 a b acid " Different superscripts among experimental diets and amino acids 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). ** Basal d i e t . IJ3 CO 99. One might s p e c u l a t e t h a t t o a c e r t a i n degree the AAA i s governed by the v a l u e s o f m e t a b o l i z a b l e energy and f e e d i n t a k e . However, e x a m i n a t i o n o f the m e t a b o l i z a b l e energy v a l u e (Table 6) and f e e d i n t a k e v a l u e (Table 7) o f the t e s t i n g r e d i e n t s i n d i c a t e s l i t t l e r e l a t i o n s h i p between m e t a b o l i z a b l e energy, f e e d i n t a k e and AAA. S i m i l a r r e s u l t s have been r e p o r t e d by Muztar and S l i n g e r (1980a, b ) . They a l s o r e p o r t e d t h a t the a v a i l a b i l i t i e s o f amino a c i d s i n f e e d s t u f f s i s o f t e n q u i t e v a r i a b l e . F u r t h e r m o r e , they s t a t e d t h a t f o r p o u l t r y f e e d p u r p o s e s , i t i s not n e c e s s a r y t o determine p r e c i s e l y the a v a i l a b i l i t y o f n o n - e s s e n t i a l amino a c i d s or the e s s e n t i a l amino a c i d s which are p r e s e n t i n the f e e d s t u f f s i n p l e n t i f u l amounts. T h e i r comment, based on t h i s a s s u m p t i o n , was t h a t one might s a c r i f i c e a c c u r a c y o f amino a c i d s such as h i s t i d i n e and t y r o s i n e t o ensure a c c u r a t e v a l u e s f o r l y s i n e and a r g i n i n e . The p r o x i m a t e a n a l y s e s o f the WFS are p r e s e n t e d i n Table 4. R e s u l t s o f c h e m i c a l c o m p o s i t i o n i n d i c a t e d s i m i l a r l e v e l s w i t h some e x c e p t i o n s . Crude f a t showed the h i g h e s t v a r i a t i o n , r a n g i n g from 3.051 (Sample 1) t o 6.14% (Sample 6 ) . The p r o t e i n c o n t e n t ranged from 12.85% (sample 8) to 14.21% (Sample 9 ) . The average t o t a l amino a c i d c o n t e n t o f WFS (Table 12 ,) was not c o m p l e t e l y p r o p o r t i o n a l t o the amount of p r o t e i n . The amino a c i d l e v e l s showed 100. r e l a t i v e l y wide v a r i a t i o n s t h a t may be expected w i t h v a r i a t i o n i n seed c o m p o s i t i o n . R e s u l t s o f t h i s study showed a h i g h c o n t e n t f o r h i s t i d i n e and a r g i n i n e i n WFS i n comparison w i t h h a rd wheat (NRC, 1977).and low c o n t e n t i n v a l i n e , l e u c i n e and p h e n y l a l a n i n e . Other e s s e n t i a l amino a c i d s were s i m i l a r i n c o m p o s i t i o n t o wheat. Among a l l amino a c i d s o f WFS, g l u t a m i c a c i d was the h i g h e s t f o l l o w e d by p r o l i n e . The l o w e s t was h i s t i d i n e f o l l o w e d by t y r o s i n e , e x c l u d i n g s u l f u r c o n t a i n i n g amino a c i d s (Table 12/) . Sample 6 was the h i g h e s t i n t o t a l amino a c i d s f o l l o w e d by sample 8. The l o w e s t was sample 3 f o l l o w e d by sample 1 (Table 1 1 ) . In r e s p e c t t o the e s s e n t i a l amino a c i d s , l y s i n e , h i s t i d i n e , a r g i n i n e and p h e n y l a l a n i n e were the h i g h e s t i n a v a i l a b i l i t y w i t h the v a l u e o f 83%, 82%, 85% and 79%, r e s p e c t i v e l y (Table 1 3 ) , i n d i c a t i n g e f f e c t i v e u t i l i z a t i o n o f the s e e s s e n t i a l amino a c i d s . The b a s a l d i e t ( d i e t 11) average v a l u e was 66%. D i e t 9 has a lower average (61%) v a l u e than the b a s a l d i e t . In comparison to o t h e r WFS samples t e s t e d , the t o t a l amino a c i d s i n d i e t 9 showed g e n e r a l l y reduced a v a i l a b i l i t y . Nesheim (1965) suggested t h a t f a c t o r s r e s p o n s i b l e f o r lowered amino a c i d a v a i l a b i l i t y from f e e d i n g r e d i e n t s i n c l u d e d p r o t e i n - s u g a r i n t e r a c t i o n s i n f e e d s t u f f s w i t h low l e v e l s o f p r o t e i n , p r o t e i n - f a t i n t e r a c t i o n s i n v o l v i n g 101. c a r b o n y l p r o d u c t s r e a c t i n g w i t h f r e e amino groups, i n h i b i t o r s o f p l a n t o r i g i n and heat t r e a t m e n t d u r i n g p r o c e s s i n g . Southgate and D u r n i n (1970) r e p o r t e d t h a t as the i n t a k e o f the d i e t a r y f i b e r i n c r e a s e d , the apparent d i g e s t i b i l i t y o f p r o t e i n (and t h e r e f o r e amino a c i d s ) and o t h e r d i e t a r y c o n s t i t u e n t s d e c r e a s e d . S e v e r a l workers (Dammers, 1965; Tao e t al_. , 1971; F l i p o t e t ' a l . , 1971) have a l s o i m p l i c a t e d crude f i b e r as a d i e t a r y f a c t o r r e d u c i n g amino a c i d d i g e s t i b i l i t y i n p r o t e i n f e e d s t u f f s , w h i l e N e l s o n (1967) suggested t h a t p h y t a t e c o n t e n t c o u l d reduce d i g e s t i o n and a b s o r p t i o n o f p r o t e i n s . However, d i e t 9 was not a f f e c t e d by e i t h e r e t h e r e x t r a c t n or by crude f i b e r . T h e r e f o r e , i t would appear t h a t d i g e s t i b i l i t y o f the p r o t e i n was m a i n l y r e s p o n s i b l e f o r the low amino a c i d a v a i l a b i l i t y . Among the t h r e e u s u a l l y l i m i t i n g e s s e n t i a l amino a c i d s , l y s i n e (83%) was s i g n i f i c a n t l y h i g h e r and m e t h i o n i n e was lo w e s t w i t h o n l y 64% a v a i l a b l e . A r g i n i n e was the h i g h e s t (85.%) i n a v a i l a b i l i t y among b o t h e s s e n t i a l and n o n - e s s e n t i a l amino a c i d s . R e s u l t s from t h i s s t u d y i n d i c a t e t h a t the amino a c i d c o n t e n t o f the FWS v a r i e d c o n s i d e r a b l y . T h i s i s e s p e c i a l l y t r u e w i t h t h o s e amino a c i d s which are c o n s i d e r e d l i m i t i n g i n c h i c k d i e t s , i . e . m e t h i o n i n e , l y s i n e , t h r e o n i n e . 102. I t w i l l be n o t e d t h a t the m e t h i o n i n e c o n t e n t ranged from 0.053% i n the case o f sample TO t o 0,113 i n the case of sample 9. The magnitude o f the l y s i n e v a r i a t i o n was a l s o g r e a t . I t -ranged from 0.271% (Sample 3) t o 0.499% (Sample 6 ) . Threonine showed the n e x t h i g h e s t magnitude o f v a r i a t i o n , r a n g i n g from 0.295% (Sample 1) to 0.472% (Sample 6 ) . No s i n g l e WFS sample showed s u p e r i o r i t y i n a l l e s s e n t i a l amino a c i d s , or even i n those which are c o n s i d e r e d l i m i t i n g . The d i f f e r e n c e s i n the a v a i l a b i l i t y o f the amino a c i d s (Table 13) were even g r e a t e r than was the v a r i a b i l i t y o f the t o t a l c o n t e n t . The g r e a t e s t extremes were observed i n the case o f t h r e o n i n e w h i c h was 56% a v a i l a b l e i n d i e t 9 and 81% a v a i l a b l e i n d i e t 3. S i m i l a r l y , t y r o s i n e has shown h i g h v a r i a t i o n ( i . e . , d i e t 5 has a v a l u e o f 60% o f a v a i l a b i l i t y v a l u e i n comparison t o d i e t 3 which as 85% a v a i l a b i l i t y v a l u e ) . A l t h o u g h the magnitude o f a v a i l a b i l i t y v a r i a t i o n s were not as extreme f o r t h r e o n i n e and t y r o s i n e , o t h e r e s s e n t i a l and n o n - e s s e n t i a l amino a c i d s as w e l l d i d show a g r e a t d e a l of a v a i l a b i l i t y v a r i a t i o n s . Extreme v a r i a t i o n was observed i n the case o f m e t h i o n i n e which was 47% a v a i l a b l e i n d i e t 9 and 77% a v a i l a b l e i n d i e t 3. Among n o n - e s s e n t i a l amino a c i d s a l a n i n e , a s p a r t i c a c i d and s e r i n e showed g r e a t e r v a r i a t i o n i n comparison t o o t h e r n o n - e s s e n t i a l amino a c i d s . A l a n i n e a v a i l a b i l i t y v a l u e 103. ranged from 55% i n d i e t 9 t o 85% i n d i e t 3. A s p a r t i c a c i d showed a measurable v a r i a t i o n , d i e t 9 showed 60% a v a i l a b i l i t y -v a l u e w h i l e d i e t 3 showed 83%. S e r i n e was the t h i r d n o n - e s s e n t i a l amino a c i d which showed h i g h v a r i a t i o n ; • i t ranged from 63% d i e t 9 t o 83% d i e t 3. The amino a c i d average c o m p o s i t i o n of WFS r e p o r t e d by S t a p l e t o n e t a l . (19 3.0) showed h i g h e r ( l y s i n e , h i s t i d i n e , g l u t a m i c a c i d , p r o l i n e , a r g i n i n e , c y s t i n e and m e t h i o n i n e ) , e q u a l ( t h r e o n i n e , l e u c i n e and i s o l e u c i n e ) and lower ( a s p a r t i c a c i d , s e r i n e , g l y c i n e , a l a n i n e , v a l i n e , t y r o s i n e and p h e n y a l a n i n e ) v a l u e s i n comparison w i t h WFS used i n t h i s s t u d y . A comparison o f wheat f e e d s c r e e i n g s w i t h wheat amino a c i d c o m p o s i t i o n r e p o r t e d by S t a p l e t o n e t al_. (19 80) showed t h a t WFS was h i g h e r . T h i s might be expected vdue to the c o n t a m i n a t i o n w i t h weed seeds. A c c o r d i n g to Tkachuk and M e l l i s h (1977) , the amino a c i d c o n t e n t o f weed seeds u s u a l l y p r e s e n t i n s c r e e n i n g s have an e x c e l l e n t amino a c i d b a l a n c e w i t h improved e s s e n t i a l amino a c i d s i n comparison to c e r e a l s . The c h e m i c a l c o m p o s i t i o n d i f f e r e n c e s between WFS by S t a p l e t o n e t a l . (1980) and the one used i n t h i s s t u d y was not s i g n i f i c a n t ; p a r t i c u l a r l y the d i f f e r e n c e between the p r o t e i n c o n t e n t which was l e s s than one p e r c e n t a g e i n f a v o u r o f WFS used i n t h i s s t u d y . 104. C o n c e r n i n g b o t a n i c a l c o m p o s i t i o n , WFS used i n t h i s s t u d y c o m p r i s e s an average v a l u e of 76%, 4%, 12% and 2% of . c r a c k e d wheat, r a p e s e e d , w i l d buckwheat and farm weeds, r e s p e c t i v e l y . I n comparison t o S t a p l e t o n e t a l . (1980), WFS c o n s i s t e d of 67%, 8%, 7% and 3% of c r a c k e d wheat, r a p e s e e d , w i l d buckwheat and farm weeds, r e s p e c t i v e l y . These were i n g r e d i e n t s which showed major d i f f e r e n c e s . Thus, the v a r i a b i l i t y i n b o t a n c i a l c o m p o s i t i o n appears t o be a major cause of v a r i a t i o n i n amino a c i d c o m p o s i t i o n . There were no r e p o r t s i n the l i t e r a t u r e on amino a c i d a v a i l a b i l i t y s tudy f o r comparison. Both the amino a c i d c o m p o s i t i o n and the a v a i l a b i l i t y o f WFS as a major g r a i n source was an e f f e c t i v e i n g r e d i e n t i n comparison to r e s u l t s w i t h wheat. H. Economic E v a l u a t i o n o f Wheat Feed S c r e e n i n g s As i n f l a t i o n , d e p r e s s i o n and r e c e s s i o n become a t h r e a t t o the comfort and p e a c e f u l l i f e o f man/kind, a c a d e m i c i a n s , p r o f e s s i o n a l s and p o l i t i c i a n s as w e l l s h o u l d assume a c o l l a b o r a t e d r e s p o n s i b i l i t y t o remove the e x i s t i n g t h r e a t . As the p o u l t r y i n d u s t r y s t r i v e s f o r g r e a t e r e f f i c i e n c y and improved p r o d u c t q u a l i t y , a t t e n t i o n needs t o be f o c u s e d on the economic f e a s i b i l i t y o f m i n i m i z i n g the c o s t o f p r o d u c t i o n o f the i n d u s t r y ' s p r o d u c t . Recent events. 105. namely h i g h c o s t o f l i v i n g and h i g h i n t e r e s t r a t e s , have s u b s t a n t i a l l y encouraged r e s e a r c h e f f o r t s to be geared on u t i l i z i n g items which used t o be c o n s i d e r e d as waste or b y - p r o d u c t s . C u r r e n t l y , c e r t a i n o f the v a r i a b l e c o s t s o f p r o d u c t i o n , s p e c i f i c a l l y f e e d i n g r e d i e n t s and f u e l c o s t s have r i s e n more r a p i d l y than o t h e r c o s t s . I t appears t h a t because o f i n c r e a s i n g w o r l d demands f o r f e e d g r a i n s and energy, these h i g h e r c o s t s are not l i k e l y t o descend t o p r e v i o u s l e v e l s . F u r t h e r m o r e , wheat s t i l l remains to be used as one o f the major c e r e a l g r a i n s i n p o u l t r y d i e t s . One o f the major o b j e c t i v e s o f t h i s s tudy was t o e v a l u a t e the economic f e a s i b i l i t y o f r e p l a c i n g wheat w i t h wheat f e e d s c r e e n i n g s . The f e e d i n g r e d i e n t s p r i c e , the mean body w e i g h t s , f e e d c o n v e r s i o n , f e e d c o s t and m o r t a l i t y are p r e s e n t e d i n T a b l e s 14 and 15, r e s p e c t i v e l y . Feed i n g r e d i e n t s p r i c e was based on A b b o t s f o r d , B r i t i s h Columbia w h o l e s a l e p r i c e dated March 27, 1981. A s i g n i f i c a n t l y (P > 0.05) h i g h e r body weight g a i n , h i g h e r f e e d c o n v e r s i o n , lower f e e d c o s t and the absence of m o r t a l i t y w i t h the e x c e p t i o n o f d i e t 10, has been shown by diets 5, 7 and 10. However, t h r e e p e r c e n t m o r t a l i t y was shown by d i e t 10. D i e t s 3, 8 and 9 a l s o produced s i g n i f i c a n t l y (P > 0.05) h i g h e r body weight g a i n but at s i g n i f i c a n t l y 106. (P < 0.05) lower r a t e of f e e d c o n v e r s i o n and h i g h e r f e e d c o s t . As i n the case o f d i e t 9 t h e r e was h i g h e r m o r t a l i t y . D i e t s 1, 2 and 4 produced s i g n i f i c a n t l y (P < 0.05) lower body weight g a i n , however, the lower body weight g a i n was compensated f o r by a s i g n i f i c a n t l y (P > 0.05) h i g h e r f e e d c o n v e r s i o n and lower f e e d c o s t . A p a r t from lower body weight g a i n , d i e t 1 has a l s o shown t h r e e p e r c e n t m o r t a l i t y . A comparison o f c o n t r o l d i e t ( d i e t 11) which comprises wheat as a major i n g r e d i e n t w i t h o t h e r d i e t s which comprise wheat f e e d s c r e e n i n g s , the c o n t r o l d i e t produced s i g n i f i c a n t l y (P < 0.05) lower body weight g a i n , lower f e e d c o n v e r s i o n and h i g h e r f e e d c o s t and w i t h seven p e r c e n t m o r t a l i t y i n c i d e n c e (Table 15) . A p a r t from the c o n t r o l d i e t ( d i e t 1 1 ) , i t i s e v i d e n t from the d a t a t h a t b i r d s s u b j e c t e d t o d i e t 6 have shown s i g n i f i c a n t l y (P < 0.05) lower body weight g a i n , f e e d e f f i c i e n c y , and h i g h e r f e e d c o s t and m o r t a l i t y than b i r d s s u b j e c t e d t o o t h e r d i e t s . The r e s u l t of such poor performance seems t o be a r e f l e c t i o n o f h i g h rapeseed c o n t e n t (Table 3) and s e v e r i t y o f amino a c i d u n balance. Samples of WFS c o n t a i n -i n g more than f i v e p e r c e n t o f rapeseed have shown poor performance e s p e c i a l l y i n body weight g a i n and i n f e e d e f f i c i e n c y . The type o f rapeseed c o n t a i n e d i n WFS was raw and u n p r o c e s s e d which i s b e l i e v e d t o c o n t a i n g l u c o s i n o l a t e s , T a b l e 14. Wholesale p r i c e l i s t o f d i e t i n g r e d i e n t s as based on March 27, 1981 p r i c e . P e r c e n t of I n g r e d i e n t D i e t i n g r e d i e n t p r i c e / m e t r i c i n g r e d i e n t I n g r e d i e n t s i n the d i e t b t o n ($) p r i c e / k g ($) Wheat 61 187 .0 0. , 12 Wheat f e e d or s c r e e n i n g s #1 61 180 .0 0 . .11 Soybean meal 25 509 .0 0. .13 Meat meal 6. 5 451 .0 0 , .03 A n i m a l t a l l o w 6. 0 555 .0 0 . .04 Limestone 0 . 5 38. 0 0. .01 Premix 1. 0 1.37/kg 0, .01 a Wheat d i e t / k g = 34.0vt Wheat f e e d s c r e e n i n g s / k g = 33.0<t b T o t a l w e i g ht o f d i e t = 70 kg 108. Table 15. Average f e e d consumption, f e e d c o n v e r s i o n , f e e d c o s t p e r kg g a i n and m o r t a l i t y o f b r o i l e r f e d d i e t s based on wheat and wheat f e e d s c r e e n -i n g s to 4 weeks o f age. Feed Feed D i e t consumption c o n v e r s i o n Feed c o s t M o r t a l i t y (kg) ( f e e d / g a i n ) U/kg g a i n ) (%) 1 1.36 b 1.59 b 50.88 b 3 2 1.39 b 1.57 b 50.24 b -3 1.44 a 1.81 a 57.92 a -4 1.36 b 1.55 b 49.60 b -5 1 . 4 1 a b 1.55 b 49.60 b -6 1 . 3 3 b c 1.83 a 58.56 a 10 7 1 . 4 2 a b 1.58 b 50.56 b -8 1.43 a 1.85 a 59.20 a -9 1 . 4 2 a b 1.83 a 58.56 a 7 10 1.45 3 1.57 b 50.24 b 3-l l 1 1.29 C 1.84 a 60.72 a 7 C o n t r o l (wheat) Means w i t h the same s u p e r s c r i p t are not 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) . 109. a substance r e s p o n s i b l e f o r m e t a b o l i c d i s o r d e r as s t a t e d e a r l i e r . D e s p i t e i t s h i g h e r f i b e r c o n t e n t and f a i l u r e t o show a h i g h e r l y s i n e c o n t e n t i n amino a c i d a n a l y s i s (Table 1 1 ) , WFS samples ( 3 , 5, 7, 8 and 9) w i t h a h i g h e r p e r c e n t a g e c o m p o s i t i o n o f w i l d buckwheat have shown a h i g h e r body weight g a i n and f e e d e f f i c i e n c y r e s ponse. The h i g h e r body weight g a i n and f e e d e f f i c i e n c y v a l u e s might a l s o be a t t r i b u t e d t o improved amino a c i d b a l a n c e . S i m i l a r t o the c o n t r o l d i e t ( d i e t 1 1 ) , two o f the WFS samples (1 and 4) w i t h h i g h e r p e r c e n t a g e c o m p o s i t i o n o f wheat have produced s i g n i f i c a n t l y (P < 0.05) lower body weight g a i n . As i n the case o f d i e t 2, i t seems t h a t the r e l a t i v e l y h i g h rapeseed e f f e c t has masked the e f f e c t o f low p e r c e n t a g e o f wheat and h i g h p e r c e n t a g e o f w i l d buckwheat (Table 3 ) . As a r e s u l t of t h i s , the body weight g a i n performance was r e l a t i v e l y poor. The p o t e n t i a l economic advantage t o the f e e d m a n u f a c t u r e r and the b r o i l e r p r o d u c e r o f r e p l a c i n g wheat g r a i n w i t h wheat f e e d s c r e e n i n g s l i e s i n i n c r e a s e d a v a i l a b i l i t y o f WFS. T h i s s h o u l d l e a d t o consequent s a v i n g s i n the c o s t o f p r o d u c t i o n o f f e e d which s h o u l d be r e f l e c t e d i n lower c o s t t o the b r o i l e r p r o d u c e r . The d e c r e a s i n g c o s t o f f e e d consumed per k i l o g r a m o f body weight g a i n as the WFS r e p l a c e s wheat i n d i c a t e s the economic worth (a minimum of $10.0 s a v i n g per t o n o f 110. WFS) o f WFS c o n t r i b u t e d t o b r o i l e r p r o d u c t i o n . The net economic wor t h o f WFS depends on the grade of WFS (the one used i n t h i s s t u d y was grade #1), h i g h m e t a b o l i z a b l e energy v a l u e as compared t o the c o n t r o l d i e t (wheat) and the p r i c e d i f f e r e n t i a l between wheat and WFS (WFS was cheaper by $10.0 per m e t r i c t o n ) . The f e e d p r i c i n g p rocedure used i n t h i s s t u d y employed a s i n g l e c o s t f o r i n g r e d i e n t s i n v o l v e d i n the e x p e r i m e n t a l d i e t w i t h r e g a r d t o the d i f f e r e n c e i n n u t r i e n t c o n t e n t were r e v e a l e d by c h e m i c a l a n a l y s i s . The f e e d m a n u f a c t u r e r s h o u l d c o n s i d e r the e f f e c t o f d i f f e r e n c e s i n n u t r i e n t c o n t e n t on f e e d c o s t s i n d e t e r m i n i n g the r e l a t i v e v a l u e o f f e e d g r a i n s o f d i f f e r i n g n u t r i t i o n a l v a l u e and, most i m p o r t a n t l y , the c o m p e t i t i o n f o r c e r e a l g r a i n by m o n o g a s t r i c animal w i t h human would be s u b s t a n t i a l l y m i n i m i z e d . T h i s s t u d y has r e v e a l e d an i n t r i n s i c d i f f e r e n c e between wheat c e r e a l g r a i n and WFS i n d i e t s f o r growing b r o i l e r s . The r e s u l t s d i d i n d i c a t e t h a t d i e t s based on WFS w i t h s u i t a b l e p r o t e i n c o n c e n t r a t e s may produce b e t t e r growth performance and f e e d e f f i c i e n c y than w i t h wheat c e r e a l g r a i n . F u r t h e r economic a n a l y s i s of the i m p l i c a t i o n s o f changes i n p r o t e i n and amino a c i d l e v e l s , m e t a b o l i z a b l e energy v a l u e s and o t h e r n u t r i t i o n a l c h a r a c t e r i s t i c s o f c e r e a l I l l : g r a i n s i n terms o f the c o s t o f p r o d u c t i o n o f meat or eggs would be v a l u a b l e t o the p o u l t r y i n d u s t r y as a guide i n p u r c h a s i n g f e e d g r a i n s . 112. IV. SUMMARY AND CONCLUSIONS B o t a n i c a l and c h e m i c a l c o m p o s i t i o n , amino a c i d c o n t e n t and a v a i l a b i l i t y , c h e m i c a l element and a v a i l a b i l i t y and m e t a b o l i z a b l e energy of wheat f e e d s c r e e n i n g s were de t e r m i n e d . Amino a c i d and c h e m i c a l element a v a i l a b i l i t y as w e l l as m e t a b o l i z a b l e energy s t u d i e s were conducted u s i n g growing b r o i l e r c h i c k s . Day o l d b r o i l e r c h i c k performance was a l s o s t u d i e d u s i n g wheat ( c o n t r o l ) and wheat f e e d s c r e e n -i n g s as a major c o n s t i t u e n t o f the d i e t . Wheat was the h i g h e s t (761) b o t a n i c a l component f o l l o w e d by w i l d buckwheat ( 1 2 % ) . Among the l e a s t were: b a r l e y and rapeseed ( 4 % ) , farm weeds ( w i l d buckwheat, green and y e l l o w f o x t a i l , and w i l d o a t s ) ' ( 4 % ) , o a t s ( 0 . 2 8 ) , and f l a x ( 0 . 2 2 ) . The c h e m i c a l a n a l y s i s o f WFS shows average v a l u e s o f about 14% crude p r o t e i n , 4431 cal/gm, 4.61 e t h e r e x t r a c t , 3.17% crude f i b r e and 2.6% ash. The ME v a l u e s o f WFS i n b a l a n c e d d i e t s were r e l a t i v e l y c l o s e . I n comparison t o the wheat d i e t w h i c h was used as a c o n t r o l d i e t , the ME v a l u e o f WFS was s i g n i f i c a n t l y (P > 0.05) h i g h e r . The replacement o f wheat w i t h WFS i n b r o i l e r r a t i o n s r e s u l t e d i n s t a t i s t i c a l l y s i g n i f i c a n t (P > 0.05) g a i n s e x c e p t f o r d i e t s 1 and 6. A l t h o u g h samples 1 and 6 produced h i g h e r growth performance than the c o n t r o l 113. d i e t the d i f f e r e n c e was 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 . However, th.e r e s u l t o f f e e d consumption showed o n l y d i e t s 1, 2, 4 and 6 which were not s i g n i f i c a n t l y h i g h e r than the c o n t r o l d i e t . The f e e d e f f i c i e n c y r a t i o f o r d i e t s 1, 2, 4, 7 and 10 were s i g n i f i c a n t l y h i g h e r than the c o n t r o l d i e t . There was an a c c o u n t a b l e d i f f e r e n c e i n the AAA among b a l a n c e d d i e t s and i n amino a c i d c o m p o s i t i o n o f WFS samples. The a v a i l a b i l i t y r e s u l t s showed a s i g n i f i c a n t d i f f e r e n c e between samples, as w e l l as between amino a c i d s . Among l i m i t i n g e s s e n t i a l amino a c i d s , the a v a i l a b i l i t y o f l y s i n e was s i g n i f i c a n t l y h i g h e r than the r e s t o f e s s e n t i a l amino a c i d s (83%) f o l l o w e d by t h r e o n i n e (67%) w h i l e m e t h i o n i n e was the l e a s t (64%) a v a i l a b l e . A r g i n i n e was the h i g h e s t (85%) i n a v a i l a b i l i t y v a l u e among e s s e n t i a l and n o n - e s s e n t i a l amino a c i d . R e s u l t s o b t a i n e d i n t h i s study and i n the l i t e r a t u r e i n d i c a t e t h a t WFS are b e t t e r b o t h i n amino a c i d c o m p o s i t i o n and a v a i l a b i l i t y compared t o wheat. C o m p o s i t i o n and a v a i l a b i l i t y o f s i x c h e m i c a l elements (Ca, P, Mg, Mn, Cu, Zn) were a l s o d e termined from WFS samples. R e s u l t s have shown an average v a l u e (dry m a t t e r b a s i s ) o f : 0.15%, 0.13%, 0.32%, 7 ppm, 3 ppm and 35 ppm f o r Ca, P, Mg, Mn, Cu and Zn, r e s p e c t i v e l y . The average a v a i l a b i l i t y o f m i n e r a l s ranged from 59% (Zn) to 84% (Cu). Among the t e s t e d m i n e r a l s , copper (84.28%), 114. manganese (76.57!) and phosphorus (74.14%) showed the h i g h e s t a v a i l a b i l i t i e s , whereas, z i n c (59%) was the l e a s t a v a i l a b l e . Based on the d a t a o f t h i s s t u d y , WFS w i t h some weed seed c o n t a m i n a t i o n has an a c c e p t a b l e p o t e n t i a l t o r e p l a c e wheat w h i c h c o n s t i t u t e s a major p o r t i o n o f the b r o i l e r d i e t . Thus, f e e d c o s t o f the b r o i l e r d i e t w i l l be reduced and u l t i m a t e l y , the p r o f i t m argin w i l l be improved f o r the p o u l t r y i n d u s t r y . 115. BIBLIOGRAPHY Achinewhu, S. C. and D. H e w i t t , 1979. 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E f f e c t of amino a c i d inbalance on the f a t e of the l i m i t i n g amino a c i d . J . Nutr. 89: 80. 137. Appendix Table 1. A n a l y s i s of variance f o r feed consumption of wheat feed screenings. Source DF Sum Sq. Mean Sq. Er r o r F-Value Prob. Treat 11 0.13622 12383.0 - 2.8723 0.14846 Er r o r 25 0.10347 4311.3 -To t a l 35 0.23969 - -138. Appendix Table 2. A n a l y s i s of variance f o r metabolizable energy of wheat feed screenings. Source DF Sum Sq, Mean Sq Er r o r F-Value Prob. Treat 11 0.52049 0.47317 76.280 0.7077 Er r o r 24 0.14887 6203.0 To t a l 35 0.53537 139. Appendix Table 3. A n a l y s i s of variance f o r feed e f f i c i e n c y of wheat feed screenings. Source DF Sum Sq. Mean Sq. Er r o r F-Value Prob. Treat 11 0.61303 0.55730 - 14.413 0.50952 Er r o r 24 0.92800 0.38667 -To t a l 35 0.70583 - -140. Appendix Table 4. A n a l y s i s of variance f o r body weight g of wheat feed screenings. Source DF Sum Sq. Mean Sq. E r r o r F-Value Prob. Treat 11 0.54239 0.49308 - 2.4887 0.29968 E r r o r 24 0.47550 0.19812 - -T o t a l 35 0.10179 - -141. Appendix Table 5. A n a l y s i s of variance f o r amino a c i d a v a i l a b i l i t y of wheat feed screenings. Source DF Sum Sq. Mean Sq. E r r o r F-Value Prob. Treat 11 8089.3 735.39 - 13.143 0.40109 ^ m i T}° 15 27796.0 1853.0 - 33. 117 0.12256 Ac i d E r r o r 165 9232.4 55.954 -T o t a l 191 45117.0 - -142. Appendix Table A n a l y s i s of variance f o r c h e m i c a l - e l e m e n t a v a i l a b i l i t y of wheat feed screenings. Source DF Sum Sq, Mean Sq, Er r o r F-Value Prob. Treat 11 650.49 59.136 Mi n e r a l 5 4351.50 870.30 3.0344 0.31280 44.657 0.21825 E r r o r 55 1071.90 19.489 T o t a l 71 6073.90 

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