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Availability of nutrients in vegetable protein supplements for the chick Nwokolo, Emmanuel R. N. 1977

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AVAILABILITY OF NUTRIENTS IN VEGETABLE PROTEIN SUPPLEMENTS FOR THE CHICK by EMMANUEL NWORA RALUCHUKWU NWOKOLO B.Sc. Hons, University of Ibadan, Nigeria, 1972 M.Sc, U n i v e r s i t y of B r i t i s h Columbia, Canada, 1975 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY i n THE DEPARTMENT OF ANIMAL SCIENCE We accept t h i s t h e s i s as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA A p r i l , 1977 (c) Emmanuel Nwora Raluchukwu Nwokolo In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of Brit ish Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the Head of my Department or by his representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of r^ NH wAU S. C\ g N > l £ The University of Brit ish Columbia Vancouver 8, Canada ABSTRACT i i 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 f o u r v e g e t a b l e p r o t e i n supplements (palm k e r n e l , soybean, c o t t o n s e e d and rapeseed meals) were determined u s i n g growing c h i c k s . 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 84.5% (palm k e r n e l meal) to 97.3% (soybean meal). Palm k e r n e l meal was lowest and soybean meal h i g h e s t i n c o n t e n t of e s s e n t i a l amino a c i d s . R e s u l t s of m i n e r a l a v a i l a b i l i t y ( c a l c i u m , phosphorus, magnesium, manganese, z i n c and copper) i n d i c a t e d high c o n t e n t and a v a i l a b i l i t y of c a l c i u m , phosphorus and magnesium; low c o n t e n t and a v a i l a b i l i t y o f z i n c and copper. Average a v a i l a -b i l i t y of m i n e r a l s v a r i e d from 50.0% (palm k e r n e l meal) to 74.3% (soybean m e a l ) . Among m i n e r a l elements t e s t e d , phos-phorus (78.0%) and c a l c i u m (72.6%) showed the h i g h e s t a v a i l a -b i l i t y w h i l e z i n c (44.0%) was l e a s t a v a i l a b l e . Crude f i b r e and p h y t i c a c i d were i m p l i c a t e d as f a c t o r s d e p r e s s i n g a v a i l a -b i l i t y of m i n e r a l s t e s t e d . Crude f i b r e 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 a v a i l a b i l i t y of a l l s i x m i n e r a l s t e s t e d w h i l e p h y t i c a c i d content s i g n i f i c a n t l y (P^O.01) a f f e c t e d a v a i l a b i l i t y of phosphorus, c a l c i u m , z i n c and magnesium. M e t a b o l i z a b l e energy (ME) of the f e e d s t u f f s determined u s i n g three week o l d b r o i l e r c h i c k s , ranged from 1957 k c a l / k g dry matter (rapeseed meal) to 2796 k c a l / k g dry matter (palm k e r n e l meal). Chemical c o n s t i t u e n t s , a v a i l a b l e c a r b o h y d r a t e and meta-b o l i z a b l e energy c o n t e n t of seven d i f f e r e n t rapeseed meals were determined. M e t a b o l i z a b l e energy v a l u e s ranged from 1492 k c a l / k g (Span A) to 1957 k c a l / k g (commercial RSM). Of a l l c hemical c o n s t i t u e n t s t e s t e d , e t h e r e x t r a c t , sugar and s t a r c h content were most s i g n i f i c a n t l y (P«%0.01) r e l a t e d t o m e t a b o l i z a b l e energy and were i n c o r p o r a t e d i n t o equations t o p r e d i c t ME of rapeseed meal from t h e i r c h e m i c a l c o n s t i t u e n t s . Content 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, Zn, Cu) were determined u s i n g the t e s t rapeseed meals. Samples were h i g h i n c a l c i u m , phosphorus and magnesium and low i n copper i n comparison to o t h e r v e g e t a b l e p r o t e i n supplements. Average a v a i l a b i l i t y of m i n e r a l s ranged from 52.2% (Span A) to 64.0% (commercial RSM). Among m i n e r a l s t e s t e d , phosphorus (75.3%), copper (74.3%) and c a l c i u m (68.0%) showed the h i g h e s t a v a i l a b i l i t i e s . Z i n c was l e a s t a v a i l a b l e (44.1%). Treatment of palm k e r n e l meal with 3%, 5% or 7% NaOH i n an attempt to d e l i g n i f y the m a t e r i a l and improve i t s n u t r i t i v e v a l u e , caused a r e d u c t i o n i n p r o t e i n , a c i d d e t e r g e n t f i b r e and a c i d d e t e r g e n t l i g n i n c ontent o f the meal. There was c o n s i d e r -a b l e amino a c i d d e s t r u c t i o n , the extent b e i n g d i r e c t l y r e l a t e d to the s e v e r i t y of the a l k a l i treatment. I n c o r p o r a t i o n of a l k a l i - t r e a t e d meal -at 30% l e v e l i n t o b r o i l e r s t a r t e r r a t i o n s depressed growth r a t e and feed e f f i c i e n c y of c h i c k s . I n c l u s i o n o f palm k e r n e l meal at 10%, 20% or 30% i n t o a st a n d a r d b r o i l e r s t a r t e r d i e t s i g n i f i c a n t l y (P«»0.05) i n c r e a s e d average d a i l y g a i n o f c h i c k s over c o n t r o l s . H i g h e s t growth r a t e and feed e f f i c i e n c y were observed i n c h i c k s on the 10% PKM r a t i o n . I n c r e a s e d l e v e l of PKM i n c o r p o r a t i o n s l i g h t l y d e pressed feed e f f i c i e n c y but not growth r a t e o f c h i c k s . The need for increased u t i l i z a t i o n of vegetable protein supplements in chick r a t i o n s e s p e c i a l l y i n the developing countries was discussed. V TABLE OF CONTENTS Page A b s t r a c t . . . . . i i L i s t o f T a b l e s v i i L i s t o f A p p e n d i x T a b l e s i x Acknowledgements . . . . . x I n t r o d u c t i o n 1 L i t e r a t u r e Review 3 Methods o f d e t e r m i n i n g amino a c i d a v a i l a b i l i t y . . 3 A v a i l a b i l i t y o f amino a c i d s i n p l a n t p r o t e i n f e e d s t u f f s 10 F a c t o r s a f f e c t i n g a v a i l a b i l i t y o f amino a c i d s . . . 13 Methods o f d e t e r m i n i n g m e t a b o l i z a b l e e n e r g y o f f e e d i n g r e d i e n t s 16 M e t a b o l i z a b l e energy 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 19 T e c h n i q u e s f o r e s t i m a t i n g m i n e r a l a v a i l a b i l i t y . . 24 A v a i l a b i l i t y o f m i n e r a l s i n v e g e t a b l e p r o t e i n s o u r c e s 28 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 30 C u r r e n t i n f o r m a t i o n on n u t r i t i v e v a l u e o f palm k e r n e l meal . 36 D e l i g n i f i c a t i o n o f h i g h f i b r e f e e d s t u f f s 38 MATERIALS AND METHODS 39 T r i a l 1 Amino a c i d a v a i l a b i l i t y 40 T r i a l 2 M e t a b o l i z a b l e e n e r g y 43 T r i a l 3 M i n e r a l a v a i l a b i l i t y 45 T r i a l 4 Crude f i b r e and p h y t i c a c i d as 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 o f v e g e t a b l e p r o t e i n s u p p l e m e n t s 47 T r i a l 5 F a c t o r s a f f e c t i n g t h e m e t a b o l i z a b l e energy c o n t e n t o f r a p e s e e d meals 48 v i Page T r i a l 6 A v a i l a b i l i t y o f m i n e r a l s i n r a p e s e e d meals . . 49 T r i a l 7 E f f e c t s o f a l k a l i t r e a t m e n t on d i g e s t i b i l i t y , m e t a b o l i z a b l e e n e r g y and d e s t r u c t i o n o f amino a c i d s i n palm k e r n e l meal 50 RESULTS AND DISCUSSION 54 T r i a l 1 54 T r i a l 2 63 T r i a l 3 66 T r i a l 4 73 T r i a l 5 77 T r i a l 6 86 T r i a l 7 93 G e n e r a l d i s c u s s i o n "106 Summary and c o n c l u s i o n s 114 R e f e r e n c e s 118 Ap p e n d i x 135 v i i LIST OF TABLES Page 1 C o m p o s i t i o n o f s y n t h e t i c diet:,, 41 2 C o m p o s i t i o n o f t e s t d i e t s 41 3 C o m p o s i t i o n o f r e f e r e n c e d i e t 44 4 C o m p o s i t i o n o f c o n t r o l and t e s t d i e t 52 5 P r o x i m a t e a n a l y s i s o f PKM, SBM, CSM and RSM . . . . 55 6 Amino a c i d c o m p o s i t i o n o f PKM, SBM, CSM and RSM . . 56 7 Amino a c i d a v a i l a b i l i t y i n PKM, SBM, CSM and RSM f e d t o c h i c k s 58 8 M e t a b o l i z a b l e energy o f PKM, SBM, CSM and RSM . . . 64 9 The m i n e r a l c o n t e n t o f PKM, SBM, CSM and RSM . . . 67 10 P e r c e n 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 PKM, SBM, CSM and RSM 68 11 Crude f i b r e , p h y t i c a c i d , p h y t a t e and t o t a l phos-phorus c o n t e n t o f PKM, SBM, CSM and RSM 74 12 C o r r e l a t i o n c o e f f i c i e n t s between c r u d e f i b r e o r p h y t i c a c i d c o n t e n t and a v a i l a b i l i t y o f m i n e r a l s i n PKM, SBM, CSM and RSM 75 13 P r o x i m a t e c o n s t i t u e n t s o f v a r i o u s r a p e s e e d meals . 78 14 Gross and m e t a b o l i z a b l e e n e r g y o f v a r i o u s r a p e s e e d meals 79 15 Sugar, s t a r c h and a v a i l a b l e c a r b o h y d r a t e c o n t e n t o f v a r i o u s r a p e s e e d meals 81 16 C o r r e l a t i o n o f c h e m i c a l c o n s t i t u e n t s w i t h meta-b o l i z a b l e e n e rgy o f r a p e s e e d meals 83 17 M i n e r a l c o n t e n t o f r a p e s e e d meals 87 18 A v a i l a b i l i t y o f m i n e r a l s i n r a p e s e e d meal samples . 89 19 C h e m i c a l c o m p o s i t i o n o f PKM and a l k a l i - t r e a t e d PKM 94 20 P e r c e n t r e d u c t i o n i n p r o t e i n , ADF and ADL o f PKM f o l l o w i n g a l k a l i t r e a t m e n t 94 21 Amino a c i d c o m p o s i t i o n o f PKM and a l k a l i - t r e a t e d PKM 95 v i i i Page 22 Per cent destruction of amino acids following a l k a l i treatment . . . . . 96 23 D i g e s t i b l e dry matter and d i g e s t i b l e energy of PKM and a l k a l i treated PKM 98 24 Gross and metabolizable energy of PKM and a l k a l i -treated PKM 98 25 E f f e c t of l e v e l of PKM i n r a t i o n on growth rate and feed conversion r a t i o of b r o i l e r chicks 100 26 E f f e c t of l e v e l of PKM i n r a t i o n on growth rate and feed conversion r a t i o of b r o i l e r c h i c k s : Calculated nutrient composition of test diets . . 101 27 Average nutrient intake per b i r d per day 102 28 Growth rate and feed conversion r a t i o of chicks on PKM and a l k a l i - t r e a t e d PKM d i e t s 104 29 Growth rate and feed conversion r a t i o of chicks on PKM and a l k a l i - t r e a t e d PKM d i e t s : Calculated analysis of test d i e t s 105 30 Approximate cost of feed ingredients i n Lagos, Nigeria and Vancouver, Canada (1976) 110 31 Approximate ingredient cost of formulating standard wheat-soybean s t a r t e r r a t i o n s i n Lagos, Nigeria and Vancouver, Canada I l l 32 Approximate ingredient costs of r a t i o n s formulated by s u b s t i t u t i n g PKM at 10%, 20% or 30% into standard s t a r t e r r a t i o n s 113 ix Appendix Tables Page 1 Analysis of variance f o r proximate constituents of PKM, SBM, CSM and RSM 135 2 Analysis of variance f o r amino acid a v a i l a b i l i t y of PKM, SBM, CSM and RSM 136 3 Analysis of variance f o r metabolizable energy of PKM, SBM, CSM and RSM 137 4 Analysis of variance f o r mineral a v a i l a b i l i t y of PKM, SBM, CSM and RSM 137 5 Analysis of variance f o r metabolizable energy of rapeseed meals 138 6 Analysis of variance f o r mineral a v a i l a b i l i t y of rapeseed meals 138 7 Analysis of variance f o r proximate constituents of PKM and a l k a l i - t r e a t e d PKM 139 8 Analysis of variance f o r growth rate and feed consumption of chicks fed diets containing 10%, 20% or 30% PKM 139 X ACKNOWLEDGEMENTS I would l i k e to express my sincere appreciation to my research supervisor, Dr. D. B. Bragg, Professor and Acting Chairman, Department of Poultry Science, for his unstinted support, guidance, encouragement and constructive c r i t i c i s m throughout the various aspects of t h i s work. I am also grateful to other members of my graduate committee: Dr. R. M. Tai t , Associate Professor, Department of Animal Science; Dr. W. D. K i t t s , Dean, Faculty of A g r i c u l t u r a l Sciences; Dr. I. D. Desai, Professor, D i v i s i o n of Human Nutr i t i o n ; Dr. R. M. Beames, Associate Professor, Department of Animal Science, and Dr. J. A. Shelford, Assistant Professor, Department of Animal Science, for t h e i r advice and encouragement i n the preparation and writing of t h i s thesis. My gratitude goes to the Canadian Commonwealth Scholarship Committee for awarding the scholarship that made t h i s study possible. F i n a l l y , I would l i k e to dedicate t h i s thesis to my wife, Uzoamaka, and my daughter, Ifeatu, two wonderful people. E.N.R. Nwokolo 1 INTRODUCTION I n c u r r e n t p r a c t i c e , t h e n u t r i t i v e v a l u e o f a f e e d s t u f f i s d e t e r m i n e d by t h e c o n t e n t o f the v a r i o u s n u t r i e n t s i n t h a t f e e d i n g r e d i e n t , and f e e d f o r m u l a t i o n i s based on t h e s e v a l u e s . Amino a c i d c o n t e n t i n r a t i o n s f o r v a r i o u s t y p e s o f l i v e s t o c k a r e c a l c u l a t e d on t o t a l q u a n t i t i e s o f t h e v a r i o u s amino a c i d s i n t h e mixed r a t i o n . M i n e r a l c o n t e n t o f r a t i o n s i s s i m i l a r l y c a l c u l a t e d on t h e sum o f t h e v a r i o u s m i n e r a l s i n f e e d i n g r e d i e n t s . R e c e nt r e s e a r c h has however i n d i c a t e d t h a t what i s p r e s e n t * i s not a l l a v a i l a b l e and t h e r e i s a s i g n i f i c a n t d i f f e r e n c e between t o t a l c o n t e n t o f n u t r i e n t s and q u a n t i t i e s a v a i l a b l e . J u s t as g r o s s energy i s n o t a t r u e i n d i c a t i o n o f e n e r g y a v a i l a b l e t o an a n i m a l f o r m e t a b o l i s m , so i s t o t a l l y s i n e o r phosphorus c o n t e n t not a r e l i a b l e i n d i c a t i o n o f t h e amounts a v a i l a b l e t o l i v e s t o c k . F o r most a n i m a l s i n c l u d i n g man t h e minimum r e q u i r e m e n t s and recommended l e v e l s o f amino a c i d s were d e t e r m i n e d w i t h s y n t h e t i c amino a c i d s o r h i g h q u a l i t y e a s i l y d i g e s t i b l e p r o t e i n s . More r e c e n t l y , i n c r e a s i n g amounts o f u n c o n v e n t i o n a l , v e g e t a b l e o r low q u a l i t y p r o t e i n s a r e b e i n g i n c o r p o r a t e d i n t o r a t i o n s f o r l i v e s t o c k . U n l e s s i t can be shown t h a t a v a i l a b i l i t y o f amino a c i d s from t h e s e low q u a l i t y p r o t e i n s e q u a l s t h a t f rom t h e more c o n v e n t i o n a l p r o t e i n s and from amino a c i d m i x t u r e s , i t makes no se n s e t o use w i t h o u t m o d i f i c a t i o n , t h e s e minimum r e q u i r e m e n t s and recommended l e v e l s o f amino a c i d s as p u b l i s h e d by t h e N a t i o n a l R e s e a r c h C o u n c i l . S i m i l a r l y , minimum r e q u i r e m e n t s and recommended l e v e l s o f v a r i o u s m i n e r a l s f o r d i f f e r e n t l i v e s t o c k have been d e t e r m i n e d u s i n g t o t a l m i n e r a l c o n t e n t i n mixed 2 r a t i o n s . T h i s p r a c t i c e assumes t h a t a l l m i n e r a l s i n t h e r a t i o n a r e h i g h l y a v a i l a b l e . W i t h i n c r e a s i n g use o f v e g e t a b l e and o t h e r f e e d i n g r e d i e n t s i n r a t i o n f o r m u l a t i o n , i t i s n e c e s s a r y t o d e t e r m i n e how much o f t h e t o t a l m i n e r a l c o n t e n t i s r e a l l y a v a i l a b l e t o a n i m a l s . C e r t a i n f e e d s t u f f s ^ ( e . g . soybean meal) e n j o y a l m o s t u n i v e r s a l a c c e p t a n c e i n r a t i o n f o r m u l a t i o n . O t h e r s ( e . g . palm k e r n e l meal) a r e not so w e l l a c c e p t e d m o s t l y as a r e s u l t o f p a u c i t y o f i n f o r m a t i o n c o n c e r n i n g t h e i r n u t r i t i v e v a l u e . Palm k e r n e l meal i s p r o d u c e d i n l a r g e q u a n t i t i e s i n the c o u n t r i e s o f A f r i c a and S o u t h E a s t A s i a . Y e t i n t h e s e and o t h e r c o u n t r i e s o n l y about 10% o f t h e p r o d u c t i o n i s used i n a n i m a l f e e d s , t h e r e s t o f i t b e i n g i n c o r p o r a t e d i n t o the s o i l as f e r t i l i z e r s . Rapeseed meal p r o d u c e d c o m m e r c i a l l y i n Canada i s c u r r e n t l y g a i n i n g i n c r e a s e d r e c o g n i t i o n as a p r o t e i n supplement i n p o u l t r y r a t i o n s . I n f e e d f o r m u l a t i o n , i t s c o n t r i b u t i o n i s however r e s t r i c t e d t o about 15% o f t h e p r o t e i n i n b r o i l e r r a t i o n s , and i s n o t e s s e n t i a l l y used i n s t a r t e r r a t i o n s . C o t t o n s e e d m e al, prod u c e d p r i n c i p a l l y i n s o u t h e r n U n i t e d S t a t e s and i n t h e t r o p i c a l and s u b t r o p i c a l p a r t s o f t h e w o r l d , i s a l s o used , s p a r i n g l y i n b o t h l a y e r and b r o i l e r r a t i o n s . I n an a t t e m p t t o s t i m u l a t e t h e u t i l i z a t i o n o f l e s s e r known v e g e t a b l e p r o t e i n supplements i n p o u l t r y r a t i o n s , t h e s e e x p e r i -ments were c o n d u c t e d t o d e t e r m i n e the a v a i l a b i l i t y o f amino a c i d s and m i n e r a l s i n palm k e r n e l , soybean, c o t t o n s e e d and r a p e s e e d m e a l s . The l e v e l o f i n c l u s i o n o f a l k a l i - t r e a t e d and u n t r e a t e d palm k e r n e l meal i n p o u l t r y r a t i o n , c o n s i s t e n t w i t h o p t i m a l growth r a t e and f e e d c o n v e r s i o n was d e t e r m i n e d . 3 LITERATURE REVIEW Methods of determining amino acid a v a i l a b i l i t y Chemical methods of determining amino acid a v a i l a b i l i t y are by t h e i r very nature, rapid and simple. Their accuracy has however not been f u l l y established. Dye binding (Moran et at., 1963; Mossberg, 1968) has been used to estimate the protein q u a l i t y of processed and unprocessed feed ingredients. Carpen-ter (1960) reacted 1-fluoro-2:4-dinitrobenzene with the epsilon amino group of l y s i n e i n feeds t u f f s to demonstrate a v a i l a b i l i t y of l y s i n e . Because of problems associated with the Carpenter -FDNB method, a modification was suggested by Rao et a_l. (1963). This was further investigated by Roach et a l . (1967) who deter-mined t o t a l l y s i n e i n the sample and r e s i d u a l l y s i n e i n the hydrolysate following acid hydrolysis of the FDNB treated sample. The di f f e r e n c e was taken as free epsilon l y s i n e and regarded as a v a i l a b l e l y s i n e . Kakade and Liener (1969) proposed the TNBS methods i n which they used 2, 4, 6-trinitrobenzene s u l f o n i c acid to react with the epsilon amino group of l y s i n e to form epsilon-TNP l y s i n e which was measured c o l o r i m e t r i c a l l y and regarded as a v a i l a b l e l y s i n e . The methods and importance of enzymatic digestion i n q u a l i t a t i v e estimation of protein q u a l i t y and amino acid a v a i l a b i l i t y were reviewed by Mauron (1968) who suggested that rate and order of release of the i n d i v i d u a l amino acids i n the dig e s t i v e t r a c t might be a f a c t o r determining the b i o l o g i c a l value of a prot e i n . He therefore j u s t i f i e d the enzymatic digestion procedure. In another review a r t i c l e , Meade (1972) suggested that although enzymatic l i b e r a t i o n of amino acids 4 was u s e f u l i n d e t e r m i n i n g t h e r e l a t i v e a v a i l a b i l i t i e s o f amino a c i d s , l i m i t i n g amino a c i d s and t h e l i m i t a t i o n s o f t o t a l amino a c i d v a l u e s , t h e method must be d e v e l o p e d t o the p o i n t t h a t v a l u e s would be u s e f u l i n f o r m u l a t i o n o f d i e t s f o r a n i m a l s and man. The o b s e r v a t i o n t h a t t h e c onsumption o f a p r o t e i n d e f i c i e n t i n an amino a c i d l e d t o a r e d u c e d plasma l e v e l o f t h a t amino a c i d ( A l m q u i s t , 1954) l e d G o l d b e r g and Guggenheim (1962) t o s t u d y the d i g e s t i v e r e l e a s e o f amino a c i d s and t h e i r c o n c e n t r a -t i o n s i n the p o r t a l plasma o f r a t s a f t e r p r o t e i n f e e d i n g . Smith and S c o t t (1965c) o b s e r v e d i n o v e r h e a t e d f i s h meal, t h a t t h e plasma c o n c e n t r a t i o n s o f l y s i n e and t h r e o n i n e were d e p r e s s e d , i m p l y i n g t h a t a v a i l a b i l i t y was r e d u c e d . T h i s was s i m i l a r t o t h e o b s e r v a t i o n o f G o l d b e r g and Guggenheim ( 1 9 6 2 ) . I n a n o t h e r s t u d y , S t o c k l a n d and Meade (1970) r e p o r t e d d i f f e r e n c e s i n a v a i l a b i l i t y o f i s o l e u c i n e , t h r e o n i n e and p h e n y l a l a n i n e t o t h e r a t . These s t u d i e s were q u a l i t a t i v e and no q u a n t i t a t i v e e s t i m a t e s o f p e r c e n t a v a i l a b i l i t y were r e p o r t e d . Such q u a n t i -t a t i v e e s t i m a t i o n would be d i f f i c u l t u s i n g t h i s p r o c e d u r e . M i c r o b i o l o g i c a l t e s t s have been p r o p o s e d f o r e s t i m a t i n g amino a c i d a v a i l a b i l i t y . F o r d (1962) u s i n g S t r e p t o c o c c u s  zymogenes measured " a v a i l a b l e amino a c i d s " as the amounts l i b e r a t e d by t h e m i c r o - o r g a n i s m s a f t e r p a r t i a l e n z y m a t i c h y d r o -l y s i s , i n c o m p a r i s o n t o " t o t a l amino a c i d s " r e l e a s e d f o l l o w i n g a c i d o r a l k a l i n e h y d r o l y s i s . T h i s method r e f l e c t e d d i f f e r e n c e s i n a v a i l a b i l i t y o f amino a c i d s as a s s o c i a t e d w i t h d i f f e r e n c e s i n p r o t e i n q u a l i t y and w i t h h e a t t r e a t m e n t . S t o t t and S m i t h (1966) used Tetrahymena p y r i f o r m i s W f o r m e a s u r i n g a v a i l a b i l i t y o f l y s i n e , m e t h i o n i n e , a r g i n i n e and h i s t i d i n e i n v a r i o u s p l a n t 5 and animal protein f e e d s t u f f s . In contrast with Streptococcus  zymoqenes assays of av a i l a b l e amino acids, assays with Tetra- hymena pyriformis do not require p a r t i a l enzymatic hydrolysis and o f f e r the convenience of estimation of two n u t r i t i o n a l l y important amino acids, l y s i n e and methionine with the same organism (Guggenheim, 1968). Meade (1972) suggested that these techniques would have to be useful for a large number of essen-t i a l amino acids and the accuracy of t h e i r a v a i l a b i l i t y values i n p r e d i c t i n g usefulness of protein sources f o r animals would have to be determined. The f e c a l analysis method as developed by Kuiken and Lyman (1948) measures the retention of dietary amino acids. This procedure d i f f e r e n t i a t e s between f e c a l amino acids of die t a r y and endogenous o r i g i n and therefore y i e l d s a value f o r amino acid a v a i l a b i l i t y . Bragg et a l . (1969) compared s u r g i c a l l y modified chicks and normal chicks i n a modification of t h i s procedure to determine amino acid a v a i l a b i l i t y of a feedstuff p r o t e i n . They observed that normal chicks yielded more consis-tent r e s u l t s than s u r g i c a l l y modified chicks and c a l c u l a t e d amino acid a v a i l a b i l i t y as follows: % amino acid (AA) a v a i l a b i l i t y = Total Fecal AA Total Fecal AA Tot a l AA intake - protein d i e t - non protein d i e t X 100 Tot a l AA intake The observed that amino acid a v a i l a b i l i t y represented the f r a c -t i o n of dietary amino acids a c t u a l l y taken up from the gut. Eggum (1968) reported true d i g e s t i b i l i t y of soybean amino acids f o r r a t s and pigs comparable to those of Bragg et a l . (1969) and Carlson and Bayley (1970). Amino acid a v a i l a b i l i t y values 6 obtained by the f e c a l analysis method are uniformly high and values greater than 90% commonly occur. Meade (1972) at t r i b u t e d t h i s i n part to the c o r r e c t i o n f o r metabolic f e c a l amino acids with resultant determination of true 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 i n d i v i d u a l amino acids. Smith and Scott (1965a,b,c) described a chick growth assay f o r estimating b i o l o g i c a l a v a i l a b i l i t y of amino acids i n i n t a c t p r o t e ins. A c r y s t a l l i n e amino acid standard reference d i e t shown by Dean and Scott (1964) to meet the amino acid require-ments of two-week old chicks was used as the basal d i e t . The amino acids were tested i n d i v i d u a l l y . For each amino acid being tested, a standard response curve was obtained by incorporating the amino acid at any of s i x l e v e l s (2,4,6,8,10,12 gm/chick/day i n the basal d i e t ) . The t e s t proteins were incorporated into the basal d i e t at the expense of corn s t a r c h . The t e s t protein was added at 5% l e v e l to a basal d i e t of the same composition as the reference basal d i e t but devoid of the amino acid under t e s t . They reported that i t was necessary to add small i n c r e -ments of the t e s t amino acid i n c r y s t a l l i n e form to bring chick growth up to the l i n e a r portion of the response curve. The standard response curve was tested f o r l i n e a r i t y and where necessary, points at the extreme ends of the curve were dropped. The regression equation for the best f i t t i n g l i n e so obtained was used to c a l c u l a t e the amounts of amino acids consumed i n d i e t s containing the test proteins. A v a i l a b i l i t y was estimated by comparing the calculated intake to actual intake of the test amino acid . Other methods have also been used to estimate a v a i l a b i l i t y 7 of amino acids i n feed ingredients. Gain/feed r a t i o (Gupta ejb a l . , 1958), and carcass nitrogen gained (Calhoun et a l . , 1960) have been employed i n amino acid a v a i l a b i l i t y determination. P r i c e et a l . (1953) evaluated di e t a r y amino acids and proteins by chick carcass a n a l y s i s . DeMuelenaere et al_. (1967) estimated l y s i n e a v a i l a b i l i t y of cereal products by f e c a l and growth analysis while Sarwar et a l . (1975) evaluated the a v a i l a b i l i t y of amino acids i n processed and unprocessed soybean and rape-seed meal by a combination of f e c a l and carcass a n a l y s i s . A general problem common to a l l methods of estimating amino acid a v a i l a b i l i t y i s the use of strong acids and a l k a l i s to hydrolyse proteins before chromatography. During such acid h ydrolysis, tryptophan i s completely destroyed and must be determined by a d i f f e r e n t procedure. Methionine, c y s t i n e , threonine, tyrosine and serine s u f f e r considerable destruction unless hydrolysis i s with 3N Hcl for sixteen hours. Methionine and cystine are usually oxidised with performic acid before acid h y d r o l y s i s . Chemical methods fo r estimating amino acid a v a i l a b i l i t y are rapid and simple and have the high degree of rep r o d u c a b i l i t y common to most chemical procedures. They do not however have a high c o r r e l a t i o n with animal performance and t h e i r accuracy has not been f u l l y e s t a b l i s h e d . This i s t y p i f i e d by the DNFB - a v a i l a b l e l y s i n e value of 3.0 g/16 gN fo r cod f i l l e t , which i s very high i n comparison with a value of 1.3 g/16 gN measured with r a t s and 2.2 g/16 gN measured micro-b i o l o g i c a l l y following prolonged p r o t e o l y t i c digestion (Ford and S a l t e r , 1966). The plasma free amino acid method i s both simple and r a p i d . Its c r i t i c i s m has been based on the 8 suggestion (Ford and Sa l t e r , 1966) that endogenous protein i s digested and reabsorbed and buffers changes i n the pattern of amino acids passed to the p o r t a l blood. Hence a measure of plasma free amino acids w i l l not be a true i n d i c a t i o n of a v a i l a b i l i t y of amino acids from dietary p r o t e i n . I t i s believed that the mucosal b a r r i e r may simi l a r y exercise a regulatory e f f e c t during a c t i v e transport of amino acids from the gut. Nasset (1956) concluded that the digestive t r a c t imposed a set pattern on the amino acid mixture a v a i l a b l e f o r absorption a f t e r ingestion of a t e s t meal; consequently the plasma free amino acid pattern would f a i l as an i n d i c a t o r of a v a i l a b i l i t y of amino acids from a test protein source. The micr o b i o l o g i c a l assay of Ford (1962) using Streptococcus zymoqenes required p a r t i a l enzymatic hydrolysis of the tes t protein, while the procedure of Stot t and Smith (1966) u t i l i z i n g Tetrahymena  pyriformis W eliminated the need for predigestion with proteo-l y t i c enzymes. The l a t t e r assay i s capable of simultaneously estimating a v a i l a b i l i t y of many e s s e n t i a l amino acids including l y s i n e and methionine. Both methods are rapid and easy assays to carry out but are however reported to underestimate amino acid a v a i l a b i l i t y . Stott and Smith (1966) observed that l y s i n e a v a i l a b i l i t y values estimated m i c r o b i o l o g i c a l l y were much lower (about 60%) than those obtained by the FDNB method while Ford (1964) observed that l y s i n e a v a i l a b i l i t y i n leaf proteins was lower with m i c r o b i o l o g i c a l assays than with the FDNB method. The chick growth assay i s a popular t e s t for amino acid a v a i l a b i l i t y of proteins. I t measures that f r a c t i o n of the ingested amino acids that have been a c t u a l l y u t i l i z e d f o r growth 9 and c o n s e q u e n t l y such an e s t i m a t e would be l o w e r than a v a i l a b i l i t y e s t i m a t e s by t h e f e c a l a n a l y s i s method. I t i s however a l o n g and t e d i o u s p r o c e d u r e f o r e v a l u a t i n g amino a c i d s i n d i v i d u a l l y . I t p e n a l i s e s t h e t e s t amino a c i d whenever o p t i m a l growth f a i l s t o o c c u r and does not t a k e i n t o c o n s i d e r a -t i o n t h e f a c t t h a t i n a low e n e r g y p r o t e i n supplement, s u b s t i -t u t i o n even a t 5% c a n d e p r e s s growth due t o i n s u f f i c i e n t meta-b o l i z a b l e e n e r g y . The p r o c e d u r e a l s o f a i l s t o c o n s i d e r t h e c o n t r i b u t i o n o f o t h e r amino a c i d s i n t h e t e s t p r o t e i n i n i n d u c i n g e i t h e r amino a c i d i m b a l a n c e (and t h e r e f o r e r e d u c e d growth) o r i n c r e a s e d g r o w t h . The p r a c t i c e o f d r o p p i n g extreme p o i n t s i n t h e s t a n d a r d r e s p o n s e c u r v e , t h e use o f amino a c i d m i x t u r e s which a r e not i n o p t i m a l b a l a n c e f o r t h e age o f t h e t e s t c h i c k s and t h e use o f r a c e m i c m i x t u r e s o f amino a c i d s f o r d e r i v i n g s t a n d a r d r e s p o n s e c u r v e s , a r e p o s s i b l e s o u r c e s o f e r r o r when t h i s p r o c e d u r e i s employed t o e s t i m a t e amino a c i d a v a i l a b i l i t y . The f e c a l a n a l y s i s method o f K u i k e n and Lyman (1948) and t h e a v a i l a b i l i t y p r o c e d u r e o f Bragg e t a l . (1969) o f f e r a r a p i d , e a s y and a c c u r a t e method o f e s t i m a t i n g amino a c i d a v a i l a b i l i t y . Measurement o f endogenous amino a c i d e x c r e t i o n d i f f e r e n -t i a t e s t h e s e methods from a p p a r e n t d i g e s t i b i l i t y a s s a y s and e s t i m a t e s t h e d i s a p p e a r a n c e o f amino a c i d s f rom i n g e s t e d p r o t e i n s . The methods a f f o r d an o p p o r t u n i t y t o measure a v a i l a b i l i t y o f twenty amino a c i d s s i m u l t a n e o u s l y and because t h e t e s t p e r i o d i s s h o r t , t h e n i t r o g e n e q u i l i b r i u m o f t h e t e s t b i r d s i s not u n d u l y d i s t u r b e d . I n a d d i t i o n , because a l a r g e number o f c h i c k s c a n be u t i l i z e d , s t r i n g e n t s t a t i s t i c a l t e s t s c a n be a p p l i e d , an i m p o s s i b i l i t y i n many b i o l o g i c a l a s s a y s . 10 A v a i l a b i l i t y o f amino a c i d s i n p l a n t p r o t e i n f e e d s t u f f s E s t i m a t e s o f p e r c e n t a v a i l a b i l i t y o b t a i n e d w i t h t h e v a r i o u s methods d i f f e r . Those o b t a i n e d w i t h the f e c a l a n a l y s i s method a r e g e n e r a l l y h i g h e r than t h o s e o b t a i n e d by any o f t h e b i o l o g i c a l a s s a y t e c h n i q u e s . The per c e n t a v a i l a b i l i t i e s o f amino a c i d s i n soybean meal a r e h i g h e r t h a n i n c o t t o n s e e d meal, r a p e s e e d m e a l , peanut meal o r o t h e r commonly used v e g e t a b l e p r o t e i n s u p p l e m e n t s . True d i g e s t i b i l i t y o f amino a c i d s i n soybean meal was r e p o r t e d by Eggum (1968) t o r a n g e from 85.8% t o 96.2% f o r non r u m i n a n t s . Cho and B a y l e y (1970) u s i n g p i g f e c a l a n a l y s i s e s t i m a t e d mean a p p a r e n t d i g e s t i b i l i t i e s o f amino a c i d s i n s o y -bean meal i n t h e range o f 70.0% t o 92.7%. The a p p a r e n t d i g e s t -i b i l i t y o f a l l amino a c i d s was 88.5%. F l i p o t e t a_l. (1971) u s i n g c h i c k e n s o b s e r v e d a r a n g e o f 87.0% t o 97.0% f o r a v a i l a -b i l i t y o f c o n s t i t u e n t amino a c i d s o f soy p r o t e i n . I v y e t a l . (1971) e v a l u a t e d e i g h t c o m m e r c i a l samples o f soybean m e a l . F o r a l l s amples, t h e range i n a v a i l a b i l i t y was 92.0% t o 100.0%. Sarwar e t aJL. (1975) u s i n g r a t s , r e p o r t e d a range o f 85% t o 95% f o r a v a i l a b i l i t y o f amino a c i d s i n c o m m e r c i a l soybean m e a l . U s i n g a c h i c k g r o w t h a s s a y , S m i t h (1968) r e p o r t e d a r a n g e o f 51.9% t o 103.0%. He o b s e r v e d t h a t i n g e n e r a l , a v a i l a b i l i t i e s o f amino a c i d s were h i g h w i t h t h e e x c e p t i o n o f v a l i n e ( 5 1 . 9 % ) , p h e n y l a l a n i n e ( 5 9 . 2 % ) , and i s o l e u c i n e ( 6 5 . 4 % ) . C a r l s o n and B a y l e y (1970) u s i n g p i g l e t s o b s e r v e d a r a n g e o f 82.2% t o 92.6% f o r t r u e d i g e s t i b i l i t i e s o f amino a c i d s i n soybean m e a l . K u i k e n and Lyman (1948) r e p o r t e d a r a n g e o f 63.6% t o 93.7% 11 f o r t r u e d i g e s t i b i l i t y o f e s s e n t i a l amino a c i d s i n c o t t o n s e e d f l o u r . They showed t h a t marked v a r i a t i o n s i n amino a c i d s o c c u r r e d f o r t h i s f e e d s t u f f . I n a n o t h e r s t u d y , K u i k e n (1952) e s t i m a t e d the a v a i l a b i l i t y o f e s s e n t i a l amino a c i d s i n commer-c i a l c o t t o n s e e d p r o d u c t s . The range f o r amino a c i d a v a i l a b i l i -t i e s o f t h e v a r i o u s c o t t o n s e e d p r o d u c t s were as f o l l o w s : h y d r a u l i c meal 67.0% t o 95.0%; h y d r a u l i c meal w i t h 2% s u l f a -s u x i d i n e 68.0% t o 93.0%; s c r e w p r e s s meal 79.0% t o 95.0%; hexane e x t r a c t e d meal 84.0% t o 98.0%; hexane e x t r a c t e d d e g o s s y -p o l i z e d meal 83.0% t o 97.0%; g l a n d f r e e meal 85.0% t o 97.0%. M e a l s w i t h l o w e s t g o s s y p o l c o n t e n t gave t h e h i g h e s t amino a c i d a v a i l a b i l i t i e s . Thyong (1967) r e p o r t e d l y s i n e a v a i l a b i l i t y i n c o t t o n s e e d cake and c o t t o n s e e d meal as 67.3% and 72,5% r e s p e c -t i v e l y . I t i s o f c o n s i d e r a b l e i n t e r e s t t o n o t e t h a t c o t t o n -seed p r o d u c t s have a h i g h l e v e l o f e s s e n t i a l amino a c i d s w h i c h a r e w e l l u t i l i z e d . W i t h t h e c u r r e n t t e c h n o l o g y now a v a i l a b l e i n t h e p r o c e s s i n g i n d u s t r y , t h e r e s h o u l d be i n c r e a s e d use o f c o t t o n s e e d meal i n non r u m i n a n t r a t i o n s . Cho and B a y l e y (1970) d e t e r m i n e d t h e a p p a r e n t 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 o f amino a c i d s i n r a p e s e e d meal by p i g f e c a l a n a l y s i s . T h e i r r e s u l t s ( 7 7 . 5 % t o 91.0%) were l o w e r t h a n the r a n g e o f 81.0% t o 92.0% r e p o r t e d by Sarwar e t a l . ( 1 9 7 5 ) . U s i n g c h i c k e n s , Tao e t al. (1971) had o b s e r v e d t h a t t r u e amino a c i d d i g e s t i b i l i t y o f r a p e s e e d meal ra n g e d from 59.8% t o 81.9%. Some o f t h e s e d i f f e r e n c e s i n p u b l i s h e d v a l u e s f o r amino a c i d a v a i l a b i l i t i e s may be due t o v a r i a t i o n s i n c o n t e n t o f t o x i c o r o t h e r s u b s t a n c e s i n samples a s s a y e d . The a v a i l a b i l i t y o f amino a c i d s i n o t h e r p r o t e i n s u p p l e -12 ments have a l s o been e s t i m a t e d . K u i k e n and Lyman (1948) o b s e r v e d h i g h a v a i l a b i l i t y o f t e n e s s e n t i a l amino a c i d s i n pea-nut f l o u r ( r ange o f 94.8% t o 9 9 . 5 % ) . Eggum (1968) a l s o r e p o r t e d h i g h 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 peanut meal (range o f 87.8% t o 95.4%) and s u n f l o w e r meal ( r a n g e o f 86.9% t o 9 6 . 3 % ) . No i n f o r m a t i o n was d i s c o v e r e d i n t h e l i t e r a -t u r e on a v a i l a b i l i t y o f amino a c i d s i n palm k e r n e l m e a l . 13 F a c t o r s a f f e c t i n g a v a i l a b i l i t y o f amino a c i d s I t i s known t h a t t h e n u t r i t i v e v a l u e o f a p r o t e i n depends no t o n l y on i t s p a t t e r n o f amino a c i d s b u t a l s o on t h e b i o l o g i c a l a v a i l a b i l i t y o f t h e s e amino a c i d s . The amounts o f amino a c i d s p r e s e n t i n a f e e d i n g r e d i e n t a r e not n e c e s s a r i l y t h e same amounts a v a i l a b l e t o t h e a n i m a l . F a c t o r s r e d u c i n g amino a c i d a v a i l a b i l i t y i n c l u d e i n c o m p l e t e d i g e s t i o n and a b s o r p t i o n , p r o c e s s i n g c o n d i t i o n s , p r e s e n c e o f i n h i b i t o r s o f d i g e s t i v e enzymes, c r u d e f i b r e , t a n n i n s and o t h e r p h y s i c a l and c h e m i c a l b i n d i n g a g e n t s . S o u t h g a t e and D u r n i n (1970) r e p o r t e d t h a t as t h e i n t a k e o f d i e t a r y f i b r e i n c r e a s e d , t h e a p p a r e n t d i g e s t i b i l i t y o f o t h e r c o n s t i t u e n t s i n t h e d i e t ( p r o t e i n , f a t , e n e r g y ) was r e d u c e d . S o u t h g a t e (1973) s u g g e s t e d t h a t t h e i n c r e a s e d b u l k o f non-a s s i m a b l e m a t e r i a l i n the l a r g e and s m a l l i n t e s t i n e had an e f f e c t on t r a n s i t t i m e , so t h a t t h e r e was l e s s t i m e f o r t h e p r o c e s s e s o f d i g e s t i o n and a b s o r p t i o n . S e v e r a l w o r k e r s (Dammers, 1965; Tao e t a l . , 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 c r u d e f i b r e as a 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 . T o x i c c o n s t i t u e n t s i n f e e d ( S t e p h e n s o n , 1972) and p h y t a t e ( N e l s o n , 1967) have been s u g g e s t e d as f a c t o r s w h i c h r e d u c e 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 . Any f a c t o r which a f f e c t s 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 w i l l c e r t a i n l y a f f e c t amino a c i d a v a i l a b i l i t y . The p r e s e n c e o f t r y p t i c and o t h e r i n h i b i t o r s o f p r o t e o l y t i c enzymes has been e s t a b l i s h e d i n many legumes. They l o w e r t h e d i g e s t i b i l i t y o f p r o t e i n s ( L e p k o v s k y ejt a _ l . , 1965) and may 14 r e d u c e a v a i l a b i l i t y o f amino a c i d s . P r o t e i n - c a r b o h y d r a t e i n t e r a c t i o n s o c c u r between amino g r o u p s o f the p r o t e i n and r e d u c i n g c a r b o h y d r a t e s p r e s e n t , t o f o r m compounds w h i c h r e n d e r amino a c i d s u n a v a i l a b l e t o a n i m a l s . Lea and Hannon (1950) u s i n g a c a s e i n - g l u c o s e system as a model showed t h a t i n a p p r o p r i a t e c o n d i t i o n s , n e a r l y a l l the l y s i n e c o u l d be r e n d e r e d u n a v a i l a b l e . The amino a c i d - c a r b o h y d r a t e complex cannot be h y d r o l y s e d by d i g e s t i v e enzymes and a r e a l o s s t o t h e a n i m a l . Nesheim (1965) s t a t e d t h a t p r o t e i n - c a r b o h y d r a t e r e a c t i o n s c o u l d p r o c e e d t o t h e p o i n t where c o m p l e t e d e s t r u c -t i o n o f t h e component amino a c i d s took p l a c e . R e a c t i o n s between the t e r m i n a l amino group o f l y s i n e and t h e c a r b o n y l s e c o n d a r y d e c o m p o s i t i o n p r o d u c t s o f a u t o o x i d i n g f a t s may r e d u c e amino a c i d a v a i l a b i l i t y , by f o r m i n g l i n k a g e s r e s i s t a n t t o t h e a c t i o n o f d i g e s t i v e enzymes. The t y p e o f damage done depends on t h e c o n d i t i o n s . Lea ejt a l . (1960) r e p o r t e d t h a t a t t e m p e r a t u r e s below 100°C, l y s i n e was l o s t by r e a c t i o n w i t h a u t o o x i d i s i n g f a t , w h i l e a t h i g h e r t e m p e r a t u r e s (115-130°C) the l o s s was a p p a r e n t l y i n d e p e n d e n t o f t h e p r e s e n c e o f f a t . Damage t o amino a c i d s i s p r o p o r t i o n a l t o t h e t i m e and t e m p e r a t u r e a p p l i e d beyond a c r i t i c a l p o i n t . Greaves e t a l . (1938) had p o i n t e d o u t t h a t c a s e i n was h e a t damaged a t 120°C bu t not a t 100°C and above t h i s c r i t i c a l t e m p e r a t u r e , t h e amount o f damage was p r o p o r t i o n a l t o t h e t i m e o f h e a t i n g . Lea and Hannon (1949) o b s e r v e d t h a t 10% t o 14% m o i s t u r e was t h e p o i n t o f h i g h e s t p r o t e i n damage when p r o t e i n was h e a t e d w h i l e C a r p e n t e r e t a l _ . (1962) r e p o r t e d t h a t l o s s o f 15 a v a i l a b l e l y s i n e i n he a t e d h e r r i n g meal was g r e a t e s t a t 5% t o 14% m o i s t u r e . T a n n i n s have a l s o been i m p l i c a t e d i n r e d u c e d amino a c i d a v a i l a b i l i t y . G l i c k and J o s y l n (1970) o b s e r v e d a t h r e e t o f o u r f o l d i n c r e a s e i n l e v e l o f a c t i v i t y o f i n t e s t i n a l p r o t e o -l y t i c enzymes o f r a t s f e d t a n n i c a c i d and a l s o c o n c l u d e d t h a t endogenous p r o t e i n s a c c o u n t e d i n p a r t f o r t h e h i g h f e c a l n i t r o g e n o b s e r v e d when t a n n i c a c i d was f e d t o r a t s . S i m i l a r l y , R ostagno et. 3d. (1973) o b s e r v e d a f o u r f o l d i n c r e a s e i n endo-genous amino a c i d e x c r e t i o n when 1.41% t a n n i c a c i d was added . t o a p r o t e i n f r e e d i e t . These w o r k e r s u s i n g sorqhum g r a i n , d e m o n s t r a t e d d e c r e a s e d average amino a c i d a v a i l a b i l i t i e s ( 7 3 . 0 % , 41.5%, 25.6% and 22.2%) as the t a n n i c a c i d c o n t e n t i n c r e a s e d ( 0.33%, 0.59%, 1.10% and 1.41% r e s p e c t i v e l y ) . T h i s was i n agreement w i t h the o b s e r v a t i o n o f Stephenson e t a l . (1971) t h a t amino a c i d a v a i l a b i l i t y v a l u e s o f h i g h t a n n i n sorghum ( G e o r g i a 609) were much lo w e r t h a n v a l u e s o f sorghum RS610. Rostagno. ej: a l . (1973) c o u l d not however e x p l a i n t h e a p p a r e n t d e p r e s s i o n o f amino a c i d a v a i l a b i l i t y by t a n n i n s . 16 Methods o f d e t e r m i n i n g m e t a b o l i z a b l e e n e r g y o f f e e d i n g r e d i e n t s A s a t i s f a c t o r y b a s i c d i e t and p r o c e d u r e f o r d e t e r m i n i n g t h e m e t a b o l i z a b l e e n ergy c o n t e n t o f f e e d i n g r e d i e n t s f o r p o u l t r y was worked out by H i l l and a s s o c i a t e s ( H i l l and Ander-s o n , 1958; H i l l e t a l . , 1 9 6 0 ) . They p r o p o s e d a w h e a t - s y n t h e t i c b a s a l d i e t i n w h i c h t h e e x p e r i m e n t a l m a t e r i a l was i n c o r p o r a t e d a t a l e v e l o f 40 p e r c e n t a t t h e expense o f g l u c o s e . T h i s p r o c e d u r e has been used e x t e n s i v e l y t o d e t e r m i n e t h e m e t a b o l i -z a b l e e n ergy o f g r a i n and g r a i n p r o d u c t s ( H i l l e t a l . , 1 9 6 0 ), soybean p r o d u c t s ( H i l l and Renner, 1960), peanut meal, sesame meal, c o t t o n s e e d m e a l, s a f f l o w e r meal and c o p r a meal ( Z a b l a n e t a l . , 1963). S i b b a l d and S l i n g e r (1962) r e p o r t e d a p r o c e d u r e u t i l i z i n g a p r a c t i c a l t y pe b a s a l d i e t i n t o w h i c h graded amounts o f t h e t e s t i n g r e d i e n t were s u b s t i t u t e d . A tremendous amount o f i n v e s t i g a t i o n i n t o the m e t a b o l i z a b l e e n e r g y c o n t e n t o f v a r i o u s f e e d i n g r e d i e n t s has been c a r r i e d o u t u s i n g t h e s e p r o c e d u r e s o r w i t h s l i g h t m o d i f i c a t i o n s i n d i c a t i n g the i m p o r t -ance o f t h e methods. Feed i n t a k e and f e c a l o u t p u t have been d e t e r m i n e d by t o t a l c o l l e c t i o n o r by use o f a marker ( L i n d a h l , 1 9 6 3 ) . I n d i c a t o r methods have t h e advantage t h a t measurement o f f e e d i n t a k e o r f e c a l o u t p u t i s u n n e c e s s a r y . However, Moore (1957) o b s e r v e d t h a t p a r t i a l s a m p l i n g p r o c e d u r e s i n d i g e s t -i b i l i t y e x p e r i m e n t s u s i n g i n d e x s u b s t a n c e s were o n l y v a l i d when t h e f e c a l e x c r e t i o n c u r v e s f o r n u t r i e n t and i n d i c a t o r were s i m i l a r and t h e r e was no s e t t l i n g o ut o r l o s s o f i n d e x sub-s t a n c e from t h e f e e d . Carew (1973) noted t h a t t h e d e t e r m i n a t i o n o f chromium was 17 t e d i o u s , t ime consuming and t h e r e s u l t s were not a l w a y s s a t i s -f a c t o r y , Kotb and Luckey (1973) o b s e r v e d t h a t the use o f s i l i c a as an i n d i c a t o r c o u l d be u n r e l i a b l e . M c C a r t h y e t a_l. (1974) and Vogtmann e_t a _ l . (1975) r e p o r t e d the p o s s i b i l i t y o f u s i n g a c i d i n s o l u b l e ash t o d e t e r m i n e m e t a b o l i z a b l e energy i n non r u m i n a n t s . These w o r k e r s o b s e r v e d t h a t t h e ash r e m a i n i n g a f t e r t r e a t m e n t o f t h e sample w i t h 4N HCl and a s h i n g the r e s i d u e c o u l d be a s u i t a b l e i n d e x f o r d e t e r m i n i n g d i g e s t i b i l i t y o f f e e d s . T h i s method i s r a p i d and l e s s t e d i o u s t h a n the t o t a l c o l l e c t i o n - o r c h r o m i c o x i d e p r o c e d u r e and has been r e p o r t e d by t h e s e w o r k e r s t o be a c c u r a t e . When i t s a c c u r a c y i s c o n f i r m e d t h r o u g h r e p e a t e d e x p e r i m e n t a t i o n , i t has t h e p o t e n t i a l o f d o m i n a t i n g o t h e r r e s e a r c h methods f o r m e t a b o l i z a b l e e n e r g y d e t e r m i n a t i o n . More r e c e n t l y , S i b b a l d (1975, 1976) p r o p o s e d a b i o a s s a y f o r d e t e r m i n a t i o n o f t r u e m e t a b o l i z a b l e e n e r g y o f f e e d i n g s t u f f s . He o b s e r v e d t h a t c o n v e n t i o n a l m e t a b o l i z a b l e e n e r g y r e s u l t s were a f f e c t e d by t h e l e v e l o f f e e d i n t a k e and because t h e combined m e t a b o l i c and endogenous l o s s e s were c h a r g e d a g a i n s t t h e energy i n t a k e , a t low l e v e l s o f f e e d c o n s u m p t i o n , n e g a t i v e m e t a b o l i z a b l e e n e r g y c o u l d be o b t a i n e d . He proposed a p r o c e d u r e i n v o l v i n g f o r c e f e e d i n g o f p r e v i o u s l y s t a r v e d a d u l t r o o s t e r s and c o l l e c -t i o n o f v o i d e d e x c r e t a . U s i n g v a r i o u s f e e d i n g s t u f f s , he r e p o r t e d a l i n e a r r e l a t i o n s h i p between e n e r g y v o i d e d as e x c r e t a i n 24 hours (Ye) and f e e d i n p u t ( X ) . True m e t a b o l i z a b l e e n ergy (TME) v a l u e s were c a l c u l a t e d as f o l l o w s : TME(kcal/kg).= (G.E. f x X) - (Ye - 9.84) 18 where G.E.^ = G r o s s energy o f f e e d X = Feed i n p u t Ye = T o t a l energy v o i d e d as e x c r e t a i n 24 h o u r s 9.84 = Sum o f m e t a b o l i c f e c a l e n e r g y ( F E m ) and endoge-nous u r i n a r y e n e r g y ( U E e ) e x c r e t e d i n d e p e n d e n t l y o f t h e f e e d i n t a k e d u r i n g 24 h o u r s The a s s a y a p p e a r s t o be r a p i d and i n v o l v e s few c h e m i c a l a n a l y s e s . S i b b a l d (1975) n o t e s t h a t development work on t h e p r o c e d u r e w i l l be r e q u i r e d b e f o r e i t can be w i d e l y a c c e p t e d and o b s e r v e s t h a t i t o f f e r s p o t e n t i a l advantages i n r e s p e c t o f t i m e , c o s t and v a l i d i t y o f d a t a o b t a i n e d . 19 M e t a b o l i z a b l e e n e r g y 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 H i l l and Renner (1960) f i r s t i n v e s t i g a t e d t h e m e t a b o l i z a b l e e n e r g y c o n t e n t o f v a r i o u s soybean p r o d u c t s f o r t h e c h i c k . They r e p o r t e d m e t a b o l i z a b l e e n ergy v a l u e s o f 44% and 50% p r o t e i n meals as 2244 k c a l / k g and 2530 k c a l / k g r e s p e c t i v e l y . Depressed m e t a b o l i z a b l e e n e r g y was o b s e r v e d f o r t h e low p r o t e i n m i l l f e e d (770 k c a l / k g ) o r h i g h p r o t e i n m i l l f e e d (1254 k c a l / k g ) . Soy-beans, raw (2420 k c a l / k g ) o r a u t o c l a v e d (3168 k c a l / k g ) gave h i g h e r m e t a b o l i z a b l e energy v a l u e s . Raw e x t r a c t e d soybean f l a k e s had a m e t a b o l i z a b l e e n e r g y v a l u e o f 616 k c a l / k g w h i l e a u t o c l a v e d soybean f l a k e s were h i g h e r (2122 k c a l / k g ) . Renner and H i l l (1960) showed t h a t m i l d heat t r e a t m e n t ( t e n m i n u t e s a t 107°C) gave t h e h i g h e s t m e t a b l i z a b l e e n e r g y v a l u e o f soybeans, o r soybean f l a k e s f o r c h i c k e n s . T h i s was due t o t h e i n a c t i v a -t i o n o f one o r more t r y p s i n i n h i b i t o r s ( B o r c h e r s e t a l . , 1948) and t h e d e s t r u c t i o n o f heat l a b i l e s o y i n ( L i e n e r , 1 9 5 3 ) . H i l l and T o t s u k a (1964) r e p o r t e d a m e t a b o l i z a b l e e n ergy v a l u e o f 2780 k c a l / k g f o r c o m m e r c i a l soybean meal w h i l e L a u t n e r and Z e n i s e k (1965) o b t a i n e d a v a l u e o f 2603 k c a l / k g . R o j a s and S c o t t (1969) r e p o r t e d t h e a v e r a g e m e t a b o l i z a b l e energy o f 50% p r o t e i n c o m m e r c i a l s o l v e n t e x t r a c t e d soybean meal as 2770 k c a l / k g . I n a n o t h e r s t u d y , t h e y o b s e r v e d t h a t t r e a t m e n t o f soybean meal w i t h p h y t a s e enzyme improved t h e m e t a b l i z a b l e e n e r g y o f 44% and 50% p r o t e i n soybean meal by 6.5% and 11% r e s p e c t i v e l y . L o d h i e t a _ l . (1969a) d e t e r m i n e d t h e a v a i l a b l e c a r b o h y d r a t e c o n t e n t o f soybean and r a p e s e e d meals i n an a t t e m p t t o e x p l a i n d i f f e r e n c e s i n m e t a b o l i z a b l e e n e r g y between t h e m e a l s . They 20 o b s e r v e d t h a t i n soybean meal, s o l u b l e s u g a r s and s t a r c h c o m p r i s e d 67% o f t h e n i t r o g e n - f r e e e x t r a c t as compared t o 40% i n r a p e s e e d m e a l . Assuming an e n ergy v a l u e o f 3.75 k c a l / g f o r t h e c a r b o h y d r a t e i n t h e two meals, t h e y c o n c l u d e d t h a t 19% o f t h e d i f f e r e n c e i n m e t a b o l i z a b l e e n ergy between soybean and r a p e s e e d meals c o u l d be a c c o u n t e d f o r by t h e d i f f e r e n c e i n amount o f a v a i l a b l e c a r b o h y d r a t e s . B o l t o n (1957) o b s e r v e d t h a t s u g a r s and s t a r c h i n soybean meal were 100% d i g e s t i b l e and u s i n g a c h e m i c a l method, showed t h a t t h e l e v e l o f s u g a r p l u s s t a r c h i n 49% p r o t e i n meal was 17.6% o f d r y m a t t e r . The h i g h m e t a b o l i z a b l e e n e r g y v a l u e s r e p o r t e d f o r c o m m e r c i a l soybean meal i s due t o a u n i q u e c o m b i n a t i o n o f h i g h a v a i l a b l e c a r b o h y -d r a t e c o n t e n t , low c r u d e f i b r e c o n t e n t and e x t e n s i v e d e n a t u r a -t i o n o f t o x i c compounds d u r i n g p r o c e s s i n g . U n t i l r e c e n t l y , the use o f c o t t o n s e e d meal was n o t p o p u l a r i n p o u l t r y d i e t s . I t i s known t o c o n t a i n g o s s y p o l , g o s s y p o l -l i k e pigments and c y c l o p r o p e n e f a t t y a c i d s , and i t i s d e f i c i e n t i n l y s i n e ( P h e l p s , 1966). These f a c t o r s c o n t r i b u t e d t o t h e r e s t r i c t e d use o f c o t t o n s e e d meal i n p o u l t r y r a t i o n s . An e a r l i e r s t u d y on t h e m e t a b o l i z a b l e e n ergy o f c o t t o n s e e d meal ( Z a b l a n e t a l . , 1963) had i n d i c a t e d t h e p o s s i b i l i t y o f u s i n g c o t t o n s e e d meal i n p o u l t r y r a t i o n s due t o t h e m e t a b o l i z a b l e e n e r g y c o n t e n t . H i l l and T o t s u k a (1964) r e c o g n i s e d t h a t t h e n u t r i t i v e v a l u e o f c o t t o n s e e d meal t o p o u l t r y was i n f l u e n c e d by such f a c t o r s as g o s s y p o l t o x i c i t y , e x t e n t o f heat damage d u r i n g p r o c e s s i n g and t h e p o s s i b l e p r e s e n c e o f a heat l a b i l e i n h i b i t o r y f a c t o r i n g l a n d l e s s c o t t o n s e e d . They s u g g e s t e d t h a t d e c r e a s e d m e t a b o l i z a b l e e n e r g y o f c o t t o n s e e d meal was due t o i n t e r f e r e n c e o f g o s s y p o l w i t h d i g e s t i o n and/or a b s o r p t i o n o f p r o t e i n o r c a r b o h y d r a t e components o f c o t t o n s e e d m e a l . They r e p o r t e d m e t a b o l i z a b l e e n e r g y v a l u e s o f 2190, 2280 and 2240 k c a l / k g , . f o r hexane e x t r a c t e d g l a n d l e s s c o t t o n s e e d m e a l, h e a t e d hexane e x t r a c t e d o r mixed s o l v e n t e x t r a c t e d c o t t o n s e e d meal r e s p e c t i v e l y . They o b s e r v e d a moderate ( b u t non s i g n i f i c a n t ) i n v e r s e c o r r e l a t i o n between c r u d e f i b r e c o n t e n t o f t h e meals and t h e i r o b s e r v e d m e t a b o l i z a b l e energy and s u g g e s t e d t h a t d i f f e r e n c e i n c r u d e f i b r e c o n t e n t c o u l d a c c o u n t f o r about a t h i r d o f t h e d i f f e r e n c e i n m e t a b o l i z a b l e e n e r g y between t h e m e a l s . The r e m a i n d e r o f t h e d i f f e r e n c e was a t t r i b u t e d t o d i f f e r e n c e s i n p r o t e i n and c a r b o h y d r a t e u t i l i z a t i o n o f t h e me a l s . They s u g g e s t e d t h a t m e t a b l i z a b l e e n e rgy o f c o t t o n s e e d , meal c o u l d be c l o s e l y r e l a t e d t o t h e e x t e n t o f heat damage t o p r o t e i n o f t h e m e a l . R o j a s and S c o t t (1969) s t u d i e d t h e m e t a b o l i z a b l e e n e r g y o f c o m m e r c i a l , g l a n d e d and g l a n d l e s s c o t t o n s e e d meals p r o d u c e d by screw p r e s s i n g , s o l v e n t e x t r a c t i o n , p r e p r e s s s o l -v e n t e x t r a c t i o n and s o l v e n t e x t r a c t i o n u s i n g a mixed a z e o t r o p i c s o l u t i o n . These w o r k e r s r e p o r t e d a range o f 1375 k c a l / k g ( 4 1 % p r o t e i n , e x p e r i m e n t a l s o l v e n t e x t r a c t e d meal) t o 2490 k c a l / k g ( 5 2 % p r o t e i n , e x p e r i m e n t a l g l a n d l e s s s o l v e n t e x t r a c t e d meal) w i t h a mean o f 2182 k c a l / k g f o r a l l samples o f c o t t o n s e e d meal t e s t e d . The m e t a b o l i z a b l e e n e r g y o f t h e g l a n d l e s s , s c r e w p r e s s and mixed s o l v e n t e x t r a c t e d c o t t o n s e e d meals were not s t a t i -s t i c a l l y d i f f e r e n t . The m e t a b o l i z a b l e e n e r g y o f g l a n d l e s s and scr e w p r e s s meals were s u p e r i o r t o t h o s e o f g l a n d e d and p r e -p r e s s s o l v e n t e x t r a c t e d m e a l s . The ave r a g e m e t a b o l i z a b l e e n e r g y c o n t e n t o f 50% p r o t e i n s o l v e n t e x t r a c t e d soybean meal was 2770 kcal/kg and i t was suggested that the d i f f e r e n c e i n metabolizable energy between cottonseed meal and soybean meal could be a t t r i b u t e d to d i f f e r e n c e s i n chemical composition i n regard to protein, f a t and f i b r e , i n protein s o l u b i l i t y and to the presence of gossypol i n cottonseed meal. Rojas and Scott (1969) and Miles and Nelson (1974) implicated content of phytic acid as a fa c t o r depressing metabolizable energy values of cottonseed meal. Metabolizable energy values were improved by treatment with a phytase enzyme. Phytase enzyme treatment apparently improved the metablizable energy by complete hydro-l y s i s of phytin, r e l e a s i n g some proteins from protein-phytate complexes and reduction i n gossypol t o x i c i t y of glanded cotton-seed meals. Considerable v a r i a t i o n has been reported i n r e s u l t s of meatabolizable energy of rapeseed meal. Factors implicated as being responsible f o r observed v a r i a t i o n include age of the experimental b i r d s (March e_fc a l . , 1973), method of assay (Potter, 1971), tannins (Yapar and Clandinin, 1972), a v a i l a b l e carbohydrate content (Lodhi et a l . , 1969a) and goitrogen content (Lodhi et a l . , 1970). Lodhi et a l . (1969b) observed metaboli-zable energy of 1104 kcal/kg while March and B i e l y (1971) reported a range of 1120 to 1730 kcal/kg f o r rapeseed meals. In other studies, March et a l . (1973) reported metabolizable energy values of 1510 and 1465 kcal/kg f o r rapeseed meal fed to b r o i l e r and white leghorn chicks r e s p e c t i v e l y . Rao and Clandinin (1971) using semi p u r i f i e d or p r a c t i c a l d i e t s reported metabolizable energy values of 1126 or 1586 kcal/kg r e s p e c t i v e l y f o r three-week old chicks while Clandinin (1973) e s t i m a t e d t h e m e t a b o l i z a b l e e n e r g y o f r a p e s e e d meal as 1760 k c a l / k g . Yapar and C l a n d i n i n (1972) o b s e r v e d t h a t e x t r a c t i o n o f t a n n i n s improved th e m e t a b o l i z a b l e e n e r g y o f r a p e s e e d meal f r o m 1171 t o 1844 k c a l / k g f o r two-week o l d c h i c k s and f rom 1171 t o 1766 k c a l / k g f o r s i x - w e e k o l d c h i c k s . Seth and C l a n d i n i n (1973) r e p o r t e d a v e r a g e m e t a b o l i z a b l e e n ergy o f 2327 k c a l / k g f o r t h r e e v a r i e t i e s o f low h u l l r a p e s e e d meal c o n t a i n i n g 7.76% t o 10.30% f i b r e and 1730 k c a l / k g f o r r e g u l a r r a p e s e e d meal c o n t a i n i n g 15% t o 17% f i b r e . The m e t a b o l i z a b l e e n e r g y v a l u e s o f two v a r i e t i e s o f r a p e s e e d meal were r e p o r t e d as 1755 and 1860 k c a l / k g f o r four-week o l d c h i c k s (March ejb a l . , 1975) w h i l e S e l l (1966) r e p o r t e d a v a l u e o f 2120 k c a l / k g f o r c o m m e r c i a l r a p e s e e d meal f e d t o l a y i n g hens. V e r y 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 i n t h e l i t e r a t u r e on t h e m e t a b o l i z a b l e e n ergy o f palm k e r n e l meal t o c h i c k s . Gohl (1975) r e p o r t e d t h a t m e t a b o l i z a b l e energy o f palm k e r n e l meal f o r p o u l t r y v a r i e d from 2150 k c a l / k g ( m e c h a n i c a l , p r e s s , 6% e t h e r e x t r a c t ) t o 3070 k c a l / k g ( m e c h a n i c a l p r e s s , 10% e t h e r e x t r a c t ) . S o l v e n t e x t r a c t e d palm k e r n e l meal was l o w e r i n m e t a b o l i z a b l e e n e r g y (2110 k c a l / k g ) . M e t a b o l i z a b l e e n e r g y v a l u e s r e p o r t e d f o r o t h e r a n i m a l s ( L a t i n A m e r i c a n T a b l e s o f Feed C o m p o s i t i o n , 1974) were swine (2310-2517 k c a l / k g ) sheep (2450-2520 k c a l / k g ) and c a t t l e (2850-3040 k c a l / k g ) u s i n g meals o f v a r y i n g f i b r e , p r o t e i n and e t h e r e x t r a c t c o n t e n t . 24 T e c h n i q u e s f o r e s t i m a t i n g m i n e r a l a v a i l a b i l i t y The a p p a r e n t d i g e s t i b i l i t y method measures t h e i n t a k e as w e l l as f e c a l and u r i n a r y o u t p u t o f t h e t e s t m i n e r a l s and a c c o r d i n g t o M i t c h e l l (1964) was one o f t h e more common methods o f d e t e r m i n i n g m i n e r a l u t i l i z a t i o n . I t d i d n o t a c c o u n t f o r the m e t a b o l i c f e c a l and endogenous u r i n a r y l o s s e s and tended t o u n d e r e s t i m a t e u t i l i z a t i o n o f t h e t e s t m i n e r a l s . T h i s p r o c e d u r e assumed t h a t endogenous m i n e r a l l o s s e s were m i n i m a l and i g n o r e d them s i n c e t h e r e were not e n t i r e l y s a t i s f a c t o r y methods o f e s t i m a t i n g t h e s e l o s s e s . E a r l y work on m i n e r a l a v a i l a b i l i t y i n r u m i n a n t s was v e r y s i m p l e , a l l t h a t was r e q u i r e d b e i n g an e s t i m a t e o f t h e i n t a k e and f e c a l e x c r e t i o n o f the m i n e r a l s t e s t e d . Rook and Campling (1962) o b s e r v e d t h a t a l o t o f t h e i n f o r m a t i o n p u b l i s h e d on magnesium a v a i l a b i l i t y f o r r u m i n a n t s was o b t a i n e d i n b a l a n c e s t u d i e s i n which a p p a r e n t d i g e s t i b i l i t y o f magnesium was c a l c u l a t e d as i n t a k e l e s s f e c a l l o s s , e x p r e s s e d as a p e r c e n t a g e o f i n t a k e . I t soon however became e v i d e n t t h a t a p p a r e n t d i g e s t i b i l i t y r e s u l t s were not i n d i c a t i v e o f t h e a v a i l a b i l i t y o f m i n e r a l s t o l i v e s t o c k and a more p r e c i s e e s t i m a t e was needed. The a v a i l a b i l i t y o r t r u e d i g e s t i b i l i t y method t a k e s i n t o a c c o u n t t h e o b s e r v a t i o n t h a t n ot a l l t h e m i n e r a l i n f e c a l o r u r i n a r y e x c r e t i o n i s o f f e e d o r i g i n . E s t i m a t i o n o f endogenous m i n e r a l e x c r e t i o n i n v o l v e s use o f p u r i f i e d m i n e r a l f r e e d i e t s o r t h e use o f r e g r e s s i o n s o f r e t e n t i o n o f t h e element on i t s i n t a k e . The p u r i f i e d d i e t s a r e so f o r m u l a t e d as t o e x c l u d e a l l m i n e r a l s b e i n g t e s t e d . D u r a t i o n o f t h e t e s t i s s h o r t , so 25 as not to s u b s t a n t i a l l y d i s t u r b the mineral equilibrium of the te s t animals. Because endogenous excretion i s taken i n t o account i n c a l c u l a t i n g true d i g e s t i b i l i t y , the r e s u l t s obtained are usually higher than apparent d i g e s t i b i l i t y r e s u l t s and are a more r e a l i s t i c estimate of mineral a v a i l a b i l i t y . The carcass analysis technique involves the use of l i t t e r mates, some of which are slaughtered at the beginning of the experiment to determine the r a t i o s of body weight to tes t minerals. The other members of the l i t t e r are fed a c o n t r o l l e d d i e t i n which the test ingredient i s the only source of the minerals under study. Feed intake records are kept. At the end of the experimental period, the test animals are slaughtered, ashed and mineral content determined. Minerals retained expressed as a f r a c t i o n of mineral intake i s an i n d i c a t o r of a v a i l a b i l i t y . Armstrong and Thomas (1952) reported no s i g n i -f i c a n t differences between calcium a v a i l a b i l i t y r e s u l t s obtained by other methods or by the carcass analysis method. The isotope d i l u t i o n technique involves i n j e c t i n g i n t r a -venously, sing l e (Hansard et a l . , 1952; 1954) or multiple (Visek et a l . , 1953) doses of radioisotopes•of the test element. At equilibrium, i f there i s no endogenous excretion of the mineral, the s p e c i f i c a c t i v i t i e s of the feces and plasma should be i d e n t i c a l . D i l u t i o n of the t o t a l element i n the feces by endogenous excretion can be measured by di f f e r e n c e i n the plasma and f e c a l s p e c i f i c a c t i v i t i e s . Pairs of animals are used i n the comparative balance technique. One i s dosed o r a l l y while the other i s in j e c t e d intravenously with a radioisotope of the tes t element. I t i s 26 assumed that the o r a l dose completely l a b e l s the d i e t a r y source of the element. Endogenous excretion i s estimated from the intravenously i n j e c t e d animal. True d i g e s t i b i l i t y can there-fore, be c a l c u l a t e d . Aubert e_fc aJL. (1963) proposed a modification of t h i s procedure, eliminating the use of paired animals by i n j e c t i o n of two d i f f e r e n t isotopes of the same element. A b i o l o g i c a l assay technique commonly used i n estimating mineral a v a i l a b i l i t y i s the bone ash method of G i l l i s e_t a l . (1954). The assay involved the establishment of a standard response curve using a semi p u r i f i e d basal d i e t and graded l e v e l s of an inorganic s a l t of the test element (assumed to be 100% u t i l i z e d at low dietary l e v e l s ) . A p l o t of per cent bone ash of solvent extracted l e f t chick t i b i a and the logarithm of the percentage d i e t a r y mineral gave a s t r a i g h t l i n e . The test ingredient was substituted f o r a small f r a c t i o n of the basal d i e t . B i o l o g i c a l a v a i l a b i l i t y was defined as the r a t i o , expressed as a percentage, of the amount of the inorganic s a l t to the amount of test ingredient which produced the same bone ash when each was added to the basal d i e t . Per cent bone ash i s the most commonly used t e s t f o r estimating mineral a v a i l a -b i l i t y i n feeds. Nelson (1967) noted that i t was one of the most s e n s i t i v e , p r a c t i c a l c r i t e r i a for evaluating the a v a i l a b i l i t y of d i e t a r y phosphorus. It i s more accurate than body weight measurement and i s l i t t l e a f f e c t e d by other d i e t a r y variables that influence growth (Nelson and Walker, 1964). Another b i o l o g i c a l assay technique which has been used i n estimating mineral a v a i l a b i l i t y i s the body weight method of 27 O ' D e l l and c o w o r k e r s ( 1 9 7 2 ) . S t a n d a r d r e s p o n s e c u r v e s a r e e s t a b l i s h e d by s u p p l e m e n t i n g b a s a l d i e t s w i t h graded l e v e l s o f t h e t e s t element i n i n o r g a n i c form (assuming 100% u t i l i z a t i o n ) . A p l o t o f w e i g h t o r w e i g h t g a i n v e r s u s t h e l o g a r i t h m o f t h e s u p p l e m e n t a l e l e m e n t g i v e s a l i n e a r r e s p o n s e c u r v e a t l o w e r l e v e l s o f s u p p l e m e n t a t i o n . The t e s t i n g r e d i e n t s a r e a n a l y s e d and s u b s e q u e n t l y s u b s t i t u t e d f o r c a r b o h y d r a t e i n t h e b a s a l d i e t a t low l e v e l s . The q u a n t i t y o f b i o l o g i c a l l y a v a i l a b l e m i n e r a l i s e s t i m a t e d from t h e s t a n d a r d c u r v e and d i v i d e d by t h e c o n t e n t o f t h e t e s t m i n e r a l i n t h e i n g r e d i e n t . N e l s o n (1967) however o b s e r v e d t h a t body w e i g h t was not an a c c u r a t e measure o f phos-ph o r u s u t i l i z a t i o n and i t s use has l e d t o m i s l e a d i n g c o n c l u -s i o n s . A number o f o t h e r b i o l o g i c a l a s s a y t e c h n i q u e s have been u t i l i z e d i n e s t i m a t i n g m i n e r a l a v a i l a b i l i t y . A v a i l a b i l i t y o f i o d i n e from v a r i o u s forms ( d r i e d k e l p , i o d i z e d l i n s e e d m e a l , p o t a s s i u m i o d i d e ) have been s t u d i e d i n t h e l a y i n g hen by o b s e r v i n g t h e i r e f f e c t s on t h e i o d i n e c o n t e n t o f t h e egg ( W i l d e r et a l . , 1933) and i n a l b i n o r a t s by p r e v e n t i o n o f e n l a r g e m e n t o f t h e t h y r o i d g l a n d ( M i t t l e r and Benham, 19 5 4 ) . A v a i l a b i l i t y o f magnesium and i r o n have been s t u d i e d based on a b i l i t y t o r e g e n e r a t e hemoglobin i n t e s t r a t s . Thompson and Raven (1959) e s t i m a t e d i r o n a v a i l a b i l i t y f r o m d i f f e r e n t herbage s p e c i e s by t h e i r a b i l i t y t o r e g e n e r a t e h e m o g l o b i n i n anemic r a t s . K i r c h g e s s n e r and Grassmann (1971) u s i n g r a t s a l s o s t u d i e d a v a i l a b i l i t y o f c o p p e r u s i n g c e r u l o p l a s r a i n as a t e s t enzyme. R e s t o r a t i o n o f e e r u l o p l a s m i n i n d e p l e t e d r a t s was t a k e n as an i n d i c a t i o n o f c o p p e r a v a i l a b i l i t y . 28 A v a i l a b i l i t y o f m i n e r a l s i n v e g e t a b l e p r o t e i n s o u r c e s V a r i o u s p r o t e i n s o u r c e s have been r e p o r t e d t o i n t e r f e r e w i t h t h e a v a i l a b i l i t y o f m i n e r a l s i n d i e t s . These i n c l u d e peas ( K i e n h o l z e t t i l . , 1959; K i e n h o l z e t a l . , 1962), i s o l a t e d soybean p r o t e i n ( G ' D e l l and Savage, 1 9 6 0 ) , sesame meal (Lease ejb a l . , 1960; L e a s e , 1966), amino a c i d and c a s e i n d i e t s ( L i k u s k i and F o r b e s , 1964), s a f f l o w e r , c o t t o n s e e d and soybean meals (Lease and W i l l i a m s , 1967a,b). I s o l a t e d soybean p r o t e i n r e d u c e s th e a v a i l a b i l i t y o f molybdenum ( R e i d e t a l . , 1 9 5 6 ) , z i n c ( O ' D e l l and Savage, 1 9 6 0 ) , and manganese and c o p p e r ( D a v i s e t a l . , 1962). I n t h e s e s t u d i e s however t h e m i n e r a l s were s u p p l e m e n t a r y and not d e r i v e d from the v e g e t a b l e o r a n i m a l f e e d s t u f f s . T h e r e a r e a few s t u d i e s on t h e a v a i l a b i l i t y o f m i n e r a l s o f p l a n t o r i g i n t o n o n - r u m i n a n t s . A r m s t r o n g and Thomas (1952) e s t i m a t e d t h a t c a l c i u m a v a i l a b i l i t y o f l u c e r n e , r e d c l o v e r and w i l d w h i t e c l o v e r were 84.89%, 83.11% and 79.95% r e s p e c t i v e l y . I n a n o t h e r s t u d y , A r m s t r o n g e t a l . (1953) r e p o r t e d t h a t a v a i l a b i l i t y o f c a l c i u m i n t h r e e herbs o f g r a s s -l a n d ( b u r n e t , c h i c o r y and n arrow l e a v e d p l a n t a i n ) were 80.38%, 87.73% and 95.28% r e s p e c t i v e l y . The c a l c i u m a v a i l a b i l i t y o f t h r e e g r a s s e s ; t i m o t h y , p e r e n n i a l r y e g r a s s and c o c k s f o o t , were 78.99%, 76.53% and 69.02% r e s p e c t i v e l y ( A r m s trong e t a l . , 1 9 5 7 ) . D e v a d a t t a and Appana (1954) r e p o r t e d t h e a v a i l a b i l i t y o f c a l c i u m i n amaranthus ( 7 4 - 7 8 % ) , s e s b a n i a g r a n d i f l o r a (85%) and m o r i n g a o l e i f e r a ( 6 9 % ) . The a v a i l a b i l i t y o f p h y t a t e phos-p h o r u s has a l s o been s t u d i e d . The committee on a n i m a l n u t r i t i o n (NAS-NRC, 1960) r e p o r t e d t h a t a p p r o x i m a t e l y 30% o f t h e 29 phosphorus i n p l a n t m a t e r i a l s c o u l d be u t i l i z e d by non-r u m i n a n t s . A s h t o n et a l . (1960) o b s e r v e d t h a t four-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 - w e e k o l d c h i c k s r e t a i n e d 36% t o 49% o f t h i s p h o s p h o r u s . Temperton and C a s s i d y (1964) 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 t h e p h y t a t e phosphorus and o n l y 50% o f the non p h y t a t e p h o s p h o r u s . Salman and M c G i n n i s (1968) o b s e r v 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 n o t s i g n i f i c a n t l y d i f f e r e n t f r o m 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 o r 0.3% p l a n t p l u s 0.3% i n o r g a n i c p h o s p h o r u s . U t i l i z a t i o n o f p hosphorus from p l a n t m a t e r i a l was t h e r e f o r e q u i t e h i g h . I t i s r e a s o n a b l e t o b e l i e v e t h a t c h i c k e n s can u t i l i z e g r e a t e r amounts o f phosphorus o f p l a n t o r i g i n t h a n i s c u r r e n t l y s u g g e s t e d . G u e n t e r and S e l l (1974) u s i n g i n t r a m u s c u l a r i n j e c -t i o n o f r a d i o a c t i v e Mg-28 r e p o r t e d a v a i l a b i l i t y v a l u e o f 61.2% f o r magnesium i n soybean m e a l . O ' D e l l e t a l . (1972) u s i n g t h e growth r e s p o n s e o f c h i c k s e v a l u a t e d t h e a v a i l a b i l i t y o f z i n c i n f e e d s t u f f s o f a n i m a l and p l a n t o r i g i n and r e p o r t e d a v a i l a b i l i t i e s o f 57%, 67% and 75% f o r sesame meal, soybean meal and f i s h m e a l r e s p e c t i v e l y . No r e p o r t was a v a i l a b l e i n t h e l i t e r a t u r e r e v i e w e d on t h e a v a i l a b i l i t y o f m i n e r a l s i n palm k e r n e l m e a l . 30 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 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 ) 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 t h e i r a v a i l a b i l i t y i n whole o r i n p a r t ( N e l s o n e t a l _ . , 1 9 6 8 ). These w o r k e r s s u g g e s t e d t h a t i t p r o b a b l y c h e l a t e d t o some e x t e n t , a l l t h e c a t i o n s r e q u i r e d by a n i m a l s . Bruce and C a l l o w (1934) i n an e a r l i e r work s u g g e s t e d t h a t i n d i e t s w i t h n a t u r a l c a l c i u m - p h o s p h o r u s r a t i o , t h e main a c t i o n o f p h y t i c a c i d would be t o r e n d e r c a l c i u m u n a v a i l a b l e . P h y t i c a c i d has been r e p o r t e d t o r e n d e r c a l c i u m u n a v a i l a b l e i n dogs (Hof f - J o r g e n s e n , 1946), man ( B r o n n e r e t a l _ . , 1954) and c h i c k s ( N e l s o n e_t a l _ . , 1 9 6 7 ) . The i n a b i l i t y o f c h i c k s t o u t i l i z e a s i g n i f i c a n t amount o f p h y t a t e phosphorus has been r e p o r t e d by G i l l s e_t j i l . (1957) and i n a r e v i e w by N e l s o n ( 1 9 6 7 ) . I n c o n t r a s t t o t h i s , the a d d i t i o n o f p h y t a t e as b r a n ( R o b e r t s and Y u d k i n , 1961) o r as a m i x t u r e o f p e n t a c a l c i u m p h y t a t e and sodium p h y t a t e ( H o f f - J o r g e n s e n , 1946) was r e p o r t e d t o i n c r e a s e a v a i l a b i l i t y o f phosphorus from c e r e a l b ased r a t i o n s . P h y t i c a c i d has been r e p o r t e d t o r e d u c e a v a i l a b i l i t y o f i r o n (McCance e t a l . , 1943), magnesium ( R o b e r t s and Y u d k i n , 1960), and z i n c (0«Dell and Savage, 1960). K r a t z e r and V o h r a (1966) s u g g e s t e d t h a t p a r t o f t h e i n t e r f e r e n c e i n z i n c a b s o r p t i o n by p h y t i c a c i d may be due t o t h e f o r m a t i o n o f z i n c phosphate r a t h e r t h a n z i n c p h y t a t e . Smith (1961) r e p o r t e d t h a t net a b s o r p t i o n o f c a l c i u m and magnesium d e c r e a s e d i n m i l k f e d c a l v e s i n g e s t i n g h i g h l e v e l s o f f i b r e as wood s h a v i n g s . A r m s t r o n g e t a l _ . (1953) i n a s t u d y on t h e a v a i l a b i l i t y o f c a l c i u m i n t h r e e h e r b s o f g r a s s l a n d , 31 o b s e r v e d e v i d e n c e o f an i n v e r s e r e l a t i o n s h i p between c a l c i u m a v a i l a b i l i t y and c o n t e n t o f c r u d e f i b r e . S o u t h g a t e (1973a) s u g g e s t e d t h a t i n man, d i e t a r y f i b r e a c t e d as a weak i o n e x c h a n g e r w h i c h bound b i l e s a l t s and p r e v e n t e d t h e i r r e a b s o r p -t i o n f r om th e g u t . Heaton (1973) a l s o s u g g e s t e d t h a t b i n d i n g o f l i t h o c h o l a t e i n t h e gut c o u l d a c c o u n t f o r r e d u c e d i n c i d e n c e o f g a l l s t o n e s i n r a t s f e d h i g h f i b r e d i e t s . K r i t c h e v s k y and S t o r y (1974) d e m o n s t r a t e d t h a t d i e t a r y f i b r e e x e r t e d a b i n d i n g e f f e c t on b i l e s a l t s i n v i t r o . V e g e t a b l e f i b r e c o n s i s t s o f a h e t e r o g e n o u s complex o f p o l y s a c c h a r i d e s and l i g n i n c a p a b l e o f s e q u e s t e r i n g w a t e r , c a t i o n s o r a n i o n s d e p e n d i n g on t h e c h e m i s t r y o f t h e c o n s t i t u e n t m a c r o m o l e c u l e s (Eastwood, 1 9 7 3 ) . I t a p p e a r s e v i d e n t t h a t d i e t a r y f i b r e s e q u e s t e r s m i n e r a l s , r e n d e r i n g them u n a v a i l a b l e . M i t c h e l l (1939) s u g g e s t e d t h a t o x a l i c a c i d i n f o o d would l e a d t o poor c a l c i u m u t i l i z a t i o n as a r e s u l t o f f o r m a t i o n o f p o o r l y a b s o r b a b l e c a l c i u m o x a l a t e . S k o r k o w s k a - Z i e l e n i e w s k a e t a l _ . (1974) u s i n g r a t s r e p o r t e d r e d u c e d c a l c i u m , magnesium and i r o n a b s o r p t i o n from d i e t s c o n t a i n i n g o x a l i c a c i d . S i m i l a r r e s u l t s were r e p o r t e d f o r c a l c i u m ( M u r i l l o e_t a l . , 1973) and phosphorus (Compere, 1 9 6 6 ) . Brune and B r e d e h o r n (1962) however o b s e r v e d t h a t p i g s u t i l i z e d c a l c i u m o x a l a t e as e f f e c t i v e l y as o t h e r c a l c i u m s o u r c e s . P a t e l ejb a l _ . (1967) r e p o r t e d t h a t most c o n c e n t r a t e s and v e g e t a b l e l e a v e s had p r a c t i c a l l y no o x a l a t e s . I t would seem t h e r e f o r e t h a t o x a l a t e s a r e n o t a r e a l p r o b l e m i n p r a c t i c a l d i e t s f o r n o n - r u m i n a n t s . T h i s v i e w was a l s o h e l d by F a s s e t t (1966) who c r i t i c a l l y e v a l u a t e d t h e l i t e r a t u r e p e r t a i n i n g t o p o s s i b l e o x a l a t e 32 i n t e r f e r e n c e w i t h c a l c i u m m e t a b o l i s m and came t o t h e c o n c l u s i o n t h a t t h e r e was v e r y l i t t l e d a nger a s s o c i a t e d w i t h i n g e s t i n g o x a l a t e c o n t a i n i n g p l a n t s . I n f l u e n c e o f c h e l a t i n g a g e n t s on m i n e r a l a v a i l a b i l i t y has been r e p o r t e d . K r a t z e r ej: a _ l . (1959) o b s e r v e d r e c o v e r y from z i n c d e f i c i e n c y symptoms i n t u r k e y p o u l t s when s m a l l amounts o f e t h y l e n e d i a m i n e t e t r a a c e t i c a c i d (EDTA) were i n c l u d e d i n t h e i r i s o l a t e d soybean p r o t e i n d i e t . S i m i l a r e f f e c t s o f EDTA have been o b s e r v e d i n c h i c k e n s ( O ' D e l l e t a l . , 1964) and r a t s ( O b e r l e a s e t ajL., 1966). L a r s e n e t a l . (1960) r e p o r t e d t h a t EDTA d e c r e a s e d i r o n a v a i l a b i l i t y t o r a t s . Suso and Edwards (1968) s t u d i e d t h e i n f l u e n c e o f v a r i o u s c h e l a t i n g a g e n t s on a b s o r p t i o n o f ^^Co, ~^Fe, ^ M n , and ^ Z n by c h i c k e n s . They 6 5 o b s e r v e d s i g n i f i c a n t i n c r e a s e s i n Zn a b s o r p t i o n and non-54 s i g n i f i c a n t i n c r e a s e s i n Mn a b s o r p t i o n w i t h i n c r e a s i n g l e v e l s 59 o f EDTA. A d d i t i o n o f EDTA d e c r e a s e d a b s o r p t i o n o f Fe and 6 0 Co. O t h e r c h e l a t i n g a g e n t s were not as e f f e c t i v e as EDTA i n i m p r o v i n g z i n c a v a i l a b i l i t y ( Vohra and K r a t z e r , 1 9 6 4 ) . The amino a c i d s c y s t e i n e and h i s t i d i n e w h i c h a r e n a t u r a l c h e l a t i n g a g e n t s have b e n e f i c i a l e f f e c t s on t h e z i n c d e f i c i e n c y syndrome ( N i e l s e n e t a l . , 1 9 6 6 ) . I n z i n c d e f i c i e n t c h i c k s f e d i s o l a t e d soybean p r o t e i n , a supplement o f 0.5% c y s t e i n e a l l e v i a t e d a l l s i g n s o f z i n c d e f i c i e n c y ( N i e l s e n e t a l . , 1966) They r e p o r t e d i n c r e a s e d body w e i g h t , improved f e a t h e r i n g and i n c r e a s e d t i b i a z i n c c o n c e n t r a t i o n , p o s s i b l y due t o improved z i n c a v a i l a b i l i t y i n t h e d i e t . S u p p l e m e n t a t i o n o f h i s t i d i n e t o a soybean d i e t a l l i e v i a t e d t h e l e g a b n o r m a l i t y but d i d not i n c r e a s e g r o w t h , improve f e a t h e r i n g o r i n c r e a s e t i b i a z i n c 33 c o n c e n t r a t i o n . A supplement o f 2% a r g i n i n e h y d r o c h l o r i d e f e d t o z i n c d e f i c i e n t c h i c k s a g g r a v a t e d b o t h t h e l e g a b n o r m a l i t y and t h e f e a t h e r d e f e c t s and t e n d e d t o d e p r e s s growth (Coleman e t a l . , 1969). I t seems t h a t i n t h e c h i c k , c y s t e i n e , h i s t i d i n e and a r g i n i n e a r e p o s s i b l e a n t a g o n i s t s o f z i n c i n some a s p e c t s o f i t s m e t a b o l i s m . The a v a i l a b i l i t y o f m i n e r a l s i n swine r a t i o n s i s i mproved by a d m i n i s t r a t i o n o f a n t i b i o t i c s ( K i r c h g e s s n e r e t a l . , 1961; K i r c h g e s s n e r , 1 9 6 5 ) . I n e i g h t e e n b a l a n c e t r i a l s u s i n g p i g s and p o u l t r y , t h e d a i l y r e t e n t i o n s o f c o b a l t and z i n c were more t h a n d o u b l e d and c o p p e r r e t e n t i o n t r i p l e d by an a n t i b i o t i c s u p p l e m e n t . They a l s o r e p o r t e d i n c r e a s e d manganese and i r o n r e t e n t i o n i n a n i m a l s r e c e i v i n g a n t i b i o t i c s . K i r c h g e s s n e r e t a l . (1961) u s i n g b a l a n c e methods, showed t h a t r e t e n t i o n o f s i l i c o n , p h o s p h o r u s , magnesium, c o b a l t , z i n c , c o p p e r , manganese and i r o n was i n c r e a s e d i n young b u t not mature p i g s . The i n f l u e n c e o f v i t a m i n D on t h e a b s o r p t i o n o f v a r i o u s c a t i o n s has been r e p o r t e d by e a r l i e r i n v e s t i g a t o r s . M e i n t z e r and Steenbock (1955) r e p o r t e d t h a t a b s o r p t i o n o f magnesium was d e p r e s s e d i n r a t s f e d low v i t a m i n D d i e t s . S o b e l and B u r g e r (1955) o b s e r v e d t h a t v i t a m i n D i n c r e a s e d t h e l e v e l s o f l e a d i n b l o o d w h i l e G r e e n b e r g (1945) d e m o n s t r a t e d an i n c r e a s e i n s t r o n t i u m a b s o r p t i o n due t o v i t a m i n D a d m i n i s t r a t i o n . Worker and M i g i c o v s k y (1961a,b) showed t h a t v i t a m i n D i n c r e a s e d a b s o r p t i o n o f c a l c i u m , s t r o n t i u m , b e r r y l i u m , magnesium, b a r i u m , z i n c and cadmium. Wasserman (1962) e x t e n d e d the l i s t t o i n c l u d e c o b a l t and t o a l e s s e r e x t e n t c e s i u m bu t r e p o r t e d t h a t sodium, p o t a s s i u m , c o p p e r , i r o n and z i n c were not i n f l u e n c e d by 34 v i t a m i n D. Masuhara and M i g i c o v s k y (1963) showed t h a t i r o n and c o b a l t a b s o r p t i o n were enhanced by v i t a m i n D. A s l i g h t i n c r e a s e i n phosphorus a b s o r p t i o n and no i n c r e a s e i n c o p p e r a b s o r p t i o n was r e p o r t e d by Wasserman ( 1 9 6 2 ) . S t u d i e s on m i n e r a l i n t e r r e l a t i o n s h i p s d a t e from e a r l y o b s e r v a t i o n s t h a t low c a l c i u m r a t i o n s i n h i b i t e d phosphorus b a l a n c e . L a t e r i n v e s t i g a t o r s r e v e a l e d f u n d a m e n t a l i n t e r -d e p e n d e n c i e s between cop p e r and molybdenum, z i n c and c a l c i u m , magnesium and p h o s p h o r u s , c a l c i u m and manganese, cadmium and z i n c ( H i l l e_t a l _ . , 1963; F o r b e s , 1963). A c o n s i d e r a b l e degree o f c o m p e t i t i o n i s f o r a b i n d i n g s i t e i n o r on the mucosal c e l l s and f o r o t h e r s i t i s c o m p e t i t i o n f o r c a r r i e r m o l e c u l e s . The b i o l o g i c a l a n t a g o n i s m between c o p p e r and z i n c was d e m o n s t r a t e d by S m i t h and L a r s o n ( 1 9 4 6 ) . Van.Reen (1953) showed t h a t c o p p e r s u p p l e m e n t a t i o n a l l e v i a t e d t h e e f f e c t s o f z i n c t o x i c i t y w h i l e t h e r e v e r s e was r e p o r t e d by R i t c h i e e_t a l _ . ( 1 9 6 3 ) . Van Campen 65 (1969) o b s e r v e d t h a t c o p p e r - i n d u c e d d e p r e s s i o n i n Zn a b s o r p t i o n was m e d i a t e d a t t h e i n t e s t i n a l l e v e l p o s s i b l y due t o d i r e c t c o m p e t i t i o n between z i n c and c o p p e r f o r a common c a r r i e r . K i r c h g e s s n e r and Grassmann (1969) r e p o r t e d t h a t h i g h l e v e l s o f c o p p e r s u l f a t e s u p p l e m e n t a t i o n i n p i g r a t i o n s produced g r e a t e r r e t e n t i o n o f i r o n , z i n c , manganese and c o b a l t . D i e t s h i g h i n c a l c i u m have a l o w e r z i n c a v a i l a b i l i t y ( S u t t l e and M i l l s , 1 9 6 6 ) . I n c r e a s e d d i e t a r y c a l c i u m was r e p o r t e d t o enhance manganese a b s o r p t i o n i n r a t s ( L a s s i t e r et a i l . , 1969), w h i l e A l c o c k and M a c l n t y r e (1960) o b s e r v e d t h a t i n c r e a s e d manganese i n t h e d i e t enhanced c a l c i u m a b s o r p t i o n . Nugara and Edwards (1962) noted t h a t h i g h d i e t a r y phosphorus r e d u c e d magnesium r e t e n t i o n a t t h e a b s o r p t i o n o r e x c r e t i o n s i t e i n c h i c k s , w h i l e O ' D e l l e t a l , (1960) showed w i t h b a l a n c e s t u d i e s t h a t a h i g h d i e t a r y phosphorus l e v e l d e c r e a s e d magnesium a b s o r p t i o n i n g u i n e a p i g s . F o r b e s (1963) r e p o r t e d t h a t c a l c i u m and phosphorus d e p r e s s e d magnesium a b s o r p t i o n and h i g h c a l c i u m l e v e l s d r a s t i -c a l l y a f f e c t e d phosphorus a b s o r p t i o n i r r e s p e c t i v e o f magnesium l e v e l s i n t h e d i e t , w h i l e H i l l e t a l . (1963) showed t h a t t h e r e were c o p p e r , z i n c and i r o n components o f cadmium t o x i c i t y . Some m i s c e l l a n e o u s f a c t o r s have a l s o been l i n k e d t o m i n e r a l a v a i l a b i l i t y . D a v i s e t a i l . (1962) r e p o r t e d t h a t i s o l a t e d soybean p r o t e i n c o n t a i n e d a component wh i c h combined w i t h z i n c , manganese and c o p p e r , c a u s i n g c h i c k s t o d e v e l o p the r e s p e c t i v e d e f i c i e n c y symptom because o f u n a v a i l a b i l i t y o f t h e s e m i n e r a l s . The a d d i t i o n o f EDTA t o su c h a d i e t r e d u c e d t h e c h i c k s * r e q u i r e m e n t f o r t h e s e e l e m e n t s . K i e n h o l z (1962) p r e s e n t e d e v i d e n c e t o i n d i c a t e t h e p r e s e n c e o f a f a c t o r ( n o t p h y t a t e ) i n peas w h i c h i n t e r f e r e d w i t h t h e a v a i l a b i l i t y o f z i n c f o r c h i c k g r o w t h . A u t o c l a v i n g t h e peas e l i m i n a t e d t h e r e q u i r e m e n t f o r s u p p l e m e n t a l z i n c . T h i s h e a t l a b i l e f a c t o r w o u l d v e r y l i k e l y be a p r o t e i n w h i c h i n t e r f e r e d w i t h d i g e s t i o n o r a b s o r p t i o n o f z i n c , r e d u c i n g i t s a v a i l a b i l i t y . 36 C u r r e n t i n f o r m a t i o n on n u t r i t i v e v a l u e o f palm k e r n e l meal Palm k e r n e l meal i s a c o m m e r c i a l b y - p r o d u c t o f t h e m e c h a n i c a l e x t r a c t i o n o f palm k e r n e l o i l from t h e k e r n e l o f t h e o i l palm t r e e , E l a e i s q u i n e e n s i s ( J a c q ) . The p o s s i b l e use o f palm k e r n e l meal i n l i v e s t o c k r a t i o n s has been known f o r some t i m e . However, v e r y l i m i t e d work has been c o m p l e t e d r e l a t i v e t o t h e n a t u r e o f t h e p r o t e i n and no s i g n i f i c a n t a t t e m p t s have been made t o e s t i m a t e t h e 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 h e meal f o l l o w i n g d i g e s t i o n . W h i l e t h e g r o s s e n e r g y , amino a c i d and m i n e r a l c o n t e n t o f t h e meal a r e known, few s t u d i e s have been r e p o r t e d on d e t e r m i n a t i o n o f m e t a b o l i z a b l e e n e r g y and no s t u d i e s on amino a c i d and m i n e r a l a v a i l a b i l i t y were d i s c o v e r e d i n t h e l i t e r a t u r e r e v i e w e d . Palm k e r n e l meal was e x t e n s i v e l y used d u r i n g t h e Second World War as a l i v e s t o c k f e e d due t o i t s low c o s t , ease o f a v a i l a b i l i t y and n u t r i t i v e v a l u e . S i n c e t h e l a t e 1940»s, use o f palm k e r n e l meal i n l i v e -s t o c k f e e d i n g has d e c l i n e d p r i m a r i l y because i t i s c o n s i d e r e d t o be g r i t t y , d r y i n t e x t u r e and u n p a l a t a b l e ( C o l l i n g w o o d , 1 9 5 8 ) . Palm k e r n e l meal has been f e d s u c c e s s f u l l y t o c a t t l e ( S c h m i d t and V o g e l , 1932; V o g e l , 1932), p i g s ( C a r s t e n e n , 1932) and t o a l e s s e r e x t e n t p o u l t r y (Temperton and Dudley, 1 9 4 1 ) . D u r i n g t h e N i g e r i a n C i v i l War (1967-1970), palm k e r n e l meal was s u c c e s s f u l l y i n c o r p o r a t e d i n t o r a t i o n s f o r a l l t y p e s o f l i v e s t o c k as a p r o t e i n s u p p l e m e n t . Palm k e r n e l meal p r o d u c t i o n from t r o p i c a l c o u n t r i e s has shown an upward t r e n d i n r e c e n t y e a r s (FAO, 1 9 7 5 ) , however l i m i t e d amounts o f t h i s p r o d u c t go i n t o non-ruminant a n i m a l d i e t s . The h i g h f i b r e and low 37 p r o t e i n c o n t e n t o f t h e meal have u s u a l l y been th e r e a s o n f o r i t s low l e v e l o f i n c l u s i o n i n non-ruminant d i e t s . I t i s commonly f o r g o t t e n t h a t palm k e r n e l meal can s u p p l y s i g n i f i c a n t amounts o f e n e r g y , p r o t e i n and m i n e r a l s and w i t h j u d i c i o u s r a t i o n f o r m u l a t i o n can be u t i l i z e d t o a g r e a t e r e x t e n t than i s c u r r e n t l y p r a c t i s e d i n m o n o g a s t r i c d i e t s ( 5 % t o 10% o f t h e r a t i o n ) . 38 D e l i g n i f i c a t i o n o f h i g h f i b r e f e e d s t u f f s C o n s i d e r a b l e i n t e r e s t has been g e n e r a t e d i n r e c e n t y e a r s on t h e use o f h i g h f i b r e c r o p r e s i d u e s and b y - p r o d u c t s as f e e d s t u f f s . Beckmann (1921) f i r s t d e m o n s t r a t e d t h a t by t r e a t i n g r oughages w i t h d e l i g n i f y i n g a g e n t s , t h e i r n u t r i t i v e v a l u e c o u l d be i m p r o v e d . The Beckmann p r o c e d u r e i n v o l v e d s o a k i n g roughages i n l a r g e v a t s o f a l k a l i , f o l l o w e d by a wash t o remove t h e r e s i d u a l a l k a l i . L o s s o f d r y m a t t e r f o l l o w i n g t h i s t r e a t m e n t was 20-30%, but i n c r e a s e d d i g e s t i b i l i t y was r e p o r t e d ( F e r g u s o n , 1 9 4 2 ) . W i l s o n and P i g d e n (1964) s u g g e s t e d a s p r a y method i n v o l v i n g l o w e r c o n c e n t r a t i o n s o f a l k a l i and no washing o f t h e t r e a t e d roughage. T h i s p r o c e d u r e has been shown t o be e f f e c -t i v e w i t h such roughages as c o r n c o b s , wheat and paddy s t r a w s , sorghum s t o v e r and sugar cane t o p s (Chandra and J a c k s o n , 1971), and f o r o t h e r c r o p r e s i d u e s ( O l o l a d e e t a l . , 1970; Rounds e_t a l . , 1 976). The main a l k a l i u t i l i z e d has been sodium h y d r o x i d e (Chandra and J a c k s o n , 1971; S i n g h and J a c k s o n , 1971; O l o l a d e e t a l . , 1970) b u t o t h e r a l k a l i s have been u s e d . These i n c l u d e p o t a s s i u m h y d r o x i d e ( K l o p f e n s t e i n and Woods, 1970), ammonium h y d r o x i d e ( G a r r e t t et: a _ l . , 1974; Rounds e_t a l _ . , 1976), c a l c i u m h y d r o x i d e (Rounds e t a l . , 1 9 7 6 ) . B l e a c h i n g powder (Chandra and J a c k s o n , 1971) and i r r a d i a t i o n (Huffman, 1970) have a l s o been s u c c e s s f u l l y u t i l i z e d . These s t u d i e s have been r e s t r i c t e d t o c o a r s e roughages and t h e p r o c e d u r e has not been a p p l i e d t o more n u t r i t i v e - h i g h -f i b r e i n g r e d i e n t s . The m a t e r i a l s so t r e a t e d have not been f e d t o n o n - r u m i n a n t s and no a t t e m p t has been made t o e s t i m a t e t h e d e s t r u c t i o n o f n u t r i e n t s i n t h e s e f e e d s t u f f s . MATERIALS AND METHODS 39 Palm k e r n e l meal (PKM) u t i l i z e d i n t h e s e t r i a l s was i m p o r t e d from N i g e r i a . The meal was produced by a screw p r e s s p r o c e s s f o l l o w e d by p u l v e r i z a t i o n . The c o m m e r c i a l soybean meal (SBM) and r a p e s e e d meal (RSM) were p r o d u c e d i n Canada by a s o l v e n t e x t r a c t i o n p r o c e s s and p u r c h a s e d l o c a l l y i n V a n c o u v e r . Commercial s o l v e n t e x t r a c t e d c o t t o n s e e d meal (CSM) was o b t a i n e d f rom M a y f l o w e r Farms, P o r t l a n d , Oregon, USA. T r i p l i c a t e samples o f each f e e d i n g r e d i e n t v/ere a n a l y z e d f o r g r o s s e n e r g y , c r u d e p r o t e i n ( % N x 6 . 2 5 ) , e t h e r e x t r a c t , c r u d e f i b r e , 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 c i d d e t e r g e n t f i b r e and l i g n i n a n a l y s e s were by t h e method o f Van S o e s t ( 1 9 6 3 ) . 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 was a c o m p l e t e l y r a n d o m i z e d d e s i g n w i t h r e p l i c a t e groups o f f o u r c h i c k s each per g r o u p . The b r o i l e r c h i c k s u t i l i z e d i n t h e s e e x p e r i m e n t s (3-4 weeks o l d ) 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 r o l l e d m e t a b o l i s m c a g e s . Feed and w a t e r 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 . Data were s u b j e c t e d t o a n a l y s e s o f v a r i a n c e (SnedecQr, 1956) and d i f f e r e n c e s between means d e t e r m i n e d by a m u l t i p l e range t e s t (Duncan, 1955). 40 T r i a l 1. Amino a c i d a v a i l a b i l i t y A v a i l a b i l i t y o f amino a c i d s i n palm k e r n e l , soybean, c o t t o n s e e d and r a p e s e e d meals was d e t e r m i n e d u s i n g g r o w i n g c h i c k s . 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 r a n d o m i z e d d e s i g n i n v o l v i n g f o u r 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 o f f o u r c h i c k s e a c h . 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 o u t a c c o r d i n g t o t h e p r o c e d u r e o f B r a gg e t a l . ( 1 9 6 9 ) . The method i n c l u d e d a n a l y s i s o f endo-genous amino a c i d s e x c r e t e d by t h e c h i c k . The amount o f 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 c l e a r l y d i s t i n g u i s h a v a i l a b i l i t y f r o m a p p a r e n t 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 c o m m e r c i a l s t a r t e r d i e t s t o t h r e e weeks o f age. A t t h e b e g i n n i n g o f t h e t e s t , t h e y 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 ( T a b l e 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 h o u r s 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 t h e marker. F e c e s from t h e 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 ) . Next day, t h e same p r o c e d u r e was r e p e a t e d , e x c e p t t h a t t h e t e s t d i e t ( T a b l e 2) r e p l a c e d t h e s y n t h e t i c d i e t . D i f f e r e n t l e v e l s o f t e s t i n g r e d i e n t s were i n c o r p o r a t e d i n t o t h e t e s t d i e t t o e q u a l i s e n i t r o g e n c o n t e n t . Dry m a t t e r c o n s u m p t i o n 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 t h e e x p e r i m e n t were r e c o r d e d . Amino a c i d s i n palm k e r n e l , soybean, c o t t o n s e e d and r a p e s e e d meals and f e c e s c o l l e c t e d from each d i e t were d e t e r m i n e d by amino a c i d a n a l y s i s (Moore e t a l . , 195 8 ) f o l l o w i n g h y d r o l y s i s w i t h 3N H C l f o r f i f t e e n hours a t 121°C. 41 T a b l e 1. C o m p o s i t i o n o f s y n t h e t i c d i e t ( T r i a l s 1, 3 and 6) I n g r e d i e n t s g/kg (D.M) S u c r o s e 810.17 C e l l u l o s e * 89.83 Co r n o i l 100.00 * C e l l u - f l o u r , N u t r i t i o n a l B i o c h e m i c a l C o r p o r a t i o n , C l e v e l a n d , O h i o . T a b l e 2, C o m p o s i t i o n o f t e s t d i e t s ( T r i a l s 1 and 3) D i e t s (g) I n g r e d i e n t s PKM SBM CSM RSM Palm K e r n e l meal Soybean meal C o t t o n s e e d meal Rapeseed meal S y n t h e t i c d i e t lOOOg 500g 750g 500g lOOOg 750g 750g 750g 42 Amino acid a v a i l a b i l i t y was calculated by the equation presented by Bragg et. aJL. (1969) % Amino acid (A.A.) a v a i l a b i l i t y = Total A.A. consumed - (Total A.A. protein feces - Total A.A. non protein feces) Total A.A. consumed Amino acid a v a i l a b i l i t y represented the percentage of amino acids a c t u a l l y retained by the chick a f t e r c o r r e c t i o n f o r endogenous amino acids measured on excreta from the amino acid-free d i e t . 43 T r i a l 2. Metabolizable energy Metablizable energy (ME) of palm kernel, soybean, cotton-seed and degummed rapeseed meal was determined using 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 chicks each per treatment. The test d i e t s contained e i t h e r palm kernel, soy-bean, cottonseed or rapeseed meal at a l e v e l of 30% i n s u b s t i -t u t i o n f o r an equal weight of the reference d i e t (Table 3). The assay period 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 acid insoluble ash method of Vogtmann et al_. (1975). Gross energy and nitrogen 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 retention was determined and ME values were c a l c u l a t e d with a co r r e c t i o n of 8.22 kcal/g n i t r o -gen retained ( H i l l and Anderson, 1958). <5 44 Table 3. Composition of reference d i e t ( T r i a l 2) I n g r e d i e n t Per c e n t o f r a t i o n Soybean meal 27.50 Wheat 63.00 Meat meal 2.00 A l f a l f a meal 1.00 A n i m a l t a l l o w 2.30 L i m s t o n e 1.00 D i c a l c i u m phosphate 1.00 V i t a m i n p r e m i x 0.50 2 M i n e r a l p r e m i x 0.50 D.L. M e t h i o n i n e 1.10 L. L y s i n e 0.10 1 Vitamin premix supplied per kg: Vitamin A, 11,000 I.U.; Vitamin D 3, 880 I.C.U.; Vitamin E, 10 I.U.; Vitamin K, 2.2 mg; Vitamin B.p* 13.2 meg; R i b o f l a v i n , 4.4 mg; Calcium pantothenate, 24.2 mg; Niacin, 36.2 mg; B i o t i n , 0.04 mg; choline ch l o r i d e , 500 mg. 2 Mineral premix supplied per kg: N:.aCl, 3.52 g; Mn, 86 mg; Zn, 49 mg; Cu, 7.7 mg; Fe, 34 mg. 45 T r i a l 3. M i n e r a l a v a i l a b i l i t y R e t e n t i o n o f c a l c i u m , p h o s p h o r u s , magnesium, manganese, z i n c and copp e r was d e t e r m i n e d w i t h four-week o l d b r o i l e r c h i c k s i n each o f palm k e r n e l , soybean, c o t t o n s e e d and r a p e -seed m e a l s . There were f o u r r e p l i c a t e s ( f o u r c h i c k s e a c h ) p e r d i e t a r y t r e a t m e n t . 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 t o 24 days o f 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 t h e f i r s t 21 days and t h e r e a f t e r groups o f f o u r were t r a n s f e r r e d t o m e t a b o l i s m c a g e s . On t h e 2 4 t h day o f 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 m a r k e r 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 h o u r s and f e d a s y n t h e t i c d i e t ( T a b l e 1) f o r f o u r h o u r s . 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 t h e s t a r t e r d i e t c o n t a i n i n g t h e m a r k e r . F e c e s from t h e s y n t h e t i c d i e t were c o l l e c t e d ( s t a r t i n g a t t h e end o f t h e f i r s t b a t c h o f marked e x c r e t a and e n d i n g a t t h e b e g i n n i n g o f t h e second b a t c h o f marked e x c r e t a ) . On t h e 2 5 t h day o f age, t h e same p r o c e d u r e was r e p e a t e d e x c e p t t h a t t h e t e s t f e e d ( T a b l e 2) r e p l a c e d t h e s y n t h e t i c d i e t . D i f f e r e n t l e v e l s o f f e e d s t u f f s were u t i l i z e d t o p r o -v i d e i s o n i t r o g e n o u s t e s t d i e t s f o r amino a c i d a v a i l a b i l i t y s t u d i e s c a r r i e d o u t s i m u l t a n e o u s l y w i t h m i n e r a l a v a i l a b i l i t y . F e c e s were a g a i n c o l l e c t e d f o l l o w i n g t h e same p r o c e d u r e . Consumption o f b o t h s y n t h e t i c and t e s t d i e t s was measured. 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 t h e 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 m i n e r a l c o n t e n t s o f t h e f e e d i n g r e d i e n t , t h e t e s t d i e t , t h e f e c e s from t h e s y n t h e t i c d i e t 46 and from t h e t e s t d i e t were d e t e r m i n e d by 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 wet d i g e s t i o n w i t h p e r c h l o r i c and n i t r i c a c i d s by t h e method o f Johnson and U l r i c h ( 1 9 5 9 ) . The phosphorus c o n t e n t o f a l l samples was d e t e r m i n e d on a Spec-t r o n i c 20 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 development o f c o l o r w i t h ammonium m o l y b d a t e . M i n e r a l c o n t e n t o f a l l samples was 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 f o l l o w i n g f o r m u l a was used t o 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 : 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 = T M I ~ ( - ^ ^ " E F M E ) x 100 where TMI = T o t a l M i n e r a l I n t a k e from i n g r e d i e n t ( T e s t Feed) TFME = T o t a l .Fecal M i n e r a l -Excreted EFME = Endogenous F e c a l M i n e r a l E x c r e t e d ( p u r i f i e d d i e t e x c r e t a ) 47 T r i a l 4. Crude f i b r e and p h y t i c a c i d as 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 o f v e g e t a b l e p r o t e i n supplements f o r t h e c h i c k . T r i p l i c a t e samples of palm k e r n e l , soybean, c o t t o n s e e d and r a p e s e e d meals were a n a l y s e d f o r t o t a l phosphorus (Johnson and U l r i c h , 1 9 5 9 ) , p h y t a t e phosphorus and p h y t i c a c i d (Wheeler and F e r r e l , 1971) and c r u d e f i b r e (A.O.A.C., 1965). M i n e r a l a v a i l a b i l i t y o f t h e t e s t i n g r e d i e n t s was d e t e r m i n e d by t h e p r o c e d u r e o u t l i n e d i n t r i a l 3, u s i n g b r o i l e r c h i c k s ( f o u r r e p l i c a t e s o f f o u r c h i c k s e a c h , per t r e a t m e n t ) . The p r o c e d u r e i n v o l v e d d e t e r m i n a t i o n o f endogenous m i n e r a l e x c r e t i o n u s i n g a p u r i f i e d m i n e r a l - f r e e d i e t . The t e s t i n g r e d i e n t s were sub-s e q u e n t l y s u b s t i t u t e d f o r a f r a c t i o n o f t h e p u r i f i e d d i e t and m i n e r a l e x c r e t i o n was d e t e r m i n e d . A v a i l a b i l i t y was c a l c u l a t e d as t r u e d e i g e s t i b i l i t y o f m i n e r a l s i n t h e f e e d s t u f f s . C o r r e l a -t i o n c o e f f i c i e n t s were c a l c u l a t e d between t h e c o n t e n t o f c r u d e f i b r e o r p h y t i c a c i d i n the t e s t d i e t and t h e a v a i l a b i l i t i e s o f s i x m i n e r a l s ( c a l c i u m , p h o s p h o r u s , magnesium, manganese, z i n c and c o p p e r ) i n t h e t e s t d i e t s . 48 T r i a l 5. F a c t o r s a f f e c t i n g t h e m e t a b o l i z a b l e energy c o n t e n t o f r a p e s e e d m e a l s . C u l t i v a r s o f t h r e e v a r i e t i e s o f r a p e s e e d meal (Span, Tower and B r o n o w s k i ) as w e l l as c o m m e r c i a l r a p e s e e d meal were e v a l u a t e d i n t h e s e e x p e r i m e n t s . The v a r i o u s samples i d e n t i f i e d as Span (A, S a n d P ) , Tower (Sask 940, Sask 1788) and B r o n o w s k i were o b t a i n e d by c o u r t e s y o f t h e Rapeseed A s s o c i a t i o n o f Canada. Commercial r a p e s e e d meal was p u r c h a s e d from l o c a l f e e d m a n u f a c t u r e r s . The e x p e r i m e n t a l arrangement was a com-p l e t e l y r a n d o m i z e d d e s i g n i n v o l v i n g seven 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 o f f o u r b r o i l e r c h i c k s ( t h r e e weeks o f a g e ) . The p r o c e d u r e was as o u t l i n e d i n t r i a l 2, a c c o r d i n g t o S i b b a l d and S l i n g e r ( 1 9 6 2 ) . Feed con s u m p t i o n and e x c r e t a o u t p u t were d e t e r m i n e d by t h e a c i d i n s o l u b l e ash method o f Vogtmann e t a l . ( 1 9 7 5 ) . G r o s s e n e r g y and n i t r o g e n c o n t e n t o f f e e d and f e c e s were d e t e r m i n e d (A.O.A.C., 1 9 6 5 ) . N i t r o g e n r e t e n t i o n was d e t e r m i n e d and m e t a b o l i z a b l e e n e r g y v a l u e s 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 o f 8.22 k c a l / g n i t r o g e n r e t a i n e d ( H i l l and A n d e r s o n , 1958). E t h e r e x t r a c t i o n , d r y m a t t e r , c r u d e p r o t e i n and c r u d e f i b r e d e t e r m i n a t i o n s were c a r r i e d out on t r i p l i c a t e samples (A.O.A.C., 1965). D e t e r -m i n a t i o n o f a v a i l a b l e c a r b o h y d r a t e s was by t h e method o f C l e g g ( 1 9 5 6 ) . C o r r e l a t i o n a n a l y s i s between m e t a b o l i z a b l e e n e r g y and c h e m i c a l c o n s t i t u e n t s was a c c o r d i n g t o Snedecor ( 1 9 5 6 ) . 4 9 T r i a l 6. A v a i l a b i l i t y o f m i n e r a l s i n v a r i o u s r a p e s e e d m e a l s . The t e s t i n g r e d i e n t s were t h e same as i n t r i a l 5 . C o n t e n t and a v a i l a b i l i t y o f c a l c i u m , p hosphorus, magnesium, manganese, z i n c and copper were d e t e r m i n e d a c c o r d i n g t o t h e p r o c e d u r e p r e s e n t e d i n t r i a l 3 . 50 T r i a l 7. E f f e c t s o f a l k a l i t r e a t m e n t on d i g e s t i b i l i t y , meta-b o l i z a b l e e n e rgy and d e s t r u c t i o n o f amino a c i d s i n palm k e r n a l meal (PKM). Ground PKM samples (lOOOg) were s p r a y e d w i t h one l i t r e o f 3, 5 o r 7% W/V NaOH s o l u t i o n . The samples were s e a l e d i n p l a s t i c bags f o r twenty f o u r hours t o f a c i l i t a t e t h e a l k a l i r e a c t i o n . Samples were s u b s e q u e n t l y d r i e d a t 60°C f o r f o r t y e i g h t h o u r s and r e g r o u n d . R e p r e s e n t a t i v e samples were a n a l y s e d f o r a c i d d e t e r g e n t f i b r e (ADF), a c i d d e t e r g e n t l i g n i n (ADL) by t h e method o f Van S o e s t ( 1 9 6 3 ) , and f o r c r u d e p r o t e i n ( C P ) , d r y m a t t e r (DM) and g r o s s energy (GE) a c c o r d i n g t o A.O.A.C. ( 1 9 6 5 ) . L o s s o f p r o t e i n due t o a l k a l i t r e a t m e n t was c a l c u l a t e d . Amino a c i d c o m p o s i t i o n o f t h e samples was d e t e r m i n e d by t h e p r o c e d u r e o f Moore e t a l . ( 1 9 5 8 ) , 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. D e s t r u c t i o n o f s i x t e e n amino a c i d s f o l l o w i n g a l k a l i t r e a t m e n t was c a l c u l a t e d . D i g e s t i b i l i t y D i g e s t i b i l i t y o f d r y m a t t e r and e n e r g y was d e t e r m i n e d i n PKM and a l k a l i - t r e a t e d PKM u s i n g t h e n y l o n bag t e c h n i q u e (Lowry, 1969). Ten grams o f each a i r d r y sample was put i n t o a p r e v i o u s l y weighed oven-dry d o u b l e bag (each o f 100 mesh n y l o n ) . S i x bags were a t t a c h e d t o t h e cap o f each 250 ml p o l y e t h y l e n e b o t t l e and submerged i n the rumen i n g e s t a o f a f i s t u l a t e d s t e e r . A l l samples were i n t r i p l i c a t e . The e x p e r i -ment was t e r m i n a t e d a f t e r f o r t y e i g h t h o u r s . The b o t t l e a s s e m b l i e s were removed from t h e rumen, a d h e r i n g i n g e s t a was r i n s e d f r e e and t h e bags d e t a c h e d . Bags c o n t a i n i n g samples 51 were d r i e d o v e r n i g h t a t 80°C, t r a n s f e r r e d t o a 110°C oven f o r e i g h t hours and weighed. 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 were d e t e r m i n e d on t h e d i g e s t e d samples f o r d r y m a t t e r and e n e r g y . M e t a b o l i z a b l e e n e r g y M e t a b o l i z a b l e energy o f PKM and a l k a l i t r e a t e d PKM was d e t e r m i n e d u s i n g t h r e e week o l d b r o i l e r c h i c k s . 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 r a n d o m i z e d d e s i g n w i t h f o u r r e p l i c a t e s ( f o u r c h i c k s each) per t r e a t m e n t . The t e s t d i e t s c o n t a i n e d e i t h e r PKM o r a l k a l i - t r e a t e d PKM a t a l e v e l o f 30% i n s u b s t i t u t i o n f o r an e q u a l w e i g h t o f t h e r e f e r e n c e d i e t ( T a b l e 3 ). The p r o c e d u r e was as p r e s e n t e d i n t r i a l 2. F e e d i n g t r i a l s PKM was s u b s t i t u t e d f o r 10%, 20% o r 30% o f a b r o i l e r s t a r t e r r a t i o n f o r two week o l d c h i c k s i n a t w e l v e day f e e d i n g t r i a l . The c o n t r o l was a s t a n d a r d wheat-soybean d i e t ( T a b l e 3 ) . T e s t 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 , and e q u a l i s e d f o r l y s i n e and m e t h i o n i n e . 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 . A l k a l i t r e a t m e n t PKM, 3%, 5% o r 7% a l k a l i t r e a t e d PKM was i n c o r p o r a t e d a t 30% i n t o a s t a r t e r r a t i o n ( T a b l e 4 ) , f o r two week o l d c h i c k s i n an e i g h t day f e e d i n g t r i a l . The c o n t r o l was a s t a n d a r d wheat-soybean r a t i o n ( s i m i l a r t o t h a t used i n e x p e r i m e n t 3 ) . T e s t r a t i o n s were i s o n i t r o g e n o u s but not i s o c a l o r i c . S u p p l e -52 T a b l e 4. C o m p o s i t i o n ( T r i a l 7 o f c o n t r o l and • , Experiment 4) t e s t d i e t I n g r e d i e n t (g/kg) C o n t r o l PKM A l k a l i - t r e a t e d PKM D i e t s 3% 5% 7% PKM - 300.0 - - -PKM + 3% NaOH - - 300.0 - -PKM + 5% NaOH - - - 300.0 -PKM + 7% NaOH - - - 300. 0 Soybean meal 275.0 225.0 225.0 225.0 225. 0 Wheat 635.0 325.0 316.0 314.5 308. 0 Meat meal 20.0 20.0 20.0 20.0 20. 0 F i s h meal - 10.0 12.0 13.0 14. 5 A l f a l f a meal 10.0 10.0 10.0 10.0 10. 0 A n i m a l t a l l o w 30.0 80.0 85.5 86.0 91. 0 L i m e s t o n e 10.0 10.0 10.0 10.0 10. 0 C a l c i u m phosphate 10.0 10.0 10.0 10.0 10. 0 i V i t a m i n premix 5.0 5.0 5.0 5.0 5. 0 2 M i n e r a l premix 5.0 5.0 5.0 5.0 5. 0 D.L. m e t h i o n i n e 1.5 1.5 1.5 1.5 1. 5 L. l y s i n e 0.1 0.1 0.1 0.1 0. 1 1 V i t a m i n p r e m i x s u p p l i e d p e r k g : 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. 2, 13.2 meg; R i b o f l a v i n , 4.4 rng; C a l c i u m p a n t o t h e n a t e 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 p r e m i x s u p p l i e d p e r k g : NaCl 3.52 g; Mn, 86 mg; Zn, 49 mg; Cu, 7.7 mg; F e , 34 mg. mentary l y s i n e and m e t h i o n i n e were i n c o r p o r a t e d where n e c e s s a r y t o meet recommended l e v e l s . C h i c k 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 . 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 . 54 RESULTS AND DISCUSSION T r i a l 1 The p r o x i m a t e a n a l y s i s o f PKM, SBM, CSM and RSM i s p r e s e n t e d i n T a b l e 5. PKM had t h e l o w e s t p r o t e i n (21.3%) and h i g h e s t c r u d e f i b r e (17.5%) c o n t e n t w h i l e SBM showed t h e h i g h e s t p r o t e i n (48.0%) and l o w e s t c r u d e f i b r e (6.5%) c o n t e n t . E t h e r e x t r a c t c o n t e n t o f PKM was h i g h e s t (7.8%) because t h e meal was p r o c e s s e d by a screw p r e s s method. The ash c o n t e n t was u n i f o r m l y h i g h i n a l l i n g r e d i e n t s . The amino a c i d c o m p o s i t i o n o f t h e f e e d i n g r e d i e n t s i s p r e s e n t e d i n T a b l e 6. A c o m p a r i s o n o f i n d i v i d u a l amino a c i d l e v e l s i n PKM t o SBM showed t h a t l y s i n e was l o w e s t ( 2 3 % o f SBM) and a r g i n i n e was h i g h e s t ( 7 7 % o f SBM) whereas c o n t e n t o f m e t h i o n i n e and t h r e o n i n e was low i n c o m p a r i s o n t o amino a c i d s i n SBM. PKM i s low i n c o n t e n t o f many amino a c i d s and d e f i c i e n t i n e s s e n t i a l amino a c i d s , t h e r e f o r e adequate s u p p l e -m e n t a t i o n w i t h an amino a c i d s o u r c e i s r e q u i r e d t o f a c i l i t a t e e f f e c t i v e u t i l i z a t i o n o f t h i s p r o d u c t i n t h e c h i c k d i e t . The amino a c i d c o m p o s i t i o n o f SBM, CSM and RSM a g r e e w e l l w i t h v a l u e s i n t h e l i t e r a t u r e (NAS-NRC, 1 9 6 9 ) . Among the e s s e n t i a l amino a c i d s o f SBM, t h e r e i s a h i g h c o n t e n t o f l e u -c i n e , a r g i n i n e and l y s i n e , moderate c o n t e n t o f t h r e o n i n e b u t low c o n t e n t o f m e t h i o n i n e . I t 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 d i e t a r y amino a c i d s f o r c h i c k d i e t s when combined w i t h a s u p p l e m e n t a r y s o u r c e o f m e t h i o n i n e and adequate l e v e l s o f e n e r g y , v i t a m i n s and m i n e r a l s . C o t t o n s e e d meal i s h i g h i n l y s i n e , moderate i n t h r e o n i n e 55 T a b l e 5. . P r o x i m a t e a n a l y s i s o f PKM, SBM, CSM and RSM ( d r y m a t t e r b a s i s ) . I n g r e d i e n t % D'.M. % P r o t e i n % F i b r e % Ash % E t h e r E x t r a c t PKM 92.0 21.3 17.5 5.0 7.8 SBM 91.1 48.0 6.5 6.0 0.6 CSM 92.4 41.0 13.6 7.0 2.0 RSM 90.5 38.0 12.0 7.2 1.5 56 Table 6. Amino acid composition of PKM, SBM, CSM and RSM (dry matter b a s i s ) . ( T r i a l 1) Protein Source (%) Amino Acids PKM SBM CSM RSM Lysine 0.69 2.95 2.19 2.08 H i s t i d i n e 0.41 1.23 1.37 0.98 Arginine 2.68 3.45 5.60 1.93 Aspartic acid 1.69 5.64 4.74 2.38 Threonine 0.66 1.88 1.51 1.48 Serine 0.90 2.48 2.15 1.48 Glutamic acid 3.62 9.01 10.32 6.22 Proline 0.50 1.21 1.58 2.16 Glycine 0.91 2.16 2.31 1.79 Alanine 0.81 2.16 2.04 1.58 Valine 0.43 1.02 1.68 0.75 Methionine 0.47 0.75 0.70 0.84 Isoleucine 0.60 1.92 1.22 1.30 Leucine 1.23 3.71 2.85 2.57 Tyrosine 0.58 1.84 1.45 1.09 Phenylalanine 0.82 2.44 2.48 1.49 57 b u t low i n m e t h i o n i n e . Of t h e f o u r p r o t e i n supplements t e s t e d , CSM was h i g h e s t i n g l u t a m i c a c i d and t h e e s s e n t i a l amino a c i d a r g i n i n e . I t has a good p a t t e r n o f amino a c i d s and c a n c o n t r i b u t e s i g n i f i c a n t l y t o d i e t a r y amino a c i d s i n p o u l t r y r a t i o n s . Rapeseed meal i s l o w e r t h a n SBM i n h i s t i d i n e , a r g i n i n e , l y s i n e and t h r e o n i n e but i s s l i g h t l y h i g h e r i n m e t h i o n i n e . C o n s i d e r i n g t h a t t h e p r o t e i n c o n t e n t o f RSM i s l o w e r t h a n SBM and CSM, r a p e s e e d meal has a good amino a c i d p a t t e r n and c a n be u t i l i z e d e f f i c i e n t l y i n p o u l t r y r a t i o n s as a major s u p p l i e r o f amino a c i d s . A v a i l a b i l i t y o f amino a c i d s i n t h e p r o t e i n supplements i s p r e s e n t e d i n T a b l e 7. Amino a c i d a v a i l a b i l i t y from PKM a v e r a g e d 84.5% ( w i t h a range o f 63.3% and 9 3 . 2 % ) . The e s s e n t i a l amino a c i d s g l y c i n e (63.3%) and v a l i n e (68.4%) showed e x c e p -t i o n a l l y low a v a i l a b i l i t y compared t o o t h e r amino a c i d s . A v a i l a b i l i t y f i g u r e s f o r l y s i n e ( 9 0 . 0 % ) , t h r e o n i n e (86.5%) and m e t h i o n i n e (91.4%) i n d i c a t e d e f f e c t i v e u t i l i z a t i o n o f t h e s e amino a c i d s . The low a v a i l a b i l i t y o f g l y c i n e and v a l i n e , c o u p l e d w i t h t h e r e l a t i v e l y low l e v e l s o f t h e s e amino a c i d s i n PKM, n e c e s s i t a t e s amino a c i d s u p p l e m e n t a t i o n o r t h e use o f c o n s i d e r a b l e amounts of o t h e r p r o t e i n s o u r c e s when PKM i s i n c o r p o r a t e d i n t o c h i c k r a t i o n s . I n c o m p a r i s o n . t o o t h e r p r o t e i n supplements t e s t e d , t h e amino a c i d s i n PKM showed g e n e r a l l y r e d u c e d a v a i l a b i l i t y . Nesheim (1965) s u g g e s t e d 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 l o w e r e d amino a c i d a v a i l a b i l i t y f r o m 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 58 Table 7. Amino acid a v a i l a b i l i t y i n PKM, SBM, CSM and RSM fed to chicks. ( T r i a l 1) Protein Source (%) Amino Acid PKM SBM CSM RSM Average Lysine 90.0 a 99 .0 C 89. 0 a 94.4 b 93 .1 H i s t i d i n e 9 0 . l a 98 .8° 93.8 b 94. 2 b 94 .2 Arginine 93.2 a 98 .8 b 95.7 a 95.8 a 95 .9 Aspartic acid 87.6 a 98 .3° 93.6 b 91.7 b 92 .8 Threonine 86.5 a 97 .9° 89.8 b 90.8 b 91 .2 Serine 88.7 a 98 .1 C 93.0 b 91.4 a b 92 .8 Glutamic acid 9 0 . l a 98 .9° 96. 3 b 94. 9 b 94 .3 Proline 68.0 a 93 .0 b 90.9 b 91.2 b 85 .8 Glycine 63.3 a 92 .9 b 91.7 b 89.4 b 84 .1 Alanine 85.5 a 97 .4 d 89.2 b 94. 2 C 91 .6 Valine 68.4 a 92 .9 b 91. l b 90.9 b 85 .6 Methionine 91. 4 a 98 .7 b 93.3 b 78.4 C 90 .4 Isoleucine 86. l a 97 .7 C 91.3 b 91.6 b 91 .7 Leucine 88. 5 a 98 .4 d 92. 4 b 94.0 C 93 .3 Tyrosine 85.0 a 98 .0° 94.2 b c 92.8 b 92 .5 Phenylalanine 90. 5 a 98 .6 C 95.2 b 94. 8 b 94 .8 Average 84.5 97 .3 92.5 91.9 Means with d i f f e r e n t superscripts among protein sources are s i g n i f i c a n t l y d i f f e r e n t (P^ 0.01). i n v o l v i n g 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 g r o u p s , i n h i b i t o r s o f p l a n t o r i g i n and h e a t 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 . S o u t h g a t e and D u r n i n (1970) r e p o r t e d t h a t as t h e i n t a k e o f d i e t a r y f i b r e i n c r e a s e d , t h e a p p a r e n t 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 w o r k e r s (Dammers, 1965; Tao e t a l . , 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 c r u d e f i b r e 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) s u g g e s t e d t h a t p h y t a t e c o n t e n t c o u l d r e d u c e 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 . PKM i s h i g h i n c r u d e f i b r e and e t h e r e x t r a c t , has a c o n s i d e r a b l e c a r b o h y -d r a t e c o n t e n t and undergoes e x t e n s i v e h e a t 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 . I t i s m o d e r a t e l y h i g h i n p h y t i c a c i d c o n t e n t , a l t h o u g h no growth i n h i b i t o r o f p l a n t o r i g i n has been r e p o r t e d . A l t h o u g h i t i s d i f f i c u l t t o e x p l a i n the r e m a r k e d l y low g l y c i n e and v a l i n e a v a i l a b i l i t y , i t i s s u g g e s t e d t h a t a c o m b i n a t i o n o f low p r o t e i n , h i g h e t h e r e x t r a c t and h i g h l e v e l s o f c r u d e f i b r e i s p r o b a b l y r e s p o n s i b l e f o r t h e g e n e r a l l y r e d u c e d amino a c i d a v a i l a b i l i t y o b s e r v e d i n PKM. The a v a i l a b i l i t y o f amino a c i d s i n SBM averaged 97.3% ( w i t h a range o f 92.0% and 9 9 . 0 % ) . T h i s r e s u l t was i n a g r e e -ment w i t h t h o s e r e p o r t e d by F l i p o t e t a l _ . (1971) and by I v y e t a l . (1971) f o r SBM, but h i g h e r t h a n v a l u e s r e p o r t e d by Cho and B a y l e y (1970) u s i n g p i g f e c a l a n a l y s i s . T h i s would be e x p e c -t e d due t o t h e absence o f a c o r r e c t i o n f o r endogenous amino a c i d s i n t h e l a t t e r s t u d y . The r e s u l t s o f t h i s s t u d y were a l s o s l i g h t l y h i g h e r t h a n t r u e d i g e s t i b i l i t y v a l u e s r e p o r t e d by Eggum (1968) but a g r e e d c l o s e l y w i t h t h o s e by Sarwar 'et a l . (1975) f o r 60 soybean meal fed to r a t s . The three usually l i m i t i n g e s s e n t i a l amino acids l y s i n e ( 9 9 . 0 % ) , methionine (98.7%) and threonine (97.9%) were highly a v a i l a b l e as were the other e s s e n t i a l amino aci d s . Glycine and valine ( 9 2 . 9 % each) showed reduced a v a i l a -b i l i t y i n comparison to other amino acids of soybean meal. Commercial solvent extracted SBM u t i l i z e d i n t h i s study was high i n protein ( 4 8 . 0 % ) , low i n crude f i b r e ( 6 . 5 % ) , ether extract (0.6%) and phytic acid content (0.85%) and was processed to minimise heat damage, the content of t r y p s i n i n h i b i t o r s , phytohemagglutinins, goitrogens, saponins and other t o x i c constituents normally present i n raw soybeans. Results indicate that commercial soybean meal i s an excellent source of die t a r y amino acids f o r the chick. I t has an ex c e l l e n t pattern of amino acids, being -well endowed with both e s s e n t i a l and non e s s e n t i a l amino acids. It i s high i n a v a i l a b i l i t y of amino acids, p a r t i c u l a r l y those considered as us u a l l y l i m i t i n g i n p r a c t i c a l poultry r a t i o n s . Amino acid a v a i l a b i l i t y of CSM averaged 92.5% with a range of 89.0% and 96.3%. Lysine (89.0%) i n CSM was lower i n a v a i l a b i l i t y than was shown f o r other protein supplements, while methionine a v a i l a b i l i t y (93.3%) was higher than values for PKM and RSM. Threonine a v a i l a b i l i t y (89.8%) was lower than observed f o r SBM and RSM. Most amino acids were approxi-mately 5.0% lower i n a v a i l a b i l i t y for CSM than was observed for SBM. Kuiken and Lyman (1948) reported the a v a i l a b i l i t y of e s s e n t i a l amino acids from hydraulic press CSM to vary from 67% to 93%, screw press meal from 79% to 95% and hexane extracted meal from 84% to 98%. Results obtained i n t h i s study 61 a g r e e d c l o s e l y f o r s o l v e n t e x t r a c t e d CSM w i t h t h o s e r e p o r t e d by K u i k e n and Lyman ( 1 9 4 8 ) . L y s i n e a v a i l a b i l i t y was h i g h e r t h a n 67.3% and 72.5% r e p o r t e d by Thyong (1967) f o r c o t t o n s e e d cake and c o t t o n s e e d meal r e s p e c t i v e l y . I t i s o f c o n s i d e r a b l e i n t e r e s t t o n o t e t h a t CSM has a h i g h c o n c e n t r a t i o n o f e s s e n t i a l amino a c i d s w h i c h a r e w e l l u t i l i z e d by p o u l t r y . H i g h l e v e l s o f r e s i d u a l g o s s y p o l i n p r o c e s s e d meals would l i m i t the use o f c o t t o n s e e d m e a l . However i t must be n o t e d t h a t as a r e s u l t o f e v e r i m p r o v i n g t e c h n o l o g y , c o n s i d e r a b l e s u c c e s s has been a c h i e v e d i n b o t h r e m o v a l o f g o s s y p o l i n c o m m e r c i a l p r o c e s s i n g as w e l l as p r o d u c t i o n o f g l a n d l e s s c o t t o n s e e d m e a l s . I n many t r o p i c a l c o u n t r i e s where c o t t o n i s produced and p r o c e s s e d , CSM c a n e f f e c t i v e l y r e p l a c e t h e more e x p e n s i v e soybean meal i n t h e d i e t o f g r o w i n g m o n o g a s t r i c a n i m a l s . C o t t o n s e e d meal w i l l however have t o be used i n c o m b i n a t i o n w i t h o t h e r p r o t e i n s o u r c e s o r amino a c i d m i x t u r e s as i t i s low i n m e t h i o n i n e c o n t e n t . I n f o r m a t i o n on the a v a i l a b i l i t y o f amino a c i d s i n RSM i s l i m i t e d and o n l y a few s t u d i e s have been r e p o r t e d . The a v a i l a b i l i t y o f amino a c i d s i n RSM v a r i e d f rom 78.4% t o 95.9% w i t h an average o f 91.9%. W i t h th e 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 , t h e 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 , a l t h o u g h most were s i g n i f i c a n t l y l o w e r t h a n i n SBM. L y s i n e (94.4%) and t h r e o n i n e (90.8%) showed h i g h e r a v a i l a b i l i t y t h a n i n CSM and PKM. R e s u l t s r e p o r t e d i n t h i s s t u d y were c o n s i d e r a b l y h i g h e r t h a n amino a c i d d i g e s t i b i l i t y o b s e r v e d by Cho and B a y l e y (1970) and by Tao e t a l . (1971) f o r RSM b u t a g r e e d c l o s e l y w i t h t h o s e 62 o f Sarwar e t a l . ( 1 9 7 5 ) . Cho and B a y l e y (1970) e m p l o y i n g p i g f e c a l a n a l y s i s r e p o r t e d a r a n g e o f 74% and 86% f o r RSM amino a c i d d i g e s t i b i l i t y . Tao e t a _ l . (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 s i x t e e n amino a c i d s o f r a p e s e e d meal v a r i e d from 59.8% t o 81.9%. However, Bragg et_ a l _ . (1969) had e a r l i e r d e m o n s t r a t e d 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 e a b i l i t y than. c o l o s t o m i z e d c h i c k s . Sarwar e_t a l . (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 r a p e s e e d meal. The l o w e r a p p a r e n t 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 amino a c i d s o b s e r v e d by Cho and B a y l e y (1970) appear t o be t h e r e s u l t o f p r o c e d u r e u t i l i z e d . A p p a r e n 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 m e a s u r i n g endogenous amino a c i d s . T h e r e f o r e an endogenous amino a c i d c o r r e c t i o n f a c t o r i s not u t i l i z e d i n c a l c u l a t i n g d i g e s t i b i l i t y . A l o w e r v a l u e c o n s e q u e n t l y r e s u l t s from t h e a p p a r e n t d i g e s t i -b i l i t y p r o c e d u r e as compared t o t h e t r u e d i g e s t i b i l i t y o r a v a i l a b i l i t y method. 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 r a p e s e e d meal have been d e v e l o p e d i n r e c e n t y e a r s and t h e p r o d u c t p r o v i d e s a good s o u r c e o f e s s e n t i a l amino a c i d s a t 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 and t h e r e f o r e r a p e s e e d meal 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 t h e d i e t o f g r o w i n g a n i m a l s . I t c e r t a i n l y has a g r e a t e r p o t e n t i a l f o r p r o v i d i n g d i e t a r y amino a c i d s t h a n i s p r e s e n t l y u t i l i z e d ( a p p r o x i m a t e l y 5% i n l a y e r d i e t s and 15% i n b r o i l e r d i e t s ) . 63 T r i a l 2 The metabolizable energy (ME) values of PKM, SBM, CSM and RSM are presented i n Table 8 and range from 1957.0 kcal/kg (RSM) to 2796.0 kcal/kg (PKM). There were no s i g n i f i c a n t d i f f e r e n c e s (P*0.05) between ME of PKM and the ME of SBM (2681.9 kcal/kg). The ME of SBM was also,.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 ME of CSM. RSM however was s i g -n i f i c a n t l y lower (P£0.05) i n ME than a l l ingredients tested. PKM, despite i t s high crude f i b r e content, had a high metabolizable.energy value. This would be expected since PKM has a high content of nitrogen free extracts, and a high ether extract l e v e l . PKM processed by a solvent ex t r a c t i o n method would be expected to show reduced metabolizable energy content. Results obtained i n the present study agreed c l o s e l y with reports by Gohl (1975) that metabolizable energy of palm kernel meal f o r poultry varied from 2150 kcal/kg (mechanical press, 6% ether extract) to 3070 kcal/kg (mechanical press, 10% ether e x t r a c t ) . PKM u t i l i z e d i n t h i s study has an ether extract content of 7.8% and metabolizable energy of 2796 k c a l / kg. The metabolizable energy r e s u l t obtained i n t h i s study ind i c a t e s that PKM i s a high energy feed ingredient comparable to soybean meal and i s capable of contributing s i g n i f i c a n t l y to meeting the energy requirements of chicks i n p r a c t i c a l r a t i o n s . Metabolizable energy of soybean meal observed in t h i s study was s l i g h t l y higher than 2530 kcal/kg reported by H i l l and Renner ( I 9 6 0 ) f o r 50% protein SBM, but was i n agreement 64 T a b l e 8. M e t a b o l i z a b l e e n e r g y o f PKM, SBM, CSM and RSM ( d r y m a t t e r b a s i s ) . ( T r i a l 2) I n o r P d i p n r M e t a b o l i z a b l e energy i n g r e d i e n t ( k c a l / k g ) Palm k e r n e l meal 2 7 9 6 . 0 a ah Soybean meal 2681.9 C o t t o n s e e d meal 2531.2° Rapeseed meal 195 7.0 Means w i t h d i f f e r e n t s u p e r s c r i p t s a r e s i g n i f i c a n t l y d i f f e r e n t P i 0.05. w i t h v a l u e s o f 2603 and 2770 k c a l / k g r e p o r t e d by L a u t n e r and Z e n i s e k (1965) and R o j a s and S c o t t (1969) r e s p e c t i v e l y . C o t t o n s e e d meal u t i l i z e d i n t h i s s t u d y had a m e t a b o l i z a b l e e n e r g y v a l u e o f 2531.2 k c a l / k g , a v a l u e s l i g h t l y h i g h e r t h a n r e s u l t s o f H i l l and T o t s u k a (1964) f o r h e a t e d hexane e x t r a c t e d and mixed s o l v e n t e x t r a c t e d c o t t o n s e e d m e a l . These r e s u l t s were a l s o s l i g h t l y h i g h e r t h a n v a l u e s r e p o r t e d by R o j a s and S c o t t (1969) f o r v a r i o u s c o t t o n s e e d m e a l s . M e t a b o l i z a b l e energy o f r a p e s e e d meals a s s a y e d i n t h i s s t u d y (1957.0 k c a l / k g ) was h i g h e r than v a l u e s r e p o r t e d by p r e v i o u s w o r k e r s (March and B i e l y , 1971; Rao and C l a n d i n i n , 1973; C l a n d i n i n , 1973). S e t h and C l a n d i n i n (1973) however o b s e r v e d a v e r a g e ME o f 2327 k c a l / k g f o r t h r e e v a r i e t i e s o f low h u l l r a p e s e e d meal c o n t a i n i n g 7.76% t o 10.30% f i b r e and ME o f 1730 k c a l / k g f o r r e g u l a r r a p e s e e d meal c o n t a i n i n g 15% t o 17% f i b r e . The r a p e s e e d meal a s s a y e d i n t h i s s t u d y was degummed Tower r a p e s e e d meal w i t h 12.0% f i b r e . T h i s may e x p l a i n why a f a i r l y h i g h m e t a b o l i z a b l e energy c o n t e n t was o b s e r v e d . 6 6 T r i a l 3 The m i n e r a l content of PKM, SBM, CSM and RSM used i n the experiment i s presented ( T a b l e 9 ) . These meals show a h i g h c o n t e n t of c a l c i u m , phosphorus and magnesium and a low l e v e l of manganese, i r o n , z i n c and copper. The content of m i n e r a l elements i n the p r o t e i n s o u r c e s w i l l not meet the minimal n u t r i t i o n a l requirements of c h i c k s at d i e t a r y l e v e l s of the p r o t e i n supplements used i n a balanced d i e t . Palm k e r n e l meal i s , however, e x c e p t i o n a l l y h i g h i n manganese and i r o n i n comparison to SBM, CSM and RSM. R e s u l t s ( T a b l e 10) show per cent a v a i l a b i l i t y of each of the m i n e r a l elements i n the p r o t e i n s o u r c e s . M i n e r a l elements i n SBM showed the h i g h e s t average a v a i l a b i l i t y (74.3%) w h i l e those i n PKM were l e a s t a v a i l a b l e (50.0%). M i n e r a l a v a i l a b i l i t y from CSM (62.1%) and RSM (64.0%) were i n t e r m e d i a t e . Calcium (72.6%) and phosphorus (78.0%) were h i g h l y a v a i l a b l e i n a l l f e e d s t u f f s . Magnesium and manganese were h i g h l y a v a i l a b l e from SBM and CSM, moderately a v a i l a b l e from RSM and lowest from PKM. Z i n c was h i g h l y a v a i l a b l e from SBM (66.5%), moderately a v a i l -a b l e from RSM (57.6%) and p o o r l y a v a i l a b l e from PKM and CSM (13.9% and 38.0% r e s p e c t i v e l y ) . Copper was moderately a v a i l a b l e from RSM (62.7%) and SBM (51.0%) with lowest a v a i l a b i l i t y of the m i n e r a l from PKM and CSM (44.7% and 42.3% r e s p e c t i v e l y ) . C a l c i u m R e s u l t s i n d i c a t e t h a t c a l c i u m was h i g h l y a v a i l a b l e from the f e e d s t u f f s t e s t e d , although a c o n s i d e r a b l e v a r i a t i o n among f e e d s t u f f was observed. The low c a l c i u m c o n t e n t o f most c e r e a l s and o t h e r feed i n g r e d i e n t s ( r e l a t i v e to d i e t a r y r e q u i r e -67 T a b l e 9. The m i n e r a l c o n t e n t o f palm k e r n e l meal, soybean m e a l , c o t t o n s e e d meal and r a p e s e e d meal ( d r y m a t t e r b a s i s ) . ( T r i a l 3) M i n e r a l s I n g r e d i e n t " Z " ~ Z Z ~ ^ Ca P Mg Mn Fe Zn Cu (mg/g) (%) (mg/g) (mg/kg) (mg/kg) (mg/kg) (mg/kg) Palm k e r n e l meal 3.60 0.80 4.37 Soybean meal 3.87 0.87 4.13 C o t t o n s e e d meal 2.60 1.20 5.63 Rapeseed meal 8.50 1.25 4.66 135.0 356.0 41.0 27.0 27.0 164.0 49.0 27.0 27.0 81.0 48.0 27.0 55.0 110.0 55.0 33.0 68 T a b l e 10. P e r c e n 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 palm k e r n e l m e a l , soybean m e a l , c o t t o n s e e d meal and r a p e s e e d m e a l . ( T r i a l 3) F e e d s t u f f s (%) M i n e r a l Element PKM SBM CSM RSM Average C a l c i u m 6 8 . 6 b 8 5 . 6 C 6 4 . 6 a 7 1 . 7 b 72.6 Phosphorus 7 0 . 8 a 8 9 . 3 C 7 6 . 9 b 74. 8 b 78.0 Magnesium 5 6 . 4 a 7 7 . 4 C 7 4 . 6 C 6 1 . l b 67.5 Manganese 4 5 . 1 7 76. l c 76. 3 C 56. 7 b 63.7 Z i n c 13. 9 a 66. 5 d 3 8 . 0 b 5 7 . 6 C 44.0 Copper 44. 7 a 5 1 . 0 b 4 2 . 3 a 62.2° 50.0 Average 50.0 74.3 62.1 64.0 Means w i t h d i f f e r e n t s u p e r s c r i p t s among p r o t e i n s o u r c e s a r e s i g n i f i c a n t l y d i f f e r e n t ( P ^ O . 0 1 ) . 69 merits) and t h e absence o f a r a p i d a s s a y method have not s t i m u l a t e d f e e d c a l c i u m a v a i l a b i l i t y s t u d i e s . However, r e s u l t s o f t h i s s t u d y compare w e l l w i t h d i e t a r y c a l c i u m r e t e n t i o n s t u d i e s u s i n g r a d i o a c t i v e i s o t o p e s by D r i g g e r s and Comar (1949) and more r e c e n t l y by Bragg e t a l . ( 1 9 7 1 ) . These i n v e s t i g a t o r s i n d i c a t e d t h a t a p p r o x i m a t e l y 70% o f the d i e t a r y c a l c i u m was r e t a i n e d by t h e l a y i n g b i r d . R e s u l t s r e p o r t e d here a r e a l s o i n agreement w i t h t h o s e o f A r m s t r o n g and Thomas ( 1 9 5 2 ) , Arm-s t r o n g e t a l _ . (1953) and A r m s t r o n g e t a l _ . ( 1 9 5 7 ) , u s i n g v a r i o u s h e r b s o f g r a s s l a n d . T h i s s t u d y i s a l s o i n agreement w i t h r e s u l t s o f D e v a d a t t a and Appana (1954) f o r c a l c i u m a v a i l a b i l i t y i n v a r i o u s v e g e t a b l e s . Phosphorus Phosphorus a v a i l a b i l i t y was t h e h i g h e s t o f a l l m i n e r a l e l e m e n t s t e s t e d , showing SBM ( 8 9 . 3 % ) , CSM ( 7 6 . 9 % ) , RSM (74.8%) and PKM ( 7 0 . 8 % ) . G i l l i s e t a l . (1954) e s t i m a t e d a v a i l a b l e phosphorus from bonemeal, bone c h a r , bone ash and d i c a l c i u m phosphate as 87%, 84%, 89% and 100% r e s p e c t i v e l y . 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 t o t h e i n f l u e n c e o f p h y t a t e s ( T a y l o r , 1 9 6 5 ) . A v a i l a b l e phosphorus v a l u e s a p p l i e d t o f e e d s t u f f s o f p l a n t o r i g i n a r e between 30% and 40% ( T a y l o r , 1 9 6 5 ) . N e l s o n e t a l . (1968) r e p o r t e d t h a t p h y t a t e phosphorus o f c o m m e r c i a l SBM was c o m p l e t e l y u n a v a i l a b l e . A s h t o n e t a l . (1960) o b s e r v e d 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% t o 49% o f t h i s p h o s p h o r u s . 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 p h o s p h o r u s . 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 70 demonstrated by Salman and McGinnis (1968) who reported that phosphorus u t i l i z a t i o n i n r a t i o n s containing 0.3% plant phos-phorus 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 containing e i t h e r 0.6% plant phosphorus or 0.3% plant plus 0.3% inorganic phosphorus. Most r e s u l t s published on phytate phosphorus a v a i l a b i l i t y have been based on retention of phosphorus from the test vegetable source assayed by the ash content of the l e f t t i b i a of the chick. The reason why the l e f t t i b i a and not the e n t i r e animal i s used has not been explained. Use of component parts of t e s t animals would invariably o_ver or- - underestimate a v a i l a b i l i t y of the minerals i n the t e s t ingredient. This may explain why previous r e s u l t s reported on a v a i l a b i l i t y of plant source phosphorus have been low. Results of t h i s study i n d i c a t e that phosphorus a v a i l a -b i l i t y of protein supplements of plant o r i g i n have been greatly underestimated. Magnesium A v a i l a b i l i t y of magnesium i n SBM, CSM, RSM and PKM were 77.4%, 74.5%, 61.1% and 56.4% r e s p e c t i v e l y . Magnesium a v a i l a b i l i t y f o r SBM observed i n t h i s study was higher than 61.2% reported by Guenter and S e l l (1974) using intramuscular 28 i n j e c t i o n of r a d i o a c t i v e Mg. No r e s u l t s were discovered i n the l i t e r a t u r e on the a v a i l a b i l i t y of magnesium in CSM, RSM and PKM. Content and a v a i l a b i l i t y of magnesium was f a i r l y high i n a l l ingredients tested and t h i s may explain why magnesium de f i c i e n c y i s not a common problem in p r a c t i c a l rations f o r poultry. Manganese Results indicate that manganese a v a i l a b i l i t y was 76.1% f o r SBM, 76.3% for CSM, 56.7% for RSM and 45.7% f o r PKM. 71 Gallup and Norris (1939a,b) and Wilgus and Patton (1939) reported that b i r d s had a high requirement f o r manganese due to poor absorption of the mineral from the d i e t . While the recommended manganese requirement i n poultry d i e t s i s 55 ppm (NAS-NRC, 1960), soybean meal contains 27 ppm, cottonseed meal 27 ppm, and rapeseed meal 55 ppm of t o t a l manganese. The problem with manganese seems to be low content i n protein supplements rather than poor a v a i l a b i l i t y . At dietary l e v e l s used to meet the protein requirements of chicks, a high supple-mental l e v e l of manganese would be necessary i n most d i e t s , even though manganese from ce r e a l grains was e f f e c t i v e l y u t i l i z e d . Zinc The a v a i l a b i l i t y of zinc i n PKM and CSM was low (13.9% and 38.0% r e s p e c t i v e l y ) and f a i r l y high i n SBM (66.5%) and RSM (57.6%). O'Dell et a l . (1972) using the growth response of chicks, evaluated the a v a i l a b i l i t y of zinc i n feed s t u f f s of animal and plant o r i g i n and reported a v a i l a b i l i t i e s of 57%, 67% and 75% f o r sesame meal, soybean meal and fishmeal r e s p e c t i v e l y . Phytate content of vegetable feed ingredients has been implicated i n reduced zinc a v a i l a b i l i t y (Lease et a l . , 1960; Likuski and Forbes, 1964; O'Dell et a l . , 1972). Results reported in t h i s study for soybean meal agree c l o s e l y with those of O'Dell et a_l. (1972). The phytic acid content of RSM and CSM (1.92% each) were equal and yet zinc a v a i l a b i l i t y d i f f e r e d i n these meals. It i s obvious therefore that some other fa c t o r a f f e c t e d zinc a v a i l a b i l i t y . One of the f a c t o r s responsible f o r t h i s d i f f e r e n c e i n zinc a v a i l a b i l i t y may be crude f i b r e content. 72 Copper Copper a b s o r p t i o n and u t i l i z a t i o n may be m a r k e d l y a f f e c t e d by s e v e r a l o t h e r m i n e r a l e l e m e n t s and d i e t a r y compo-n e n t s (Underwood, 1971). L i t t l e i s known about t h e c h e m i c a l f o r m i n which c o p p e r e x i s t s i n f o o d s . L a r g e d i f f e r e n c e s i n c o p p e r a v a i l a b i l i t y have been r e p o r t e d by M i l l s (1954) and F a r r e r and M i s t i l i s ( 1 9 6 7 ) . P h y t a t e has been r e p o r t e d by D a v i s e_t a_l. (1962) t o r e d u c e 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 c o p p e r . R e s u l t s o f t h i s s t u d y ( T a b l e 10) i n d i c a t e d poor c o p p e r a v a i l a b i l i t y i n PKM, SBM and CSM. The copper i n RSM was 62.2% a v a i l a b l e w h i l e t h a t i n SBM was 51.0% a v a i l a b l e . Lower v a l u e s were o b s e r v e d f o r PKM (44.7%) and CSM ( 4 2 . 3 % ) . The d i f f e r e n c e i n copper a v a i l a b i l i t y from t h e s e p r o t e i n s u pplements i n d i c a t e s t h a t e i t h e r i t i s p r e s e n t i n d i f f e r e n t forms o r t h e r e a r e o t h e r d i e t a r y f a c t o r s a s s o c i a t e d w i t h each i n g r e d i e n t w h i c h i n f l u e n c e d i g e s t i b i l i t y and a b s o r p t i o n o f c o p p e r . 73 T r i a l 4 P h y t i c a c i d and p h y t a t e phosphorus c o n t e n t o f PKM, SBM, CSM and RSM a r e p r e s e n t e d i n T a b l e 11. Among the v e g e t a b l e p r o t e i n s upplements t e s t e d , p h y t i c a c i d was 0.85% i n SBM, 1.42% i n PKM, 1.92% i n CSM and RSM. P h y t a t e phosphorus was l o w e r i n SBM (0.24%) and PKM (0.40%) and t h e r e was a h i g h e r p e r c e n t a g e i n CSM and RSM (0.54 % e a c h ) . P h y t i c a c i d c o n t e n t i n some o f the v e g e t a b l e supplements used i n t h i s s t u d y was low i n com-p a r i s o n t o e a r l i e r r e p o r t s . N e l s o n e t a_l_. (1968) r e p o r t e d p h y t i c a c i d v a l u e s o f 2.70% f o r c o t t o n s e e d meal ( 4 1 % p r o t e i n ) , 1.3% f o r soybean meal (44% p r o t e i n ) and 3.6% f o r sesame meal. R e s u l t s o f t h e c o r r e l a t i o n a n a l y s i s ( T a b l e 12) showed a 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 (P 0.05) between phosphorus a v a i l a b i l i t y and c r u d e f i b r e ( r = -0.91) o r p h y t i c a c i d ( r = -0.93) c o n t e n t o f f e e d i n g r e d i e n t s . T h i s r e l a t i o n s h i p was c l e a r l y e x p r e s s e d i n t h e c a s e o f SBM i n w h i c h the low c r u d e f i b r e and p h y t i c a c i d c o n t e n t r e s u l t e d i n a g r e a t e r p e r c e n t a g e o f a v a i l a b l e p h o s p h o r u s . There was a 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 ( P * 0.05 ) between c a l c i u m a v a i l a b i l i t y and c r u d e f i b r e ( r = -0.73) o r p h y t i c a c i d ( r = -0.93) c o n t e n t o f t h e f e e d i n g r e d i e n t s . C a l c i u m a v a i l a b i l i t y v a l u e s ( T a b l e 12) ra n g e d from 64.8% (CSM) t o 85.6% (SBM). The r e l a t i v e l y h i g h phosphorus and c a l c i u m a v a i l a b i l i t y f o r t h e s e f e e d s t u f f s i n d i c a t e d t h a t n e i t h e r p h y t i c a c i d nor c r u d e f i b r e was o f s i g n i f i c a n t magnitude i n t h e i n g r e d i e n t s t o s e v e r e l y a f f e c t a v a i l a b i l i t y o f t h e s e m i n e r a l s . R e s u l t s ( T a b l e 12) i n d i c a t e d a 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 ( P ^ 0 . 0 5 ) between magnesium 74 T a b l e 11. Crude f i b r e , p h y t i c a c i d , p h y t a t e and t o t a l p hosphorus c o n t e n t o f PKM, SBM, CSM and RSM ( d r y m a t t e r b a s i s ) . ( T r i a l 4) Feed -s t u f f s Dry M a t t e r % Crude F i b r e % P h y t i c A c i d - * % P h y t a t e Phosphorus % T o t a l Phosphorus % PKM 92.5 1 7 . 5 C 1.42 b 0.40 b 0.80 a SBM 91.2 6.5 a 0.85 a 0.24 a 0.87 a CSM 92.4 1 3 . 6 b 1.92 c 0.54 c 1.20 b RSM 90.5 1 2 . 0 b 1.92 C 0.54° 1.25 b Means w i t h d i f f e r e n t s u p e r s c r i p t s a r e 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) between f e e d s t u f f s . C a l c u l a t e d as 3.55 t i m e s t h e p h y t a t e p h o s p h o r u s . 75 T a b l e 12. C o r r e l a t i o n c o e f f i c i e n t s between c r u d e f i b r e and p h y t i c a c i d c o n t e n t and a v a i l a b i l i t y o f m i n e r a l s i n PKM, SBM, CSM and RSM. ( T r i a l 4) M i n e r a l A v a i l a b i l i t y (%) F e e d s t u f f s • P Ca Mg Mn Zn Cu PKM 70.8 68.6 56.4 45.7 13.9 44.7 SBM 89.3 85.6 77.4 76.1 66.5 51.0 CSM 76.9 64.6 74.6 76.3 38.0 42.3 RSM 74.8 71.7 61.1 56.7 44.0 62.2 ^ - C o r r e l a t i o n c o e f f i c i e n t (a) c r u d e f i b r e -0.91* -0.73* -0.81* -0.78* -0.98* -0.56* (b) p h y t i c a c i d -0.93* -0.93* -0.61* -0.51 -0.77* -0.53 1 C o r r e l a t i o n c o e f f i c i e n t between m i n e r a l a v a i l a b i l i t y and c r u d e f i b r e o r p h y t i c a c i d c o n t e n t . * S i g n i f i c a n t (P£0.05). 76 a v a i l a b i l i t y and crude f i b r e (r = -0.81) or phytic acid (r = -0.61) content. Manganese a v a i l a b i l i t y was however s i g n i f i c a n t l y (Ps? 0.05) r e l a t e d to crude f i b r e (r = -0.78) but not to phytic acid content. There was a s i g n i f i c a n t (P£ 0.05) inverse r e l a t i o n s h i p between zinc a v a i l a b i l i t y and crude f i b r e (r = -0.98) or phytic acid (r = -0.77) content of the feed ingredients. Influence of phytic acid i n depressing zinc a v a i l a b i l i t y has been reported by O'Dell and Savage (1960) and L i k u s k i and Forbes ( 1 9 6 4 ) . The a v a i l a b i l i t y of copper was s i g n i f i c a n t l y ( P ^ 0.05) r e l a t e d to crude f i b r e content (r = - 0 . 5 6 ) , however phytic acid content of the feed ingredients had no influence on a v a i l a b i l i t y of copper. The depressing influence of phytic acid on mineral a v a i l a b i l i t y was demonstrated with phosphorus, calcium, magnesium and zinc whereas the crude f i b r e content depressed the a v a i l a b i l i t y of a l l minerals tested. It would appear that while the influence of phytic acid on mineral a v a i l a b i l i t y has i n the past been well emphasized, the e f f e c t of crude f i b r e has not been well documented. 77 T r i a l 5 The proximate constituents of the various rapeseed meals are presented i n Table 13. Crude protein content averaged 37.3% with a range of 30.8% (Sask 940) to 41.9% (Bronowski). The average crude f i b r e content was 14.5% with a range of 12.0% f o r the commercial rapeseed meal and 16.1% f o r Span A. The mean ether extract content was 1.5% with the lowest content (0.3%) i n Span A and the highest (3.3%) i n Sask 940. The average dry matter content was 91.6% with a range of 90.6% (Span A) and 93.1% (Sask 940). The metabolizable energy (ME) values of the various rape-seed meals are presented i n Table 14. There were no s i g n i f i -cant differences (P^ 0.01) between ME values of commercial rapeseed meal (1957 kcal/kg), Sask 940 (1953 kcal/kg) and Span P (1859 kcal/kg). There were also no s i g n i f i c a n t d i f ferences (P^ 0.01) between ME values of Span P and Bronowski (1787 k c a l / kg) but ME values of commercial rapeseed meal and Sask 940 were s i g n i f i c a n t l y higher (P£ 0.01) than ME of Bronowski. Span A and Span S were s i g n i f i c a n t l y lower (P£ 0.01) i n ME than a l l other meals tested. The metabolizable energy values of Span A and Span S were low and were comparable to RSM meta-b o l i z a b l e energy values reported by various workers (Lodhi e_t a l . , 1969; March and Biely, 1971; Rao and Clandinin, 1971; March et a l . , 1973). The s i g n i f i c a n t l y higher ME values reported f o r commercial rapeseed meal and Sask 940 were compatible with reports by March e_t al_. (1975) and by Seth and Clandinin (1973) using low h u l l rapeseed meals. 78 T a b l e 13. P r o x i m a t e c o n s t i t u e n t s o f v a r i o u s r a p e s e e d meals ( d r y m a t t e r b a s i s ) . ( T r i a l 5) Dry Crude Crude E t h e r Sample Matter: P r o t e i n F i b r e E x t r a c t % % % % Span A 90.6 39.5 16.1 0.3 Span P 91.9 36.5 15.3 2.1 Span S 91.0 36.6 14.5 0.8 Sask 940 93.1 30.8 12.4 3.3 Sask 1788 92.3 38.1 15.6 1.4 B r o n o w s k i 92.1 41.9 15.6 1.4 Commercial RSM 90.0 38.0 12.0 1.5 Average 91.6 37.3 14.5 1.5 T a b l e 14. G r o s s and m e t a b o l i z a b l e e n e r g y o f v a r i o u s r a p e s e e d meals ( d r y m a t t e r b a s i s ) . ( T r i a l 5) Gross M e t a b o l i z a b l e Sample Energy Energy ( k c a l / k g ) ( k c a l / k g ) Span A 4791 1 4 9 2 d Span P 4832 1 8 5 9 a b Span S 4591 1 5 6 5 d Sask 940 5137 1 9 5 3 a Sask 1788 4676 1749° Br o n o w s k i 4620 be 1787 c Commercial RSM 4826 1 9 5 7 a Average 4782 1766 Means w i t h d i f f e r e n t s u p e r s c r i p t s a r e s i g n i f i c a n t l y d i f f e r e n t ( P ^ 0.01). 80 I n t e r m e d i a t e ME v a l u e s o b s e r v e d f o r Sask 1788 and B r o n o w s k i were c l o s e t o r e p o r t s by Yapar and C l a n d i n i n (1972) and by C l a n d i n i n ( 1 9 7 3 ) . R e s u l t s o f e s t i m a t i o n o f a v a i l a b l e c a r b o h y d r a t e ( s u g a r p l u s s t a r c h ) c o n t e n t o f the v a r i o u s r a p e s e e d meals a r e p r e s e n t e d i n T a b l e 15. The a v e r a g e sugar c o n t e n t was 9.51% w i t h a range o f 5.14% (Span A) t o 11.65% (Span P ) . H i g h s u g a r c o n t e n t were a l s o o b s e r v e d i n c o m m e r c i a l r a p e s e e d meal ( 1 1 . 0 0 % ) , Span S ( 1 0 . 6 4 % ) , and Sask 1788 (10.26%) w h i l e low v a l u e s were o b t a i n e d i n B r o n o w s k i (8.52%) and Span A. Sugar c o n t e n t i n Sask 940 (9.36%) was a p p r o a c h i n g t h e o b s e r v e d a v e r a g e . The s t a r c h c o n t e n t a v e r a g e d 5.69% w i t h a range o f 4.66% (Span P) t o 6.66% ( B r o n o w s k i ) . Sask 940 (6.59%) and c o m m e r c i a l r a p e -seed meal (6.13%) were a l s o h i g h i n s t a r c h c o n t e n t . Low s t a r c h c o n t e n t was o b s e r v e d i n Span P, w h i l e Span A ( 5 . 4 2 % ) , Sask 1788 (5.30%) and Span S (5.06%) were i n t e r m e d i a t e f o r t h e samples t e s t e d . The average a v a i l a b l e c a r b o h y d r a t e c o n t e n t was 15.20% w i t h a range o f 10.56% (Span A) t o 17.13% ( c o m m e r c i a l r a p e s e e d m e a l ) . Span P (16.31%) was h i g h and c o m m e r c i a l r a p e s e e d meal was e x c e p t i o n a l l y h i g h . The a v e r a g e a v a i l a b l e c a r b o h y d r a t e c o n t e n t o b t a i n e d i n t h i s s t u d y was comparable t o 14.1% r e p o r t e d by L o d h i et. a_l. (1969) f o r n i n e samples o f r a p e s e e d meal using, t h e same c h e m i c a l method as u t i l i z e d i n t h i s s t u d y . I t i s i n t e r e s t i n g t o note t h a t L o d h i e t a _ l . (1969) r e p o r t e d a v a l u e o f 23.6% f o r a v a i l a b l e c a r b o h y d r a t e c o n t e n t o f soybean m e a l . 81 T a b l e 15. Su g a r , s t a r c h and a v a i l a b l e c a r b o h y d r a t e c o n t e n t o f v a r i o u s r a p e s e e d meals ( d r y m a t t e r b a s i s ) ( T r i a l 5) A v a i l a b l e Sample Sugar S t a r c h C a r b o h y d r a t e % % % Span A 5.14 5.42 10.56 Span P 11.65 4.66 16.31 Span S 10.64 5.06 15.70 Sask 940 9.36 6.59 15.95 Sask 1788 10.26 5.30 15.56 B r o n o w s k i 8.52 6.66 15.18 Commercial RSM 11.00 6.13 17.13 Average 9.51 5.69 15.20 82 C o r r e l a t i o n c o e f f i c i e n t s between t h e p r o x i m a t e c o n s t i t u e n t s as w e l l as a v a i l a b l e c a r b o h y d r a t e s and m e t a b o l i z a b l e e n e r g y o f t h e v a r i o u s r a p e s e e d meals a r e p r e s e n t e d i n T a b l e 16. There were s i g n i f i c a n t (P^-0.01) p o s i t i v e r e l a t i o n s h i p s between t h e e n e r g y components ( s t a r c h p l u s s u g a r p l u s e t h e r e x t r a c t ) and th e m e t a b o l i z a b l e energy o f t h e me a l s . T h e r e was however a s i g n i f i c a n t ( P < 0.01) i n v e r s e r e l a t i o n s h i p between t h e c r u d e f i b r e c o n t e n t o f t h e meals and t h e i r m e t a b o l i z a b l e e n e r g y as i n d i c a t e d by t h e n e g a t i v e c o r r e l a t i o n c o e f f i c i e n t . The c o n t e n t o f c r u d e p r o t e i n was not r e l a t e d t o t h e m e t a b o l i z a b l e e n e r g y c o n t e n t o f t h e m e a l s . E t h e r e x t r a c t c o n t e n t was r e s p o n s i b l e f o r 62.4% o f t h e v a r i a t i o n i n ME among t h e m e a l s . A v a i l a b l e c a r b o h y d r a t e c o n t e n t s i n g l y a c c o u n t e d f o r 57.8% o f t h e v a r i a -t i o n o b s e r v e d between t h e ME v a l u e s o f t h e me a l s , whereas e t h e r e x t r a c t and a v a i l a b l e c a r b o h y d r a t e c o n t e n t were j o i n t l y r e s p o n s i b l e f o r 74.0% o f t h e o b s e r v e d v a r i a t i o n among t h e ME o f t h e m e a l s . T h e r e f o r e i t a p p e a r s t h a t e n e r g y components and c r u d e f i b r e a c c o u n t f o r most o f t h e d i f f e r e n c e s between t h e ME o f t h e v a r i o u s m e a l s . Span A which i s l o w e s t i n e t h e r e x t r a c t and a v a i l a b l e c a r b o h y d r a t e c o n t e n t and h i g h e s t i n c r u d e f i b r e c o n t e n t , had t h e l o w e s t m e t a b o l i z a b l e energy c o n t e n t . The h i g h e s t m e t a b o l i z a b l e e n e r g y v a l u e s were r e p o r t e d i n c o m m e r c i a l r a p e s e e d meal and Sask 940 w h i c h were h i g h e s t i n c o n t e n t o f t h e e n e r g y components and l o w e s t i n c r u d e f i b r e c o n t e n t . Span P had a f a i r l y h i g h c r u d e f i b r e c o n t e n t b u t t h e h i g h l e v e l o f e n e r g y components ( e t h e r e x t r a c t , s u g a r and s t a r c h ) were e f f e c t i v e i n i m p r o v i n g the a v a i l a b l e e n e r g y o f th e sample. C o n s e q u e n t l y Span P had a h i g h m e t a b o l i z a b l e T a b l e 16. C o r r e l a t i o n o f c h e m i c a l c o n s t i t u e n t s w i t h m e t a b o l i z a b l e e n e r g y o f r a p e s e e d meals ( T r i a l 5) C o r r e l a t i o n w i t h C h e m i c a l c o n s t i t u e n t s m e t a b o l i z a b l e e n e rgy E t h e r e x t r a c t + s u g a r + s t a r c h 0.86** E t h e r e x t r a c t 0.79** A v a i l a b l e c a r b o h y d r a t e s ( s u g a r + s t a r c h ) 0.76** Sugar 0.56 S t a r c h 0.46 Crude f i b r e -0.66** Crude p r o t e i n -0.43 * * S i g n i f i c a n t P«0.01. 84 energy c o n t e n t . Span S, Sask 1788 and Bronowski were i n t e r -mediate i n t h e i r c ontent of energy components. T h e i r c o n t e n t of crude f i b r e was a l s o a p p r oximately average. The combination r e s u l t e d i n m e t a b o l i z a b l e energy l e v e l s t h a t were i n t e r m e d i a t e to o t h e r samples t e s t e d . P r e v i o u s workers (Carpenter and Clegg , 1956; Davidson e_t a l . , 1961; S i b b a l d e_t a_l., 1963 ) r e c o g n i s e d the need f o r a r a p i d assay c a p a b l e of 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 of f e e d s t u f f s . The equation of Carpenter and Clegg (1956), confirmed by S i b b a l d e_t _al_. (196 3) as capable of p r e d i c t i n g m e t a b o l i z a b l e energy with s u f f i c i e n t p r e c i s i o n was e v a l u a t e d with the t e s t i n g r e d i e n t s as w e l l as with soybean, c o t t o n s e e d and palm k e r n e l meals. Only the m e t a b o l i z a b l e energy 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 of a c c u r a c y . ME of rapeseed meal was d e f i n i t e l y o v e r e s t i m a t e d . C a r p e n t e r and C l e g g (1956) u t i l i z e d mainly c e r e a l s and c e r e a l by-products 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 extremely high content of s t a r c h and with the e x c e p t i o n of o a t s , a f a i r l y low content of crude f i b r e as compared to most v e g e t a b l e p r o t e i n supplements. 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 to a l l c l a s s e s of feed i n g r e d i e n t s w i t h a r e s p e c t a b l e degree of a c c u r a c y . M u l t i p l e l i n e a r r e g r e s s i o n e q u a t i o n s d e r i v e d with rapeseed meals and u s e f u l i n p r e d i c t i n g ME v a l u e s of rapeseed meals were developed. Of the c h e m i c a l c o n s t i t u e n t s a n a l y s e d , o n l y the t o t a l energy components (% sugar + 1.1 x % s t a r c h + 2.25 x %. e t h e r e x t r a c t ) and crude f i b r e were s i g n i f i c a n t l y ( P ^ O . O l r e l a t e d to m e t a b o l i z a b l e energy. 85 The multiple l i n e a r equations Y = 954.75 + 41.73 % sugar + l . l [ ( % starch) + 2.25(% ether extract)] and Y = 1241.54 - 14.57 % C.F. +37.81 % sugar+ 1.1 (% starch) + 2.25 (% ether extract) had an r2 value of 0.77 and 0.79 respectively. Both equations are capable of predicting metabolizable energy of rapeseed meals with a considerable degree of accuracy. T o t a l energy components are highly s i g n i f i c a n t l y (P^O.01) re l a t e d to metabolizable energy (r = 0.88) and for most prac-t i c a l purposes, w i l l afford a rapid method of estimating meta-b o l i z a b l e energy of rapeseed meals. It i s suggested that instead of using broad-based predic-t i v e equations for estimating ME of feed ingredients from t h e i r chemical composition, s p e c i f i c equations derived from ingredients of the same c l a s s be used. 86 T r i a l 6 The m i n e r a l c o n t e n t o f t h e v a r i o u s r a p e s e e d meals i s p r e s e n t e d ( T a b l e 1 7 ) . The a v e r a g e c a l c i u m c o n t e n t o f t h e meals was 6.5 mg/g w i t h a range o f 5.6 mg/g (Sask 940) t o 8.5 mg/g ( c o m m e r c i a l RSM). C a l c i u m c o n t e n t o f Sask 940, Sask 1788 (5.8 mg/g), B r o n o w s k i (6.1 mg/g) and Span P (6.2 mg/g) were l o w e r than a v e r a g e f o r t h e m e a l s , w h i l e Span A (6.6 mg/g) and c o m m e r c i a l RSM had h i g h e r t h a n average c a l c i u m c o n t e n t . The r a p e s e e d meals had a h i g h phosphorus c o n t e n t w i t h an a v e r a g e o f 1.22% and a ran g e o f 1.20% t o 1.25%. Phosphorus c o n t e n t was comparable t o t h a t i n c o t t o n s e e d meal (1.20%) b u t h i g h e r t h a n phosphorus c o n t e n t o f palm k e r n e l meal (0.80%) and soybean meal ( 0 . 8 7 % ) . The magnesium c o n t e n t o f t h e r a p e s e e d meals a v e r a g e d 5.0 mg/g w i t h a ra n g e o f 4.7 mg/g ( c o m m e r c i a l RSM) and 5.5 mg/g ( B r o n o w s k i ) . The meals showed a h i g h magnesium c o n t e n t , c o m parable t o v a l u e s r e p o r t e d f o r palm k e r n e l , soybean and c o t t o n s e e d meals i n t r i a l 3. Most v e g e t a b l e p r o t e i n s upplements a r e h i g h i n magnesium c o n t e n t and i n p r a c t i c a l p o u l t r y r a t i o n s , magnesium d e f i c i e n c y i s n o t a common p r o b l e m . The average manganese c o n t e n t o f t h e meals (54 mg/kg) was h i g h e r t h a n v a l u e s o b s e r v e d i n soybean and c o t t o n s e e d meals (27 mg/kg e a c h ) , but was much s m a l l e r t h a n 135 mg/kg i n palm k e r n e l meal. Sask 940 and Sask 1788 had a s l i g h t l y l o w e r t h a n average c o n -t e n t o f manganese w h i l e B r o n o w s k i had a h i g h e r than a v e r a g e c o n t e n t . I r o n c o n t e n t o f t h e v a r i o u s meals averaged 153 mg/kg w i t h a range o f 110 mg/kg f o r co m m e r c i a l RSM and 180 mg/kg f o r B r o n o w s k i . T h i s was s i m i l a r t o t h e i r o n c o n t e n t o f soybean meal (164 mg/kg), h i g h e r t h a n i n c o t t o n s e e d meal (81 mg/kg) b u t 87 T a b l e 17. M i n e r a l c o n t e n t o f r a p e s e e d meals ( d r y m a t t e r b a s i s ) . ( T r i a l 6) Samples C a P M g M n F e C u Z n p mg/g % mg/g mg/kg mg/kg mg/kg mg/kg Span A 6.6 1.20 5.2 55 140 12 64 Span P 6.2 1.20 4.9 50 148 11 59 Span S 6.5 1.25 5.1 52 147 12 59 Sask 940 5.6 1.20 4.5 49 167 10 49 Sask 1788 5.8 1.25 5.1 49 177 11 55 B r o n o w s k i 6.1 1.20 5.5 67 180 14 62 Commercial RSM 8.5 1.25 4.7 55 110 33 55 Average 6.5 1.22 5.0 54 153 15 58 88 much lo w e r t h a n c o n t e n t o f i r o n i n palm k e r n e l meal (356 mg/kg). The c o p p e r c o n t e n t o f t h e meals ( e x c e p t c o m m e r c i a l RSM) was l o w e r t h a n o b s e r v e d f o r palm k e r n e l , soybean and c o t t o n s e e d meals (27 mg/kg e a c h ) . Copper c o n t e n t o f c o m m e r c i a l RSM (33 mg/kg) was much h i g h e r t h a n o b s e r v e d i n o t h e r r a p e s e e d meals and was comparable t o v a l u e s r e p o r t e d i n o t h e r v e g e t a b l e p r o t e i n supplements (NAS-NRC, 1969). Copper i s t o x i c and t h i s may e x p l a i n the low c o n t e n t o f coppe r i n f e e d i n g r e d i e n t s used i n p r a c t i c a l p o u l t r y r a t i o n s . The z i n c c o n t e n t o f t h e v a r i o u s meals averaged 58 mg/kg w i t h a range o f 49 mg/kg (Sask 940) and 64 mg/kg (Span A ) . The z i n c c o n t e n t o f the meals was comparable t o v a l u e s r e p o r t e d f o r soybean meal (49 mg/kg) and c o t t o n s e e d meal (48 mg/kg) but s l i g h t l y h i g h e r t h a n z i n c c o n t e n t o f palm k e r n e l meal (41 mg/kg) as shown i n t r i a l 3. Pe r c e n t a v a i l a b i l i t i e s o f s i x m i n e r a l s i n t h e v a r i o u s r a p e s e e d meals a r e p r e s e n t e d i n T a b l e 18. Average a v a i l a b i l i t y f o r a l l m i n e r a l s v a r i e d from 52.2% (Span A) t o 69.5% (Span S) w i t h a mean o f 62.9%. Of a l l r a p e s e e d meals t e s t e d , Span A was low i n a v a i l a b i l i t y o f m i n e r a l s w h i l e Span P showed appr o x -i m a t e l y average a v a i l a b i l i t y . Average m i n e r a l a v a i l a b i l i t y was l o w e r than 74.3% o b s e r v e d f o r soybean meal, b u t was h i g h e r than 50.0% and 62.1% shown f o r palm k e r n e l meal and c o t t o n s e e d meals r e s p e c t i v e l y . 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 59.7% (Span A) t o 75.6% (Span S) w i t h a mean o f 68.0%. Most meals showed a h i g h e r than a v e r a g e a v a i l a b i l i t y f o r c a l c i u m . Average c a l c i u m a v a i l a b i l i t y was l o w e r t h a n 85.6% r e p o r t e d f o r soybean meal but 89 T a b l e 18. A v a i l a b i l i t y o f m i n e r a l s i n r a p e s e e d meal samples ( T r i a l 6) Samples Ca P A v a i l a b i l i t y Mg Mn • % Cu Zn Ave. Span A. 59.7 a 65. o a 52.5 a 45. 5 a 67. 5 b 23.0 a 52.2 Span P 68.9 b 75. Q b c 60. 0 b 51.5 a b be 73.0 D C 46.5° 62.5 Span S 75.6 b 81. 0 C 66.5 b 60.0 C 85.0 d 49.1 c d 69.5 Sask 940 70.3 b 79. 5 b c 66.0 b 57.0 b c 82.0 c d 36.0 b 65.1 Sask 1788 61.0 a 74. 5 b 62.0 b 5 3 . l b 77.0 b c d51.2 d 63.1 B r o n o w s k i 6 9 . l b 77. 0 b c 62.5 b 54.4 b c 73.6 b c 45.0 C 63.6 Commercial RSM 71.7 b 74. 8 b 6 1 . l b 56.7 b c 62.2 a 57.6 e 64.0 Average 68.0 75. 3 61.5 54.0 74.3 44.1 mm Means w i t h d i f f e r e n t s u p e r s c r i p t s a r e s i g n i f i c a n t l y d i f f e r e n t between meals ( P ^ 0 . 0 5 ) . 90 was comparable to 64.6% and 68.6% observed f o r palm k e r n e l and co t t o n s e e d meals r e s p e c t i v e l y . These r e s u l t s were comparable to those r e p o r t e d by Devadatta and Appana (1954) f o r c a l c i u m a v a i l a b i l i t y i n v e g e t a b l e s but s l i g h t l y lower than f i g u r e s r e p o r t e d f o r herbs o f g r a s s l a n d (Armstrong and Thomas, 1952; Armstrong ejt a_l., 1 9 5 3 ) . Phosphorus A v a i l a b i l i t y of phosphorus i n rapeseed meals v a r i e d from 65.0% (Span A) to 81.0% (Span S) wit h an average of 75.3%. T h i s was much h i g h e r than a v a i l a b i l i t y of 30% to 40% u s u a l l y a s s o c i a t e d with phosphorus from p l a n t o r i g i n , and was comparable t o r e s u l t s o b t a i n e d f o r a v a i l a b i l i t y of phos-phorus i n palm k e r n e l meal (70.8%), c o t t o n s e e d meal (76.9%) and soybean meal (89.3%) i n t r i a l 3. I t i s however s l i g h t l y h i g h e r than 60% a v a i l a b i l i t y r e p o r t e d by Temperton and C a s s i d y (1964) who observed t h a t c h i c k s c o u l d meet a c o n s i d e r a b l e p r o p o r t i o n of t h e i r phosphorus requirements from v e g e t a b l e s o u r c e s . I t i s a l s o compatible w i t h r e p o r t s by Salman and FicGinnis (1968) who r e p o r t e d that hens c o u l d u t i l i z e a s u b s t a n t i a l p r o p o r t i o n of the phosphorus i n p l a n t m a t e r i a l s . Rapeseed meal i s h i g h i n phosphorus c o n t e n t , a s i g n i f i c a n t p o r t i o n o f which i s a v a i l a b l e to c h i c k s . I t i s suggested t h e r e f o r e t h a t t h i s source o f a v a i l a b l e phosphorus be taken i n t o account i n f o r m u l a t i o n o f r a t i o n s t hat meet the c h i c k s requirement f o r phosphorus. Magnesium Magnesium a v a i l a b i l i t y i n rapeseed meals ranged from 52.5% (Span A) to 66.5% (Span S) w i t h a mean of 61.5%. Most meals had a h i g h e r than average a v a i l a b i l i t y . R e s u l t s r e p o r t e d i n t h i s study were h i g h e r than 56.4% observed f o r a v a i l a b i l i t y o f magnesium i n palm k e r n e l meal but lower than 91 74.6% and 77.4% o b t a i n e d i n c o t t o n s e e d and soybean meals r e s p e c t i v e l y . Rapeseed m e a l s , l i k e palm k e r n e l , soybean and c o t t o n s e e d m e a l s , showed a h i g h c o n t e n t and a v a i l a b i l i t y o f magnesium Manganese A v e r a g e manganese a v a i l a b i l i t y (54.0%) was l o w e r than o b s e r v e d i n soybean meal (76.1%) and c o t t o n s e e d meal (76.3%) b u t was h i g h e r t h a n 45.7% d e t e r m i n e d f o r palm k e r n e l meal. Manganese a v a i l a b i l i t y r a n g e d from 45.5% (Span A) t o 60.0% (Span S ) . Of the r a p e s e e d meals t e s t e d , o n l y Span S, Sask 940 (57.0%) and c o m m e r c i a l RSM (56.7%) had a h i g h e r than a v e r a g e a v a i l a b i l i t y . A c o m b i n a t i o n o f low c o n t e n t and poor a v a i l a b i l i t y o f manganese from r a p e s e e d meal may cause manganese d e f i c i e n c y p r oblems i n p r e d o m i n a n t l y r a p e s e e d meal d i e t s f o r c h i c k s . Copper Rapeseed meals a s s a y e d i n t h i s e x p e r i m e n t showed h i g h c o p p e r a v a i l a b i l i t y . Average a v a i l a b i l i t y was 74.3% w i t h a r a n g e o f 62.2% ( c o m m e r c i a l RSM) and 85.0% (Span S ) . Copper c o n t e n t o f c o m m e r c i a l RSM was a p p r o x i m a t e l y t h r i c e t h e c o n t e n t o f t h e o t h e r r a p e s e e d m e a l s . I n t r i a l 3, palm k e r n e l , soybean and c o t t o n s e e d meals had t h e same copper c o n t e n t (27 mg/kg) y e t t h e a v a i l a b i l i t y o f t h e i r c o p p e r was 44.7%, 51.0% and 42.3% r e s p e c t i v e l y . I t seems t h e r e f o r e t h a t n ot o n l y c o p p e r c o n t e n t but a l s o t h e p h y s i c a l o r c h e m i c a l n a t u r e o f t h e c o p p e r c o u l d a f f e c t a v a i l a b i l i t y . Z i n c Z i n c a v a i l a b i l i t y f r o m r a p e s e e d meals was low (44.1%) r a n g i n g from 23.0% (Span A) t o 57.6% ( c o m m e r c i a l RSM). A v a i l -a b i l i t y o f z i n c has been shown t o be s i m i l a r l y low i n palm k e r n e l meal (13.9%) and c o t t o n s e e d meal (38.0%) b u t f a i r l y h i g h 92 i n soybean meal ( 6 6 . 5 % ) . O ' D e l l e t a l . (1972) r e p o r t e d z i n c a v a i l a b i l i t i e s o f 57% and 67% f o r sesame and soybean meals r e s p e c t i v e l y . R e s u l t s r e p o r t e d i n t r i a l 4 had i m p l i c a t e d p h y t i c a c i d and c r u d e f i b r e c o n t e n t i n r e d u c e d z i n c a v a i l a b i l i t y . Because o f t h e low z i n c a v a i l a b i l i t y r e p o r t e d i n t h e s e m e a l s , z i n c d e f i c i e n c y c o u l d be a p r o b l e m i n r a t i o n s i n which t h e p r o t e i n s o u r c e i s p r e d o m i n a n t l y r a p e s e e d m e a l . 93 T r i a l 7 P r o x i m a t e c o n s t i t u e n t s o f PKM and a l k a l i - t r e a t e d PKM a r e p r e s e n t e d ( T a b l e 1 9 ) . PKM i s low i n p r o t e i n , h i g h i n a c i d d e t e r g e n t f i b r e (ADF) and a c i d d e t e r g e n t l i g n i n ( A D D . A l k a l i t r e a t m e n t o f PKM was d e s i g n e d t o reduce t h e f i b r e and l i g n i n c o n t e n t o f PKM and r e s u l t s o f t h i s t r e a t m e n t a r e shown ( T a b l e 2 0 ) . Treatment w i t h 3% NaOH caused a 25.8% r e d u c t i o n i n ADF and 16.4% i n ADL. I n c r e a s i n g t h e a l k a l i l e v e l s t o 5% o r 7% cau s e d a r e d u c t i o n o f 38.0% o r 48.6% r e s p e c t i v e l y i n ADF c o n t e n t . T here was a c o r r e s p o n d i n g r e d u c t i o n o f 24.9% and 30.1% i n ADL. Tre a t m e n t w i t h a l k a l i a l s o c a u s e d a d e c r e a s e i n c r u d e p r o t e i n c o n t e n t . Amino a c i d c o m p o s i t i o n o f PKM and a l k a l i - t r e a t e d PKM i s p r e s e n t e d i n T a b l e 21 and changes i n amino a c i d c o n t e n t f o l l o w i n g a l k a l i t r e a t m e n t a r e shown i n T a b l e 22. Palm k e r n e l meal i s low i n l y s i n e , t h r e o n i n e , m e t h i o n i n e and o t h e r e s s e n t i a l amino a c i d s . T reatment w i t h 3% NaOH d e s t r o y e d l a r g e amounts o f l y s i n e ( 4 2 . 0 % ) , a r g i n i n e (25.4%) and t h r e o n i n e (24.2%) w i t h l o w e r d e s t r u c t i o n o f the o t h e r amino a c i d s t e s t e d . I n c r e a s i n g t h e l e v e l o f a l k a l i t r e a t m e n t s caused a s e v e r e d e s t r u c t i o n o f a l l amino a c i d s . Treatment w i t h 7% NaOH showed i n c r e a s e d d e s t r u c t i o n o f a r g i n i n e ( 7 8 . 7 % ) , l y s i n e ( 7 1 .0%), s e r i n e (55.5%), t h r e o n i n e (51.5%) and h i s t i d i n e ( 4 6 . 3 % ) . The l a r g e d e c r e a s e i n l y s i n e , a r g i n i n e and t h r e o n i n e p r e c l u d e s t h e u t i l i z a t i o n o f 7% a l k a l i - t r e a t e d PKM as a s o u r c e o f p r o t e i n i n p r a c t i c a l p o u l t r y r a t i o n s Dry m a t t e r d i s a p p e a r a n c e (DMD) and d i g e s t i b l e e n e r g y (DE) 94 T a b l e 19. C h e m i c a l c o m p o s i t i o n o f PKM and a l k a l i - t r e a t e d PKM ( d r y m a t t e r b a s i s ) . ( T r i a l 7) . . . DM CP ADF ADL I n g r e d i e n t ( % ) ( % ) ( % ) ( % ) PKM 92.0 21.30 43.70 21.10 PKM + 3% NaOH " 95.0 18.94 32.40 17.60 PKM + 5% NaOH 94.9 17.80 27.08 15.80 PKM + 7% NaOH 95.0 17.76 22.46 14.73 T a b l e 20. P e r c e n t r e d u c t i o n i n p r o t e i n , ADF and ADL of PKM f o l l o w i n g a l k a l i t r e a t m e n t . ( T r i a l 7) Treatment CP ADF ADL (%) (%) (%) PKM + 3% NaOH 1 0 . 9 a 2 5 . 8 a 1 6 . 4 a PKM + 5% NaOH 1 6 . 3 b 3 8 . 0 b 2 4 . 9 b PKM + 7% NaOH 1 6 . 5 b 4 8 . 6 C 3 0 . 1 C Means w i t h d i f f e r e n t s u p e r s c r i p t s a r e s i g n i f i c a n t l y d i f f e r e n t ( P ^ 0.01) between t r e a t m e n t s . 95 Table 21. Amino acid composition of PKM and a l k a l i - t r e a t e d PKM (dry matter b a s i s ) . ( T r i a l 7) A l k a l i treatment of PKM Amino acids — PKM 3% 5% 7% Lysine 0 .69 0 .40 0. 24 0 .20 H i s t i d i n e 0 .41 0 .35 0. 27 0 .22 Arginine 2 .68 2 .00 1. 14 0 .57 Aspartic acid 1 .69 1 .43 1. 43 1 .33 Threonine 0 .66 0 .50 0. 50 0 .32 Serine 0 .90 ." .0 ."80 0. 59 0 .40 Glutamic acid 3 .62 3 .35 3. 18 2 .75 Proline 0 .50 0 .42 0. 42 0 .42 Glycine 0 .91 0 .80 0. 72 0 .66 Alanine 0 .81 0 .70 0. 68 0 .65 Valine 0 .43 0 .40 0. 35 0 .32 Methionine 0 .47 0 .40 0. 37 0 .37 Isoleucine 0 .60 0 .60 0. 53 0 .46 Leucine 1 .23 1 .04 1. 04 1 V02 Tyrosine 0 .58 0 .48 0. 37 0 .33 Phenylalanine 0 .82 0 .75 0. 70 0 .50 96 Table 22. Per cent destruction of amino acids following a l k a l i treatment ( T r i a l 7) A l k a l i treatment of PKM Amino acids 3% 5% 7% Lysine 42.0 65.2 71.0 H i s t i d i n e 14.6 34.1 46.3 Arginine 25.4 57.5 78.7 Aspartic acid 15.4 15.4 21.3 Threonine 24.2 24.2 51.5 Serine 11.1 34.4 55.5 Glutamic acid 7.5 12.2 24.0 Proline 16.0 16.0 16.0 Glycine 12.1 20.9 27.5 Alanine 13.6 16.0 19.8 Valine 7.0 18.6 25.6 Methionine 14.9 21.3 21.3 Isoleucine 0.0 11.7 23.3 Leucine 15.4 15.4 21.0 Tyrosine 17.2 36.2 43.1 Phenylalanine 8.5 14.6 39.0 97 o f PKM and a l k a l i - t r e a t e d PKM a r e p r e s e n t e d i n T a b l e 23. There were no s i g n i f i c a n t d i f f e r e n c e s ( P ^ O . 0 1 ) between t h e DMD o f PKM (81.1%) and 3% NaOH - t r e a t e d PKM ( 8 0 . 5 % ) . Treatment w i t h 5% o f 7% NaOH c a u s e d a s i g n i f i c a n t i n c r e a s e ( P ^ O . 0 1 ) i n DMD o f palm k e r n e l m e a l . F u r t h e r m o r e s i g n i f i c a n t i n c r e a s e s (P^.0.01) were o b s e r v e d i n d i g e s t i b l e e n e r g y o f a l k a l i - t r e a t e d PKM. I n c r e a s i n g t h e l e v e l o f a l k a l i t r e a t m e n t s i g n i f i c a n t l y (P^.0.01) improved t h e d r y m a t t e r d i s a p p e a r a n c e and d i g e s t i b l e e n e r g y o f PKM f o r the r u m i n a n t . R e s u l t s o b s e r v e d i n t h i s s t u d y were i n agreement w i t h r e p o r t s by p r e v i o u s w o r k e r s ( O l o l a d e e t a l . , 1970; Chandra and J a c k s o n , 1971; Rounds e t a l . , 1976). L e v e l s o f a l k a l i used i n t h e e x p e r i m e n t showed no a d v e r s e e f f e c t on n u t r i e n t d i g e s t i b i l i t y i n t h e rumen. A l k a l i t r e a t m e n t i s a p r o v e n method o f i m p r o v i n g t h e n u t r i t i v e v a l u e o f poor q u a l i t y r oughages f o r r u m i n a n t 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 PKM and a l k a l i - t r e a t e d PKM have a g r e a t e r p o t e n t i a l i n r u m i n a n t n u t r i t i o n t h a n has been p r e v i o u s l y r e c o g n i s e d . M e t a b o l i z a b l e energy v a l u e s f o r PKM and a l k a l i - t r e a t e d PKM d e t e r m i n e d w i t h t h r e e week o l d c h i c k s a r e p r e s e n t e d i n T a b l e 24. M e t a b o l i z a b l e e n e r g y o f PKM (2796.0 k c a l / k g ) was s i g n i f i c a n t l y ( P ^ 0.01) h i g h e r t h a n ME o f a l k a l i - t r e a t e d PKM. Ther e were s i g n i f i c a n t d i f f e r e n c e s (P< 0.01) between m e t a b o l i -z a b l e e n ergy o f 3% (1845.3 k c a l / k g ) , 5% (1327.4 k c a l / k g ) and 7% (950.7 k c a l / k g ) a l k a l i - t r e a t e d PKM. The more s e v e r e t h e a l k a l i t r e a t m e n t , t h e g r e a t e r t h e d e p r e s s i o n o b s e r v e d i n meta-b o l i z a b l e e n e r g y o f t h e sample. I t appeared t h a t a l k a l i t r e a t -ment a d v e r s e l y a f f e c t e d e n e r g y components such as c a r b o h y d r a t e s and f a t s i n a d d i t i o n t o p r o t e i n d e s t r u c t i o n . Depressed f e e d 98 Table 23. Di g e s t i b l e dry matter (DDM) and d i g e s t i b l e energy (DE) of PKM and a l k a l i - t r e a t e d PKM ( T r i a l 7, Experiment 1) Treatment DDM DE (g/lOOg) (kcal/g) PKM 81.10 a 3.710a PKM + 3% NaOH 80.50 a 3.765 b PKM + 5% NaOH 83.72 b 3.881C PKM + 7% NaOH 87.70° 4.060d Means with d i f f e r e n t superscripts are s i g n i f i c a n t l y d i f f e r e n t (P^O.01) between treatments. Table 24. Gross and metabolizable energy of PKM and a l k a l i - t r e a t e d PKM (dry matter b a s i s ) . ( T r i a l 7) ingredient (kcal/kg) (kcal/kg) PKM 4673.0 2796.0 a PKM + 3% NaOH 4502.0 1845.3 b PKM + 5% NaOH 4500.0 1327.4° PKM + 7% NaOH 4407.0 950.7 d Means with d i f f e r e n t superscripts are s i g n i f i c a n t l y d i f f e r e n t (P^O.01) among ingredients. 9 9 i n t a k e was o b s e r v e d i n c h i c k s f e d a l k a l i - t r e a t e d PKM, t h e h i g h e r t h e l e v e l o f a l k a l i t r e a t m e n t , t h e l o w e r the f e e d i n t a k e . T h i s i n d i c a t e d t h a t r e s i d u a l a l k a l i a f f e c t e d p a l a t a b i l i t y and c o u l d p a r t l y e x p l a i n t h e d e p r e s s i o n i n m e t a b o l i z a b l e e n e r g y f o l l o w i n g a l k a l i t r e a t m e n t . •Re s u l t s ( T a b l e 25) i n d i c a t e t h a t i n c l u s i o n o f PKM a t 10%, 20% o r 30% i n t o a s t a n d a r d s t a r t e r d i e t (wheat-soybean) s i g n i -f i c a n t l y ( P ^ 0 . 0 5 ) i n c r e a s e d t o t a l body w e i g h t g a i n and average d a i l y g a i n o f t e s t c h i c k s o v e r c o n t r o l s . T o t a l f e e d consump-t i o n was however s i g n i f i c a n t l y ( P ^ 0 . 0 5 ) i n c r e a s e d by i n c l u s i o n o f PKM i n t h e d i e t s . There were no s i g n i f i c a n t d i f f e r e n c e s (P*»0.05) between t h e f e e d c o n v e r s i o n r a t i o (FCR) o f c h i c k s on th e 10% PKM and c o n t r o l r a t i o n s . Feed c o n v e r s i o n r a t i o o f c h i c k s on t h e 20% and 30% PKM r a t i o n s were n o t s i g n i f i c a n t l y d i f f e r e n t ( P ^ 0 . 0 5 ) from each o t h e r b u t were s i g n i f i c a n t l y h i g h e r (P-^0.05) t h a n t h o s e on t h e 10% PKM r a t i o n . C a l c u l a t e d n u t r i e n t c o m p o s i -t i o n o f t h e t e s t d i e t s i s shown i n T a b l e 26. A l l r a t i o n 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 and were b a l a n c e d f o r c o n t e n t o f l y s i n e , m e t h i o n i n e , t h r e o n i n e , c a l c i u m and phos-p h o r u s . D i f f e r e n c e s i n growth r a t e would t h e r e f o r e be due t o v a r i a t i o n s i n n u t r i e n t i n t a k e . The a v e r a g e n u t r i e n t i n t a k e p e r b i r d ( T a b l e 27) i n d i c a t e d t h a t f e e d , e n e r g y , p r o t e i n and c r u d e f i b r e i n t a k e was h i g h e s t i n t h e c h i c k s on t h e 30% PKM d i e t and l o w e s t i n b i r d s on the c o n t r o l d i e t . The d i f f e r e n c e s i n 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 between t h e PKM d i e t s and t h e c o n t r o l d i e t may be e x p l a i n e d by t h e h y p o t h e s i s t h a t i n c r e a s e d l e v e l o f d i e t a r y f i b r e i n t h e t e s t d i e t s h a s t e n e d t r a n s i t t i me o f t h e i n g e s t e d f e e d i n t h e d i g e s t i v e t r a c t o f the c h i c k s , and 100 T a b l e 25. E f f e c t o f l e v e l o f PKM i n r a t i o n on 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 o f b r o i l e r c h i c k s ( T r i a l 7, E x p e r i m e n t 3 ) . R a t i o n t r e a t m e n t Body wt g a i n p e r b i r d Feed c o n s u m p t i o n p e r b i r d ADG FCR C o n t r o l 2 1 9 . 8 a 3 6 6 . 0 a 1 8 . 3 a 1 . 6 7 a b 10% PKM 2 7 5 . 4 b 4 4 3 . 6 b 2 3 . 0 b 1.61 a 20% PKM 2 6 5 . 4 b 4 6 3 . 0 b 22. l b 1 . 7 4 b c 30% PKM 2 7 1 . 2 b 4 9 6 . 6 C 2 2 . 6 b 1.83 C Means w i t h d i f f e r e n t s u p e r s c r i p t s between t r e a t m e n t s a r e s i g n i f i c a n t l y d i f f e r e n t ( P ^ 0 . 0 5 ) . T a b l e 26. E f f e c t o f l e v e l o f PKM i n r a t i o n on 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 o f b r o i l e r c h i c k s . C a l c u l a t e d n u t r i e n t c o m p o s i t i o n o f t e s t d i e t s ( T r i a l 7, Experiment ; 3 ) . 10% PKM I n g r e d i e n t % o f r a t i o n ME CP L y s Meth T h r e o Ca p C o n t r o l r a t i o n 89.80 2526.0 20.5 1.13 0.41 0.71 0.92 0 .63 PKM 10.00 257.2 2.0 0.07 0.05 0.07 0.04 0 .08 S u p p l e . Lys 0.05 - 0.05 - - - -L i m e s t o n e 0.15 - - - - - 0.05 -100.00 2783.2 22.5 1.25 0.46 0.78 1.01 0 .71 20% PKM C o n t r o l r a t i o n 79.70 2241.9 18.3 1.01 0.37 0.63 0.82 0 .56 PKM 20.00 514.5 3.9 0.14 0.10 0.14 0.08 0 .16 S u p p l e . Lys 0.10 - - 0.10 - - - -L i m e s t o n e 0.30 - - - - - 0.10 -100.00 2756.4 22.2 1.25 0.47 0.77 1.00 0 .72 30% PKM C o n t r o l r a t i o n 69.40 1952.1 16.0 0.88 0.32 0.55 0.71 0 .49 PKM 30.00 771.7 5.9 0.21 0.15 0.21 0.12 0 .24 S u p p l e . L y s 0.15 - - 0.15 - - - -L i m e s t o n e 0.45 — — — _ — 0.15 100.00 2723.8 21.9 1.24 0.47 0.76 0.98 0.73 102 T a b l e 27. Average n u t r i e n t i n t a k e p e r b i r d p e r day ( T r i a l 7, E x p e r i m e n t 3 ) . Feed Energy ~ P r o t e i n Crude f i b r e D i e t s i n t a k e i n t a k e i n t a k e i n t a k e (g) ( k c a l ) (g) (g) C o n t r o l 30.50 85.79 6.95 1.08 10% PKM 36.97 102.89 8.32 1.83 20% PKM 38.58 106.34 8.56 2.45 30% PKM 41.38 112.71 9.06 3.20 103 consequently increased t o t a l feed consumption per day. This led to increased t o t a l protein and energy intake and r e t e n t i o n and therefore to higher average d a i l y gain. I t appears that chicks need more di e t a r y f i b r e f o r optimum growth than i s supplied by the standard wheat-soybean s t a r t e r r a t i o n . I t also appears that i n high f i b r e d i e t s , there may be an increased requirement for protein or energy or both. Among the PKM d i e t s , d i f f e r e n c e s i n growth rate and feed conversion r a t i o are harder to e x p l a i n . I t i s however suggested that i n c l u s i o n of PKM at 10% provides that l e v e l of d i e t a r y f i b r e at which growth rate and feed u t i l i z a t i o n are optimised. The growth rate and feed conversion r a t i o of chicks fed PKM and a l k a l i - t r e a t e d PKM d i e t s are presented i n Table 28. Growth rate was i n i t i a l l y depressed i n the test d i e t s but r a p i d l y returned to normal i n the PKM and 3% a l k a l i - t r e a t e d PKM r a t i o n s . Lower growth rate was observed i n the 5% and 7% a l k a l i - t r e a t e d PKM rations throughout the experiment, corres-ponding to depressed feed intake. Chicks on the PKM r a t i o n gained f a s t e r than those on the a l k a l i - t r e a t e d PKM r a t i o n s , although no s i g n i f i c a n t d i f f e r e n c e s (P4 0.01) were observed i n feed conversion r a t i o among these treatments. Average d a i l y gain and feed conversion r a t i o were s i m i l a r i n control and PKM r a t i o n s . D e l i g n i f i c a t i o n of a l k a l i treatment did not improve the n u t r i t i v e value of PKM f o r non-ruminants but rather confounded the already e x i s t i n g p a l a t a b i l i t y problem. 104 Table 28. Growth rate and feed conversion r a t i o of chicks on PKM and a l k a l i - t r e a t e d PKM d i e t s . ( T r i a l 7, Experiment 4) Cumulative weight gain per b i r d (g) Treatment Days — " " g *ADG TCR Control 22.1 57.0 PKM 4.8 34.3 PKM + 3% NaOH 8.8 40.7 PKM + 5% NaOH 4.0 33.8 PKM + 7% NaOH 3.5 23.8 78.7 126 .2 15.8 a 1.63 a 76.8 121 .4 15. 2 a 1.67 a b 76.8 116 .8 14.6 a 1.80 b 67.7 103 .1 12.9 b 1.83 b 48.0 72 .6 9.1 c 1.83 b *ADG and FCR were subjected to s t a t i s t i c a l a n a l y s i s . Means with d i f f e r e n t superscripts were s i g n i f i c a n t l y d i f f e r e n t (P^O.01), between treatments. V 105 T a b l e 29. C a l c u l a t e d a n a l y s i s o f t e s t d i e t s ( T r i a l 7, E x p e r i m e n t 4 ) . Metabo-M e t h i o - T h r e o - Phos- Crude l i z a b l e D i e t s L y s i n e n i n e n i n e C a l c i u m phorus P r o t e i n Energy (%) (%) (%) (%) (%) (%) ( k c a l / k g ) C o n t r o l 1.26 0.46 0. 79 1.02 0 .70 22.86 2812 .85 PK 1.25 0.46 0. 78 1.14 0 .79 .22:98 2837 .16 PK + 3% NaOH 1.25 0.46 0. 74 1.01 0 .80 22.45 2702 .10 PK + 5% NaOH 1.25 0.47 0. 72 1.06 0 .81 22.49 2565 .35 PK + 7% NaOH 1.26 0.48 0. 72 1.07 0 .83 22.54 2500 .00 106 The need for increased u t i l i z a t i o n of vegetable fee d s t u f f s i n chick d i e t formulation. The problem of world food shortage i s r e a l , and everyday hundreds of thousands of human beings, e s p e c i a l l y i n the developing countries, go to bed hungry and malnourished. Plant foodstuffs such as c e r e a l s , yam and cassava c o n s t i t u t e a major f r a c t i o n of the diets of the people, p r i n c i p a l l y because animal protein i s i n short supply. But i t does not have to be so. Increased u t i l i z a t i o n of vegetable protein supplements i n animal feed formulation i s a way to turn poor q u a l i t y proteins i n t o n u t r i t i o n a l l y superior animal proteins. Many t r o p i c a l countries produce considerable quantities of peanut, coconut, palm kernel, soybean, cottonseed, sunflower seed and other vegetable meals capable of u t i l i z a t i o n i n animal n u t r i t i o n . The Food and A g r i c u l t u r e Organization of the United Nations (F.A.O., 1974) reported that i n 1974 countries of A f r i c a exported well over one m i l l i o n metric tons of oil s e e d cakes, earning an estimated $127.4 m i l l i o n . Nigeria exported 61,100 metric tons of o i l s e e d cakes and earned $11.4 m i l l i o n i n the process. 280,668 tons (metric) of peanut meal, 170,622 tons of cottonseed meal, 107,773 tons of palm kernel meal, 32,105 tons of rapeseed meal and 13,481 tons of coconut meal were exported by A f r i c a n countries i n 1974. Most of these products were imported by European countries f o r feed and f e r t i l i z e r produc-t i o n while the countries of A f r i c a imported 96,825 metric tons of oi l s e e d cakes p r i n c i p a l l y cottonseed meal (13,35.6 metric tons), soybean meal (8,000 metric tons), and coconut meal (213 metric tons). 107 The use o f soybean meal i n l i v e s t o c k r a t i o n s i n t r o p i c a l c o u n t r i e s has been r e c o g n i s e d f o r a l o n g t i m e . Soybean, pea-nut and f i s h m e a l s have t r a d i t i o n a l l y been t h e main s u p p l i e r s o f d i e t a r y amino a c i d s i n non-ruminant r a t i o n s i n N i g e r i a . N i g e r i a does not however produce s u f f i c i e n t soybean meal t o meet i t s r e q u i r e m e n t s f o r a n i m a l n u t r i t i o n . L o c a l l y p roduced soybean meal i s so e x p e n s i v e t h a t i t i s p r i c e d out o f t h e r e a c h o f t h e average f a r m e r , y e t i m p o r t a t i o n has u n t i l r e c e n t l y been c u r t a i l e d . C o t t o n s e e d meal i s n e i t h e r produced n o r u t i l i z e d i n a n i m a l r a t i o n s t o any s i g n i f i c a n t e x t e n t i n N i g e r i a . C o t t o n -seeds produced i n N i g e r i a (11,126 m e t r i c t o n s i n 1974) a r e s t r i c t l y f o r e x p o r t . C o t t o n s e e d meal has a proven r e c o r d o f u t i l i z a t i o n i n a n i m a l r a t i o n s . What i s needed i n N i g e r i a and o t h e r A f r i c a n c o u n t r i e s i s t e c h n o l o g y t o p r o c e s s t h e meal and r e d u c e i t s g o s s y p o l c o n t e n t . The p r o d u c t i s w e l l endowed w i t h c o n s i d e r a b l e q u a n t i t i e s o f h i g h l y a v a i l a b l e d i e t a r y amino a c i d s and c a n c o n t r i b u t e s i g n i f i c a n t l y t o p r o d u c t i o n o f a n i m a l p r o t e i n s i n N i g e r i a . Rapeseed meal i s a r e l a t i v e l y newcomer t o t h e s c ene o f non-ruminant n u t r i t i o n . Recent r e s e a r c h i n Canada and t h e U.S. has i n d i c a t e d t h a t c o m m e r c i a l r a p e s e e d meal i s a good s o u r c e o f d i e t a r y amino a c i d s and w i t h j u d i c i o u s i n c o r p o r a t i o n i n t o r a t i o n s , can c o n t r i b u t e s i g n i f i c a n t l y t o a n i m a l p r o d u c t i o n . Palm k e r n e l meal i s not c o n s i d e r e d a major f e e d i n g r e d i e n t i n most t r o p i c a l c o u n t r i e s . The p r o d u c t i s r e s t r i c t e d t o 5% t o 10% o f c h i c k d i e t s and a s i g n i f i c a n t f r a c t i o n o f t h e t o t a l p r o d u c t i o n i s used f o r f u e l p r o d u c t i o n and s o i l f e r t i l i z a t i o n . 108 Most t r o p i c a l c o u n t r i e s p r o duce tremendous amounts o f palm k e r n e l meal w h i c h can be more e f f i c i e n t l y u t i l i z e d i n l i v e s t o c k r a t i o n s when mixed w i t h s y n t h e t i c amino a c i d s o r o t h e r p r o t e i n s o u r c e s . - Palm k e r n e l meal has a p o t e n t i a l f o r c o n t r i b u t i n g s i g n i f i c a n t l y t o s o l v i n g t h e p e r e n n i a l f o o d problem o f t r o p i -c a l c o u n t r i e s . I n 1968/69, c o r n , m i l l e t and sorghum p r o d u c t i o n i n N i g e r i a were 1,039, 2,152 and 3,425 m i l l i o n t o n s . Of t h i s amount o n l y 1.96 thousand t o n s of each c e r e a l was u t i l i z e d i n a n i m a l f e e d m a n u f a c t u r e . The r e s t of t h e p r o d u c t i o n was f o r human consump-t i o n , average d a i l y i n t a k e p e r p e r s o n o f c o r n , m i l l e t and sorghum b e i n g e s t i m a t e d a t 38.18, 83.04 and 129.84 grams. A l o t more o f t h e s e g r a i n s c o u l d have gone i n t o m a n u f a c t u r e of a n i m a l f e e d s , were they not so much p a r t o f t h e N i g e r i a n d i e t . O l a y i d e e t a l . (1972) p r o j e c t e d t h a t demand f o r c o r n , m i l l e t and sorghum f o r human c o n s u m p t i o n i n 1980 would be 1.20, 2.75 and 4.31 m i l l i o n m e t r i c t o n s r e s p e c t i v e l y . However t h e p r o j e c t e d s u p p l y o f t h e s e c e r e a l s would be 1.11, 2.03 and 2.88 m i l l i o n m e t r i c t o n s r e s p e c t i v e l y . P r o j e c t e d demand would t h e r e -f o r e exceed p r o j e c t e d s u p p l y o f c o r n , m i l l e t and sorghum by 0.09, 0.72 and 1.43 m i l l i o n m e t r i c t o n s r e s p e c t i v e l y . They o b s e r v e d t h a t a t t h e e x i s t i n g compound r a t e o f growth o f f o o d s u p p l y , N i g e r i a would not be a b l e t o f e e d i t s p e o p l e i n decades ahead, b e g i n n i n g from 1972 and warned t h a t t h e f o o d s i t u a t i o n was a s e r i o u s n a t i o n a l d i s a s t e r which r e q u i r e d u r g e n t s o l u t i o n and/or p l a n n e d a t t a c k . O l a y i d e and c o w o r k e r s (1972) s u g g e s t e d t h a t s u p p l y d f c e r e a l s s h o u l d i n c r e a s e a t 6.5% and f a rm p r o d u c -t i o n a t 8.0% p e r y e a r t o meet c u r r e n t and f u t u r e demands f o r 109 c e r e a l p r o d u c t s f o r human and a n i m a l c o n s u m p t i o n . The a p p r o x i m a t e c o s t s o f f e e d i n g r e d i e n t s i n L a g o s , N i g e r i a and V a n c o u v e r , Canada a r e p r e s e n t e d i n T a b l e 30. There i s a $320 p r i c e d i f f e r e n t i a l i n t h e c o s t o f one t o n o f soybean meal between Lagos and V a n c o u v e r . A l m o s t a l l the soybean u t i l i z e d i n a n i m a l f e e d f o r m u l a t i o n i n N i g e r i a i s p r o d u c e d l o c a l l y and when demand f a r exceeds s u p p l y , p r i c e s r i s e . There i s however o n l y a $31 d i f f e r e n c e between wheat c o s t s i n Lagos and Vancouver. Because o n l y a l i t t l e wheat i s grown i n N i g e r i a , a l m o s t a l l t h e wheat used i n f e e d m a n u f a c t u r e i s i m p o r t e d , and when b u l k p u r c h a s e s a r e made e s p e c i a l l y a t low e x p o r t p r i c e s , c o s t o f wheat i n Lagos can compare f a v o u r a b l y w i t h c o s t i n V a n c o u v e r . The a p p r o x i m a t e i n g r e d i e n t c o s t s o f f o r m u l a t i n g one t o n o f s t a n d a r d wheat-soybean s t a r t e r r a t i o n i n Lagos and Vancouver a r e p r e s e n t e d i n T a b l e 31. I t i s a p p r o x i m a t e l y $96 more e x p e n s i v e t o f o r m u l a t e a t o n o f wheat-soybean s t a r t e r r a t i o n i n Lagos t h a t i t i s i n V a n c o u v e r . Because o f the h i g h c o s t o f c o r n i n N i g e r i a (WlOO/ton), i t would be l e s s e x p e n s i v e t o f o r m u l a t e a c o r n - s o y b e a n s t a r t e r r a t i o n i n Vancouver t h a n t o f o r m u l a t e t h e same r a t i o n i n Lagos u s i n g c o r n grown i n N i g e r i a . To r e l i e v e t h e p r e s s u r e on t h e s e c e r e a l s , O l a y i d e e_t a l _ . (1972) s u g g e s t e d t h e u t i l i z a t i o n o f o t h e r c e r e a l s and g r a i n legumes f o r human c o n s u m p t i o n . A p o s s i b l e a l t e r n a t i v e would be t o meet a f r a c t i o n o f the p r o t e i n and e n e r g y r e q u i r e m e n t s o f a n i m a l s w i t h l e s s c o n v e n t i o n a l f e e d s t u f f s l i k e palm k e r n e l m e a l . The a p p r o x i m a t e c o s t s o f r a t i o n s f o r m u l a t e d by s u b s t i t u t i n g PKM a t 10%, 20% o r 30% i n t o 110 T a b l e 30. A p p r o x i m a t e c o s t o f f e e d i n g r e d i e n t s a t Lagos, N i g e r i a and V a n c o u v e r , Canada ( 1 9 7 6 ) . I n g r e d i e n t Lagos p r i c e i n N a i r a ( N ) V t o n Vancouver p r i c e D o l l a r s ( $ ) l / t o n Soybean W400 $224 Wheat M100 $110 Meat, meal W143 $186 A l f a l f a meal W 63 . $ 80 T a l l o w H250 $340 L i m e s t o n e W8.50 $8.50 C a l c i u m phosphate ( D i b a s i c ) M104 $146 V i t a m i n - M i n e r a l p r e mix W2/ton o f f i n i -shed f e e d $3.50/ton f i n i -shed f e e d DL m e t h i o n i n e N l / l b $ 1 . 4 0 / l b L - l y s i n e M2.75/lb $ 3 . 8 5 / l b PKM W 50 $105* "Assuming a 50% mark up on N i g e r i a n p r i c e s . C o n v e r s i o n r a t e i s NI = $1.41 C a n a d i a n . I l l T a b l e 31. A p p r o x i m a t e i n g r e d i e n t c o s t o f f o r m u l a t i n g s t a n d a r d what-soybean s t a r t e r r a t i o n s i n L a g o s , N i g e r i a and V a n c o u v e r , Canada. T „ „ ^ . „, Lagos Vancouver I n g r e d i e n t N i g e r i a Cn) Canada ($) Soybean 98.18 61.60 Wheat 62.23 69.85 Meat meal 2.86 3.72 A l f a l f a meal 0.63 0.80 T a l l o w 5.75 7.13 L i m e s t o n e 0.12 0.12 C a l c i u m phosphate 1.04 1.46 ( D i b a s i c ) V i t a m i n - M i n e r a l 2.00 3.50 premix D-L m e t h i o n i n e 2.80 3.92 L - l y s i n e 4.48 6.16 180.09 158.26 112 s t a n d a r d s t a r t e r r a t i o n s a r e p r e s e n t e d i n T a b l e 32. I n t r o d u c i n g PKM a t 10% l e v e l , r educed i n g r e d i e n t c o s t s p e r t o n o f f e e d by $14.78. I n t r o d u c t i o n a t 20% o r 30% r e d u c e d c o s t s by $29.32 and $44.34 per t o n r e s p e c t i v e l y . R e s u l t s i n e x p e r i m e n t 3, T r i a l 6 have shown t h a t a v e r a g e d a i l y g a i n o f t h e b i r d s on t h e PKM r a t i o n s were not s i g n i f i c a n t l y d i f f e r e n t from each o t h e r ( P ^ 0.05) but were s i g n i f i c a n t l y ( P ^ 0 . 0 5 ) h i g h e r t h a n c o n t r o l s . The l o w e s t f e e d c o n v e r s i o n r a t i o was shown by b i r d s on t h e 10% PKM r a t i o n and t h e h i g h e s t by t h o s e on t h e 30% PKM r a t i o n . A l l f a c t o r s c o n s i d e r e d , t h e 20% PKM r a t i o n may be the b e s t r a t i o n t o f e e d . 113 Table 32. Approximate ingredient costs of rations formulated by s u b s t i t u t i n g PKM at 10%, 20% or 30% into stand-dard s t a r t e r r a t i o n s . ( T r i a l 7, Experiment 3) Costs at Lagos Costs at Vancouver Ingredients Nigeria Canada N $ 10% PKM die t Standard s t a r t e r r a t i o n 161.72 142.12 PKM 5.00 50.50 L-l y s i n e 2.80 3.85 Limestone 0.01 0.01 169.53 156.48 20% PKM diet Standard s t a r t e r r a t i o n 143.53 126.13 PKM 10.00 21.00 L-lys i n e 5.60 7.70 Limestone 0.02 0.02 159.15 154.85 30% PKM die t Standard s t a r t e r r a t i o n 124.98 109.83 PKM 15.00 31.50 L-lysine 8.40 11.55 Limestone 0.04 0.04 148.42 152.92 114 SUMMARY AND CONCLUSIONS 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 , m i n e r a l , c o n t e n t 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 o f palm k e r n e l , soybean, c o t t o n s e e d and r a p e s e e d meals were d e t e r m i n e d u s i n g g r o w i n g b r o i l e r c h i c k s . Palm k e r n e l meal was l o w e s t and soybean meal h i g h e s t i n c o n t e n t o f e s s e n t i a l amino a c i d s , o f a l l v e g e t a b l e p r o t e i n s upplements t e s t e d . Average amino a c i d a v a i l a b i l i t y v a r i e d from 84.5% (palm k e r n e l meal) t o 97.3% (soybean m e a l ) . Amino a c i d a v a i l a b i l i t y i n c o t t o n s e e d meal (92.5%) and r a p e -seed meal (91.9%) were s i m i l a r . C o n t e n t o f c a l c i u m , phosphorus and magnesium were h i g h i n a l l f e e d s t u f f s t e s t e d . Manganese was low i n soybean and c o t t o n s e e d meals b u t h i g h i n palm k e r n e l m e a l . C o n t e n t o f i r o n was e x c e p t i o n a l l y h i g h i n palm k e r n e l meal (356 ppm) and low i n c o t t o n s e e d meal (81 ppm). Copper c o n t e n t was low i n a l l f e e d s t u f f s t e s t e d . Mean a v a i l a b i l i t y o f m i n e r a l s v a r i e d from 50.0% (palm k e r n e l meal) t o 74.3% (soybean m e a l ) . M i n e r a l a v a i l a b i l i t y i n c o t t o n s e e d meal (62.1%) and r a p e s e e d meal (64.0%) were s i m i l a r . Among m i n e r a l e l e m e n t s t e s t e d , phos-p h o r u s (78.0%) and c a l c i u m (72.6%) showed t h e h i g h e s t a v a i l a -b i l i t y w h i l e z i n c (44.0%) was l e a s t a v a i l a b l e . Crude f i b r e c o n t e n t o f t h e f e e d s t u f f s s i g n i f i c a n t l y (P£0.05) d e p r e s s e d a v a i l a b i l i t y o f a l l m i n e r a l s t e s t e d w h i l e p h y t i c a c i d c o n t e n t s i g n i f i c a n t l y ( P * 0.05) a f f e c t e d a v a i l a -b i l i t y o f p h o s p h o r u s , c a l c i u m , z i n c and magnesium b u t n o t manganese and c o p p e r . I t was s u g g e s t e d t h a t w h i l e t h e i n f l u e n c e o f p h y t i c a c i d on m i n e r a l a v a i l a b i l i t y was w e l l 115 documented, t h e e f f e c t o f c r u d e f i b r e had not been p r e v i o u s l y w e l l e m phasized. The m e t a b o l i z a b l e e n ergy (ME) o f t h e f e e d s t u f f s was d e t e r m i n e d u s i n g t h r e e week o l d b r o i l e r c h i c k s . M e t a b o l i -z a b l e energy v a l u e s were s i m i l a r t o t h o s e r e p o r t e d i n t h e l i t e r a t u r e and ranged from 1957 k c a l / k g d r y m a t t e r ( r a p e s e e d meal) t o 2796 k c a l / k g d r y m a t t e r (palm k e r n e l m e a l ) . There were no s i g n i f i c a n t d i f f e r e n c e s ( P ^ 0 . 0 5 ) between m e t a b o l i -z a b l e energy c o n t e n t o f palm k e r n e l and soybean m e a l s . C h e m i c a l c o n s t i t u e n t s , a v a i l a b l e c a r b o h y d r a t e and m e t a b o l i z a b l e e n e r g y o f seven d i f f e r e n t r a p e s e e d meals were d e t e r m i n e d . There were s i g n i f i c a n t d i f f e r e n c e s (P<£0.01) i n m e t a b o l i z a b l e e n e r g y o f t h e me a l s , the v a l u e s r a n g i n g from 1492 k c a l / k g (Span A) t o 1957 k c a l / k g ( c o m m e r c i a l RSM). Of a l l c h e m i c a l c o n s t i t u e n t s t e s t e d , e t h e r e x t r a c t , s u g a r and s t a r c h c o n t e n t were h i g h l y s i g n i f i c a n t l y ( P ^ 0.01) r e l a t e d t o m e t a b o l i z a b l e e n e r g y . M u l t i p l e l i n e a r r e g r e s s i o n e q u a t i o n s were d e v e l o p e d t o p r e d i c t m e t a b o l i z a b l e e n e r g y o f r a p e s e e d meals from t h e i r c h e m i c a l c o n s t i t u e n t s . C o n t e n t 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, Zn, Cu) were d e t e r m i n e d u s i n g t h e t e s t r a p e s e e d meals. Samples were h i g h i n c a l c i u m , p h o s p h o r u s , and magnesium and low i n c o p p e r c o n t e n t i n c o m p a r i s o n t o palm k e r n e l , soybean, c o t t o n -s eed and o t h e r v e g e t a b l e p r o t e i n s u p p l e m e n t s . Average a v a i l a b i l i t y o f m i n e r a l s r a n g e d from 52.2% (Span A) t o 64.0% ( c o m m e r c i a l RSM). Among t h e m i n e r a l s t e s t e d , phosphorus ( 7 5 . 3 % ) , c o p p e r (74.3%) and c a l c i u m (68.0%) showed the h i g h e s t a v a i l a b i l i t i e s . Z i n c was l e a s t a v a i l a b l e ( 4 4 . 0 % ) . 116 Palm kernel meal, d e l i g n i f i e d by treatment with 3%, 5% or 7% NaOH was analysed for amino acid destruction and subse-quently u t i l i z e d i n growth and other t r i a l s . There was a considerable reduction i n content of protein, acid detergent f i b r e and acid detergent l i g n i n following a l k a l i treatment of palm kernel meal. Reduction i n proximate constituents was d i r e c t l y r e l a t e d to l e v e l of a l k a l i used. A l k a l i treatment of palm kernel meal caused destruction of constituent amino acids. The l e v e l of destruction was s i m i l a r l y d i r e c t l y related to the severity of a l k a l i treatment. Various amino acids were affected d i f f e r e n t l y . Treatment with 7% a l k a l i caused a 21.3% destruction i n methionine content but 71.0% destruction of l y s i n e . A l k a l i treatment depressed metabolizable energy of palm kernel meal. There were s i g n i f i c a n t differences between metabolizable energy of untreated PKM (2796 kcal/kg) and 3% (1845 kcal/kg), 5% (1327 kcal/kg), and 7% (951 kcal/kg) a l k a l i -treated PKM. Inclusion of a l k a l i treated PKM at 30% l e v e l into a standard b r o i l e r s t a r t e r r a t i o n depressed growth rate and feed e f f i c i e n c y of test chicks as compared to control chicks. In another growth t r i a l , i t was shown that i n c l u s i o n of palm kernel meal at 10%, 20% or 30% into a standard s t a r t e r d i e t s i g n i f i c a n t l y (P^0.05) increased t o t a l body weight gain and average d a i l y gain of test chicks over controls on a stan-dard s t a r t e r d i e t . Chicks on the 10% PKM d i e t had the highest growth rate and feed e f f i c i e n c y . Increased l e v e l of PKM incorporation s l i g h t l y depressed feed e f f i c i e n c y but not growth rate of test c h i c k s . 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DM CF A c i d Phosphorus Phosphorus 3 1.7733* 41.613* 0.5191* 0.0408* 0.10387* 2 0.7199 0.0799 0.0061 0.00045 0.0002 6 0.3333 0.5733 0.0088 0.00085 0.0019 Treatment R e p l i c a t e s E r r o r • S i g n i f i c a n t ( P * 0 . 0 5 ) . 136 Appendix Table 2. Analysis of variance for amino acid a v a i l a b i l i t y of PKM, SBM, CSM and RSM Source Mean Squares * Of - : • '• ; : : : V a r i a t i o n d.f. Lys. H i s t . Arg. Asp. Threo. Ser. Glu. Pro. Gly. Ala. Val. Meth. l i e . Leu. Tyr. Phe. Treatment 3 0.0084 0.0050 0.0021 0.0079 0.0092 0.0063 0 . 0 0 5 6 : 0.0863 0.0777 0.0112 0.0531 0.0298 0.0090 0.0068 0.01179 0.0044 Replicates 3 0.00019 0.00025 0.00003 0.000006 0.00003 0.00003 O.OOOOiOS 0.0014 0.0001 0.00004 0.00058 0.00244 0.000081 0.000048 0.000031 0.00017 Error 9 0.00011 0.00017 0.00012 0.00008 0.00014 0.00016 0.00005 0.0037 0.0.0087 0.00005 0.0028 0.00376 0.00013 0.00004 0.00045 0.00015 137 Appendix Table 3. Analysis of variance f o r metabolizable energy of PKM, SBM, CSM and RSM ( T r i a l 2). Source of Va r i a t i o n d.f. Mean Square Treatment 3 276760* Replicates 3 16415 Error 9 188.13 • S i g n i f i c a n t (P* 0.05). Appendix Table 4. Analysis of variance for mineral a v a i l a b i l i t y of PKM, SBM, CSM and RSM ( T r i a l 3 ) . Source Mean Squares of V a r i a t i o n d.f. Ca P Mg Mn Zn Cu * * * * * * * * Treatment 3 332.01 252.98 416.87 912.36 2175.8 316.57 Replicates 3 1.461 2.888 7.731 6.058 6.263 2.268 Err o r 9 2.1045 2.694 3.510 2.489 3.538 5.299 *»Significant ( P « 0.01). 138 Appendix T a b l e 5. 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 e n e r g y o f r a p e s e e d meals ( T r i a l 5 ) . Source o f v a r i a t i o n d . f . M.S. Tre a t m e n t 6 13096.0** R e p l i c a t e s 3 1991.5 E r r o r 18 2436.9 • • S i g n i f i c a n t ( P ^ 0.01) Appendix T a b l e 6. A n a l y s i s o f v a r i a n c e f o r m i n e r a l a v a i l a b i l i t y o f r a p e s e e d meals ( T r i a l 6 ) . Source Mean Square o f V a r i a t i o n d . f . Ca P Mg Mn Cu Zn Treatment 6 108.80* 95.90* 77.83* 74.17* 122.79* 334.56* R e p l i c a t e s 2 0.009 8.167 2.042 2.042 37.501 1.047 E r r o r 12 16.403 9.867 12.142 12.143 27.401 5.644 • S i g n i f i c a n t (P« 0.05). 139 Appendix T a b l e 7. A n a l y s i s o f v a r i a n c e f o r p r o x i m a t e c o n s t i t u e n t s o f PKM and a l k a l i - t r e a t e d PKM ( T r i a l 7 ) . So u r c e o f V a r i a t i o n d . f . Mean Squares DM CP ADF ADL GE ME Treatment 3 4.405* 5.447*166.66*15.693* 0.0241* 1.2779* R e p l i c a t e s 1 0.405 0.180 2.000: 0.500 0.0133 0.00839 E r r o r 3 0.458 0.140 2.573 0.513 0.0039 0.000142 • S i g n i f i c a n t ( P * 0 . 0 5 ) . A p p e n d i x T a b l e 8. A n a l y s i s o f v a r i a n c e f o r growth r a t e and f e e d c o n s u m p t i o n o f c h i c k s f e d d i e t s c o n t a i n i n g 10%, 20% o r 30% PKM ( T r i a l 7 ) . Source o f V a r i a t i o n d . f , Body Weight Mean Squares Feed Consumption ADG FCR Treatment 3 66577* R e p l i c a t e s 3 1586.2 E r r o r 9 3384.6 306570* 10934 8068.0 463.28* 11.08 23.51 .0377* .0032 .0056 • S i g n i f i c a n t (P< 0.05). PUBLICATIONS Nwokolo, E.N., 1975. E f f e c t of RALGRO ( K e s o r c y l i c a c i d , l a c t o n e ) i m p l a n t a t i o n on growth r a t e , feed effien'cy and c a r c a s s composition of Hereford s t e e r s . M.Sc. Th e s i s , The U n i v e r s i t y of B r i t i s h Columbia, Nov. •-' 1975. Nwokolo, E.N., 1976. 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Bragg and H.S. Saben, 1977. .A N u t r i t i v e e v a l u a t i o n of palm k e r n e l meal f o r use i n p o u l t r y r a t i o n s . Submitted f o r p u b l i c a t i o n , ..'.., T r o p i c a l Science, London, England. Nwokolo, E.N. and D.B. Bragg, 1977. I n f l u e n c e of p h y t i c a c i d and crude f i b r e on the a v a i l a b i l i t y of mineral; from fo u r p r o t e i n supplements i n growing ch i c k s . -Accepted f o r p u b l i c a t i o n , .Can. J . Anim. S c i . , v o l " 57. Nwokolo, E.N. and D.B. Bragg, 1977. F a c t o r s a f f e c t i n g m e t a b o l i z a b l e energy content of rapeseed meals. . •...' Submitted f o r p u b l i c a t i o n , P o u l t r y Science. Nwokolo, E.N. and D.B. Bragg, 1977. A v a i l a b i l i t y ' o f m i n e r a l s i n repeseed meals. Submitted f o r p u b l i c a -t i o n , Can. J . Anim. S c i . 

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