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UBC Theses and Dissertations

The effect of feeding management during the growing and laying periods on productivity and the characteristics.. 1979

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THE EFFECT OF FEEDING MANAGEMENT DURING THE GROWING AND LAYING PERIODS ON PRODUCTIVITY AND THE CHARACTERISTICS OF ADIPOSE TISSUE OF THE BROILER BREEDERS by - /STANLEY ' SOON-WAI,\CHU B .SCV (Ag-r.) , University-of B r i t i s h Columbia, 1977 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE i n THE FACULTY OF GRADUATE STUDIES DEPARTMENT OF POULTRY SCIENCE We accept t h i s t h e s i s as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA December, 1979 (c> Stanley Soon-Wai .Chu, 1979 In presenting t h i s thesis i n p a r t i a l f u l f i l l m e n t of the requirements f o r an advanced degree at the University of B r i t i s h Columbia, I agree that the Library s h a l l make i t f r e e l y a v a i l a b l e f o r reference and study. I further agree that permission f o r extensive copying of t h i s thesis for s c h o l a r l y purposes may be granted by the Head of my Department or by h i s representatives. I t i s understood that copying or p u b l i c a t i o n of t h i s thesis f o r f i n a n c i a l gain s h a l l not be allowed without my written permission. Department of POULTRY SCIENCE The University of B r i t i s h Columbia 2075 Wesbrook Place Vancouver, Canada V6T 1W5 Date December 1979 A B S T R A C T T h e p r e s e n t e x p e r i m e n t w a s u n d e r t a k e n t o s t u d y t h e e g g p r o d u c t i o n a n d a b d o m i n a l f a t a c c u m u l a t i o n o f b r o i l e r b r e e d e r f e m a l e c h i c k e n s w h i c h h a d b e e n s u b j e c t e d t o d i f f e r e n t f e e d i n g m a n a g e m e n t p r o c e d u r e s . B r o i l e r b r e e d e r f e m a l e c h i c k s ( 1 0 2 2 ) w e r e d i v i d e d i n t o t w o p o p u l a t i o n s . O n e p o p u l a t i o n w a s f e d b e t w e e n 8 a n d 1 0 a . m . u s i n g c o n v e n t i o n a l f e e d e r s . T h e o t h e r p o p u l a t i o n w a s f e d t w i c e d a i l y t h e s a m e a m o u n t o f f e e d a s t h e f e e d e r - f e d p o p u l a t i o n b u t g i v e n f e e d b r o a d c a s t o n t h e l i t t e r b e t w e e n 8 a . m . a n d 1 0 p . m a n d b e t w e e n 3 : 3 0 p . m . a n d 4 : 3 0 p . m . P h y s i c a l a c t i v i t y a n d t h e e x t e n s i o n o f f e e d i n g t i m e o f t h e f l o o r - f e d p o p u l a t i o n w e r e t h e r e f o r e g r e a t e r t h a n w a s t h e c a s e w i t h t h e f e e d e r - f e d p o p u l a t i o n . T h e f l o o r - f e d b r i d s w e r e l i g h t e r i n w e i g h t u n d e r a d l i b i t u m f e e d i n g f r o m 2 t o 4 w e e k s o f a g e . T h e r e a f t e r t h e f l o o r - f e d b i r d s w e r e h e a v i e r u n d e r q u a n t i t a t i v e f e e d r e s t r i c t i o n . A t 1 8 w e e k s o f a g e e a c h p o p u l a t i o n w a s d i v i d e d i n t o f o u r g r o u p s , h e a v i e s t , u p p e r m e d i u m , l o w e r m e d i u m a n d l i g h t e s t , b a s e d o n b o d y w e i g h t . T h e b i r d s o f t h e l i g h t e r g r o u p s s u b s e q u e n t l y g r e w f a s t e r t h a n t h o s e o f t h e h e a v i e r g r o u p s a n d b y 4 7 w e e k s o f a g e t h e w e i g h t s w e r e n o t s i g n i f i c a n t l y d i f f e r e n t . T h e a m o u n t a n d p r o p o r t i o n (% o f b o d y w e i g h t ) o f a b d o m i n a l f a t i n t h e f l o o r - f e d p u l l e t s a t 2 6 - 2 7 w e e k s o f a g e w e r e h i g h e r t h a n i n t h e f e e d e r - f e d p u l l e t s . A b d o m i n a l f a t increased w i t h increased body weight i n those groups of p u l l e t s which gained up to 1200 g i n body weight a f t e r the d i v i s i o n at 18 weeks of age, but decreased i n p r o p o r t i o n to body weight i n those groups of p u l l e t s which gained i n excess of 1200 g. The data suggested t h a t the more v i t a l p a r t s of the body, such as the muscle and s k e l e t a l t i s s u e s , developed at a f a s t e r r a t e than the abdominal f a t pad i n the l i g h t e s t group of p u l l e t s . F l o o r feeding d i d not a f f e c t the age at which the p u l l e t s reached sexual maturity. Egg production, c a l c u l a t e d on hen-day b a s i s , was s i m i l a r i n a l l groups. When egg production was c a l c u l a t e d on a hen-housed b a s i s , however, the feeder-fed p u l l e t s showed a higher r a t e of egg production than d i d the f l o o r - f e d p u l l e t s . Furthermore, the b i r d s of the heavier groups w i t h i n both feeding systems had a higher r a t e of production than d i d the b i r d s i n the l i g h t e r groups. F l o o r - f e d p u l l e t s l a i d s i g n i f i c a n t l y l a r g e r eggs than feeder-fed p u l l e t s . Egg weight was not s i g n i f i c a n t l y d i f f e r e n t among the four weight-groups of p u l l e t s i n each feeding system. B i r d s fed on the l i t t e r had lower m o r t a l i t y during the brooding p e r i o d but t h e r e a f t e r had a higher m o r t a l i t y than di d the b i r d s fed from feeders.. The major cause of death was g i z z a r d impaction w i t h l i t t e r m a t e r i a l . M o r t a l i t y was the highest i n the l i g h t e s t groups on both feeding systems during the l a y i n g p e r i o d . - i v - TABLE OF CONTENTS Page ABSTRACT i i TABLE OF CONTENTS i v LIST OF TABLES v i i LIST OF FIGURES X LIST OF APPENDICES x i ACKNOWLEDGEMENTS. x i i INTRODUCTION 1 CHAPTER I . THE EFFECT OF FEEDING MANAGEMENT DURING THE GROWING AND LAYING PERIODS ON PRODUCTIVITY AND THE CHARACTERISTICS OF ADIPOSE TISSUE OF BROILER BREEDERS 3 1.0 INTRODUCTION 4 1.1 LITERATURE REVIEW. 6 1.1.1 P h y s i c a l A c t i v i t y 6 1.1.1.1 P h y s i c a l a c t i v i t y and body c o n f o r m a t i o n 6 1.1.1.2 O b e s i t y and egg p r o d u c t i o n 7 1.1.1.3 P h y s i c a l a c t i v i t y and r e p r o d u c t i o n 8 1.1.2 R e s t r i c t e d F e e d i n g . 10 1.1.2.1 Q u a n t i t a t i v e f e e d r e s t r i c t i o n . . . 10 1.1.2.1.1 Methods 10 1.1.2.1.2 E f f e c t on body w e i g h t 11 1.1.2.1.3 E f f e c t on egg p r o d u c t i o n 12 1.1.2.1.4 E f f e c t on m o r t a l i t y 13 - v - 1.1.2.2 R e s t r i c t i o n o f t ime a l l o w e d f o r f e e d i n g 13 1.1.2.2.1 R e s t r i c t e d f o r one o r two hours d a i l y 13 1.1.2.2.2 Skip - a - d a y f e e d i n g 14 1.1.2.3 R e d u c t i o n i n t h e energy l e v e l i n t h e d i e t 15 1.1.2.3.1 Methods 15 1.1.2.3.2 E f f e c t on body w e i g h t age a t s e x u a l m a t u r i t y and egg p r o d u c t i o n 16 1.1.2.3.3 Economic IV 1.1.2.4 R e d u c t i o n i n p r o t e i n c o n t e n t i n t h e d i e t IV 1.1.2.4.1 P r o t e i n and energy l e v e l s IV 1.1.2.4.2 D e p r i v a t i o n o f e s s e n t i a l amino a c i d 18 1.2 MATERIAL AND METHODS 20 1.2.1 Source o f B i r d s 20 1.2.2 B r o o d i n g P e r i o d (0-4 weeks) 20 1.2.3 R e a r i n g P e r i o d (5-18 weeks) 22 1.2.4 H o l d i n g P e r i o d (19-25 weeks) 2V 1.2.5 L a y i n g P e r i o d (26-4V weeks) 28 1.3 RESULTS AND DISCUSSION 30 1.3.1 Body Weight 3 0 1.3.1.1 Comparison of t h e f e e d i n g management p r o c e d u r e s 30 1.3.1.2 Comparison of the f o u r w e i g h t - g r o u p s 33 - v i - 1.3.2 Abdominal F a t . • 39 1.3.3 Egg Pro d u c t i o n . 44 1.3.3.1 Sexual maturity- 44 1.3.3.2 Rate of l a y 44 1.3.3.3 Egg weight 50 1.3.4 M o r t a l i t y . . 54 1.4 SUMMARY 57 CHAPTER I I . THE EFFECT OF PROLONGED FEED RESTRICTION DURING THE GROWING PERIOD ON SEMEN PRODUCTION 60 2.0 INTRODUCTION 61 2.1 LITERATURE REVIEW 62 2.1.1 Overfeeding and Male Fowl Reproductive Performance • • 62 2.1.2 I n a n i t i o n and Male Fowl Reproductive Performance 64 2.2 MATERIAL AND METHODS 66 2.2.1 Source of B i r d s 66 2.2.2 C o l l e c t i o n of Semen 66 2.2.3 Post-Mortem Stud i e s 6 9 2.3 RESULTS AND DISCUSSION- 70 2.3.1 Treatment E f f e c t 70 2.3.2 Body Weight, Testes Weight and Semen C h a r a c t e r i s t i c s 75 2.4 SUMMARY 77 LITERATURE CITED 7 8 APPENDICES • 8 6 - v i i - L I S T O F T A B L E S T a b l e P a g e 1 . 1 C o m p o s i t i o n o f d i e t 1 . 1 2 3 1 . 2 C u m u l a t i v e f e e d c o n s u m p t i o n o f t h e f e e d e r - f e d p u l l e t s 2 5 1 . 3 T h e e f f e c t o f f e e d e r - f e d a n d f l o o r - f e d f e e d i n g m a n a g e m e n t s o n b o d y w e i g h t s d u r i n g t h e b r o o d i n g , r e a r i n g , h o l d i n g a n d l a y i n g p e r i o d s . . . 3 1 1 . 4 T h e b o d y w e i g h t i n g r a m o f a l l w e i g h t - g r o u p s o f f e e d e r - f e d a n d f l o o r - f e d p u l l e t s a t e a c h w e i g h i n g p e r i o d s 3 4 1 . 5 S u m m a r y o f m e a n s q u a r e s o f t h e a n a l y s i s o f v a r i a n c e o f b o d y w e i g h t s o f a l l g r o u p s o f p u l l e t s f r o m 2 t o 4 7 w e e k s o f a g e s 3 7 1 . 6 B o d y w e i g h t o n t h e d a y o f a u t o p s y ( a t 2 6 - 2 7 w e e k s ) , b o d y w e i g h t g a i n a f t e r 1 8 w e e k s o f a g e t o t h e d a y o f a u t o p s y , t o t a l b o d y w e i g h t g a i n m i n u s a b d o m i n a l f a t w e i g h t , a b d o m i n a l f a t w e i g h t a n d t h e p e r c e n t a g e o f a b d o m i n a l f a t p e r b o d y w e i g h t o f t h e h e a v i e s t , u p p e r m e d i u m , l o w e r m e d i u m a n d l i g h t e s t g r o u p s o f p u l l e t s m a n a g e d o n f e e d e r - f e d o r f l o o r - f e d s y s t e m 4 0 1 . 7 M e a n s q u a r e s f r o m t h e a n a l y s i s o f v a r i a n c e o f b o d y w e i g h t s o n t h e d a y o f a u t o p s y ( a t 2 6 - 2 7 w e e k s ) , t o t a l b o d y w e i g h t g a i n a f t e r 1 8 w e e k s o f a g e t o t h e d a y o f a u t o p s y , t o t a l b o d y w e i g h t g a i n m i n u s a b d o m i n a l f a t , a b d o m i n a l f a t w e i g h t a n d t h e p e r c e n t a g e o f a b d o m i n a l f a t p e r b o d y w e i g h t o f t h e h e a v i e s t , u p p e r m e d i u m , l o w e r m e d i u m a n d l i g h t e s t g r o u p s o f p u l l e t s m a n a g e d o n f e e d e r - f e d o r f l o o r - f e d s y s t e m 4 1 - v i i i - 1.8 The e f f e c t s o f f e e d e r - f e d and f l o o r - f e d managements on t h r e e e s t i m a t e s of age a t s e x u a l m a t u r i t y 4 5 1.9 The e f f e c t s o f f e e d e r - f e d and f l o o r - f e d f e e d i n g managements on c u m u l a t i v e p e r c e n t a g e o f egg p r o d u c t i o n c a l c u l a t e d on a hen-day b a s i s t o v a r i o u s ages f o r d i f f e r e n t w e i g h t - g r o u p s o f b r o i l e r b r e e d e r p u l l e t s 4 6 1.10 The e f f e c t s o f f e e d e r - f e d and f l o o r - f e d f e e d i n g managements on hen-day p e r c e n t p r o d u c t i o n by three-week p e r i o d s o v e r a p e r i o d o f twenty weeks f o r d i f f e r e n t w e i g h t - g r o u p s o f b r o i l e r b r e e d e r p u l l e t s 48 1.11 The e f f e c t s o f f e e d e r - f e d and f l o o r - f e d managements on c u m u l a t i v e p e r c e n t a g e of egg p r o d u c t i o n c a l c u l a t e d on a hen- housed b a s i s t o v a r i o u s ages f o r d i f f e r e n t w e i g h t - g r o u p s o f b r o i l e r b r e e d e r p u l l e t s 49 1.12. The e f f e c t s o f f e e d e r - f e d and f l o o r - f e d f e e d i n g managements on mean egg w e i g h t i n grams + s.d. a t s e v e r a l ages among d i f f e r e n t w e i g h t - g r o u p s o f b r o i l e r b r e e d e r p u l l e t s 51 1.13 The a n a l y s i s of v a r i a n c e o f t h e e f f e c t s o f f e e d e r - f e d and f l o o r - f e d f e e d i n g managements on mean egg w e i g h t a t 34, 38 and 47 weeks o f ages among d i f f e r e n t w e i g h t - g r o u p s o f b r o i l e r b r e e d e r p u l l e t s 52 1.14 The c u m u l a t i v e m o r t a l i t y and t h e m o r t a l i t y d u r i n g t h e b r o o d i n g , r e a r i n g , h o l d i n g and l a y i n g p e r i o d s o f t h e f e e d e r - f e d and f l o o r - f e d p u l l e t s 55 2.1 R e s t r i c t e d f e e d i n g programs d u r i n g the g rowing p e r i o d 67 2.2 C o m p o s i t i o n o f d i e t 2.1 68 2.3 Treatments e f f e c t on m o r t a l i t y , body w e i g h t a t 60 weeks o f age, t e s t e s w e i g h t and t e s t e s w e i g h t p e r body w e i g h t 71 - i x - Length o f f e e d r e s t r i c t i o n o f b r o i l e r b r e e d e r males d u r i n g t h e growing p e r i o d on subsequent volume o f semen per e j a c u l a t i o n , spermatozoa c o n c e n t r a t i o n and m i l l i o n s o f spermatozoa p e r e j a c u l a t i o n C o r r e l a t i o n c o e f f i c i e n t o f body w e i g h t a t 60 weeks, t e s t e s w e i g h t , p e r c e n t a g e o f t e s t e s w e i g h t o v e r body w e i g h t , semen volume, semen c o n c e n t r a t i o n and number o f spermatozoa p e r e j a c u l a t i o n - x - LIST OF FIGURES F i g u r e Page 1.1 F e e d e r - f e d c h i c k s d u r i n g the b r o o d i n g p e r i o d . 21 1.2 F l o o r - f e d c h i c k s d u r i n g t h e b r o o d i n g p e r i o d 21 1.3 F e e d e r - f e d p u l l e t s d u r i n g t h e r e a r i n g p e r i o d 2 6 1.4 F l o o r - f e d p u l l e t s d u r i n g t h e r e a r i n g p e r i o d 2 6 1.5 F e e d e r - f e d p u l l e t s d u r i n g the l a y i n g p e r i o d 2 9 1.6 F l o o r - f e d p u l l e t s d u r i n g t h e l a y i n g p e r i o d 2 9 1.7 Amount o f abdominal f a t and t h e body w e i g h t g a i n minus f a t w e i g h t i n f e e d e r - f e d p u l l e t s , and f l o o r - f e d p u l l e t s w i t h d i f f e r e n t body w e i g h t g a i n a f t e r t h e p u l l e t s were s e p a r a t e d i n t o f o u r groups, h e a v i e s t , upper medium, lo w e r medium and l i g h t e s t , by w e i g h t a t 18 weeks o f age t o 27 weeks o f age 43 1.8 The d i s t r i b u t i o n o f egg w e i g h t s o f t h e h e a v i e s t , upper medium, low e r medium and l i g h t e s t groups o f p u l l e t s from f e e d e r - f e d and f l o o r - f e d f e e d i n g managements a t 34, 38 and 47 weeks o f age 53 - x i - L I S T O F A P P E N D I C E S A p p e n d i x F i g u r e s 2 . 1 R e g r e s s i o n l i n e f o r s p e r m a t o z o a c o u n t s o n t h e b a s i s o f o p t i c a l d e n s i t y r e a d i n g ( 6 6 0 m i l l i m i c r o n s ) A p p e n d i x T a b l e 2 . 2 B o d y w e i g h t a t 6 0 w e e k s o f a g e , t e s t e s w e i g h t , p e r c e n t a g e o f t e s t e s w e i g h t p e r b o d y w e i g h t , s e m e n v o l u m e , s p e r m c o n c e n t r a t i o n a n d n u m b e r o f s p e r m a t o z o a p e r e j a c u l a t i o n o f i n d i v i d u a l b r o i l e r m a l e s t u d i e d i n t h i s e x p e r i m e n t - x i i - ACKNOWLEDGEMENTS I am g r e a t l y indebted to P r o f e s s o r B.E. March, f o r p r o v i d i n g her i n v a l u a b l e a s s i s t a n c e i n a l l aspects of my graduate program. S i n c e r e thanks are a l s o due to the members of my a d v i s o r y committee: Drs. D.B. Bragg, C.W. Roberts and J . Vanderstoep, f o r t h e i r h e l p f u l c r i t i c i s m s of the p r e l i m i n a r y d r a f t of t h i s t h e s i s . My g r a t i t u d e i s f u r t h e r extended to B. Chan, W. Ho, S. Homewood, M. Hudson, C. MacMillan, E. P e t e r s , R. Poon, G. Shermann and R. Soong, who f a c i l i t a t e d the course of t h i s r e s e a r c h i n many ways. F i n a l l y , I would l i k e to thank my dear f r i e n d , David H i c k l i n g , who f r e q u e n t l y o f f e r e d h i s a s s i s t a n c e i n the e d i t i n g of t h i s manuscript. - 1 - INTRODUCTION S i n c e t h e Second World War, p r o d u c t i o n o f po u l t r y - meat i n Canada has e x t e n s i v e l y expanded. The h i g h p r o d u c t i v e e f f i c i e n c y and q u a l i t y o f t h e f i n a l p r o d u c t a s s o c i a t e d w i t h r a p i d l y a d v a n c i n g t e c h n o l o g y has s h a r p l y r a i s e d t h e p r o d u c t i v e volume o f p o u l t r y commodities. C o n s e q u e n t l y , t h e c o s t o f p o u l t r y p r o d u c t i o n has d e c l i n e d and t h e share o f p o u l t r y meat i n t h e Canadian d i e t has r i s e n . A c c o r d i n g t o a p u b l i c a t i o n from t h e Economic Branch, Canada Department o f A g r i c u l t u r e , by Emmery (1967), p o u l t r y meat consumption p e r c a p i t a i n Canada r o s e from 16 pounds t o 40 pounds, a 150 p e r c e n t i n c r e a s e , d u r i n g the p e r i o d from 1949 t o 1966. While i n t h e same p e r i o d , consumption per c a p i t a o f a l l o t h e r t y p e s o f meats r o s e from 135 pounds t o 148 pounds o r o n l y a 9.6 p e r c e n t i n c r e a s e . The a p p a r e n t d o m e s t i c d i s a p p e a r a n c e o f b r o i l e r c h i c k e n s from commercial s u p p l i e s i s c o n t i n u o u s l y growing. The r a t e o f growth was 13.2% f o r t h e f i r s t q u a r t e r o f 1979 over the same p e r i o d i n 1978 ( E l a n c o , 1979). T h e r e f o r e , t h e demand f o r b r o i l e r h a t c h i n g eggs i s o b v i o u s l y i n c r e a s i n g i n Canada. D. Murray o f t h e S t a t i s t i c s S e c t i o n , P o u l t r y D i v i s i o n o f A g r i c u l t u r e Canada, announced l a s t y e a r i n a p r o f i l e o f commercial b r o i l e r and r o a s t e r placements i n Canada i n 1977, t h a t 25 p e r cen t o f b r o i l e r c h i c k s h a t c h e d i n Canada were from i m p o r t e d h a t c h i n g eggs. - 2 - The b r o i l e r - t y p e b r e e d e r s a r e s p e c i f i c a l l y b r e d f o r meat p r o d u c t i o n . They p o s s e s s th e g e n e t i c p o t e n t i a l f o r r a p i d g rowth, and t h e y are v e r y s u b j e c t t o o b e s i t y . Low egg p r o d u c t i o n and i n f e r t i l i t y may be s e r i o u s problems. N u t r i t i o n i s t s have t r i e d t o r e s o l v e t h e above problems by m o d i f y i n g the b r o i l e r b r e e d e r d i e t i n o r d e r t o i n c r e a s e t h e egg p r o d u c t i o n o f t h e female b r e e d e r s and the semen q u a l i t y o f the male b r e e d e r s . N e v e r t h e l e s s , t h e r e p r o d u c t i v e performance o f b r o i l e r - t y p e b r e e d e r s i s not s a t i s f a c t o r y . The p r e s e n t s t u d i e s were und e r t a k e n i n an attempt t o i n c r e a s e our knowledge o f t h e e f f e c t s o f f e e d i n g management on t h e r e p r o d u c t i v e performance o f b r o i l e r b r e e d e r s . T h i s t h e s i s c o n t a i n s two c h a p t e r s . C h a p t e r One, w h i c h d e a l s w i t h t h e s t u d y o f t h e e f f e c t o f f e e d i n g management d u r i n g t h e growing and l a y i n g p e r i o d s on p r o d u c t i v i t y and t h e c h a r a c t e r i s t i c o f a d i p o s e t i s s u e o f t h e b r o i l e r b r e e d e r s , s e r v e s as t h e major p a r t o f t h e t h e s i s . C h a p t e r Two, w h i c h d e a l s w i t h the s t u d y o f the e f f e c t o f p r o l o n g e d f e e d r e s t r i c t i o n d u r i n g the gorwing p e r i o d on subsequent semen p r o d u c t i o n , i s a r e s e a r c h n o t e f o r r e c o r d . - 3 - C H A P T E R I . T H E E F F E C T O F F E E D I N G M A N A G E M E N T D U R I N G T H E G R O W I N G A N D L A Y I N G P E R I O D S O N P R O D U C T I V I T Y A N D T H E C H A R A C T E R I S T I C S O F A D I P O S E T I S S U E O F T H E B R O I L E R B R E E D E R S . - 4 - 1.0 INTRODUCTION O b e s i t y has u n d e s i r a b l e e f f e c t s on t h e r e p r o d u c t i v e p e r f o r m a n c e o f b r o i l e r b r e e d e r p u l l e t s . I t i s a l w a y s a s s o c i a t e d w i t h i n a c t i v i t y , h i g h m o r t a l i t y , p o o r f e r t i l i t y and low egg p r o d u c t i o n w i t h h i g h f e e d c o n s u m p t i o n p e r egg p r o d u c e d . T h e r e i s a need f o r new management p r o c e d u r e s t o m i n i m i z e o b e s i t y i n b r o i l e r b r e e d e r c h i c k e n s . S c i e n t i s t s have u s e d v a r i o u s methods t o m a n i p u l a t e t h e c o m p o s i t i o n o f t h e d i e t o r t o i n c r e a s e t h e p h y s i c a l a c t i v i t y o f t h e e x p e r i m e n t a l a n i m a l s i n o r d e r t o m i n i m i z e o b e s i t y . Swimming, r u n n i n g and b i c y c l e r i d i n g a r e commonly employed i n e x p e r i m e n t s t o i n c r e a s e t h e p h y s i c a l a c t i v i t y w i t h i n t h e c a s e o f r a t s o r men. T h e r e a r e no s t a n d a r d s c i e n t i f i c p r o c e d u r e s f o r t e s t i n g t h e e f f e c t s o f p h y s i c a l a c t i v i t y on t h e b i o l o g i c a l r e s p o n s e s o f c h i c k e n s . In modern p o u l t r y f a r m management d i f f e r e n t methods o f r e s t r i c t i n g f e e d c o n s u m p t i o n a r e u s e d t o c o n t r o l t h e o v e r w e i g h t and o b e s i t y o f b r o i l e r b r e e d e r p u l l e t s . The most common methods i n c l u d e q u a n t i t a t i v e f e e d r e s t r i c t i o n , r e s t r i c t i o n o f f e e d i n g t i m e , r e d u c t i o n i n e n e r g y a n d / o r p r o t e i n c o n t e n t i n t h e d i e t . O t h e r methods, s u c h as r e d u c t i o n i n w a t e r i n t a k e , i n c r e a s e o f t e m p e r a t u r e , a l t e r a t i o n o f t h e l i g h t i n g p a t t e r n and d e b e a k i n g have a l s o b e en u s e d t o r e s t r i c t f e e d i n t a k e . A l l t h e above methods r e t a r d g r o w t h and d e l a y - 5 - s e x u a l m a t u r i t y depending upon the s e v e r i t y o f t r e a t m e n t . However, the o n t o g e n e s i s o f each i n d i v i d u a l b i r d i s not s t r i c t l y c o n t r o l l e d by t h e q u a l i t y o f t h e d i e t o r t h e amount o f t h e f e e d i n t a k e a l o n e , b u t i s a l s o i n v o l v e d w i t h many o t h e r p r e n a t a l and p o s t n a t a l f a c t o r s . The p r e n a t a l f a c t o r s i n c l u d e g e n e t i c v a r i a t i o n , n u t r i t i o n a l environment f o r t h e d e v e l o p i n g embryo and c o n d i t i o n s d u r i n g t h e i n c u b a t i o n . P o s t n a t a l f a c t o r s i n c l u d e s o c i a l peck o r d e r , s t r e s s , a d a p t i v i t y , d i s e a s e , h u m i d i t y , l i g h t , t e m p e r a t u r e and a l t i t u d e i n a d d i t i o n t o n u t r i t i o n a l s t a t u s . The p r e s e n t e x p e r i m e n t was u n d e r t a k e n on two p o p u l a t i o n s o f b r o i l e r b r e e d e r p u l l e t s . One p o p u l a t i o n was f e d between 8 and 10 a.m. u s i n g c o n v e n t i o n a l f e e d e r s . The o t h e r p o p u l a t i o n was f e d t w i c e d a i l y t h e same amount of f e e d as t h e f e e d e r - f e d p o p u l a t i o n , but g i v e n f e e d b r o a d c a s t on t h e l i t t e r between 8 a.m. and 10 p.m. and between 3:30 p.m. and 4:30 p.m. P h y s i c a l a c t i v i t y and t h e e x t e n s i o n o f f e e d i n g time of the f l o o r - f e d p o p u l a t i o n were t h e r e f o r e g r e a t e r t h a n was t h e case w i t h t h e f e e d e r - f e d p o p u l a t i o n . A t 18 weeks o f age each p o p u l a t i o n was e q u a l l y d i v i d e d i n t o f o u r groups on t h e b a s i s o f body w e i g h t . The abdominal f a t a c c u m u l a t i o n a t s e x u a l m a t u r i t y and t h e subsequent egg p r o d u c t i o n and egg s i z e among f o u r groups o f p u l l e t s i n each p o p u l a t i o n were s t u d i e d . 6 - 1.1 LITERATURE REVIEW... 1.1.1 P h y s i c a l A c t i v i t y 1.1.1.1 P h y s i c a l a c t i v i t y and body c o n f o r m a t i o n P h y s i c a l a c t i v i t y has p r o f o u n d e f f e c t s on t h e c o u r s e o f o n t o g e n e s i s and the subsequent body c o n f o r m a t i o n . These e f f e c t s have been t h o r o u g h l y i n v e s t i g a t e d i n r a t s and humans, bu t not i n d o m e s t i c f o w l s . been e i t h e r r a i s e d i n cages w i t h a r e s t r i c t i o n o f p h y s i c a l a c t i v i t y o r have been r a i s e d on t h e f l o o r w i t h r e l a t i v e freedom t o move around and a g i t a t e one a n o t h e r . t h a t b i r d s r e a r e d on .range had a h i g h e r p e r c e n t a g e of b r e a s t m u scle, l e g muscle, and t o t a l e d i b l e p o r t i o n t h a n had t h o s e w h i c h were r e a r e d i n co n f i n e m e n t (Harshaw, 1936). S i n c e t h e n , the l i t e r a t u r e i s i n agreement t h a t d o m e s t i c f o w l c o n s t r a i n e d i n cages have a h i g h e r p e r c e n t . and t o t a l body f a t d e p o s i t i o n t h a n t h o s e managed on f l o o r , r e g a r d l e s s o f s p e c i e s and sex (White Leghorns: J e f f r e y and B r i t h , 1941; Leo and Change, 1975) ( b r o i l e r s : Deaton e t a l . , 1974) ( t u r k e y s : Andrews and Marrow, 1978) . A c c o r d i n g t o t h e l i t e r a t u r e , p u l l e t s have Over f o u r decades ago, i t was o b s e r v e d - 7 - By u s i n g r a d i o g r a p h i c t e c h n i q u e s , i t has been shown t h a t t h e r e i s a s i g n i f i c a n t l y h i g h e r bone d e n s i t y i n men and women w i t h i n c r e a s i n g l e v e l s o f p h y s i c a l a c t i v i t y (Emiola and O'Shes, 1978). S i m i l a r l y , Wabeck and L i t t l e f i e l d (1972) showed t h a t wing and l e g breakage a f t e r p r o c e s s i n g was h i g h e r f o r b r o i l e r s r e a r e d i n cages t h a n f o r t h o s e r e a r e d i n f l o o r pens. And Reece e t a l . (1971) demonstrated t h a t l e g weakness i s s i g n i f i c a n t l y g r e a t e r f o r c o n s t r a i n e d t h a n f o r u n c o n s t r a i n e d b i r d s . J e f f r e y and B r i t t (1941) f u r t h e r i n d i c a t e d t h a t l a c k o f e x e r c i s e o f p u l l e t s r e s u l t e d i n p a r t i a l a t r o p h y o f t h e h e a r t , l i v e r , and g i z z a r d when the confinement p e r i o d was as l o n g as one y e a r . High l i v e r f a t i n hens housed a t h i g h cage d e n s i t y was a l s o r e p o r t e d by Leo and Change (1975). The f a t c o n t e n t o f eggs, on t h e o t h e r hand, was found t o be s i m i l a r whether hens were k e p t i n cages o r on t h e f l o o r (Oluyemi and R o b e r t s , 1975). 1.1.1.2 O b e s i t y and egg p r o d u c t i o n R e c e n t l y Chaney and F u l l e r (197 5) b r o u g h t two groups of b r o i l e r b r e e d e r p u l l e t s i n t o p r o d u c t i o n a t t h e same time w i t h w i d e l y d i f f e r e n t l e v e l s o f c a r c a s s f a t , by u s i n g d i f f e r e n t d a y l e n g t h and f e e d i n g regimes. There was a s i g n i f i c a n t l y h i g h e r per c e n t o f c a r c a s s f a t a t s e x u a l m a t u r i t y f o r growing p u l l e t s under f u l l f e e d and w i t h - 8 - d e c r e a s i n g d a y l e n g t h (26% c a r c a s s f a t ) t h a n f o r t h o s e under r e s t r i c t e d energy i n t a k e and w i t h i n c r e a s i n g d a y l e n g t h (19% c a r c a s s f a t ) . The d i f f e r e n c e i n c a r c a s s f a t was not a s s o c i a t e d w i t h egg p r o d u c t i o n , and t h e egg p r o d u c t i o n and c a r c a s s f a t were r o u g h l y r e l a t e d t o energy i n t a k e i n t h e i r s t u d i e s . S t u d i e s by S i n g s e n e t a_l. (1959) suggested t h a t meat-type p u l l e t s a r e not c a p a b l e o f a d e q u a t e l y r e g u l a t i n g energy i n t a k e when they a r e f e d ad_ l i b i t u m . I n t h e s t u d y , t h e y became obese and s u f f e r e d h i g h m o r t a l i t y w h i c h appeared t o be d i r e c t l y r e l a t e d t o e x c e s s i v e c a l o r i c i n t a k e . However, o b e s i t y p e r se d i d n o t appear t o reduce egg p r o d u c t i o n . Combs e t a^L. (1961) r e p o r t e d a s i m i l a r o b s e r v a t i o n . When Columbian Plymouth Rock p u l l e t s were r e s t r i c t e d t o an energy i n t a k e o f 87.0 per c e n t o f t h e c o n t r o l t h e average p e r c e n t c a r c a s s e t h e r e x t r a c t and average b l o o d serum c h o l e s t e r o l were lower t h a n i n t h e c o n t r o l , but no s i g n i f i c a n t d i f f e r e n c e s i n egg p r o d u c t i o n , m o r t a l i t y o r Haugh U n i t s c o r e s were found. 1.1.1.3 P h y s i c a l a c t i v i t y and r e p r o d u c t i o n Even though p h y s i c a l a c t i v i t y reduces o b e s i t y and o b e s i t y does n o t a f f e c t egg p r o d u c t i o n , egg p r o d u c t i o n may be a f f e c t e d by p h y s i c a l a c t i v i t y . Thus, p h y s i c a l a c t i v i t y p e r se r a t h e r t h a n o b e s i t y may be d i r e c t l y a l t e r i n g t h e r e p r o d u c t i v e p h y s i o l o g y o f t h e l a y i n g hens. - 9 - T h e r e a r e c o n t r o v e r s i a l r e p o r t s a s t o w h e t h e r e x e r c i s e h a s a b e n e f i c i a l o r a n a d v e r s e e f f e c t o n e g g p r o d u c t i o n . L o w r y e t a l . ( 1 9 5 6 ) r e p o r t e d o n a f o u r - y e a r s t u d y o f c a g e s v e r s u s f l o o r m a n a g e m e n t t h a t t h e p u l l e t s k e p t o n t h e f l o o r w e r e f o u n d t o b e s u p e r i o r i n e g g p r o d u c t i o n t h a n t h o s e k e p t i n c a g e s . Q u e r n e r a n d T u l l e r ( 1 9 6 6 ) a n d C h r i s t m a s e t a l . ( 1 9 7 2 ) r e p o r t e d t h a t t h e b i r d s o n d e e p l i t t e r p r o d u c e d m o r e e g g s t h a n t h o s e i n c a g e s . T h i s s u b s t a n t i a t e d t h e r e s u l t s o f t h e a n n u a l C a l i f o r n i a r a n d o m s a m p l e t e s t s f o r 1 9 5 7 t o 1 9 6 0 i n c l u s i v e i n w h i c h l a y e r s o n d e e p l i t t e r c o n s i s t e n t l y l a i d m o r e e g g s t h a n t h o s e i n c a g e s ( K o s e n , 1 9 6 7 ) . C o n v e r s e l y , M i l l e r a n d Q u i s e n b e r r y ( 1 9 5 9 ) , B a i l e y e t a _ l . ( 1 9 5 9 ) , S h u p e a n d Q u i s e n b e r r y ( 1 9 6 1 ) , T h o m a s o n e t a l . ( 1 9 7 2 ) , O l u y e m i a n d R o b e r t s ( 1 9 7 5 ) , a n d T h o m a s o n e t a l . ( 1 9 7 6 ) r e p o r t e d t h a t m a t u r e p u l l e t s p l a c e d i n c a g e s a p p e a r e d t o h a v e a s i g n i f i c a n t l y h i g h e r r a t e o f e g g p r o d u c t i o n . F u r t h e r - m o r e , t h e h i g h e r v o l u n t a r y f e e d i n t a k e r e s u l t e d i n h e a v i e r b o d y w e i g h t s f o r t h e c a g e d b i r d s t h a n f o r t h o s e m a i n t a i n e d o n l i t t e r - f l o o r . A n d r e w s a n d M o r r o w ( 1 9 7 8 ) s u b j e c t e d t u r k e y p o u l t s t o f o u r f e e d i n g r e g i m e s : f u l l - f e d o r 2 0 p e r c e n t r e s t r i c t i o n d u r i n g r e a r i n g a n d / o r l a y i n g p e r i o d s . B i r d s f r o m e a c h f e e d i n g r e g i m e w e r e p l a c e d i n i n d i v i d u a l c a g e s o r f l o o r p e n s , w h e n t h e y w e r e 3 2 w e e k s o f a g e . A l l c a g e d h e n s w e r e m o r e p e r s i s t e n t i n e g g p r o d u c t i o n f o r t h e s i x 2 8 - d a y p e r i o d s o f t h e s t u d y . - 10 - O n t h e o t h e r h a n d , D e D o r t a l (1966) , F r a n c i s a n d R o b e r t s o n (1963) a n d A n d r e w s (1977) f a i l e d t o f i n d a n y s i g n i f i c a n t d i f f e r e n c e b e t w e e n t h e c a g e d a n d t h e d e e p l i t t e r h e l d c h i c k e n s i n e g g p r o d u c t i o n . 1.1.2 R e s t r i c t e d F e e d i n g I n t h e l a s t f e w d e c a d e s , i t h a s b e e n g r a d u a l l y r e c o g n i z e d t h a t p r o p e r r e s t r i c t e d f e e d i n g o f r a p i d l y g r o w i n g b r o i l e r - t y p e p u l l e t s f o r b r e e d i n g p u r p o s e s i s n e c e s s a r y i n o r d e r t o c o n t r o l a d i p o s i t y a n d t o m a x i m i z e e g g p r o d u c t i o n . T h e n u t r i t i o n a l m e t h o d s a d o p t e d t o r e s t r i c t f e e d i n t a k e i n o r d e r t o a c h i e v e t h e a b o v e o b j e c t i v e s i n c l u d e t h e f o l l o w i n g : ( a ) q u a n t i t a t i v e f e e d r e s t r i c t i o n , ( b ) r e s t r i c t i o n o f t h e t i m e a l l o w e d f o r f e e d i n g , ( c ) r e d u c t i o n o f t h e e n e r g y l e v e l i n t h e d i e t , ( d ) r e d u c t i o n o f p r o t e i n i n t h e d i e t . I n t h i s r e v i e w , t h e m e t h o d s a n d t h e i r e f f e c t s o n m a t u r i t y , f i n a l b o d y w e i g h t , m o r t a l i t y a n d s u b s e q u e n t e g g p r o d u c t i o n w i l l b e d i s c u s s e d . 1.1.2.1 Q u a n t i t a t i v e f e e d r e s t r i c t i o n 1.1.2.1.1 M e t h o d s F l o c k s o f f u l l y - f e d c o n t r o l c h i c k e n s a r e u s u a l l y e m p l o y e d i n t h i s m e t h o d . T h e w e e k l y f o o d c o n s u m p t i o n - 11 - of the f u l l y - f e d c o n t r o l group i s taken as a b a s i s f o r predetermining the amount of feed allowed f o r the r e s t r i c t e d f ed groups i n the f o l l o w i n g week. The q u a l i t y of the d i e t i s balanced w i t h r e s p e c t to a l l amino a c i d s and other e s s e n t i a l n u t r i e n t s . Most r e s e a r c h e r s have i n i t i a t e d r e s t r i c t e d f e e d i n g of the p u l l e t s between 6 and 8 weeks of age and f i n i s h e d r e s t r i c t i o n between 21 and 24 weeks of age (Howes and C o t t i e r , 1964; Schneider e t aJL. , 1955; Schumaier and McGinnis, 1969; Waldroup et a l . , 1966). P u l l e t s a l s o have been r e s t r i c t e d i n food consumption from 0 week by L e c l e r c q e t a l . (1970), from 2 weeks by Ringrose (1958), from 3, 4 and 5 weeks by S t r a i n et a l . (1965) and from 5 weeks by Maclntyre and Gardiner (1964). 1.1.2.1.2 E f f e c t on body weight The r e d u c t i o n i n growth r a t e of the r e s t r i c t e d group depends on the degree of feed r e s t r i c t i o n . Lee et a l . (1971) c a l c u l a t e d , from the e x i s t i n g data i n the l i t e r a t u r e , a r e g r e s s i o n l i n e of food i n t a k e of r e s t r i c t e d group as a percentage of food i n t a k e of f u l l y - f e d c o n t r o l (X) versus l i v e - weight as percentage of f u l l y - f e d c o n t r o l (Y):Y = 21.82 + 0.82X. A f t e r t e r m i n a t i o n of r e s t r i c t e d f e e d i n g the subsequently body weight was a f f e c t e d . The above authors a l s o r e p o r t e d t h a t there were 78 comparisons of body weight a t the end of the l a y i n g p e r i o d , - 12 - and i n o n l y 20 c a s e s was t h e body w e i g h t of r e s t r i c t e d - r e a r e d p u l l e t s e q u a l t o , or g r e a t e r t h a n , t h a t o f the f u l l y f e d c o n t r o l s . T h i s r e s u l t e d i n a lower energy r e q u i r e m e n t f o r maintenance o f t h e former b i r d s and b e t t e r f e e d e f f i c i e n c y f o r egg p r o d u c t i o n . 1.1.2.1.3 E f f e c t on egg p r o d u c t i o n The o n s e t o f l a y i n g was d e l a y e d i n the r e s t r i c t e d group. B u l l o c k e t a l . (1963), based on t h e d a t a o f A s h c r o f t (1961), p r e d i c t e d t h a t f o r e v e r y 1 p e r c e n t drop i n r e s t r i c t e d f e e d i n g l e v e l from 90 p e r c e n t t o 70 per c e n t o f t h e c o n t r o l s , t h e r e would be a d e l a y i n r e a c h i n g 4 0 per c e n t egg p r o d u c t i o n o f 0.6 days. A c c o r d i n g t o s t u d i e s of 87 c a s e s by Lee e t a l . (1971), 52 c a s e s showed e q u a l o r h i g h e r hen-day p r o d u c t i o n f o r t h e r e s t r i c t e d groups compared w i t h the c o n t r o l s . Because th e m a t u r i t y o f r e s t r i c t e d - r e a r e d p u l l e t s i s d e l a y e d and t h e whole p r o d u c t i v e c u r v e d i s p l a c e d , t h e r e i s an i n c r e a s e i n average egg w e i g h t . S c h n e i d e r e t a l . (1955) r e p o r t e d an i n c r e a s e o f 19.1 per c e n t o f s e t t a b l e eggs from heavy l a y e r hens r e s t r i c t e d t o 21 per c e n t o f f e e d i n t a k e from day o l d t h r o u g h t h e growing p e r i o d t o 28 weeks o f age. - 13 - 1.1.2.1.4 E f f e c t on m o r t a l i t y U n f o r t u n a t e l y , however, q u a n t i t a t i v e f e e d r e s t r i c t i o n i n d u c e d r e l a t i v e l y h i g h m o r t a l i t y d u r i n g t h e r e a r i n g p e r i o d . I s a a c k s e t a l . (1960) r e p o r t e d t h a t 30 p e r c e n t r e s t r i c t i o n o f f e e d i n t a k e o f meat-type r e p l a c e m e n t p u l l e t s r e s u l t e d i n 18.95 p e r c e n t m o r t a l i t y , w h i c h was 12.36 p e r c e n t h i g h e r t h a n t h e m o r t a l i t y i n t h e f u l l y - f e d c o n t r o l b i r d s . One p o s s i b l e r e a s o n f o r t h i s may be t h a t t h e f e e d consumption o f b i r d s l o w e r i n t h e peck o r d e r i s more s e v e r e l y r e s t r i c t e d than t h a t o f b i r d s h i g h e r i n t h e o r d e r . Lee e t ajL. (19 72) r e p o r t e d t h a t d u r i n g f e e d r e s t r i c t i o n , p u l l e t s might be more prone t o dis.ease. An ou t b r e a k o f s t a p h y l o c o c a l a r t h r i t i s i n r e s t r i c t e d p u l l e t s was r e p o r t e d by Berg and Bearse (1961); r e s p i r a t o r y d i s e a s e , by B r u c k n e r and H i l l (1959); c o c c i d i o s i s , by S c h n e i d e r e t a l . (1955) and by P r o u d f o o t and Gowe (1967). 1.1.2.2 R e s t r i c t i o n o f t h e time a l l o w e d f o r f e e d i n g 1.1.2.2.1 R e s t r i c t e d f o r one or two hours d a i l y P u l l e t s have been a l l o w e d 1 or 2 hours d a i l y f o r f e e d i n g by R i n g r o s e (1958), S c h n e i d e r e t a l . (1955), Schumaier and M c G i n n i s (1969), L e p k o r s k y e t a l . (1960) and B a l l a m (1978). By u s i n g t h i s f e e d i n g system, enough f e e d i n g space must be p r o v i d e d i n o r d e r t o reduce t h e c o m p e t i t i o n f o r f o o d among b i r d s and a l l o w u n i f o r m consumption. The r e s t r i c t e d p u l l e t s a r e i n c l i n e d t o e a t more q u i c k l y and hence - 14 - d e v e l o p a c a p a c i t y t o s t o r e l a r g e r amounts o f f o o d i n t h e i r c r o p s than do t h e f u l l y - f e d c o n t r o l s . Lepkovsky e t a l . (1960) ob s e r v e d t h a t t h e c r o p s o f c h i c k e n s , t r a i n e d t o e a t d u r i n g 2 hours d a i l y , were c o n s i s t e n t l y h e a v i e r i n o r d e r t o s t o r e more f o o d , b u t t h a t t h e r e was no s i m i l a r a d a p t a t i o n i n t h e g i z z a r d , i n t e s t i n e and p a n c r e a s . Schumaier and M c G i n n i s (1969) r e p o r t e d t h a t when heavy-type p u l l e t s were r e s t r i c t e d i n d a i l y f e e d i n g from 1 t o 3 hours between 8 t o 55 weeks of age, t h e egg p r o d u c t i o n , per c e n t f e r t i l i t y and h a t c h a b i l i t y o f eggs, and growth o f c h i c k s h a t c h e d were u n a f f e c t e d . 1.1.2.2.2 Skip - a - d a y f e e d i n g A l t e r n a t e day and s k i p - o n e o r two-days- per-week f e e d i n g systems have a l s o become p o p u l a r f o r growing meat-type b r e e d e r r e p l a c e m e n t p u l l e t s . Harms e t a l . (1968) f e d meat-type p u l l e t s on a a l t e r n a t e day f e e d i n g regime w i t h a 16% c r u d e p r o t e i n d i e t from 8 t o 24 weeks of age. The f e e d consumption d u r i n g t h e r e s t r i c t e d p e r i o d was 7.13 kg o f f e e d p e r p u l l e t f o r t h e r e s t r i c t e d group and 12.95 kg o f f e e d per p u l l e t s f o r t h e f u l l - f e d c o n t r o l group. On t h e s k i p p e d day regimen 910 gm o f whole o a t s was g i v e n on t h e r e s t r i c t e d day p e r 100 b i r d s i n t h e l i t t e r . S e x u a l m a t u r i t y , d e f i n e d as age a t 30 per c e n t p r o d u c t i o n , was a t 197.6 days and 173.6 days f o r t h e r e s t r i c t e d group and c o n t r o l group r e s p e c t i v e l y . - 15 - M o r t a l i t y d u r i n g t h e growing p e r i o d was h i g h e r i n t h e r e s t r i c t e d group (2 3.7%) t h a n i n t h e c o n t r o l group (15.7%). D u r i n g the l a y i n g phase, from 25 weeks t o 56 weeks o f age t h e numbers o f eggs w e i g h i n g over 52 gm per hen were 117.9 and 111.5 f o r p u l l e t s f e d on the a l t e r n a t e day program and p u l l e t s f e d ad l i b i t u m r e s p e c t i v e l y . Y a t e s and S c h a i b l e (1963) r e a r e d Leghorn- t y p e p u l l e t s on a skip-one-day-per-week f e e d i n g program. They found t h a t t h e r e d u c t i o n i n f o o d consumption, compared w i t h f u l l y - f e d c o n t r o l s , ranged from n i l , when t h e d i e t a r y energy l e v e l was 3.15 k c a l / g , t o 10 per c e n t when i t was 1.48 k c a l / g . The m a t u r i t y o f t h e group r e c e i v i n g the d i e t c o n t a i n i n g 1.4 8 k c a l / g was markedly d e l a y e d . 1.1.2.3 R e d u c t i o n i n the energy l e v e l i n t h e d i e t 1.1.2.3.1 Methods N u t r i t i o n a l l y i n e r t m a t e r i a l s , such as o a t h u l l s , c e l l u l o s e , v e r m i c u l i t e , k a o l i n and sand have been i n c l u d e d i n t h e d i e t i n attempt t o lower t h e d i e t a r y energy c o n c e n t r a t i o n . However, u n l e s s s u b s t a n t i a l amounts o f i n e r t m a t e r i a l s a r e added t o t h e d i e t , t h e b i r d i s a b l e , w i t h i n l i m i t s , t o a d j u s t f e e d i n t a k e a c c o r d i n g l y and a s i g n i f i c a n t r e d u c t i o n i n c a l o r i c i n t a k e cannot be o b t a i n e d . Lee e t a l . (1971) e s t i m a t e d t h a t a t m e t a b o l i s a b l e energy l e v e l s below 2.0 k c a l / g o f f e e d , growth r a t e i s p r o g r e s s i v e l y r e d u c e d . - 16 - 1.1.2.3.2 E f f e c t s on body weight, age a t ' s e x u a l m a t u r i t y and egg p r o d u c t i o n Isaacks e t a l . (1960) r e s t r i c t e d c a l o r i c i n t a k e o f b r o i l e r - t y p e p u l l e t s from 9 weeks to 21 weeks of age by adding to d i e t s e i t h e r 15 or 25 per cent f i b r e from ground oat h u l l s . A c c o r d i n g l y , the p r o d u c t i v e energy of the d i e t s was decreased t o 1.07 k c a l / g , or 0.74 k c a l / g . The c o n t r o l d i e t c o n t a i n e d 2.15 k c a l M.E. per kg of feed. The body weights of the t r e a t e d b i r d s were 15.4 per cent or 23.9 per cent r e s p e c t i v e l y lower than those of the c o n t r o l s by the end of 21 weeks o f age. R e s t r i c t i o n had no s i g n i f i c a n t e f f e c t on egg p r o d u c t i o n i n t h i s experiment. Summers, e t al_. (1967) f e d b i r d s w i t h a r a t i o n c o n t a i n i n g 8 0 per cent wheat bran from 8 to 23 weeks of age. Feed i n t a k e of the bran-fed b i r d s was approximately 50 per cent g r e a t e r than t h a t of the c o n t r o l s . The body weight of the bran-fed b i r d s was 2.27 kg and the c o n t r o l b i r d s was 2.66 kg a t 23 weeks of age. However, o n l y s l i g h t d i f f e r e n c e s i n age a t sexual m a t u r i t y , egg p r o d u c t i o n and egg weight were noted between the bran-fed group and the c o n t r o l group. - 17 - 1.1.2.3.3 Economic A h i g h p e r c e n t a g e of i n e r t m a t e r i a l , about 30 t o 40 per c e n t , i s r e q u i r e d t o d i l u t e t h e d i e t s u f f i c i e n t l y t o d e l a y m a t u r i t y . I t i s c l a i m e d t o be i n c o n v e n i e n t t o t r a n s p o r t a l a r g e volume o f low energy d i e t and c o n s e q u e n t l y t h e p r a c t i c e o f d i e t a r y d i l u t i o n would p r o b a b l y be uneconomic (Lee e t a l . , 1972). 1.1.2.4 R e d u c t i o n i n p r o t e i n c o n t e n t i n t h e d i e t 1.1.2.4.1 P r o t e i n and energy l e v e l s R e d u c t i o n o f p r o t e i n a l o n e , and n o t energy, i n t h e d i e t i s not an a p p r o p r i a t e method of r e s t r i c t i n g f e e d i n g . D a v i d son (1964) showed t h a t c a r c a s s f a t l e v e l was g r e a t e r i n b i r d s f e d d i e t s i n w h i c h t h e r a t i o s o f c r u d e p r o t e i n t o m e t a b o l i s a b l e energy had been lowered c o n s i d e r a b l y below t h a t c o r r e s p o n d i n g t o 20 per c e n t p r o t e i n and 2.9 k c a l m e t a b o l i s a b l e energy per gram o f d i e t . B i r d s f e d on such low p r o t e i n d i e t s tended t o o v e r e a t i n o r d e r t o compensate f o r i n a d e q u a t e c o n c e n t r a t i o n o f amino a c i d s i n t h e d i e t . The e x c e s s m e t a b o l i s a b l e energy i n t a k e r e s u l t e d i n a g r e a t e r l o s s o f t h i s energy, m a i n l y as h e a t , per u n i t o f l i v e body w e i g h t . C o n s e q u e n t l y , t h e f e e d e f f i c i e n c y was lower i n t h e b i r d s f e d w i t h t h e lower p r o t e i n d i e t s . - 18 - B u l l o c k and M o r r i s (1963) d e c r e a s e d energy o r p r o t e i n t o 70% o f t h e c o n t r o l (M.E. 2.6 k c a l / g , p r o t e i n 1 5 % ) . R e s t r i c t i n g energy a l o n e r e t a r d e d growth and d e l a y e d age a t 50 per c e n t p r o d u c t i o n by 7 days. A 3 0 per c e n t r e d u c t i o n o f p r o t e i n caused 4.5 days d e l a y . R e s t r i c t i n g b o t h energy and p r o t e i n d e l a y e d m a t u r i t y by 10-11 days. Thus, the e f f e c t s o f energy and p r o t e i n r e s t r i c t i o n on m a t u r i t y appeared t o be a d d i t i v e . I n g e n e r a l p r a c t i c e , b o t h energy and p r o t e i n l e v e l s s h o u l d be d e c r e a s e d i n t h e d i e t . 1.1.2.4.2 D e p r i v a t i o n o f e s s e n t i a l amino a c i d D e p r i v a t i o n o f any e s s e n t i a l amino a c i d from the d i e t , i f s e v e r e enough, can markedly d e p r e s s t h e growth o f d e v e l o p i n g c h i c k s . S e v e r a l - e x p e r i m e n t s have s u c c e s s f u l l y d e l a y e d s e x u a l m a t u r i t y o f growing p u l l e t s w i t h a d i e t low i n l y s i n e (Berg and B e a r s e , 1958; B e r g , 1959; Waldroup and Harms, 19 62; L i l l i e and Denton, 19 66; Gous, 1977 and 1978). Lee e t a l . (1971) s t a t e d t h a t maximum l i v e - w e i g h t g a i n can be a t t a i n e d i n growing p u l l e t s a t l y s i n e i n t a k e s o f about 0.55 t o 0.6 0 gm per b i r d p e r day, depending on t h e breed o f b i r d . When l y s i n e i n t a k e s drop below 0.4 0 gm p e r b i r d p e r day, t h e d e c l i n e i n t h e l i v e - w e i g h t g a i n i s r a p i d and t h e i n c r e a s e of v o l u n t a r y f e e d i n t a k e i s no l o n g e r enough t o compensate f o r t h e lower l y s i n e l e v e l i n t h e d i e t . - 19 - Severe p r o t e i n and l y s i n e r e s t r i c t i o n i n growing p u l l e t s i n d u c e s f e a t h e r p e c k i n g , c a n n i b a l i s m , m o r t a l i t y , l e g weakness and r u p t u r e o f t h e g a s t r o c n e m i u s tendon. These adver s e e f f e c t s have been f u l l y r e p o r t e d by Carnaghan and Hanson (195 8) and Lee e t ' a l . (.1971) . An a p p a r e n t l y s a t i s f a c t o r y f e e d i n g manage- ment p r o c e d u r e f o r growing b r o i l e r b r e e d e r p u l l e t s by u s i n g low p r o t e i n and l y s i n e i n d i e t was suggested by S i n g s e n e t a l . (1964, 1965). A f t e r a s e r i e s o f e x p e r i m e n t s of f e e d i n g low l y s i n e and p r o t e i n d i e t s t o b r o i l e r b r e e d e r p u l l e t s a t d i f f e r e n t ages. S i n g s e n e t a l . recommended t h a t 0.57 per c e n t l y s i n e and 20 p e r c e n t p r o t e i n be f e d from 0 t o 8 weeks, and 0.47 per c e n t l y s i n e and 16 per c e n t crude p r o t e i n be f e d from 9 t o 21 weeks o f age. Gous (1978) suggested t h a t t h e most f a v o u r a b l e method o f r e s t r i c t i o n appeared t o be t h e f e e d i n g o f a low l y s i n e o r low p r o t e i n d i e t , s i n c e r e a r i n g c o s t s were low and t h e performance o f t h e p u l l e t s on t h e s e t r e a t m e n t s was good. - 2 0 - 1 . 2 M A T E R I A L S A N D M E T H O D S 1 . 2 . 1 S o u r c e o f B i r d s O n e t h o u s a n d a n d t w e n t y - t w o f e m a l e a n d 1 5 5 m a l e d a y - o l d b r o i l e r b r e e d e r c h i c k s f r o m H e i s d o r f a n d N e l s o n s t o c k , i n o c u l a t e d w i t h M a r e k 1 s d i s e a s e v a c c i n e , w e r e d e l i v e r e d b y a i r f r o m t h e S t a t e o f W a s h i n g t o n , U . S . A . , t o V a n c o u v e r I n t e r n a t i o n a l A i r p o r t o n O c t o b e r 1 2 t h , 1 9 7 8 . T h e c h i c k s w e r e i m m e d i a t e l y t r a n s p o r t e d t o t h e p o u l t r y e x p e r i m e n t a l f a r m a t t h e U n i v e r s i t y o f B r i t i s h C o l u m b i a a n d w e r e h e l d i n c h i c k - b o x e s u n t i l t h e f o l l o w i n g d a y . 1 . 2 . 2 B r o o d i n g P e r i o d ( 0 - 4 w e e k s ) A l l c h i c k s w e r e r a n d o m l y d i s t r i b u t e d i n t o 1 6 g r o u p s e a c h w i t h e i t h e r 7 3 o r 7 4 f e m a l e s a n d 9 o r 1 0 m a l e s . T h e y w e r e s u b j e c t e d t o t w o f e e d i n g m a n a g e m e n t p r o g r a m s . H a l f o f t h e m s e r v e d a s f e e d e r - f e d g r o u p s f e d a d l i b i t u m o n t h e c o n v e n t i o n a l l o n g m e t a l f e e d t o u g h s . T h e r e m a i n i n g g r o u p s , w h i c h s e r v e d a s f l o o r - f e d g r o u p s , w e r e g i v e n f e e d a d l i b i t u m o n p a p e r ( e m p t y f e e d b a g s ) a n d a s s u c h t h e y w e r e t r a i n e d t o p i c k u p f e e d f r o m t h e g r o u n d . T h e f l o o r - f e d g r o u p s w e r e a g i t a t e d d a i l y d u r i n g f e e d i n g i n o r d e r t o i n c r e a s e t h e i r a c t i v i t y . T h e f e e d e r - f e d a n d f l o o r - f e d m a n a g e m e n t s a r e s h o w e d i n F i g u r e s 1 . 1 a n d 1 . 2 r e s p e c t i v e l y . F i g u r e 1 . 2 F l o o r - f e d c h i c k s d u r i n g t h e b r o o d i n g p e r i o d . - 22 - The c o m p o s i t i o n of t h e d i e t f e d from h a t c h i n g t o s e x u a l m a t u r i t y i s shown i n T a b l e 1.1. I t c o n t a i n e d 15.35% crud e p r o t e i n and 2686 k c a l m e t a b o l i z a b l e energy/kg. D u r i n g the b r o o d i n g p e r i o d t h e d i e t was p r o v i d e d i n crumble form. Heat was p r o v i d e d by two 500 w a t t heat lamps (2 f e e t above f l o o r ) p e r pen t h r o u g h t h e b r o o d i n g p e r i o d . C h i c k s were weighed, wing-banded, and v a c c i n a t e d i n t r a o c u l a r l y a g a i n s t N e w c a s t l e d i s e a s e and i n f e c t i o u s b r o n c h i t i s , when t h e y were 12 days o l d . C h i c k s were weighed a g a i n a t 2 6 days o f age. 1.2.3 R e a r i n g P e r i o d (5-18 weeks) On t h e f i r s t day o f t h e r e a r i n g p e r i o d , the average f e e d consumption o f t h e b i r d s was 79.0 g per b i r d per day. T h e r e a f t e r , the amount of f e e d g i v e n was g r a d u a l l y reduced t o f i n a l l y p r o v i d e by 6 weeks o f age 60 g per b i r d per day. B e g i n n i n g a t 7 weeks of age a l l b i r d s were r e s t r i c t e d i n f e e d i n t a k e , so t h a t they grew t o t h e t a r g e t body w e i g h t o f 1.64 kg (3.60 l b ) by t h e end o f t h e r e a r i n g p e r i o d (18 weeks), as recommended by t h e P f i z e r H e i s d o r f and N e l s o n b r o i l e r b r e e d e r management program. The m o d i f i e d f o r m u l a used t o c o n t r o l , on a d a i l y b a s i s , t h e body w e i g h t g a i n was: A E = 5.90 (e°*^ Wl - e°' 9 W2) (Eden, 1977), Wx = i n i t i a l body w e i g h t ( k g ) , W2 = f i n a l body w e i g h t ( k g ) , A E = amount of m e t a b o l i z a b l e energy T a b l e 1.1 C o m p o s i t i o n o f d i e t 1. I n g r e d i e n t s G/kg Ground wheat 746* Ground c o r n 100 Soybean meal 80 Rapeseed meal 40 Limestone 10 D i c a l c i u m phosphate 20 I o d i z e d s a l t 4 M i c r o i n g r e d i e n t s ** **add m i c r o i n g r e d i e n t s p e r kg z i n c o x i d e 50 mg manganese o x i d e 25 mg c h o l i n e 50% 1,000 mg c a l c i u m p a n t o t h e n a t e 3 mg r i b o f l a v i n 3 mg v i t a m i n B^^ 0.01 mg v i t a m i n A 5,000 u n i t s v i t a m i n D-, 500 u n i t s v i t a m i n E 12 u n i t s e t h o x y q u i n 150 mg amprol ( c o c c i d i o s t a t ) 500 mg l i n c o m y c i n 2 mg 15 kg o f ground wheat was r e p l a c e d by 15 kg o f a l f a l f a meal a f t e r i o weeks o f age . - 24 - (Meal) r e q u i r e d f o r i n c r e a s i n g body w e i g h t from W-̂  t o W2 o f heavy t y p e b i r d . C u m u l a t i v e f e e d consumption on b i - w e e k l y b a s i s f o r t h e f e e d e r - f e d b i r d s t h r o u g h t h e r e s t r i c t e d p e r i o d i s l i s t e d i n T a b l e 1.2. Feed was changed from crumble form t o p e l l e t form a t t h e b e g i n n i n g o f t h e r e a r i n g p e r i o d . Water was g i v e n ad l i b i t u m t h r o u g h t h e whole experiment e x c e p t over 15 t o 18 weeks p e r i o d , when water was r e s t r i c t e d f o r 14.5 hr d a i l y (from 5:30 pm. t o 8:00 a.m.). F e e d e r - f e d groups were f e d between 8 and 10 a.m. e v e r y day from hanging tube f e e d e r s . A t 9 weeks o f age, the wood s h a v i n g s used as l i t t e r were r e p l a c e d w i t h c o a r s e r oa t s t r a w i n t h e pens c o n t a i n i n g t h e f l o o r - f e d b i r d s t o enhance t h e s c r a t c h i n g b e h a v i o r of t h e b i r d s a s s o c i a t e d w i t h l o o k i n g f o r t h e p e l l e t e d f e e d . The f l o o r - f e d groups were f e d t w i c e d a i l y t h e same amount o f f e e d as t h e f e e d e r - f e d group. The p e l l e t s were b r o a d c a s t on t h e l i t t e r between 8 a.m. and 10 p.m. and between 3:30 p.m. and 4:30 p.m. F i g u r e s 1.3 & 1.4 show t h e f e e d e r - f e d and f l o o r - f e d managements d u r i n g the r e a r i n g p e r i o d . S i n c e t h e f e e d r e q u i r e m e n t f o r males was h i g h e r t h a n f o r f e m a l e s , some o f the males d i d not grow o r even l o s t body w e i g h t . T h e r e f o r e , a l l males were removed from t h e experiment a t 9 weeks o f age. I n o r d e r t o make pen space f o r t h e newly grouped males, one group o f females was e q u a l l y and randomly r e d i s t r i b u t e d i n t o t h e o t h e r seven groups f o r b o t h t h e f e e d e r - f e d and f l o o r - f e d p o p u l a t i o n s . - 25 - T a b l e 1.2 C u m u l a t i v e f e e d consumption o f the f e e d e r - f e d p u l l e t s . Age-Weeks Gm. o f Feed Consumed P e r P u l l e t 2 217 4 897 6 1,855 8 2,488 10 3,235 12 4,076 14 4,973 16 6,033 18 7. 044 20 8,575 A f t e r 20 weeks o f age, 130 gm o f f e e d g i v e n p e r p u l l e t p e r day u n t i l t h e t e r m i n a t i o n o f the ex p e r i m e n t . F i g u r e 1 . 4 F l o o r - f e d p u l l e t s d u r i n g t h e r e a r i n g p e r i o d . - 2 7 - A l l h e a t l a m p s w e r e r a i s e d t o 5 f e e t a b o v e t h e f l o o r a t 5 w e e k s o f a g e . O n e h e a t l a m p w a s r e m o v e d f r o m e a c h p e n a t 1 3 w e e k s . T h e r e m a i n i n g h e a t l a m p w a s r e p l a c e d w i t h a 6 0 w a t t l i g h t b u l b i n t h e f o l l o w i n g w e e k . T h e l i g h t b u l b s g a v e l i g h t f r o m 7 a . m . t o 4 p . m . A n e x t e n d e d h o u r o f d i m l i g h t w a s g i v e n b y t h e l i g h t s i n t h e c o r r i d o r o u t s i d e t h e p e n s t o a v o i d f r i g h t e n i n g t h e b i r d s w i t h s u d d e n c o m p l e t e d a r k n e s s . A l l p u l l e t s w e r e r e v a c c i n a t e d a g a i n s t N e w c a s t l e d i s e a s e a n d b r o n c h i t i s a t 1 6 w e e k s o f a g e . B i r d s w e r e w e i g h e d b i - w e e k l y t h r o u g h t h e r e a r i n g p e r i o d , a n d t h e y w e r e w e i g h e d a p p r o x i m a t e l y 1 5 h o u r s a f t e r f e e d i n g . 1 . 2 . 4 . H o l d i n g P e r i o d ( 1 9 - 2 5 w e e k s ) B a s e d o n t h e b o d y w e i g h t a t t h e e n d o f t h e r e a r i n g p e r i o d ( 1 8 w e e k s ) , e a c h o f t h e f e e d e r - f e d a n d f l o o r - f e d p o p u l a t i o n s w a s e q u a l l y d i v i d e d i n t o f o u r g r o u p s , h e a v i e s t , u p p e r m e d i u m , l o w e r m e d i u m a n d l i g h t e s t , e a c h w i t h t w o r e p l i c a t e s . T h e y w e r e t r a n s f e r r e d f r o m t h e r e a r i n g h o u s e a n d h e l d i n t h e l a y i n g h o u s e . A m i n i m u m p h o t o p e r i o d e x t e n d i n g f r o m 7 a . m . t o 8 p . m . w a s p r o v i d e d w i t h t h e a i d o f a r t i f i c i a l l i g h t s . O v e r t h e c o u r s e o f t h e h o l d i n g p e r i o d a n d a t t h e b e g i n n i n g o f t h e l a y i n g p e r i o d t h e r e w a s a n i n c r e a s e i n n a t u r a l d a y l e n g t h w h i c h e x t e n d e d t h e b i r d s ' p h o t o p e r i o d . T h e a m o u n t o f d a i l y f e e d p r o v i d e d p e r b i r d w a s g r a d u a l l y i n c r e a s e d t o 1 3 0 g p e r b i r d b y 2 0 w e e k s o f a g e , t h e n m a i n t a i n e d a t 1 3 0 g u n t i l t h e e n d o f t h e e x p e r i m e n t . - 28 - 1.2.5 La y i n g P e r i o d (26-47 weeks) Between 2 6 and 2 7 weeks of age a t sexual m a t u r i t y , 5 b i r d s c l o s e s t to the mean body weight were s e l e c t e d from each group f o r examination of the abdominal f a t pad. A commercial b r o i l e r breeder d i e t r e p l a c e d the grower d i e t at 27 weeks of age. The d i e t contained 16 per cent p r o t e i n 2860 M.E. k c a l / k g . D a i l y egg p r o d u c t i o n was recorded. The eggs l a i d on one day a t 34.- 38 and 47 weeks of age from a l l groups were weighed. Body weights were recorded a t 41 and 47 weeks o f age. F i g u r e s 1.5 and 1.6 show the f e e d e r - f e d and f l o o r - f e d managements a t 45 weeks of age. F i g u r e 1.6 F l o o r - f e d p u l l e t s d u r i n g the l a y i n g p e r i o d . - 30 - 1.3 RESULTS AND DISCUSSION 1.3.1 Body Weight 1.3.1.1 Comparison of the f e e d i n g management pr o c e d u r e The average body w e i g h t o f t h e . f e e d e r - f e d and f l o o r - f e d p u l l e t s from 2 weeks t o 47 weeks o f age i s p r e s e n t e d i n T a b l e 1.3. The average ad l i b i t u m f e e d con- sumption o f t h e f e e d e r - f e d groups by 4 weeks o f age (27 days) was 897 g p e r b i r d . The f l o o r - f e d groups d u r i n g the same p e r i o d were g i v e n 1039 g o f f e e d p e r b i r d t o ensure t h e y were f e d t o a p p e t i t e . Under ad l i b i t u m f e e d i n g , the f l o o r - f e d b i r d s were s i g n i f i c a n t l y (P < 0.05) l i g h t e r t h a n t h e f e e d e r - f e d b i r d s by 7.9 g and 37.7 g a t 2 and 4 weeks r e s p e c t i v e l y . R e d u c t i o n i n body w e i g h t g a i n has a l s o been obse r v e d i n r a t s w h i c h r e c e i v e d p h y s i c a l e x e r c i s e . O s c a i e t a l . (1972), found t h a t r a t s s u b j e c t e d t o an e x e r c i s i n g program of swimming from 15 t o 360 min d a i l y o v e r a p e r i o d o f 14-16 weeks o f age g a i n e d w e i g h t more s l o w l y than the s e d e n t a r y c o n t r o l r a t s when t h e y were b o t h p r o v i d e d w i t h f o o d and water ad l i b i t u m . Jones e t a l . (1964), H o l l o s z y (1967), Crews e t a l . (1969) and Oscae e t a l . (1971) r e p o r t e d s i m i l a r o b s e r v a t i o n s . - 31 - T a b l e 1.3 The e f f e c t o f f e e d e r - f e d and f l o o r - f e d f e e d i n g managements on body w e i g h t s d u r i n g t h e b r o o d i n g , r e a r i n g , h o l d i n g and l a y i n g p e r i o d s . A g e in- • Averages o f Body Weights - gm. v/eweeks F e e d e r - f e d P u l l e t s F l o o r - f e d P u l l e t s 2 125 . ' - a 117 b 4 405 a 367 b 6 739 b 767 a 8 847 b • 914 a 10 1005 1075 a 12 1173 b 1253 a 14 1238 b 1367 a 16 1493 b 1584 a 18 1574 b 1656 a 20 1957 b 2058 a 25 2494 a 2520 a 41 3267 b 3352 a 47 3341 b 3404 a a, b, In the a n a l y s i s o f v a r i a n c e , t h e averages o f body w e i g h t s a t t h e same age w h i c h c a r r y the same l e t t e r a re n o t s i g n i f i c a n t l y d i f f e r e n t (P > 0.05). - 32 - A f t e r 5 weeks of age the amount of feed g i v e n d a i l y was g r a d u a l l y r e s t r i c t e d to both f e e d e r - f e d and f l o o r - f e d p u l l e t s . The average body weight of the f l o o r - f e d p u l l e t s s h i f t e d t o be h e a v i e r than the f e e d e r - f e d b i r d s a t 6 weeks of age. T h i s might be because the former p i c k e d up some e x t r a feed l e f t over i n the l i t t e r from the ad l i b i t u m f e e d i n g p e r i o d . From 6 weeks of age onward, the body weights of the f l o o r - f e d b i r d s were c o n s i s t e n t l y h e a v i e r than the f e e d e r - f e d b i r d s . I t suggested t h a t the f l o o r - f e d b i r d s were a b l e to p i c k up almost a l l the feed among the straw and they were a l s o observed to engage coprophagy. The f e e d e r - f e d b i r d weighed 1.57 kg and the f l o o r - f e d b i r d weighed 1.6 6 kg a t 18 weeks of age. They were thus c l o s e t o the t a r g e t weight of 1.64 kg as was recommended by H e i s d o r f and Nelson b r o i l e r breeder management program. A f t e r the r e a r i n g p e r i o d , d a i l y feed i n t a k e r a p i d l y i n c r e a s e d from 75 g to 13 0 g per b i r d per day by the end of 2 0 weeks of age, and maintained on 130 g per b i r d u n t i l the end of the experiment. During t h i s f e e d i n g p e r i o d the f e e d e r - f e d b i r d s gained body weight f a s t e r than the f l o o r - f e d b i r d s . By 25 weeks of age, the f l o o r - f e d p u l l e t s were s l i g h t l y but not s i g n i f i c a n t l y h e a v i e r than the f e e d e r - f e d p u l l e t s . - 3 3 - D u r i n g t h e l a y i n g p e r i o d , e v e n t h o u g h f e e d c o n s u m p t i o n w a s m a i n t a i n e d a t 1 3 0 g p e r d a y , b o t h p o p u l a t i o n s o f b i r d s i n c r e a s e d i n w e i g h t . H o w e v e r , t h e f l o o r - f e d b i r d s a g a i n b e c a m e s i g n i f i c a n t l y h e a v i e r t h a n t h e f e e d e r - f e d b i r d s a t 4 1 a n d 4 7 w e e k s o f a g e . 1 . 3 . 1 . 2 C o m p a r i s o n o f t h e f o u r w e i g h t - g r o u p s A t t h e e n d o f t h e r e a r i n g p e r i o d t h e b i r d s w e r e e q u a l l y d i v i d e d i n t o f o u r d i f f e r e n t w e i g h t - g r o u p s b a s e d o n t h e b o d y w e i g h t a t 1 8 w e e k s o f a g e . T h e g r o w t h h i s t o r y o f i n d i v i d u a l b i r d s w a s s t u d i e d . T h e m e a n b o d y w e i g h t o f e a c h g r o u p b e f o r e 1 8 w e e k s o f a g e w a s c a l c u l a t e d a n d t h e s u b s e q u e n t b o d y w e i g h t s a r e r e p o r t e d i n T a b l e 1 . 4 . I t w a s f o u n d t h a t e v e n a t 2 w e e k s o f a g e t h e l i g h t e s t g r o u p w a s a l r e a d y s i g n i f i c a n t l y ( P < 0 . 0 5 ) l i g h t e r t h a n t h e h e a v i e s t a n d t h e u p p e r m e d i u m g r o u p s i n t h e f e e d e r - f e d m a n a g e m e n t . T h e r e w a s , h o w e v e r , n o s i g n i f i c a n t d i f f e r e n c e b e t w e e n t h e h e a v i e s t a n d t h e l i g h t e s t g r o u p s o f b i r d s m a n a g e d o n t h e f l o o r t h r o u g h o u t t h e e n t i r e b r o o d i n g p e r i o d . F e e d r e s t r i c t i o n w a s b e g u n a t t h e b e g i n n i n g o f t h e r e a r i n g p e r i o d ( 5 w e e k s ) . T h e m e a n o f b o d y w e i g h t s o f t h e f o u r w e i g h t - g r o u p s o f b i r d s s h o w e d s i g n i f i c a n t d i f f e r e n c e f r o m e a c h o t h e r i n b o t h p o p u l a t i o n s o f b i r d s b y 8 w e e k s o f a g e . T h e d i f f e r e n c e w a s a c c o u n t e d f o r b y a t l e a s t t w o f a c t o r s , t h e g e n e t i c v a r i a t i o n a n d s o c i a l p e c k o r d e r . - 34 - T a b l e 1.4 The body w e i g h t i n gram o f a l l w e i g h t - g r o u p s o f f e e d e r - f e d and f l o o r - f e d p u l l e t s a t each w e i g h i n g p e r i o d ( o n l y p u l l e t s s u r v i v i n g t o 13 weeks were c o n s i d e r e d i n t h e c a l c u l a t i o n ) . Average o f Body Weights o f Feeder-Fed P u l l e t s Age Upper Lower i n Weeks H e a v i e s t Medium Medium L i g h t e s t 2 128 a 128 a 125 ab 123 be 4 420 a 413 ab 400 be 394 c 6 772 a 750 ab 734 be 714 c 8 923 c 871 d 840 e 777 f 10 1122 c 1043 c 988 f 897 h 12 1339 b 1223 c 1149 d 1027 f 14 1439 b 1302 c 1205 d 1045 f 16 1739 b 1575 d 1451 f 1235 g 18 1831 b 1645 d 1532 f 1312 g 20 2152 b 2043 c 1923 d 1728 e 25 2583 ab 2579 ab 2460 be 2361 c 41 3293 ab 3325 ab 3245 ab 3294 b 47 3367 a 3368 a 3331 a 3296 a C o n t i n u e d - 3 5 - T a b l e 1 . 4 ( c o n t i n u e d ) A v e r a g e o f B o d y W e i g h t s o f F l o o r - f e d P u l l e t s A g e U p p e r L o w e r i n W e e k s H e a v i e s t M e d i u m M e d i u m L i g h t e s t 2 1 1 9 c d 1 1 7 d 1 1 6 d 1 1 6 d 4 3 7 2 d 3 6 4 d 3 6 4 d 3 6 6 d 6 7 8 5 a 7 6 4 a b 7 6 0 a b 7 6 1 a b 8 1 0 4 5 a 9 5 7 b 9 0 1 c 8 5 2 d e 1 0 1 3 0 6 a 1 1 6 5 b 1 0 8 6 d 9 7 4 g 1 2 1 5 3 7 a 1 3 5 0 b 1 2 4 1 c 1 0 7 7 e 1 4 1 6 8 9 a 1 4 3 9 b 1 3 3 0 c 1 1 1 4 e 1 6 1 9 4 3 a 1 6 9 4 c 1 5 2 6 e 1 2 3 1 g 1 8 1 8 7 4 a 1 7 7 8 c 1 5 9 6 e 1 2 8 9 g 2 0 2 3 0 4 a 2 1 3 7 b 2 0 1 4 c 1 7 7 6 e 2 5 2 6 9 1 a 2 6 0 2 a 2 4 1 3 c 2 3 6 1 c 4 1 3 4 0 1 a 3 3 4 5 a b 3 3 5 8 a b 3 2 9 5 a b 4 7 3 4 1 7 a 3 4 1 6 a 3 4 1 6 a 3 3 6 1 a a , b , c , d , e , f , g I n t h e s t u d e n t N e w m a n - K e u l s m u l t i p l e r a n g e t e s t , t h e b o d y w e i g h t s o f f e e d e r - f e d a n d f l o o r - f e d p u l l e t s a t e a c h w e i g h i n g p e r i o d f o l l o w e d w i t h t h e s a m e l e t t e r a r e n o t s i g n i f i c a n t d i f f e r e n t ( P > . 0 5 ) . - 36 - The s t r o n g e r b i r d s probably consumed more feed, gained weight f a s t e r and t h e r e f o r e s u f f e r e d a l e s s e r degree of feed r e s t r i c t i o n than the l i g h t e r b i r d s d u r i n g the r e a r i n g p e r i o d (5-18 weeks). A f t e r the r e a r i n g p e r i o d , d a i l y feed consumption r a p i d l y i n c r e a s e d from 75 g to 130 g per b i r d per day i n two weeks as mentioned b e f o r e . The l i g h t e r b i r d s grew f a s t e r than the h e a v i e r b i r d s . By 41 weeks of age th e r e was no s i g n i f i c a n t d i f f e r e n c e (P > 0.05) i n body weight among weight-groups from each f e e d e r - f e d and f l o o r - f e d management (Table 1.4). The a n a l y s i s of v a r i a n c e (Table 1.5) showed t h a t the d i f f e r e n c e o f body weight among weight-groups decreased to be not s i g n i f i c a n t by 47 weeks of age. T h e r e f o r e , the b i r d s i n the l i g h t e s t group was almost able to f u l l y compensate f o r t h e i r p r e v i o u s slower growth r e l a t i v e to the h e a v i e s t groups by 4 7 weeks of age. D i f f e r e n c e s of mean body weights among weight groups i n the f l o o r - f e d b i r d s were c o n s i s t e n t l y l a r g e r than t h a t i n the f e e d e r - f e d b i r d s (Table 1.4). I t suggested t h a t c o m p e t i t i o n f o r feed was probably more r i g o r o u s among f l o o r - f e d b i r d s than the f e e d e r - f e d b i r d s . O b s ervation of the body weight d i f f e r e n c e among fou r weight-groups from d i f f e r e n t f e e d i n g managements i n d i c a t e d t h a t the i n t e r a c t i o n between f e e d i n g management and weight-group was brought about by the Table 1.5 Summary of mean squares of the analysis of variance of body weights of a l l groups of pullets from 2 to 47 weeks of ages (only pullets surviving to 18 weeks were considered in the calculation). Time of Weighing (week) Source of Variation d.f. Brooding and Rearing Periods 10 12 14 16 Feeder-fed vs.Floor-fed (F) 16377 340433 135162 1523350 3007266 2679112 4140837 1770785 * Weight groups (G) 904 * 11378 * 65417 1067862 2744816 5500158 # * * * 8575806 13822886 F X G 169 n. s. 5314 12843 30827 149363 223802 333281 432076 n. s. n. s. Error 832 213 2453 6899 9317 16033 17452 19620 12835 Continued Table 1.5 (continued) Time of Weighing (week) Source of Variation Holding Period Laying Period d.f. 18 d.f. 20 d.f. 25 d.f. 41 d.f. 47 Feeder-fed vs. Floor-fed (F) 1 1245814 1 2237537 1 194294 1 1268280 1 670620 * * n.s. * * Weight groups (G) 3 12646915 3 8062554 3 3055125 367173 153979 n.s. F X G 3 215446 22952 3 194150 n.s. n.s. 53516 n.s. 5956 n.s. Error 813 21541 804 . 80755 777 142918 692 127339 675 160929 At 2 and 4 weeks of ages the sedentary feeder-fed birds were heavier than the exercised floor- fed pullets, thereafter, the exercised floor-fed pullets were heavier. * Significant (P < .05) n.s. Not significant - 39 - m o r e r a p i d r e s p o n s e i n b o d y w e i g h t i n c r e a s e i n t h e h e a v i e r g r o u p s m a n a g e d o n t h e f l o o r - f e d s y s t e m ( T a b l e 1.4, T a b l e 1.5). T h i s i n t e r a c t i o n w a s o n l y o b s e r v e d d u r i n g t h e r e a r i n g p e r i o d w h e n t h e p u l l e t s w e r e u n d e r r e s t r i c t e d f e e d i n g . 1.3.2 A b d o m i n a l F a t B e t w e e n 26 a n d 27 w e e k s o f a g e , 5 b i r d s c l o s e ' , t o t h e m e a n b o d y w e i g h t o f e a c h g r o u p f r o m t h e f e e d e r - f e d a n d f l o o r - f e d p o p u l a t i o n s w e r e k i l l e d f o r a b d o m i n a l f a t s t u d i e s . T h e m e a n b o d y w e i g h t a n d t h e a b d o m i n a l f a t w e i g h t a r e l i s t e d i n T a b l e 1.6. T h e a v e r a g e b o d y w e i g h t o f e a c h 20 b i r d s s e l e c t e d f r o m t h e f e e d e r - f e d a n d f l o o r - f e d p u l l e t s w e r e 2.83 k g a n d 2.78 k g r e s p e c t i v e l y , a n d w e r e n o t s i g n i f i c a n t l y d i f f e r e n t ( P > 0.05). H o w e v e r , t h e a b d o m i n a l f a t o f t h e f e e d e r - f e d b i r d s w e i g h e d 126.0 g w h i c h w a s s i g n i f i c a n t l y ( P > 0.05) h i g h e r t h a n t h e f a t c o n t e n t o f t h e f l o o r - f e d b i r d s w h i c h w e i g h e d 102.2 g . T h e p r o p o r t i o n o f a b d o m i n a l f a t p e r b o d y w e i g h t w a s a l s o s i g n i f i c a n t l y h i g h e r ( P < 0.05) i n t h e f e e d e r - f e d (4.44%) t h a n i n t h e f l o o r - f e d (3.69%) b i r d s . T h u s , b r o i l e r b r e e d e r p u l l e t s s u b j e c t e d t o e x e r c i s e p r o g r a m b y f e e d i n g o n l i t t e r i n t h i s e x p e r i m e n t s h o w e d l e s s a b d o m i n a l f a t d e p o s i t i o n b o t h q u a n t i t a t i v e l y a n d p r o p o r t i o n a l l y t h a n t h o s e p u l l e t s r a i s e d o n c o n v e n t i o n a l f e e d e r - f e d m a n a g e m e n t . J o h n s o n e t _ a l . (1956) i n a s t u d y o f o b e s i t y i n h i g h s c h o o l g i r l s r e p o r t e d t h a t i n a c t i v i t y w a s e v e n m o r e i m p o r t a n t t h a n o v e r e a t i n g i n a s s o c i a t i o n w i t h o b e s i t y , o n a s t a t i s t i c a l Table 1.6 Body weight on the day of autopsy (at 26-27 weeks), total body weight gain after 18 weeks of age to the day of autopsy, total body weight gain minus abdominal fat weight, abdominal fat weight and the percentage of abdominal fat per body weight of the heaviest, upper medium, lower medium and lightest groups of pullets managed on feeder-fed or floor-fed system. Body Weight Kg. Total Gain in gm. Total Gain Minus abdominal fat in gm. Abdominal Fat Gm. % Body Weight Feeder-fed Heaviest Upper medium Lower medium Lightest Mean 93 88 2.79 abc 2.73 be 2.83 1098 cd 1192 be 1248 be 1282 ab 1205 980 cd 1048 be 1123 be 1165 b 1079 118 ab 145 a 125 ab 117 ab 126 4.04 ab 5.02 a 4.45 ab 4.24 ab 4.44 Floor-fed Heaviest 2.84 ab 845 e 751 e 94 b 3.30 b Upper medium 2.79 abc 981 de 876 de 105 ab 3.72 ab Lower medium 2.81 abc 1168 be , 1049 be 119 ab 4.27 ab Lightest 2.66 c 1411 a 1320 a 92 b 3.45 ab Mean 2.78 1101* 999* 102* 3.69* a,b,c,d,e A l l values in each column followed by the same letter are not significantly different (P < .05), according to Duncan multiple range test. * Significant difference (P < .05) with the mean in the feeder-fed management. Table 1.7 Mean squares from the analysis of variance of body weights on the day of autopsy (at 26-27 weeks), body weight gain after 18 weeks of age to the day of autopsy, body weight gain minus abdominal fat, abdominal fat weight and the percentage of abdominal fat per body weight of the heaviest, upper medium, lower medium and lightest groups of pullets managed on feeder-fed or floor-fed system. Source of Variation Mean Squares Body Weight * Body Weight Gain Minus Abdominal Abdominal Fat d.f. Body Weight Gain Abdominal Fat Fat Weight Body Weight I 4- Feeder-Fed vs. Floor-fed 1 (F) Weight Groups 3 (G) F X G 3 Error 32 31,584 64,031* 6,201 14,491 107,537* 259,414* 74,111* 14,087 63,853* 265,323* 71,374* 13,725 5,666* 1,126 479 1,017 5.66* 1.29 0.52 1.21 * Significant (P < 0.05) - 42 - b a s i s . The obese s u b j e c t s had a lower c a l o r i c i n t a k e ; thus, t h e i r r e l a t i v e l y g r e a t e r energy balance r e s u l t e d from a r e l a t i v e l y l e s s e r a c t i v i t y . Mayer e t 'al. (1954) a l s o made a s i m i l a r c o n c l u s i o n based on a study of caged and e x e r c i s e d mice. Deaton e t a l . (1974) r e a r e d male and female b r o i l e r s i n cages and l i t t e r - f l o o r pens under feed and water ad l i b i t u m c o n d i t i o n s up to 7, 8 and 9 weeks of age. Caged b r o i l e r s c o n s i s t e n t l y had more abdominal f a t and ether e x t r a c t percentage of body weight than the b r o i l e r s r e a r e d i n l i t t e r - f l o o r pens. A f t e r the s e g r e g a t i o n of p u l l e t s i n t o four groups by weight at 18 weeks of age, the l i g h t e r groups gained weight f a s t e r than the h e a v i e r groups (Tables 1.6, 1.7, F i g u r e 1.7). The amount and p r o p o r t i o n of the abdominal f a t pad (% of body weight) at sexual m a t u r i t y of the f e e d e r - f e d p u l l e t s were higher (P < 0.05) than of the f l o o r - f e d p u l l e t s . Abdominal f a t i n c r e a s e d w i t h i n c r e a s e d body weight i n those groups of p u l l e t s which gained up to 1200 g i n body weight a f t e r the s e g r e g a t i o n , but decreased i n p r o p o r t i o n to body weight i n those groups of p u l l e t s which gained i n excess of 1200 g (Figure 1.7). The l i g h t e s t group had hi g h e r body weight than any of the other groups but these l i g h t e r p u l l e t s c o ntained the l e a s t amount of abdominal f a t . I t should be noted t h a t the l i g h t e s t group, which s u f f e r e d the s e v e r e s t feed r e s t r i c t i o n p r i o r to s e g r e g a t i o n , was s u b j e c t e d t o the l e a s t feed r e s t r i c t i o n a f t e r s e g r e g a t i o n . - 43 - 20U0, 1600 BOOT WE]CUT CAIM KI.MUS ABDCMNU, FAT 1600 _ ABDCKINAI. ra 11*00 00 g CO in M H 1200 1000 eoo 6oo 1*001 zool 3 B 4 B 3 2 E eoo 1000 1200 woo BODY WEIGHT GAIN — g. Figure 1.7 Amount of abdominal fat and the body weight gain minus abdominal f a t weight i n feeder-fed p u l l e t s (B ), and f l o o r - f e d p u l l e t s ( • ) with d i f f e r e n t body weight gains af t e r the pu l l e t s were separated into four groups, heaviest (1), upper medium (2), lower medium (3) and l i g h t e s t (4), by weight at 18 weeks of age to 27 weeks of age. - 44 - The d a t a s uggest t h a t t h e more v i t a l p a r t s o f t h e body, such as muscle and s k e l e t a l t i s s u e s d e v e l o p e d a t a f a s t e r r a t e t h a n d i d t h e abdominal f a t i n t h e l i g h t e s t group o f p u l l e t s . 1.3.3 Egg P r o d u c t i o n 1.3.3.1 S e x u a l m a t u r i t y S e x u a l m a t u r i t y i s shown i n Ta b l e 1.8 wh i c h shows t h e mean number of days t o t h e f i r s t egg, 3 0 and 50 p e r c e n t p r o d u c t i o n f o r d i f f e r e n t w e i g h t - g r o u p s i n each f e e d i n g management. The mean days t o f i r s t egg l a i d , 30% and 50% egg p r o d u c t i o n were 194, 208 and 214 f o r the f e e d e r - f e d p u l l e t s and 192, 207 and 213 f o r t h e f l o o r - f e d p u l l e t s r e s p e c t i v e l y . Thus, p u l l e t s managed on f l o o r - f e d . system showed no e f f e c t on age a t s e x u a l development a c c o r d i n g t o t h e t h r e e p a r a m e t e r s . S e x u a l m a t u r i t y o f t h e l i g h t e r groups tended t o be d e l a y e d , however, t h e d i f f e r e n c e was not s i g n i f i c a n t . 1.3.3.2 Rate o f l a y Accumulated egg p r o d u c t i o n per hen per day on hen day b a s i s i s shown i n Ta b l e 1.9 f o r d i f f e r e n t w e i g h t - g r o u p s o f p u l l e t s from f e e d e r - f e d and f l o o r - f e d - 45 - T a b l e 1.8 The e f f e c t o f f e e d e r - f e d and f l o o r - f e d managements on t h r e e e s t i m a t e s o f age a t s e x u a l m a t u r i t y . Days t o Days t o 30% Days t o 50% Weight-Groups F i r s t Egg P r o d u c t i o n P r o d u c t i o n F e e d e r - f e d H e a v i e s t 193 207.'.. 213 Upper medium 193 205.; 213 Lower medium 194 209 213' L i g h t e s t 197. 210, 214 Means 194 208 214 F l o o r - f e d H e a v i e s t 190 207 214 Upper medium 192 206 213 Lower medium 194 207 214 L i g h t e s t 192 207 213 Means 192 207 213 -46- Table 1.9 The effect of feeder-fed and floor-fed feeding managements on cumulative percentage of egg production calculated on a hen-day bases to various ages for different weight-groups of broiler breeder pullets. To 30 To 33 To 36 To 39 To 42 To 45 To 47 wks. wks. wks. wks. wks. wks. wks. Feeder-fed Heaviest 10. 4 36. 2 48. 9 53. 5 5.5. .9 56. 7 57. 5 Upper medium 12. 4 39. 6 50. 9 54. 2 56 .6 57. 7 59. .2 Lower medium 7. 7 32. 1 46. 7 51. 9 54 .2 56. ,0 56. ,5 Lightest 7. ,0 30. 3 45. 3 51. .4 54 .6 56. ,3 57. ,1 Mean 9. .4 34. 6 48. 0 52. 8 55 .3 56. 6 57. 6 Floor-fed Heaviest 12. .2 36. .6 49, .1 54. .9 58 .1 60. .1 60, .6 Upper medium 12, .7 34. .6 45, .8 50, .4 53 .0 55, .0 55, .1 Lower medium 10 .5 32. .8 45. .3 51. .8 54 .8 57. .0 57, .2 Lightest 8, .3 33, .0 44, .6 50, .3 54 .6. 57, .4 57 .9 Mean 11 .1 34 .3 46 .2 51 .9 55 .1 57 .4 57 .7 - 4 7 - f e e d i n g m a n a g e m e n t s . U p t o 3 0 w e e k s o f a g e , t h e b i r d s f r o m t h e f l o o r - f e d g r o u p s p r o d u c e d h i g h e r n u m b e r o f e g g s t h a n t h e f e e d e r - f e d g r o u p s . T h e e a r l y h i g h a c c u m u l a t e d e g g p r o d u c t i o n w a s r e l a t e d t o e a r l i e r m a t u r i t y o f t h e f l o o r - f e d g r o u p s . T h e f e e d e r - f e d g r o u p s o v e r c a m e t h i s e a r l y a d v a n t a g e o f t h e f l o o r - f e d g r o u p s w i t h a h i g h e r r a t e o f l a y s u b s e q u e n t t o 3 3 w e e k s o f a g e . T o v e r i f y t h i s p o i n t , t h e h e n - d a y p e r c e n t e g g p r o d u c t i o n b y t h r e e - w e e k p e r i o d s o v e r a p e r i o d o f t w e n t y w e e k s w a s a n a l y z e d ( T a b l e 1 . 1 0 ) . T h e a n a l y s i s i n d i c a t e d t h a t t h e m e a n e g g p r o d u c t i o n o f t h e f e e d e r - f e d g r o u p s w a s s l i g h t l y h i g h e r b u t n o t s i g n i f i c a n t l y s o ( P > 0 . 0 5 ) , t h a n o f t h e f l o o r - f e d g r o u p s d u r i n g 3 1 t o 3 6 w e e k p e r i o d . A s s h o w n i n T a b l e 1 . 1 1 , t h e f l o o r - f e d g r o u p s h a d h i g h e r c u m u l a t i v e e g g p r o d u c t i o n o n a h e n - h o u s e d b a s i s t h a n t h o s e f r o m t h e f e e d e r - f e d g r o u p s a t u p t o 3 0 w e e k s o f a g e . T h e r e a f t e r , t h e f e e d e r - f e d g r o u p s c o n s i s t e n t l y h a d h i g h e r c u m u l a t i v e e g g p r o d u c t i o n o n a h e n - h o u s e d b a s i s t h a n t h o s e f r o m t h e f l o o r - f e d g r o u p s . T h i s p a t t e r n o f p r o d u c t i o n w a s a c c o u n t e d f o r b y t w o f a c t o r s : t h e f e e d e r - f e d g r o u p s i n c r e a s e d h e n - d a y p r o d u c t i o n a t a f a s t e r r a t e a f t e r 3 0 w e e k s • o f a g e , a n d t h e f l o o r - f e d g r o u p s h a d h i g h e r m o r t a l i t y . T h e l i g h t e s t g r o u p s l a i d f e w e r e g g s p e r h e n - d a y a n d p e r h e n - h o u s e d t h a n t h e h e a v i e s t g r o u p s u n d e r e a c h f e e d i n g m a n a g e m e n t . T h i s w a s d u e t o b o t h t h e l o w e r r a t e o f l a y a n d h i g h e r m o r t a l i t y o f t h e l i g h t e s t p u l l e t s c o m p a r e d w i t h t h e h e a v i e s t p u l l e t s . -48- Table 1.10. The effect of feeder-fed and floor-fed feeding managements on hen-day percent production by three-week periods over a period of twenty weeks for different weight-groups of broiler breeder pullets. 27-30* 31-33 34-36 37-39 40-42 43-45 46-47** wks. wks. wks. wks. wks. wks. wks. Feeder-fed Heaviest 10. .4 62. .1 74. ,1 67. .4 65. ,7 60. .3 62. 8 Upper medium 12. .4 66. .7 73. ,5 64. .0 66. .3 63. .2 68. .1 Lower medium 7. .7 56. .5 76. .0 67. .5 63. .5 64. .7 59. .5 Lightest 7. .0 53. .6 75. .3 69. .9 67. .4 64. .5 61. .8 Mean 9. .4 59. .7 74. .7 67. .2 65. .7 63. .2 63. .1 Floor-fed Heaviest 12.2 Upper medium 12.7 Lower medium 10.5 Lightest 8.8 Mean 11.1 61.1 73.9 72.6 56.6 68.3 64.1 55.2 70.3 71.1 57.1 68.0 67.4 57.5 70.1 68.8 70.9 70.1 63.5 63.5 64.7 55.7 66.7 67.9 58.9 71.6 71.6 60.6 68.2 68.6 59.7 * this period included four weeks, this period included two weeks. -49 Table 1.11 The effect of feeder-fed and floor-fed feeding management on cumulative percentage of egg production calculated on a hen-housed basis to various ages for different weight-groups of broiler breeder pullets. To 30 To 33 To 36 To 39 To 42 To 45 To 47 wks. wks. wks. wks. wks. wks. wks. Feeder-fed Heaviest 10.4 Upper medium 12.1 Lower medium 7.7 Lightest 6.7 Mean 9.2 36.2 48.9 53.5 38.4 49.2 52.2 31.8 46.0 51.1 29.1 43.2 49.0 33.9 46.8 51.5 55.9 56.7 57. 5 54.5 55.7 55. 8 53.3 54.7 54. 8 52.0 53.5 54. 0 53.9 55.2 55.5 Floor-fed Heaviest 12. 0 35.7 47. 8 53. 3 56.3 58.1 58.4 Upper medium 12. 5 33.8 44. 3 48. 2 50.4 51.8 51.7 Lower medium 10. 2 31.3 41. 9 47. 5 50.1 51.7 51.7 Lightest 8. 5 30.3 40. 0 44. 6 48.1 50.3 50.6 Mean 10. 8 32.8 43. 5 48. 4 51.2 53.0 53.1 - 50 - 1.3.3.3 Egg weight Egg weights and the a n a l y s i s of v a r i a n c e o f the e f f e c t of f e e d i n g management on egg weight are shown i n Table 1.12 and Table 1.13 r e s p e c t i v e l y . There was a s i g n i f i c a n t e f f e c t due to the f e e d i n g managements on egg weight. The b i r d s of the f l o o r - f e d groups c o n s i s t e n t l y l a i d h e a v i e r eggs than d i d those of the f e e d e r - f e d groups. The d i f f e r e n c e i n egg weight was s t a t i s t i c a l l y s i g n i f i c a n t (P < 0.05) a t 38 and 47 weeks of ages. The eggs l a i d by p u l l e t s i n the d i f f e r e n t weight-groups were not s i g n i f i c a n t l y d i f f e r e n t . The d i s t r i b u t i o n of egg weights of the h e a v i e s t , upper medium, lower medium and l i g h t e s t groups of p u l l e t s from feeder and f l o o r f e e d i n g managements a t 34, 38 and 47 weeks of ages were shown i n F i g u r e 1.8. The p r o d u c t i o n o f l a r g e r eggs i n c r e a s e d as the age of the p u l l e t s i n c r e a s e d . The f l o o r - f e d groups l a i d l a r g e r p r o p o r t i o n of eggs over 65 g than those o f the f e e d e r - f e d groups. Although the f l o o r - f e d groups had l e s s abdominal f a t a t the onset of l a y (as shown i n Table 1.6) and c o n s i s t e n t l y l a i d h e a v i e r eggs, i t should not be concluded t h a t the f l o o r - f e d groups had a b e t t e r feed e f f i c i e n c y f o r egg p r o d u c t i o n . The hen-day egg p r o d u c t i o n was not s u p e r i o r and the cumulative number of eggs per hen-housed per day was c o n s i s t e n t l y lower i n the f l o o r - f e d groups than i n the f e e d e r - fed groups. These two f a c t o r s were probably accounted f o r the h e a v i e r eggs l a i d by the f l o o r - f e d groups. -51- Table 1.12 The effect of feeder-fed and floor-fed feeding managements on mean egg weights in grams +s.d. at several ages among different weight-groups of broiler breeder pullets. Feeder-fed F i r s t 10 Eggs at the Onset 34 38 47 of Lay wks. wks. wks. Heaviest Upper medium Lower medium Lightest 55.1+10.3 52.2+6.5 49.7+5.6 52.3+10.9 64.3+4.0 64.7+5.4 65.5+7.5 63.7+7.4 66.5+7.1 66.6+4.4 65.9+5.2 64.9+5.3 68.4+5.0 69.9+4.2 68.8+4.9 69.6+7.7 Mean 52.3+8.4 64.6+6.4 65.9+4.9 69.2+5.6 Floor-fed Heaviest Upper medium Lower medium Lightest 55.0+10.8 51.3+5.8 51.7+5.1 55.3+12.5 65.1+5.3 65.8+6.7 64.1+3.3 66.2+8.7 67.5+7.1 66.6+8.8 67.5+6.3 67.5+5.0 71.4+6.0 71.8+7.7 69.9+4.5 71.3+4.2 Mean 53.3+9.0 65.3+6.4 67.3+6.8 71.0+6.0 Table 1.13 The analysis of variance of the effect of feeder-fed and floor-fed feeding managements on mean egg weight at 34, 38 and 47 weeks of ages among different weight-groups of broiler breeder pullets. Source of Variation Feeder-fed vs. Floor-fed (F) Weight-groups (G) F X G Error 34-weeks d.f. m.s. 38-weeks d. f. m.s. 47-weeks d.f. m.s. 3 7.4 3 75.8 514 40.6 1 230.2* 3 10.7 3 23.9 420 34.8 1 291.7* 3 45.3 3 18.4 364 33.4 * Significant (P < 0.05) - 5 3 - FEEDER—FED sof 3*t-weeke. 40 so so FLOOR—FEO 3*f-weeks iof 38-weeks 40»- e • e 0. f 38-weeks 50! f 47-weeks S0J-4O0 4SJ-9O0 SMO 60.1-610 C701 3CJ-60H 4&>^00 Egg weight gm. Figure 1.8 The distribution of egg weights of the heaviest ( ) , upper medium ( ), lower medium (. ), a n d lightest (• ~) groups of pullets from feeder-fed and floor-fed feeding managements at 34, 38 and 47 weeks of ages. - 54 - 1.3.4 M o r t a l i t y T wenty-four (4.7%) c h i c k s from the f e e d e r - f e d groups and o n l y two (0.4%) from t h e o t h e r groups d i e d a t 12 days; o f age, oh t h e day when a l l c h i c k s were weighed, v a c c i n a t e d and wing-banded. T h i s s u g g e s t e d t h a t b i r d s s u b j e c t e d t o a g r e a t e r a c t i v i t y p r o b a b l y had d e v e l o p e d h i g h e r r e s i s t a n c e t o s t r e s s t h a n those t h a t were l e s s a c t i v e . The t o t a l m o r t a l i t y of the f e e d e r - f e d b i r d s was 6.85% and of t h e f l o o r - f e d b i r d s was 1.76% a t t h e end o f the b r o o d i n g p e r i o d . The c u m u l a t i v e m o r t a l i t y and t h e m o r t a l i t y d u r i n g b r o o d i n g , r e a r i n g , h o l d i n g and l a y i n g p e r i o d s o f the f e e d e r - f e d and f l o o r - f e d p u l l e t s a r e shown i n T a b l e 1.14. The f l o o r - f e d b i r d s c o n s i s t e n t l y had a h i g h e r m o r t a l i t y t h a n t h e f e e d e r - f e d b i r d s t h r o u g h t h e r e a r i n g t o l a y i n g p e r i o d . The major cause of d e a t h o f t h e f l o o r - f e d b i r d s was g i z z a r d i m p a c t i o n o r i n t e s t i n a l b l o c k a g e w i t h l i t t e r m a t e r i a l . A t about 30 weeks o f age numerous p u l l e t s were d i s c o v e r e d t o have v i s u a l problems. One o r b o t h o f t h e i r eyes were g r e y and some o f them were a p p a r e n t l y e n l a r g e d . The problem was i d e n t i f i e d t o be b l u i s h d i s c o l o r a t i o n o f t h e l e n s . I n t r a c i n g back t h e h i s t o r y o f m o r t a l i t y , t h e r e was found 1 b i r d k i l l e d w i t h s e r i o u s tremor o f t h e head and neck a t 5 weeks o f age, and seven b i r d s (0.6% o f a l l c h i c k s ) - 5 5 - T a b l e 1 . 1 4 T h e c u m u l a t i v e m o r t a l i t y a n d t h e m o r t a l i t y d u r i n g t h e b r o o d i n g , r e a r i n g , h o l d i n g a n d l a y i n g p e r i o d s o f t h e f e e d e r - f e d a n d f l o o r - f e d p u l l e t s . T o t h e E n d o f E a c h P e r i o d % C u m u l a t i v e M o r t a l i t y F e e d e r - F e d F l o o r - F e d B r o o d i n g R e a r i n g H o l d i n g L a y i n g 6 . 8 5 1 1 . 9 4 1 5 . 5 0 1 7 . 4 0 1 . 7 6 2 0 . 5 5 2 7 . 7 9 3 3 . 2 3 % M o r t a l i t y i n E a c h P e r i o d B r o o d i n g 6 . 8 5 1 . 7 6 R e a r i n g 5 . 4 5 1 9 . 1 3 H o l d i n g : h e a v i e s t 3 . 9 6 1 . 0 5 u p p e r m e d i u m 2 . 7 3 4 . 1 2 l o w e r m e d i u m 1 . 7 9 2 . 1 1 l i g h t e s t 6 . 3 1 1 3 . 1 3 L a y i n g : h e a v i e s t 0 . 0 0 4 . 5 5 u p p e r m e d i u m 2 . 9 4 6 . 8 2 l o w e r m e d i u m 1 . 9 0 ' 1 1 . 3 6 l i g h t e s t 5 . 0 5 1 3 . 5 8 - 56 - s i t t i n g on t h e i r backs w i t h a t a x i a d u r i n g the r e a r i n g p e r i o d . Serum samples t h e r e f o r e were c o l l e c t e d from p u l l e t s w i t h opaque l e n s e s , and were examined i n t h e A b b o t s f o r d V e t e r i n a r y R e s e a r c h S t a t i o n . F i v e out o f e i g h t samples o f serum were r e p o r t e d t o c o n t a i n A v i a n e n c e p h a l o m y e l i t i s a n t i b o d i e s . D u r i n g t h e l a y i n g p e r i o d the l i g h t e s t groups had h i g h e r m o r t a l i t y t h a n t h e h e a v i e s t groups. Most of t h e b i r d s t h a t d i e d had f a t t y l i v e r s . - 5 7 - 1 . 4 S U M M A R Y T w o p o p u l a t i o n s o f b r o i l e r b r e e d e r c h i c k s f r o m H e i s d o r f a n d N e l s o n s t o c k w i t h 5 1 1 c h i c k s e a c h w e r e s u b j e c t e d t o t w o f e e d i n g m a n a g e m e n t r e g i m e s . O n e p o p u l a t i o n w a s f e d o n c e d a i l y u s i n g c o n v e n t i o n a l f e e d e r . T h e o t h e r p o p u l a t i o n w a s f e d t w i c e d a i l y t h e s a m e a m o u n t o f f e e d a s t h e f e e d e r - f e d p o p u l a t i o n , b u t g i v e n f e e d b r o a d c a s t o n t h e l i t t e r . P h y s i c a l a c t i v i t y , a n d t h e e x t e n s i o n o f f e e d i n g t i m e o f t h e f l o o r - f e d p o p u l a t i o n w a s t h e r e f o r e g r e a t e r t h a n w a s t h e c a s e w i t h t h e f e e d e r - f e d p o p u l a t i o n . B o t h p o p u l a t i o n s w e r e g i v e n f e e d a n d w a t e r a d l i b i t u m f r o m 1 t o 4 w e e k s o f a g e . T h e r e a f t e r t h e b i r d s i n b o t h t r e a t m e n t s w e r e g i v e n t h e s a m e w e i g h t o f f e e d e a c h d a y . T h e a m o u n t o f f e e d i n t a k e w a s a d j u s t e d d a i l y t o r e s t r i c t g r o w t h t o a t a r g e t b o d y w e i g h t o f 1 . 6 5 k g a t 1 8 w e e k s o f a g e . W a t e r w a s g i v e n a d l i b i t u m t h r o u g h o u t t h e w h o l e e x p e r i m e n t e x c e p t d u r i n g t h e p e r i o d f r o m 1 5 t o 1 8 w e e k s , w h e n w a t e r w a s r e s t r i c t e d f o r 1 4 . 5 h o u r s d a i l y ( f r o m 5 : 3 0 p . m . t o 8 : 0 0 a . m . ) . A t 1 8 w e e k s o f a g e , e a c h p o p u l a t i o n w a s d i v i d e d i n t o f o u r g r o u p s , h e a v i e s t , u p p e r m e d i u m , l o w e r m e d i u m a n d l i g h t e s t , b a s e d o n b o d y w e i g h t . B o d y w e i g h t , a b d o m i n a l f a t w e i g h t a t s e x u a l m a t u r i t y , e g g p r o d u c t i o n a n d m o r t a l i t y o f e a c h g r o u p o f b i r d s f r o m t h e t w o p o p u l a t i o n s u n d e r d i f f e r e n t f e e d i n g m a n a g e m e n t s w e r e s t u d i e d . - 5 8 - T h e f e e d e r - f e d b i r d s w e r e h e a v i e r t h a n t h e f l o o r - f e d b i r d s u n d e r a d l i b i t u m f e e d i n g f r o m 2 t o 4 w e e k s o f a g e . T h e r e a f t e r , t h e f l o o r - f e d b i r d s w e r e h e a v i e r t h a n t h e f e e d e r - f e d b i r d s w h e n t h e y w e r e u n d e r q u a n t i t a t i v e f e e d r e s t r i c t i o n . A f t e r t h e s e g r e g a t i o n o f f o u r g r o u p s b a s e d o n b o d y w e i g h t , t h e l i g h t e r g r o u p s g r e w f a s t e r t h a n t h e h e a v i e r g r o u p s . B y 4 7 w e e k s o f a g e , b o d y w e i g h t w e r e n o t s t a t i s t i c a l l y d i f f e r e n t ( P > 0 . 0 5 ) a m o n g t h e f o u r g r o u p s . T h e a m o u n t a n d p r o p o r t i o n (% o f b o d y w e i g h t ) o f t h e a b d o m i n a l f a t p a d i n t h e f e e d e r - f e d p u l l e t s a t 2 6 - 2 7 w e e k s o f a g e w e r e h i g h e r t h a n i n t h e f l o o r - f e d p u l l e t s . A b d o m i n a l f a t i n c r e a s e d w i t h i n c r e a s e d b o d y w e i g h t i n t h o s e g r o u p s o f p u l l e t s w h i c h g a i n e d u p t o 1 2 0 0 g i n b o d y w e i g h t a f t e r t h e s e g r e g a t i o n a t 1 8 w e e k s o f a g e , b u t d e c r e a s e d i n p r o p o r t i o n t o b o d y w e i g h t i n t h o s e g r o u p s o f p u l l e t s w h i c h g a i n e d i n e x c e s s o f 1 2 0 0 g . T h e l i g h t e s t g r o u p o f p u l l e t s h a d g r e a t e r b o d y w e i g h t g a i n s t h a n a n y o f t h e o t h e r g r o u p s , b u t t h e s e l i g h t e r p u l l e t s c o n t a i n e d t h e l e a s t a b d o m i n a l f a t . T h e d a t a s u g g e s t e d t h a t t h e m o r e v i t a l p a r t s o f t h e b o d y , s u c h a s t h e m u s c l e a n d s k e l e t a l t i s s u e s , d e v e l o p e d a t a f a s t e r r a t e t h a n t h e a b d o m i n a l f a t p a d i n t h e l i g h t e s t g r o u p o f p u l l e t s . F l o o r f e e d i n g d i d n o t a f f e c t t h e a g e a t w h i c h t h e p u l l e t r e a c h e d s e x u a l m a t u r i t y . E g g p r o d u c t i o n , c a l c u l a t e d o n h e n - d a y b a s i s , w a s s i m i l a r i n a l l g r o u p s . W h e n e g g p r o d u c t i o n w a s - 59 - C a l c u l a t e d o n a h e n - h o u s e d b a s i s , h o w e v e r , t h e f e e d e r - f e d p u l l e t s s h o w e d a h i g h e r r a t e o f e g g p r o d u c t i o n t h a n d i d t h e f l o o r - f e d p u l l e t s . F u r t h e r m o r e , t h e h e a v i e r p u l l e t s w i t h i n . b o t h f e e d i n g s y s t e m s h a d a h i g h e r r a t e p r o d u c t i o n t h a n d i d t h e l i g h t e r b i r d s . E g g s l a i d b y t h e f l o o r - f e d p u l l e t s w e r e s i g n i f i c a n t l y ( P < 0 . 0 5 ) h e a v i e r t h a n t h o s e l a i d b y t h e f e e d e r - f e d p u l l e t s . A v e r a g e e g g w e i g h t s w e r e 6 7 . 3 g a n d 7 1 . 0 g f o r t h e f l o o r - f e d p u l l e t s a n d 6 5 . 9 g a n d 6 9 . 2 g f o r t h e f e e d e r - f e d p u l l e t s a t 3 8 a n d 4 7 w e e k s o f a g e s r e s p e c t i v e l y . - 60 - CHAPTER I I . THE EFFECT OF PROLONGED FEED RESTRICTION DURING THE GROWING PERIOD ON SUBSEQUENT SEMEN PRODUCTION. - 61 - 2 . 0 INTRODUCTION The r e p r o d u c t i v e p h y s i o l o g y o f t h e male f o w l i s i n f l u e n c e d by d i f f e r e n t p o s t n a t a l e n v i r o n m e n t a l f a c t o r s , such as n u t r i t i o n , p h o t o p e r i o d i s m , t e m p e r a t u r e , d i s e a s e , drugs and b e h a v i o r . Of t h e s e f a c t o r s , n u t r i t i o n i s s t i l l o f t h e most co n c e r n t o t h e p r a c t i s i n g farmer r a i s i n g d o m e s t i c male f o w l s . T h i s i s p a r t i c u l a r l y i m p o r t a n t f o r heavy-type b i r d s , because p r o p e r body s i z e , i s a s s o c i a t e d w i t h low m o r t a l i t y , h i g h f e r t i l i t y and s e x u a l a c t i v i t y . A c c o r d i n g t o a s u r v e y o f f e r t i l i t y and h a t c h a b i l i t y o f 63 f l o c k s o f b r o i l e r - b r e e d e r s i n t h e lower F r a s e r V a l l e y (Chu and March, 1976) h a t c h a b i l i t y r e a c h e d a peak a t some time between 31 t o 40 weeks o f age, a f t e r w h i c h i t d e c l i n e d . D u r i n g t h e d e c l i n e p e r i o d f e r t i l i t y dropped more r a p i d l y t h a n h a t c h a b i l i t y . I t was o b v i o u s t h a t t h e f e r t i l i z i n g c a p a c i t y of t h e aged b r e e d e r f l o c k s showed a d e c l i n e w h i c h might be due t o poor semen q u a l i t y o f males. The p r e s e n t experiment was u n d e r t a k e n t o determine i f t h e r e i s any a s s o c i a t i o n i n aged b r o i l e r b r e e d e r males, o f semen volume and sperm c o n c e n t r a t i o n w i t h e a r l y d i e t a r y f e e d r e s t r i c t i o n . 2.1 2.1.1 LITERATURE REVIEW O v e r f e e d i n g and Male Fowl R e p r o d u c t i v e Performance O b e s i t y i n d u c e d by o v e r f e e d i n g as i t a d v e r s e l y a f f e c t s male r e p r o d u c t i v e performance was d i s c u s s e d by I n g l e (1950). He o b s e r v e d t h a t a t r o p h y o f t h e t e s t e s was found i n obese male a n i m a l s , when the o b e s i t y was i n d u c e d by o v e r f e e d i n g Kennedy (1926) i n a r e v i e w n o t e d t h a t o b e s i t y i n t h e male may be a s s o c i a t e d w i t h d e c r e a s e d f e r t i l i t y t h r o u g h o l i g o s p e r m i a P o u l t r y b r e e d e r s a l s o have l o n g been aware t h a t o b e s i t y i s a s s o c i a t e d w i t h reduced f e r t i l i t y and l i b i d o o f the male f o w l s . N i r e t a l . (1975) f o r c e - f e d 20 week o l d White Leghorn c o c k e r e l s . By t h e end o f 2 5 weeks o f age, t h e r e was an i n c r e a s e i n t h e mean body w e i g h t o f 827 gm i n the c a s e o f t h e f o r c e - f e d b i r d s , and o f o n l y 77 gm i n t h e c o n t r o l b i r d s . The average abdominal a d i p o s e t i s s u e weighed 96.7 gm i n the f o r c e - f e d b i r d s and 36 gm i n t h e c o n t r o l b i r d s . O b e s i t y was f o l l o w e d by t e s t i c u l a r r e g r e s s i o n , an e i g h t - f o l d r e d u c t i o n i n t h e number o f spermatozoa i n t h e v a s a d e f e r e n t i a and a d e p r e s s i o n i n sperm m o t i l i t y . The b l o o d plasma t e s t o s t e r o n e was reduced and l u t e i n i s i n g hormone showed an i n c r e a s e . Comb s u r f a c e and b l o o d packed c e l l volume b o t h i n c r e a s e d . A d i s t u r b a n c e o f body t e m p e r a t u r e r e g u l a t i o n was shown w i t h an i n c r e a s e i n r e c t a l t e mperature bu t a d e c r e a s e i n s k i n and comb t e m p e r a t u r e s . - 6 3 - I t h a s b e e n r e p o r t e d t h a t q u a i l , i n w h i c h o b e s i t y w a s i n d u c e d b y o v e r f e e d i n g , s h o w e d a 3 0 p e r c e n t r e d u c t i o n i n t e s t i c u l a r w e i g h t a n d a 5 0 p e r c e n t r e d u c t i o n i n t h e s p e r m a t o z o a c o n c e n t r a t i o n i n t h e t e s t i s a n d d u c t i d e f e r e n t e s . P l a s m a t e s t o s t e r o n e a n d s e x u a l m a t u r i t y a l s o d e c r e a s e d w i t h o b e s i t y ( N i r , 1 9 7 7 ) . L a n e a n d D i c k i e ( 1 9 5 4 ) a n d L i d e l l a n d H e l l m e n ( 1 9 6 6 ) h o w e v e r i n d i c a t e d t h a t t h e e n d o c r i n e f u n c t i o n o f m i c e w i t h h e r e d i t a r y o b e s i t y w a s i m p a i r e d . F o o d r e s t r i c t i o n d i d n o t c a u s e i m p r o v e m e n t o f t h e h o r m o n a l p r o d u c t i o n o f t h e t e s t e s , i n d i c a t i n g t h a t o v e r e a t i n g p e r s e w a s n o t t h e c a u s e o f t h e i m p a i r m e n t . L i d e l l a n d H e l l m a n ( 1 9 6 6 ) s t a t e d t h a t , " i t s h o u l d f u r t h e r m o r e b e p o i n t e d o u t t h a t o u r d a t a i n m i c e d o n o t e x c l u d e t h e p o s s i b i l i t y o f a c o m m o n d e n o m i n a t o r f o r t h e o b e s i t y a n d t h e r e d u c e d t e s t i c u l a r a c t i v i t y n o r t h a t t h e l a t t e r f u n c t i o n i n s o m e c a s e s m i g h t b e a p r i m a r y c a u s e o f o b e s i t y " . T h e c o m m o n d e n o m i n a t o r m a y b e l o c a t e d i n t h e h y p o t h a l a m u s , w h i c h p l a y s a c e n t r a l r o l e i n g o n a d a l d e v e l o p m e n t : t h e r e l e a s e o f g o n a d o t r o p h i c h o r m o n e s , t e r m o r e g u l a t i o n a n d f o o d a n d w a t e r i n t a k e ( P a n d s e p p , 1 9 7 5 ) . T h e m e c h a n i s m b y w h i c h o b e s i t y a n d f e r t i l i t y m a y b e r e g u l a t e d b y t h e h y p o t h a l a m u s a r e s t i l l , h o w e v e r , p o o r l y u n d e r s t o o d . - 64 - 2.1.2 I n a n i t i o n and Male R e p r o d u c t i v e 1 Performance The g e n e r a t i v e organs o f male domest i c a n i m a l s a r e f a i r l y r e s i s t a n t t o c a l o r i c d e f i c i e n c y . R e s t r i c t e d f e e d i n g o f boars and b u l l s up t o 4 0 per c e n t o f ad l i b i t u m causes a d i s t i n c t r e t a r d a t i o n i n growth, b u t t h e f e r t i l i t y and t o t a l semen volume produced by t h e s e a n i m a l s a r e not s i g n i f i c a n t l y a f f e c t e d (Nalbandov, 1976). S i m i l a r l y , K i n g (1972) s t u d i e d t h e e n e r g e t i c s o f r e p r o d u c t i o n i n w i l d b i r d s and c o n c l u d e d t h a t a n e g l i g i b l e f r a c t i o n o f t h e males energy budget used f o r s e a s o n a l growth of t h e t e s t e s . T e s t i c u l a r f u n c t i o n i s h i g h l y r e s i s t a n t t o c a l o r i c s h o r t a g e . Sperm p r o d u c t i o n and v i t a l i t y a r e not i m p a i r e d u n t i l t h e l o s s o f body w e i g h t approaches 30 p e r c e n t o f normal w e i g h t . Boone (1969) r e p o r t e d t h a t complete s t a r v a t i o n o f a d u l t f o w l f o r 4 t o 6 days caused a s i g n i f i c a n t d e c r e a s e i n semen volume. However, semen volume r e t u r n e d t o normal w i t h i n 8 t o 16 days a f t e r r e t u r n i n g b i r d s t o f e e d and w a t e r . I n f a c t , a moderate energy and p r o t e i n r e s t r i c t i o n o f growing male d o m e s t i c f o w l s , p a r t i c u l a r l y t h e heavy-type b i r d s , has no a d v e r s e e f f e c t on subsequent r e p r o d u c t i v e performance, even though s e x u a l m a t u r i t y may be d e l a y e d . T e s t e s w e i g h t , semen c o n c e n t r a t i o n and f e r t i l i t y have been r e p o r t e d t o i n c r e a s e more i n m o d e r a t e l y r e s t r i c t e d - b i r d s t h a n i n f u l l - f e d c o n t r o l s ( A r s c o t l and P a r k e r , 1963; Jones e t a l . , - 65 - 1967; W i l s o n e t ' a l . , 1965, 1971; V o i t l e . e t a l . , 1971, 1972). However, t o o s e v e r e and p r o l o n g e d i n a n i t i o n may s t o p g o n a d a l f u n c t i o n e n t i r e l y , and may permanently i m p a i r male r e p r o d u c t i v e performance. P a r k e r and A r s c o t l (196 3) r e p o r t e d t h a t p r o l o n g e d energy r e s t r i c t i o n t o 40 per c e n t o f c o n t r o l a d u l t White Leghorn male f o r 13 weeks d e c r e a s e d subsequent volume and f e r t i l i z i n g c a p a c i t y o f semen, and t e s t i c u l a r and body w e i g h t . W i l son e t a l . (1972) s u b s t a n t i a t e d t h a t b r o i l e r b r e e d e r males f e d a low p r o t e i n (9.3%) d i e t from 4 t o 18 weeks of age, showed a d e c r e a s e i n f e r t i l i t y b u t t h a t t h e h a t c h a b i l i t y o f f e r t i l e eggs was not a f f e c t e d . - 66 - 2.2 MATERIAL AND METHODS 2.2.1 Source o f B i r d s A group o f 27 54-week o l d b r o i l e r - t y p e male c h i c k e n s was p l a c e d i n i n d i v i d u a l cages on t h e 30th o f May, 1978. P r e v i o u s l y , a l l c h i c k e n s were s u b j e c t e d t o f e e d r e s t r i c t i o n programs o f d i f f e r e n t l e n g t h s , w h i c h a r e l i s t e d on T a b l e 2.1. Each t r e a t m e n t was t e s t e d w i t h 8 t o 10 b i r d e x c e p t t h e c o n t r o l group w h i c h c o n t a i n e d 12 b i r d s . A l l b i r d s were f e d t h e d i e t l i s t e d on T a b l e 2.2, from day o l d t o 54 weeks. The d i e t was then changed t o a l a y e r d i e t u n t i l the end o f the e x p e r i m e n t . 2.2.2 C o l l e c t i o n o f Semen A c h i c k e n h o l d e r d e v e l o p e d by Burrow and Quinn (1937) was used f o r c o l l e c t i n g semen. The b i r d s had been c o n d i t i o n e d i n cages f o r one week, then t h e y were t r a i n e d on a l t e r n a t i v e days f o r 2 weeks t o g i v e semen. F i v e semen c o l l e c t i o n s were o b t a i n e d d u r i n g t h e age o f 57 t o 58 weeks o f age. Samples were t a k e n i n i n d i v i d u a l t e s t tubes and examined w i t h i n 2 hours a f t e r c o l l e c t i o n . The whole semen volume, i n c l u d i n g the t r a n s p a r e n t f l u i d from t h e s w o l l e n l y m p h f o l d , was measured by m i c r o p i p e t t e s g r a d u a t e d t o 25 m i c r o l i t e r . Spermatozoa c o n c e n t r a t i o n i n t h e whole semen sample was e s t i m a t e d by Table 2.1 Restricted feeding programs during the growing period. Feeding Programs (Age-Dates) Start of Free Access Feeding Restricted Feeding Length of Feed Treatment No. No Feed to Feed to >j hr.daily ad libitum Restriction (wks) 1 (control)lst-2nd 3rd 0 2 lst-3rd 4 th 5th-llth 12th 1 3 lst-3rd 4th 5th-18th 19th 2 4 lst-3rd 4th 5th-33rd 34th 4 5 lst-3rd 4th 5th-54th 55th 7 6 lst-3rd 4th 5th-68th 69th 9 7 lst-3rd 4 th 5th-82nd 83rd 11 8 lst-3rd 4th 5th-96th 97th 13 - 68 - T a b l e 2.2 C o m p o s i t i o n o f d i e t 2.1. I n g r e d i e n t s Ground wheat 31.0 Ground c o r n 31.0 Ground o a t s 2 0.0 Soybean meal 12.8 Dehydrated c e r e a l g r a s s 2.0 I o d i z e d s a l t 0. 5 Limestone 1.2 Calciumphosphate 1.5 M i c r o n u t r i e n t s ** Crude p r o t e i n 15.2% M e t a b o l i z a b l e energy 2861 k c a l / k g * * M i c r o n u t r i e n t s p e r kg o f d i e t manganese s u l f a t e (5 H^O) 150 mg z i n c o x i d e 62 mg c h o l i n e c h l o r i d e 1320 mg r i b o f l a v i n 3 mg' v i t a m i n 13.2 mg v i t a m i n A 4400 I.U. v i t a m i n D 3 440 I.C.U. amprol* 12 5 mg * Amprol ( c o c c i d i o s t a t ) s u p p l i e d c o u r t e s y o f Marck, Sharp and Dohme Canada L t d . - 69 - o p t i c a l d e n s i t y t e c h n i q u e , w h i c h has been f u l l y d e s c r i b e d by McCartney and Brown (1959). Only t h o s e samples w i t h more tha n 0.1 c . c . were s u b j e c t e d t o t h e measurement o f spermatozoa c o n c e n t r a t i o n . A s t a n d a r d c u r v e (Appendix F i g u r e ^ 2 . 1 ) was e s t a b l i s h e d , as d e s c r i b e d by McCartney and Brown (1959), and was used i n t h i s e x p e r i m e n t . 2.2.3 Post-Mortem S t u d i e s A l l b i r d s were k i l l e d by c e r v i c a l d i s l o c a t i o n a t 60 weeks o f age. They were weighed i m m e d i a t e l y a f t e r d e a t h . T e s t e s were e x c i s e d and weighed. 2.3 RESULTS AND DISCUSSION 2.3.1 Treatment E f f e c t Based on t h e number o f b i r d s examined i n t h i s e x p e r i m e n t , f e e d r e s t r i c t i o n o f one t o t h i r t e e n weeks d u r i n g t h e growing p e r i o d appeared t o have no e f f e c t on body w e i g h t a t 60 weeks of age compared w i t h t h e c o n t r o l (Table 2.3). Even though p r o l o n g e d f e e d r e s t r i c t i o n r e t a r d e d body w e i g h t g a i n u n t i l 3 3 weeks o f age, as r e p o r t e d by B a l l a m (1978), t h e s u r v i v i n g b i r d s had f u l l y compensated f o r t h e e a r l i e r s l o w e r growth by 60 weeks o f age. The mean t e s t e s w e i g h t and p e r c e n t t e s t e s w e i g h t p e r body w e i g h t o f each t r e a t m e n t groups 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 t h e c o n t r o l group (Table 2.3), even though t h e r e was a s l i g h t n e g a t i v e c o r r e l a t i o n between the l e n g t h of f e e d r e s t r i c t i o n and t e s t i c u l a r w e i g h t (Table 2.5). The average t e s t i c u l a r w e i g h t and p e r c e n t t e s t i c u l a r w e i g h t per. body w e i g h t o f a l l e x p e r i m e n t a l b i r d s were 36.58 gm and 0.76 per c e n t r e s p e c t i v e l y . Two c o n t r o l b i r d s had t e s t e s w e i g h i n g 8 5.42 gm and 58.96 gm (1.68% and 1.18% o f body a t r e s p e c t i v e l y ) w h i c h were th e two b i g g e s t t e s t e s p a i r s among a l l t h e b i r d s , of w h i c h t e s t e s w e i g h t s were l i s t e d on Appendix T a b l e 2.2. These.two b i r d s appeared h e a l t h y , b u t t h e y a g g r e s s i v e l y r e f u s e d t o g i v e any semen t h r o u g h o u t the e x p e r i m e n t . Table 2.3 Treatments effect on mortality, body weight at 60 weeks of age, testes weight and testes weight per body weight. No. of Length of Feed No. of Birds Died Body0Weight Testes Testes Wt. Treatment Restriction Birds Between at 60-wks. Weight % Bodv wt—'' No. (wks) at 54 wks. 55-60 wks. (kg) (gm) u y 1 (control) 0 6 0 4. 93+0.15 48. 12+8.85 0.97+0. 16 2 1 3 1 4. 85+0.02 55. 63+0.86 1.14+0. 04 3 2 3 0 5. 14+0.36 40. 03+8.99 0.76+0. 14 4 4 6 0 4. 59+0.20 24. 73+2.54 0.55+0. 07 5 7 2 1 4. 55 32. 86 0.72 6 9 4 2 4. 57+0.05 25. 09+13.10 0.56+0. 30 7 11 1 0 4. 43 14. 43 0.33 8 13 2 1 5. 60 38. 89 0.52 Average s 4.82+0.10 36.58+3.77 0.76+0.07 - 7 2 - S e m e n v o l u m e , s p e r m a t o z o a c o n c e n t r a t i o n a n d n u m b e r o f s p e r m a t o z o a p e r e j a c u l a t i o n w e r e n o t f o u n d t o a f f e c t e d b y t h e e x p e r i m e n t a l t r e a t m e n t s ( T a b l e 2 . 4 , T a b l e 2 . 5 ) . T h e a v e r a g e s e m e n v o l u m e i n c . c . + S E p e r e j a c u l a t i o n a m o n g a l l b i r d s w a s 0 . 8 3 + 0 . 1 5 a n d m i l l i o n s o f s p e r m a t o z o a p e r c . c . o f s e m e n w a s 0 . 6 1 0 + 0 . 1 4 0 . S i e g e l e t a l . ( 1 9 6 9 ) r e p o r t e d t h a t W h i t e R o c k c o c k e r e l s g i v e n 6 t o 1 4 h o u r s o f l i g h t p e r d a y p r o d u c e d 0 . 3 4 a n d 0 . 3 2 c . c . s e m e n v o l u m e , a n d 1 . 0 0 a n d 1 . 5 7 m i l l i o n s s p e r m a t o z o a p e r c . c . o f s e m e n r e s p e c t i v e l y . T h e s e m e n c h a r a c t e r i s t i c s , f r o m t h e i r r e p o r t , a p p e a r e d l o w e r i n v o l u m e a n d h i g h e r i n s p e r m a t o z o a c o n c e n t r a t i o n t h a n i n t h e p r e s e n t e x p e r i m e n t . T h e d i s c r e p a n c y m i g h t b e b e c a u s e m o r e t r a n s p a r e n t f l u i d ( p r o d u c e d b y t h e s w o l l e n l y m p h f o l d ) w a s c o l l e c t e d i n o u r e x p e r i m e n t . H o w e v e r , t h e t o t a l n u m b e r o f s p e r m a t o z o a p e r e j a c u l a t i o n w a s s i m i l a r i n c o c k s f r o m t h i s e x p e r i m e n t a n d c o c k s r e c e i v i n g 1 4 h o u r s o f l i g h t i n t h e e x p e r i m e n t o f S i e g e l e t a l . M o r t a l i t y i n t h e c o n t r o l b i r d s w a s 3 8 % a n d i n t h e r e s t r i c t e d b i r d s w a s 5 1 % b y 3 8 w e e k s o f a g e . T o t a l m o r t a l i t y i n c r e a s e d t o 5 1 % a n d 6 6 % r e s p e c t i v e l y b y 5 4 w e e k s . N o c o n t r o l b i r d s d i e d s u b s e q u e n t l y ; b u t m e a n w h i l e , f i v e b i r d s d i e d f r o m t h e t r e a t m e n t g r o u p s ( T a b l e 2 . 3 ) . T h e e f f e c t o f e a r l y f e e d r e s t r i c t i o n m a y a l s o e x t e n d t o a f f e c t t h e v i a b i l i t y o f t h o s e s u r v i v i n g c o c k s e v e n u p t o o n e y e a r o f a g e . T a b l e 2.4 Le n g t h o f f e e d r e s t r i c t i o n of b r o i l e r b r e eder males d u r i n g t h e g rowing p e r i o d on subsequent volume of semen per e j a c u l a t i o n , spermatozoa c o n c e n t r a t i o n and m i l l i o n s o f spermatozoa p e r e j a c u l a t i o n . Treatment No. Length o f Feed R e s t r i c t i o n (wks.) Volume (c.c.) o f Spermatozoa Per E j a c u l a t i o n Spermatozoa C o n c e n t r a t i o n M i l l i o n s / c . m m . M i l l i o n s o f Spermatozoa Per E j a c u l a t i o n 1 ( c o n t r o l ] 0 1. 14+0. 52 ( 4 ) * 1.067+0. 480 710+228 2 1 0. 82+0. 10 (2) 0.353+0. 213 268+139 3 2 1. 34+0. 57 (3) 0.430+0. 150 413+179 4 4 0. 55+0. 18 (6) 0.413+0. 130 160+050 5 7 0. 31 (1) 0.097 030 6 9 0. 60+0. 03 (2) 0.593+0. 510 341+288 7 11 (0) 8 13 1. 07 (1) 1. 658 1774 Average: .0. 83+0. 15 (19) 0.610+0. 140 424+107 number o f b i r d s . Table 2.5 Correlation coefficient of body weight at 60 weeks, testes weight, percentage of testes weight over body, semen volume, semen concentration and number of spermatozoa per ejaculation. Kg of Body+ Weight at 60 weeks Gm.of Testes Weight % Testes Wt. Body Wt.+ c.c. of Semen Volume Per Ejaculation Millions of sperm per c.c. of Semen Millions of sperm per Ejaculation Weeks of feed restriction 0.03 n. s. -0.22 n. s. -0.24 n. s. -0.18 n. s. 0.08 n.s. 0.22 n.s. Kg. of body weight+ at 60 weeks 0.49 * 0.22 n.s. 0.62 0.12 n.s. 0.60 * Gm. of testes weight 0.96 * 0.50 * -0.12 n.s. 0.30 n.s. Testes Weight * Body Weight + 0.35 n.s. -0.17 n.s. 0.14 n.s. c.c. of semen volume per ejaculation -0.21 n.s. 0.50 * Millions of sperm per c.c. of semen 0.55 n. s. + not significant * significant (P < .05) not including testes weight - 75 - 2.3.2 Body Weight T e s t e s Weight and Semen C h a r a c t e r i s t i c s R e g a r d l e s s of t h e t r e a t m e n t e f f e c t s , body w e i g h t ( e x c l u d i n g t e s t e s w e i g h t ) was p o s i t i v e l y c o r r e l a t e d w i t h the t e s t e s w e i g h t (P < 0.05), semen volume (P < 0.05) and number o f spermatozoa per e j a c u l a t i o n (P < 0.05) (Table 2.5). The o b s e r v a t i o n r e p o r t e d by Burger e t a l . (19 62) and Payne e t a l . (19 60) i s t h e r e b y s u b s t a n t i a t e d . I t i s suggested t h a t a b i g g e r b i r d has a l a r g e r g e n i t a l organ w h i c h i s c a p a b l e of p r o d u c i n g a l a r g e r volume of semen and a g r e a t e r number of spermatozoa, when t h e y a r e under v o l u n t a r y f e e d i n t a k e . On the o t h e r hand, b i r d s i n w h i c h o b e s i t y i s i n d u c e d by f o r c e - f e e d i n g may show t e s t i c u l a r r e g r e s s i o n . N i r et_ a l . (1975) f o r c e - f e d White Leghorn c o c k e r e l s t w i c e as much f e e d as the ad l i b i t u m i n t a k e f o r 5 weeks. T e s t i s w e i g h t was 17.5% l e s s , even though t h e body w e i g h t g a i n was more th a n t e n - f o l d o f t h e c o n t r o l group. An even more pronounced e f f e c t on t e s t i c u l a r r e g r e s s i o n was found i n f o r c e - f e d male Japanese q u a i l ( N i r , 1971). B r o b i c k (1946) showed t h a t t h e o b e s i t y o b s e r v e d i n r a t s w i t h h y p o t h a l a m i c l e s i o n was consequent t o o v e r f e e d i n g . I n t h e case o f f o w l , r e n d e r e d obese by f o r c e d - f e e d i n g , the h y p o t h a l a m a l - h y p o p h y s e a l complex might be damaged and t h e normal s e c r e t i o n o f g o n a d o t r o p h i c hormones d i s t u r b e d . The t e s t e s t h e r e f o r e r e g r e s s e d . F u r t h e r m o r e , f o r c e d - f e e d i n g has a l s o been found t o be a b l e t o a l t e r s e v e r a l p h y s i o l o g i c a l phenomena o f t h e male domest i c f o w l . N i r and Shapina (1974) - 76 - showed t h a t f o r c e - f e e d i n g o f young c h i c k s f o r 15 days i n c r e a s e d k i d n e y a r g i n a s e a c t i v i t y and l i v e r exanthime dehydrogenase a c t i v i t y , and a l s o i n c r e a s e d o v e r a l l s e c r e t i o n o f d i g e s t i v e .enzymes. N i r e t ' a l . (.1975) r e p o r t e d t h a t i n c r e a s e o f t h e r e c t a l t e m p e r a t u r e and d e c r e a s e of t h e s k i n and comb t e m p e r a t u r e , a r e d u c t i o n i n t h e b l o o d packed c e l l volume and a d e c r e a s e o f t e s t o s t e r o n e and an i n c r e a s e o f l u t e i n i s i n g hormone c o n c e n t r a t i o n s i n t h e b l o o d plasma were obser v e d i n a d u l t male f o w l s a f t e r 5 weeks o f r e c e i v i n g f e e d two f o l d more than t h e ad l i b i t u m i n t a k e . R e c e n t l y , N i r (1977) s t u d i e d male Japanese q u a i l . a n d r e p o r t e d t h a t o b e s i t y i n d u c e d by f o r c e d - f e e d i n g was accompanied by i n c r e a s e s i n c o l o n i c t e m p e r a t u r e (about .3°C), and p e r i p h e r a l l e g t e m p e r a t u r e (about 3°C) and by a d e c r e a s e o f t h e m i d - s c a p u l a r s k i n t e m p e r a t u r e (about .6°C). The t e s t i s w e i g h t o f t h e s u r v i v i n g cocks i n the p r e s e n t e x p e r i m e n t was p o s i t i v e l y c o r r e l a t e d (P < .05) w i t h body w e i g h t (Table 1.5) i n c o n t r a s t t o t h e e f f e c t r e p o r t e d by o t h e r i n v e s t i g a t o r s who s t u d i e d f o r c e - f e d a n i m a l s . The a d v e r s e e f f e c t caused by p r o l o n g e d d i e t a r y f e e d r e s t r i c t i o n d u r i n g t h e g rowing p e r i o d was e v i d e n c e d by i n c r e a s e d m o r t a l i t y . However, as l o n g as t h e p r e v i o u s l y r e s t r i c t e d b i r d s s u r v i v e d , t h e i r t e s t i c u l a r s i z e was r e l a t i v e t o t h e i r body w e i g h t s as i n t h e normal s i t u a t i o n (Burger e t a l . , 1962). 2 . 4 S U M M A R Y S e v e n g r o u p s o f d a y - o l d b r o i l e r - t y p e m a l e s w i t h 8 t o 1 0 b i r d s e a c h w e r e r e s t r i c t e d t o h a l f a n h o u r f e e d i n g f r o m 0 w e e k s t o 1 , 2 , 4 , 7 , 9 , 1 1 o r 1 3 w e e k s o f a g e s d u r i n g t h e g r o w i n g p e r i o d . A l l g r o u p s o f b i r d s w e r e g i v e n w a t e r a n d f e e d a d l i b i t u m a f t e r t h e f e e d r e s t r i c t i o n . T h e e f f e c t s o f d i e t a r y f e e d r e s t r i c t i o n o n b o d y w e i g h t , t e s t e s w e i g h t , a n d s e m e n c h a r a c t e r i s t i c s w e r e s t u d i e d w h e n t h e b i r d s w e r e 5 7 t o 5 8 w e e k s o l d . N o s i g n i f i c a n t e f f e c t o f t h e d i f f e r e n t p e r i o d o f d i e t a r y f e e d r e s t r i c t i o n o n b o d y w e i g h t , t e s t e s w e i g h t , s e m e n v o l u m e , s p e r m a t o z o a c o n c e n t r a t i o n a n d n u m b e r o f s p e r m a t o z o a p e r e j a c u l a t i o n w a s f o u n d c o m p a r e d w i t h t h e c o n t r o l g r o u p w h i c h h a d f r e e a c c e s s t o f e e d t h r o u g h o u t t h e e x p e r i m e n t . T h e a v e r a g e s o f s e m e n v o l u m e p e r e j a c u l a t i o n , s p e r m a t o z o a c o n c e n t r a t i o n , n u m b e r o f s p e r m a t o z o a p e r e j a c u l a t i o n o f a l l b i r d s e x a m i n e d i n t h i s s t u d i e s w e r e 0 . 8 3 c . c . / e j a c , 0 . 6 1 0 m i l l i o n s / c . m m . a n d 4 2 4 m i l l i o n s / e j a c . r e s p e c t i v e l y . 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L . D a m r o n a n d R . H . H a r m s . 1 9 6 6 . T h e e f f e c t o f l o w p r o t e i n h i g h f i b r e g r o w e r d i e t s o n t h e p e r f o r m a n c e o f b r o i l e r p u l l e t s . P o u l . S c i . 4 5 : 3 9 3 - 4 0 2 . W i l s o n , H . R . , P . W . W a l d r o u p , J . E . J o n e s , D . J . D u e r r e a n d R . H . H a r m s . 1 9 6 5 . P r o t e i n l e v e l i n g r o w i n g d i e t s a n d r e p r o d u c t i v e p e r f o r m a n c e o f c o c k e r e l s . J . N u t r i t . 8 5 : 2 9 - 3 7 . W i l s o n , H . R . , L . O . R o w l a n d a n d R . H . H a r m s . 1 9 7 1 . U s e o f l o w p r o t e i n g r o w e r d i e t s t o d e l a y s e x u a l m a t u r i t y o f b r o i l e r b r e e d i n g m a l e s . B r . P o u l . S c i . 1 2 : 1 5 7 - 1 6 3 . W i l s o n , H . R . , R . A . V o i t l e a n d R . H . H a r m s . 1 9 7 2 . R e p r o d u c t i o n c a p a c i t y o f b r o i l e r m a l e f o l l o w i n g p r o t e i n r e s t r i c t i o n a t v a r i o u s a g e s . N u t r i t . R e p . I n t e r . 5 : 9 . Y a t e s , J . D . a n d P . J . S c h a i b l e . 1 9 6 3 . S k i p - f e e d i n g a n d e n e r g y l e v e l o f t h e r a t i o n f o r d e v e l o p i n g L e g h o r n - t y p e p u l l e t s . F e e d s t u f f s , M i s m e a p . 3 5 : 1 8 - 1 9 . - 85a - - 86 - Appendix Figure 2.1. Regression l i n e for spermatozoa counts on the basis of o p t i c a l density reading (660 millimicrons). Y 80 r 0.1 0.2 0.3 Optical Density Aooendix Table 2 2. Body weight at 60 weeks of age, testes weight, percentage of testes weight per body weight, semen volume, sperm concentration and number of spermatozoa per ejaculation of individual broiler male studied in this experiment. Kg. of Testes Millions B i l l i o n s Body Gm. of Weight c.c.of semen of sperm of Sperm Weeks of Feed Weight Testes * Body Volume per per c.c. per Bird No. Restriction at 60 wks. Weight Weight Ejaculation of semen Ejaculation 8029 0 8016 0 8020 0 8021 0 8034 0 8018 0 8005 1 8008 1 8096 2 8098 2 7949 2 8067 4 8184 4 8074 4 8051 4 8167 4 8054 4 8140 7 8038 9 8144 9 8177 11 8152 13 4.59 27.11 5.01 58.96 5.08 85.42 4.94 39.32 4.45 30.22 5.48 47.70 4.97 54.77 4.82 56.49 4.46 22.36 5.67 46.00 5.29 51.72 3.69 27.06 4.63 13.50 4.53 26.63 4.87 26.65 4.64 31.80 5.18 22.73 4.55 32.86 4.62 25.76 4.52 38.22 4.43 14.43 5.60 38.89 0.59 0.23 1.18 1.68 0.80 2.54 0.68 0.46 0.87 0.91 1.10 0.72 1.17 0.92 0.50 0.21 0.81 2.11 0.98 1.69 0.73 0.10 0.29 0.43 0.59 0.49 0.55 1.44 0.69 0.41 0.44 0.44 0.72 0.31 0.56 0.57 0.85 0.63 0.33 0.52 1.07 2.468 0.568 0.496 1.260 0.384 0.177 0.921 0.838 0.566 0.407 0.140 0.129 0.682 0.143 0.164 0.345 0.444 0.751 0.685 0.069 0.082 0.035 0.314 0.154 0.102 0.147 0.419 0.172 0.097 0.030 0.097 0.030 1.102 0.628 0.836 0.053 1.658 1.774

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