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The effects of sodium hydroxide treatment and other factors on the utilization of DPW by the chicks Kwok, Ming Cheung 1977

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THE EFFECTS OF SODIUM HYDROXIDE TREATMENT AND OTHER FACTORS ON THE UTILIZATION OF DPW BY THE CHICKS  by MING CHEUNG KWOK B.Sc.(Agri), University of Alberta, 1974  A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE STUDIES (Dept. of Poultry Science)  We accept this thesis as conforming to the required standard  THE UNIVERSITY OF BRITISH COLUMBIA February, 1977  c  Ming Cheung Kwok, 1977  In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make i t freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the Head of my Department or by his representatives.  It is understood that copying or publication  of this thesis for financial gain shall not be allowed without my written permission.  Department of  Poultry Science  The University of British Columbia 2075 WesSrook Place Vancouver, Canada V6T 1W5  Date  February 17,  1977  ABSTRACT Broiler performance was studied with diets containing 10, 15 and 20% dried poultry waste (DPW) or sodium hydroxide treated DPW.  Feeding trials  in evaluating the utilization of non-protein nitrogen in the DPW, the supplemental energy requirement, the effects of amino acid supplementation, and antibiotic supplementation on the utilization of nutrients i n the diets containing DPW were carried out.  Metabolism studies were conducted to deter-  mine the availability of protein and minerals i n DPW. Studies showed that DPW when added to the broiler diet at levels between 10-20% would support growth related to the dietary energy.  Inclusion of DPW  in the diet did not affect growth but lowered the feed efficiency when compared to the control diets containing similar energy and protein contents. Alkali treatment at various concentrations markedly improved the growth and feed efficiency of diets containing various levels of DPW. The metabolizable energy values of untreated DPW or DPW treated with 2, 3 or 5% sodium hydroxide were determined to be 827, 1155, 1245 and 1205 kcal/kg dry matter respectively. Supplementing the basal diets which were suboptimal in protein level with uric acid, urea, diammonium citrate or from the NPN i n the DPW did not improve the growth of chicks.  Nitrogen retention was reduced by the  supplementation and uric acid excretion was increased indicating that these nitrogen sources would not be utilized for growth by chicks. The availability of total nitrogen and true protein of untreated  DPW,  DPW treated with 2, 3 or 5% sodium hydroxide were 63.6 and 50.5%; 83.2 and 66.1%; 83.3 and 70.2%; and 90.4 and 72.2% respectively.  The availability of  cal cium and phosphorus in untreated DPW was 53.8 and 19.8% respectively.  iii  The calcium and phosphorus availabilities were not significantly affected by the alkali treatments.  The sodium availability of untreated DPW  was 84.4%,  which was decreased to 41.8%-48.3% by the alkali treatments. Supplementing the basal diets with 0.2% methionine significantly improved the growth of chicks fed the control diet but did not affect those fed the DPW DPW  diets (untreated or alkali treated).  Growth of chicks fed the  diets were better than that of the control (without supplementation).  These indicated that the amino acids in DPW  could be utilized for growth.  Increasing the energy level of the diets by adding 2% fat improved the growth and nitrogen utilization of chicks indicating the poorer performance of chicks fed DPW  diets was related to its energy dilution effect.  In the absence of antibiotics, the dietary fat (tallow) utilization was impaired with the inclusion of DPW  in the diet.  The metabolizable energy of  the diets was directly related to fat utilization. completely ameliorated the adverse effect of DPW edly increased the M.E. efficiency.  Antibiotics addition  on fat utilization and mark-  of the diets and improved the growth and feed  Antibiotics supplementation had. no effect on the nitrogen and  minerals retention of the diets.  TABLE OF CONTENTS Page Abstract  i i  Table of Contents  .-  iv  List of Tables  vi  Acknowledgement  .  viii  Introduction  1  Literature Review  3  A.  Factors affecting the composition of poultry wastes  3  B.  Poultry wastes as feeds for ruminants  7  1.  House Litter  7  2.  Dried poultry waste (DPW)  or caged manure  11  C.  Poultry wastes as feeds for swine  15  D.  Poultry wastes as feeds for poultry  16  E.  Effect of feeding poultry wastes on animal health  27  F.  Effect of intestinal micro-organisms in nutrients utilization....29  Methods and materials Experiment 1. Experiment 2.  Experiment 3.  Experiment 4. Experiment 5.  Experiment 6.  Experiment 7.  33  Effect of sodium hydroxide treatment on the chemical composition of DPW  33  Performance of broiler chicks fed untreated DPW or DPW treated with various concentrations of sodium hydroxide and the M.E. values  34  Utilization of the non-protein nitrogen from the DPW or from the various nitrogenous compounds by broiler chicks  36  Availability of total nitrogen, true protein and minerals in DPW and sodium hydroxide treated DPW  37  Effect of amino acid supplementation on the performance of chicks fed diets containing untreated DPW or alkali-treated DPW  40  Effect of increasing the energy content of the diets with supplementary tallow on performance of chicks fed the diets containing untreated DPW or alkali-treated DPW Effect of antibiotics supplementation on the performance of chicks fed with the DPW diets  iv  ..41 45  Results and discussion Experiment 1. Experiment 2.  Experiment 3.  47  Effect of sodium hydroxide treatment on the chemical composition of DPW.  47  Performance of broiler chicks fed untreated DPW or DPW treated with various concentrations of sodium hydroxide and the M.E. values  50'  Utilization of the non-protein nitrogen from the DPW or from the various nitrogenous compounds by broiler chicks  54  Experiment 4. Availability of total nitrogen, true protein and minerals in DPW and sodium hydroxide treated DPW.......61 Experiment 5. Effect of amino acid supplementation on the performance of chicks fed diets containing untreated DPW or alkali-treated DPW  75  Experiment 6. Effect of increasing the energy content of the diets with supplementary tallow on performance of chicks fed the diets containing untreated DPW or alkali-treated DPW  80  Experiment 7.  Effect of antibiotics supplementation on the performance of chicks fed with the DPW diets  90  Summary and conclusion  103  Literature cited  106  v  LISTS OF TABLES Table 1.  Chemical composition of poultry manure and poultry l i t t e r  Table 2.  Composition of the diets i n Experiment 2  35  Table 3.  Composition of diets used in Experiment 3  38  Table 4.  Available amino acid content of the diets (calculated).  42  Table 5.  Composition of diets used in Experiment 6  44  Table 6.  Effect of sodium hydroxide treatment on chemical composition of DPW  48  Amino acid composition of a sample of untreated DPW and the sample treated with 2% NaOH.-.  49  Effect of including untreated and sodium hydroxide treated DPW in.diets on 3 weeks body weight gain, feed consumption and feed conversion ratio  51  Table 7. Table 8.  Table 9., Effect, of sodium hydroxide treatment on metabolizable energy value of DPW  4  53  Table 10. Body weight gains, feed conversion ratio and feed consumption of chicks fed the different diets for 4 weeks in Experiment 3....55 Table 11. Effect of feeding DPW and non-protein nitrogen supplemented diets on nitrogen metabolism of the chicks..  57  Table 12. Availability of total nitrogen, true protein, calcium, phosphorus and sodium in untreated and NaOH treated DPW...  63  Table 13. Effect of crude fibre and^phytic acid content on calcium and phosphorus availability of various feedstuffs.  ..67  Table 14. Calcium and magnesium contents of the feedstuffs in relation to the degree of chelation of phytic acid with calcium.  72  Table 15. Effect of sodium hydroxide treatment on the calcium, phosphorus and phytic acid contents of DPW  74  Table 16. Effect of amino acid supplementation on 4 week body weight gains, total feed consumption and feed conversion ratio of chicks fed the control and the DPW diets  76  Table 17 "Effect of fat supplementation on body weight gains, feed consumption andifeed conversion ratio of chicks fed the control and DPW diets  81  Yi  Table 18. Apparent fat digestibility, metabolizable energy values and nitrogen retention of the different diets in Experiment 6  84  Table 19. Effect of antibiotics supplementation on body weight gains of chicks at 1; 2, 3 and 4 week of age..  91  Table 20. Total feed consumption and feed conversion ratio of chicks fed the diets for 4 weeks in experiment 7  92  Table 21. Effects of age and antibiotics feeding on fat digestibility of the diets i n Experiment 7 Table 22. Effect of age and antibiotics feeding on the metabolizable energy values of the diets i n Experiment 7 Table 23. Effects of antibiotics feeding on nitrogen, calcium and phosphorus retention of chicks fed the experimental diets at 2 week of age. Table 24. Feed conversion ratio of chicks fed the experimental diets at weekly intervals i n Experiment 7  vii  ...93 98  ...100 101  ACKNOWLEDGMENTS The author is deeply indebted to Dr. D. Bragg, Professor of Poultry Science, University of British Columbia, for his invaluable guidance, constructive criticism and financial assistance throughout this study.  Sincere  thanks are also extended to Professor J. Biely and Dr. H. Saben for their advice and enthusiasm, and to Dr. W.D. Kitts and Dr. R.C. Fitzsimmons as members of the committee. The technical assistance given by Mr. Raymond Soong, Mr. Mel Hudson and other farm operators i s greatly  appreciated.  The author i s grateful for the financial support by Agriculture Canada and B.C. Ministry of Agriculture that made this study possible.  The dried  poultry waste supplied by Mr. Bruce McAnish (Fraser Valley Organic Ltd., Abbotsford, B.C.) i s also gratefully acknowledged. It i s the author's wish to dedicate this thesis to the honor of his mother, Mrs. C.C. Kwok, and his wife, Katie Kwok.  viii  1  INTRODUCTION In the past two decades, the trend toward confinement production has been well-established in the swine, dairy and particularly in the poultry industries. The concentration of animals in fewer and larger operation permits greater efficiency in the animal production as well as economy of operation.  The  accumulation of droppings creates a problem not only for the poultrymenrbut also to the quality of the environment in which the poultry industry i s concentrated.  Disposal of animal manure becomes an increasing cost to the  operation due to concentration of animals and poultry units near metropolitan areas and the need to transport waste over greater distance for land use. Also the animal wastes createx water, air and s o i l pollution.  Recently, a  machine was developed which may be practical ofor the dehydration of poultry and livestock waste.  This provides a means for easy handling of the manure  as well as preventing contamination of the environment.  The dried product  can be sold as f e r t i l i z e r or can be recycled by incorporating into the feed. However, the high cost of handling manure has reduced i t s competitive position as f e r t i l i z e r .  Conversely, the rising cost of feed ingredients increases the  possibility of including animal waste in the feed.  Dried poultry waste (DPW)  has been shown to contain considerable amount of nutrients. Such nutrients in DPW have definite nutritive value for animals.  It has been demonstrated  that poultry l i t t e r and DPW can be utilized by the ruminants.  The. inclusion  of DPW in the poultry rations has also been studied by several investigators. Results indicate that DPW i s low in metabolizable energy due to the high fibre content.  It has been shown that alkali treatment can effectively de-  grade the fibre and c e l l wall constituents thus increase the digestibility of the fibre for ruminants.  Smith et a l . (1969) also showed that treating cow  waste with alkali increased the digestibility of dry matter of the manure for  2 cattle.  Therefore, DPW was treated with various levels of sodium hydroxide  solution in an attempt to reduce the fibre content. DPW and alkali-treated  The nutritive values of  DPW were analysed in the following study.  Feeding trials including a determination of the dietary level of waste that chicks can u t i l i z e , evaluation of utilization of non-protein nitrogen and amino acids in the DPW and of supplemental energy requirement were performed. Metabolism studies were conducted to determine the availability of protein and mineral in the DPW with chicks. Finally, the effect of antibiotic supplementation on the utilization of nutrients in DPW was studied.  3  LITERATURE REVIEW A.  Factors Affecting the Composition of Poultry Wastes The two broad types of wastes produced by poultry enterprises are:  a)  caged poultry manure, the waste collected from the birds (such as layers)  which are confined to wire cages or batteries, and b), poultry houses l i t t e r which is the solid waste composed of base bedding material and excreta. poultry waste (DPW)  Dried  refers to the manure collected from the cages or batteries  and thermally dehydrated to a moisture content of not more than 15%.  The  average composition and range of variation of caged poultry manure and poultry house l i t t e r are shown in Table 1 (Blair & Knight, 1973a; El-Sabban et a l . , 1969). Generally the moisture content of the floor l i t t e r is significantly lower as compared to fresh manure. The crude protein content of the l i t t e r s , on dry matter basis, is higher than that of the manure, presumably due mainly to the contribution of wasted feed particles, bacterial synthesis, and to a minor extent the direct contribution of the base material.  An important factor is  that l i t t e r base tends to lower the moisture content, thus reducing nitrogen loss.  the  The base material is a major contributing factor for the  higher crude fibre content of the l i t t e r s .  However, the total ash content  of the manure ni's: higher than any of the l i t t e r s . Poultry manure and l i t t e r vary widely in both physical and chemical composition due to the effect of various factors.  These factors include:  kind of feed, type of birds, age of the birds, number of birds per unit area, amount of l i t t e r , climatic condition during l i t t e r or manure production, methods of handling and storage of the waste. The true protein content of the poultry waste is fairly constant while  4  Table 1.  Chemical composition of poultry manure and poultry l i t t e r ,  Poultry Manure  Nutrients  Average  Range  Poultry Litter Average  Range  35.1  — ^ *.. "*  69.4  —  89.0  82.7-95.0  85.5  79.0-90.0  Crude protein (N x 6.25)  25.3  15.2-38.8  28.7  19.6-32.2  True protein  10.5  8.1-14.9  16.6  12.9-21.8  Uric acid  6.3  2.8-11.4  8.5  Ether extract  1.8  0.9- 3.0  2.3  1.7- 3.1  35.6  26.4-45.1  27.1  25.0-29.0  6.7  2.2-13.9  Crude fibre  13.8  10.7-19.3  24.3  16.3-32.4  Ash  26.5  18.8-40.8  14.1  13.4-14.9  Calcium  7.8  4.9-12.5  2.5  1.8- 3.2  Phosphorus  2.2  1.7- 2.8  1.6  1.2- 2.4  Sodium  0.42  0.1- 0.96  0.42  —  Potassium  1.37  0.04-2.09  1.77  —  Iron  0.2  0.1- 0.42  0.05  —  Magnesium  0.63  0.4- 1.03  0.35  Chloride  0.93  0.56-1.39  —  —  Copper (ppm)  61  47 - 94  23  —  Bromide (ppm)  16  7-22  —  —  Dry matter (before drying) (after drying) Composition of Dry Matter  N.F.E. Available carbohydrate  —  —  —  0.33-0.38  Manganese (ppm)  291  190 - 405  225  —  Zinc (ppm)  325  210 - 448  343  —  1. Data taken from Blair and Knight, 1973; and El-Sabban. et a l .., 1969. 2. The values, otherwise stated, are expressed in percentage.  5  the non-protein nitrogen content rather widely.  (NPN), u r i c a c i d i n p a r t i c u l a r l y , v a r i e s  U r i c acid i s the f a c t o r that l a r g e l y accounts f o r the v a r i -  a b i l i t y i n t o t a l N or crude p r o t e i n of the waste.  The true proteins i n the  wastes represent the undigested p r o t e i n residues i n the feed, endogenous p r o t e i n from the b i r d s , dead microorganisms and feather debris and the nonp r o t e i n nitrogenous urine.  compounds are mainly from metabolic wastes excreted i n  The amount of nitrogen i n waste i s influenced by the type of feed  given the b i r d s .  Creek and V a s a i t i s (1961) showed that the amount and per-  centage of d i e t a r y nitrogen excreted as u r i c acid increased w i t h p r o t e i n l e v e l i n the d i e t .  Kubena et a l . (1973) also observed that t o t a l nitrogen  and t o t a l amino acids i n the excreta increased w i t h i n c r e a s i n g d i e t a r y amino acids from 80%to 120% of the requirement. also e f f e c t s the nitrogen excretion.  Type of p r o t e i n used i n the feed  Neshein and Carpentar (1967) observed  that the proportion of the t o t a l u r i n a r y N contributed by u r i c a c i d v a r i e d with the type of p r o t e i n , and was greater with heat-damaged p r o t e i n s .  Thomas  et a l . (1969) also showed that the proportion of t o t a l d i e t a r y nitrogen excreted as urate was higher w i t h feeding groundnut meal (generally considered as poor q u a l i t y protein) than w i t h good-quality fishmeal. The manure and l i t t e r c o l l e c t e d from b r o i l e r s appear to contain more crude p r o t e i n than those c o l l e c t e d from l a y e r s .  The two major f r a c t i o n s of  crude p r o t e i n s , true p r o t e i n and non-protein nitrogen, were also s i g n i f i c a n t l y higher i n b r o i l e r waste (El-Sabban et a l . , 1969).  This can be explained on  the b a s i s that b r o i l e r r a t i o n s contain a higher p r o t e i n content than l a y e r rations.  B r o i l e r s are grown i n l a r g e r numbers per u n i t area when compared to  l a y e r s , thus producing more manure.  A l s o , the higher moisture content of the  wastes produced from layers and longer periods of accumulation of the hen excreta permit greater l o s s of nitrogen i n the form of ammonia.  Age i s also  6  a factor since Kubena et a l . (1973) demonstrated that total nitrogen in the excreta increased with the age of the birds, from 5 to 8 weeks of age.  The  total ash content is markedly higher in the layer excreta, especially the calcium and phosphorus content, due to the higher levels of these minerals used in the laying ration (El-Sabban et a l . , 1969). Various factors such as bird density, l i t t e r depth, and poultry house conditions (ventilation, insulation and house temperature) affect the dry matter and the nitrogen contents of the waste material.  El-Sabban et a l .  (1969) showed that the crude protein content is positively correlated with the dry matter content of the waste.  It is probably under moist, cool con-  ditions which favor anaerobic break-down and release of nitrogen as ammonia. Burnett and Dondero (1969) showed that extended storage of a small batch of manure containing 75% moisture resulted in a rapid decrease in the uric acid followed by the formation of the odorous substances, ammonia and aliphatic amines. However, Kubena et a l . (1973) showed that when excreta was maintained under aerobic conditions there was no appreciable degradation of amino acids or loss of nitrogen.  Perkins and Parker (1971), and Biely (1972) reported  that the length of time that manure was kept in the house before collection had l i t t l e effect- on the composition of the manure i f the house was wellventilated and air-conditioned. Various treatments and processing of the waste had a significant effect on the chemical composition.  Dry heating significantly reduced the gross  energy and nitrogen content (Manoukas et a l . , 1964; Shannon and Brown, 1969; Caswell et: a l . , 1975) . The amount of loss in nitrogen was found to be correlated with the drying temperature (Shannon and Brown, 1969) and the length of drying period (Kubena et a l . , 1972). The greatest loss of energy and nitrogen occurred when the sample was dried at 40  o  C in a vacuum oven  7  (Shannon and Brown, 1969).  Fontenot'_et 'ail. (1971) showed t h a t t h e l o s s o f  crude p r o t e i n was r e f l e c t e d  i n l o s s e s o f a s i m i l a r magnitude f o r p r o t e i n and  n o n - p r o t e i n n i t r o g e n and a l a r g e l o s s i n ammonia. pH 6.0 p r i o r t o d r y heat p r o c e s s i n g d e c r e a s e d Other  treatments  al., 1975).  the n i t r o g e n l o s s  substantially.  r e s u l t i n g i n loss of nitrogen include dry-heating followed  by a d d i t i o n o f paraformaldehyde et  A c i d i f y i n g the l i t t e r to  and f u m i g a t i o n w i t h e t h y l e n e o x i d e  (Caswell  F r e e z e d r y i n g , a u t o c l a v i n g and steam c o o k i n g , treatment  B - p r o p i o l a c e t o n e a r e r e p o r t e d to have l i t t l e  with  e f f e c t on the t o t a l and u r i c  a c i d n i t r o g e n o r o t h e r n u t r i e n t s o f t h e waste (Shannon and Brown, 1969; Fontenot £ t a l . , 1971; B i e l y , 1972; and C a s w e l l e t a l . , 1975).  B.  1.  P o u l t r y wastes as f e e d s f o r  House l i t t e r ;  Bhattacharya  ruminants  and Fontenot  r e p o r t e d t h a t when p o u l t r y l i t t e r was used  (1965) and P a r i g i - B i n i  (1969)  t o r e p l a c e i s o l a t e d soy p r o t e i n o r  soybean meal, p a r t i a l l y o r c o m p l e t e l y as the s o l e s o u r c e of supplemental t e i n i n t h e r a t i o n , d i g e s t i b i l i t y o f d r y matter r a t i o n s by sheep decreased  or  isolated  soy p r o t e i n .  and crude p r o t e i n o f t h e  s i g n i f i c a n t l y w i t h each i n c r e a s e i n l i t t e r  T h i s i n d i c a t e s t h a t the p o u l t r y l i t t e r  On t h e o t h e r hand, B h a t t a c h a r y a  and Fontenot  w i t h 25% and 50% o f peanut h u l l or woodshaving b r o i l e r l i t t e r s ,  et  level.  i s l e s s d i g e s t i b l e than soybean meal  showed t h a t s u b s t i t u t i n g the b a s a l r a t i o n of a l f a l f a hay and s h e l l e d  little  pro-  e f f e c t on t h e crude p r o t e i n d i g e s t i b i l i t y of the r a t i o n s .  a l . (1966) r e p o r t e d t h a t the apparent  (1966)  corn  t h e r e was Ammerman  d i g e s t i o n c o e f f i c i e n t s of dry matter,  n i t r o g e n and crude f i b r e forlambs f e d r a t i o n s c o n t a i n i n g 65% c i t r u s p u l p base p o u l t r y l i t t e r were i n g e n e r a l h i g h e r than those f e d the b a s a l m i x t u r e o f Bermuda g r a s s hay and c o r n meal. When p o u l t r y l i t t e r  s u p p l i e d 25 and 50% o f t h e t o t a l n i t r o g e n i n the  8  r a t i o n , d i g e s t i b i l i t y of crude p r o t e i n i n the l i t t e r , c a l c u l a t e d by d i f f e r e n c e , was  67 and 65% r e s p e c t i v e l y as compared to 71% f o r i s o l a t e d soy p r o t e i n .  The  d i g e s t i b i l i t y of crude p r o t e i n i n the l i t t e r was 58% w i t h 100% of nitrogen supplied from the l i t t e r (Bhattacharya and Fontenot, 1965).  Other reports  showed that the apparent d i g e s t i b i l i t y of crude p r o t e i n from p o u l t r y l i t t e r with sheep v a r i e d from 65 to 82% (Ammerman et a l . , 1966;  Bhattacharya  and  Fontenot, 1966; Mclnnes et a l . , 1968; Jeroch j i t a l . , 1970). P o s i t i v e nitrogen r e t e n t i o n was obtained i n sheep fed d i e t s containing various l e v e l s of p o u l t r y l i t t e r s .  When 25 or 50% of the d i e t a r y nitrogen  was supplied by the l i t t e r , nitrogen r e t e n t i o n was not s i g n i f i c a n t l y lower than when soy p r o t e i n supplied a l l of the d i e t a r y nitrogen (Bhattacharya Fontenot, 1965).  and  Furthermore, Ammerman et a l . (1966) reported that animals  r e c e i v i n g the p o u l t r y l i t t e r d i e t retained higher)-prpportioncofc-dietary n i t r o g e n than those fed the b a s a l hay and corn meal mixture.  Parigi-Bini  (1969) showed that although excretion of nitrogen i n feces was greater on the p o u l t r y l i t t e r d i e t , urine was not a f f e c t e d .  These data i n d i c a t e d that  p o u l t r y l i t t e r nitrogen can b e u u t i l i z e d e f f i c i e n t l y by ruminants, e s p e c i a l l y when the l e v e l of l i t t e r nitrogen does not exceed 50% of the t o t a l nitrogen intake. P o u l t r y l i t t e r can be a source of energy f o r ruminants a l s o .  Studies  i n which woodshaving and peanut h u l l l i t t e r s were s u b s t i t u t i n g f o r 25 and 50% of the hay-corn g r a i n r a t i o n Bhattacharya  and Fontenot (1966) reported  that the average d i g e s t i b i l i t y of energy of the l i t t e r s was 64% ( c a l c u l a t e d by d i f f e r e n c e ) . Average b r o i l e r l i t t e r contains 2440 k c a l . of d i g e s t i b l e energy per kg, 2200kkcal M.E.  per kg and 59.8% TDN  (1969) also reported s i m i l a r M.E.  (dry b a s i s ) .  value f o r p o u l t r y l i t t e r (2217  Parigi-Bini kcal/kg,  D.M.). Brugman et a l . (1968) showed that the apparent d i g e s t i b i l i t y of  9  energy i n l a y i n g house l i t t e r by c a t t l e was  59.2%.  L i t t e r has been estimated by d i f f e r e n t i n v e s t i g a t o r s to contain 16.2  to  24% d i g e s t i b l e crude p r o t e i n , (Muftic et ' a l . , 1968; Jeroch et a l . , 1970), starch equivalent of 35.8, and d i g e s t i b l e energy of 2440 kcal/kg.  These  values compared favorably with those of good q u a l i t y hay such as a l f a l f a .  In  a d d i t i o n , p o u l t r y l i t t e r s are a good source of calcium and phosphorus (Mclnnes et a l . , 1968; M u f t i c et a l . , 1968). Fontenot et a l . (1971) noted that there were no s i g n i f i c a n t d i f f e r e n c e s i n nitrogen u t i l i z a t i o n among animals fed b r o i l e r l i t t e r processed by the o  d i f f e r e n t methods i n c l u d i n g autoclaving, dry heating at 150 and dry heating a f t e r a c i d i f i c a t i o n .  C f o r four hours,  Caswell et a l . (1975) also reported  that dry heating, dry heating a f t e r the a d d i t i o n of paraformaldehyde and fumigation with ethylene oxide did not s i g n i f i c a n t l y a f f e c t the apparent d i g e s t i b i l i t i e s of the r a t i o n containing the treated l i t t e r w i t h respect to dry matter, crude p r o t e i n , crude f i b r e , nitrogen f r e e e x t r a c t and ether extract. B r o i l e r l i t t e r was s u c c e s s f u l l y e n s i l e d w i t h corn forage which r e s u l t e d i n a sharp increase i n crude p r o t e i n content  (Fontenot and Webb, 1974).  The  use of 15 or 30% l i t t e r (dry basis) i n s i l a g e improved dry matter intake and nitrogen r e t e n t i o n and had no marked e f f e c t on apparent d i g e s t i b i l i t y of dry matter. P a l a t a b i l i t y of the r a t i o n s containing p o u l t r y l i t t e r can be a problem during the i n i t i a l period of feeding.  Southwell et a l . (1958) observed that  w i t h i n the f i r s t few days of the t e s t , p a l a t a b i l i t y of the g r a i n - l i t t e r mixture decreased as the amount of p o u l t r y l i t t e r was  increased from 15 to 30%.  Steers became accustomed to p o u l t r y l i t t e r w i t h i n 3-4 weeks and t h e r e a f t e r a c c e p t a b i l i t y was s a t i s f a c t o r y . When c a t t l e had access to r a t i o n s containing  10  d i f f e r e n t proportions of b r o i l e r l i t t e r ( c a f e t e r i a s t y l e ) the a c c e p t a b i l i t y of r a t i o n s decreased as the l e v e l of l i t t e r i n the r a t i o n increased (Fontenot et_ a l . , 1971).  Fontenot et a l . (1966) reported that during the e a r l y period  of feeding a mixture containing s h e l l e d corn and 25% l i t t e r w i t h no considerable d i g e s t i v e disturbances i n c l u d i n g marked diarrhea was hence a l i m i t e d amount of long hay was  hay  encountered,  necessary.  Noland at a l . (1955) were among the f i r s t to report that w i t h equal energy intake, r a t e of gain of f a t t e n i n g steers fed p o u l t r y l i t t e r s i m i l a r to c a t t l e fed cottonseed meal.  was  Southwell et a l . (1958) showed that  rate of gain of steers fed a f a t t e n i n g r a t i o n containing 30% corn cob b r o i l e r l i t t e r supplying a l l the supplemental nitrogen was s i m i l a r to that of c o n t r o l steers.  Fontenot et a l . (1966) showed that r a t e of gain of steers fed a  f a t t e n i n g mixture containing 25% peanut h u l l or woodshaving b r o i l e r l i t t e r was s i m i l a r when compared to the c o n t r o l . The r e l a t i v e value of feeding d i f f e r e n t base l i t t e r s i n f a t t e n i n g mixtures at 25 and 40% l e v e l s was by Drake et a l . (1965).  studied  Feeding l i t t e r with the four base m a t e r i a l s , peanut  h u l l , corn cob, grass hay and soy-bean h u l l r e s u l t e d i n s i m i l a r performance. Ray and C h i l d (1964) reported s i m i l a r performance f o r f a t t e n i n g steers fed r a t i o n s containing 25% r i c e h u l l or r i c e h u l l - b r o i l e r l i t t e r which supp l i e d the roughage p o r t i o n ; whereas beef calves and y e a r l i n g s fed  cottonseed  h u l l and r i c e h u l l p o u l t r y l i t t e r as roughage i n the f i n i s h i n g r a t i o n gained more r a p i d l y and e f f i c i e n t l y than steers fed p r a i r i e hay (Ray and Cate, 1966). Ray and C h i l d (1965) reported that beef cows and calves were s u c c e s s f u l l y wintered on t a l l fescue pastures supplemented w i t h a mixture of 20% corn and 80% oat straw b r o i l e r l i t t e r . Fontenot _et _al. (1966) reported that the carcass grade and dressing percent tended to be lower f o r the steers fed the p o u l t r y l i t t e r .  However,  11  there were no significant difference in the carcass characteristics. Feeding broiler l i t t e r did not adversely affect the taste of meat (Fontenot et a l . , 1966; Fontenot et a l . , 1971). Performance of gestating-lactating ewes fed a ration containing ground chicken l i t t e r was reported to be similar to that of ewes fed soybean meal ration (Noland et^ a l . , 1955).  Merino wethers were given a .mixture of wood-  shaving broiler l i t t e r and wheat during periods of drought by Mclnnes et a l . (1968).  The mean body weight of the group was not significantly different  from the group fed only wheat. 2.  Dried poultry waste (DPW) or caged manure: The partial or complete re-  placement of barley or groundnut cake in the concentrate with DPW resulted in decreased digestibilities of dry matter and crude protein of ruminant rations (Lowman and Knight, 1970; Jayal and Misba, 1971).  El-Sabban et al. (1970) and  Bucholtz et al. (1971) also reported that the crude protein digestibility of rations containing autoclaved caged manure or DPW were significantly lower compared to the ration containing soybean meal as the sole source of protein. However, Rodriguez-Guedas (1966) showed that replacing 60% of corn meal in the  concentrate with DPW increased the digestibilities of dry matter and  crude protein of the diets with sheep.  Bull and Reid (1971) indicated that  adding graded levels of air-dried manure to a nitrogen deficient diet resulted in increases in digestibilities of dry matter, total dietary protein and total carbohydrate with steers. Lowman and Knight (1970) determined the digestibilities of nutrients in DPW either directly by feeding 100% DPW or calculated from the regression equations on digestibilities of the proportion of DPW  in the diet.  The-mean  of the direct and extrapolated coefficients for energy was 60% and for total nitrogen was 77.2%. Thus, DPW was calculated to contain a digestible energy  12  v a l u e of 2170  k c a l / k g D.M.  and 20% apparent d i g e s t i b l e crude p r o t e i n .  Bull  and R e i d (1971) showed t h a t the d i g e s t i b i l i t y of crude p r o t e i n i n DPW,  cal-  c u l a t e d by d i f f e r e n c e , to be between 73.3 - 82.3% w h i l e J a y a l and M i s b a  (1971)  r e p o r t e d 68.8%. Even  though the crude p r o t e i n i n the manure appeared  b l e than t h a t of soybean  meal the n i t r o g e n from DPW  to be l e s s  digesti-  i s r e p o r t e d to be  u t i l i z e d as e f f i c i e n t l y as the n i t r o g e n from soybean meal by ruminants. Sabban et al.  (1970) showed t h a t the n i t r o g e n r e t e n t i o n i n sheep  c o n t a i n i n g a u t o c l a v e d or cooked  El-  fed rations  caged manure as the s o l e s o u r c e of p r o t e i n  were s i m i l a r to those f e d soybean meal.  B u c h o l t z e t a l . (1971) r e p o r t e d  s i m i l a r n i t r o g e n r e t e n t i o n by sheep f e d DPW  or soybean meal as  supplemental  n i t r o g e n source. S t u d i e s have shown t h a t the main n i t r o g e n o u s compound ( u r i c a c i d ) cont a i n e d i n the l i t t e r Rodriguez-Guedas i n the rumen.  and manure can b e u u t i l i z e d by rumen microorganisms.  (1966) c a l c u l a t e d  t h a t 55% of the u r i c a c i d was  O l t j e n e t a l . (1968) observed t h a t u r i c a c i d was  i n the rumen a t a slower r a t e than u r e a .  broken down broken down  In t h e i r s t u d i e s t h e r e was  a trend  towards more e f f i c i e n t n o n - p r o t e i n n i t r o g e n u t i l i z a t i o n when u r i c a c i d used, compared to u r e a . who  was  T h i s i s f u r t h e r supported by Fontenot and Webb (1974)  observed t h a t r e t e n t i o n of n i t r o g e n was  23% of i n t a k e from s t e e r s f e d  u r i c a c i d compared w i t h 18% f o r those f e d u r e a . B u l l and R e i d (1971) showed t h a t the c a l c i u m and; phosphorus are r e a d i l y a v a i l a b l e to the ruminant  and are w e l l - u t i l i z e d .  over 90% o f absorbed c a l c i u m and 70% absorbed phosphorus  i n manure  In t h e i r study,  from manure were  b e i n g r e t a i n e d by the s t e e r s . B u l l and R e i d (1971) concluded t h a t p a l a t a b i l i t y o f caged manure i s not a s e r i o u s diet: problem as l o n g as the d r i e d manure c o n t a i n e d l e s s than  20%  13  moisture.  B u c h o l t z e t a l . (1971) observed  t a i n i n g DPW periment.  r e f u s e d p a r t of the f e e d d u r i n g the f i r s t When a more g r a d u a l change-over was  a b i l i t y problems. B u l l and R e i d of 7-21  made, t h e r e were no  (1971) suggested  Moreover, i t was  accept-  t h a t an a d o p t a t i o n p e r i o d  c o u l d s h o r t e n the a d o p t a t i o n time  i n a more c o n s i s t e n t i n t a k e .  The  high-moisture  t r o l l e d dust and p a r t i c l e s e p a r a t i o n i n the mix; aroma of the e n s i l e d Bucholtz et _al.  c o r n masked any  in  s t e e r s f e d the soybean meal supplemented r a t i o n was  per u n i t weight g a i n was  moisture  and  corn completely  conand  DPW.  (1971) r e p o r t e d t h a t average d a i l y g a i n of  soybean meal, or h a l f DPW  con-  i n a d d i t i o n , the a c i d i t y  odor apparent  the groups supplemented w i t h DPW  con-  ex-  shown t h a t the use of the e n s i l e d h i g h  c o r n as the b a s a l g r a i n w i t h DPW  than  few days of the  days i s needed b e f o r e a c h i e v i n g maximum consumption of d i e t s  t a i n i n g DPW.  resulted  t h a t cows f e d the c o n c e n t r a t e  yearling  significantly  (32% i n the r a t i o n ) , h a l f DPW  greater +  half  + h a l f u r e a ; but economic v a l u e based on f e e d c o s t b e s t f o r the \ DPW  - % u r e a supplemented group.  M e r e g a l l i e t a l . (1971a) i n d i c a t e d t h a t s t e e r s f e d a c o n c e n t r a t e c o n t a i n i n g 25% DPW  i n p l a c e of soybean meal and b r a n  v a l e n t p r o t e i n and although  i n the b a s a l r a t i o n ,  with e q u i -  energy c o n t e n t , grew as f a s t as those on the b a s a l r a t i o n  the f e e d e f f i c i e n c y was  s l i g h t l y poorer.  El-Sabban et a l . (1970)  r e p o r t e d t h a t the performance of s t e e r s f e d a u t o c l a v e d manure r a t i o n were not s i g n i f i c a n t l y d i f f e r e n t from those f e d soybean meal. w i t h 21% DPW  grew s l i g h t l y f a s t e r  B u l l s fed  than those f e d c o n c e n t r a t e w i t h 25%  f l o w e r o i l meal even though b o t h were e q u a l i n energy and ( M e r e g a l l i e t a l . , 1971b). w i t h a l l the soy and ( O l i p h a n t , 1974).  Growth and  acceptability  (El-Sabban  were the same as the  e t a l . , 1970;  diet  control  shown i n a number of r e p o r t s t h a t f e e d i n g DPW  caged manure d i d not a d v e r s e l y a f f e c t  sun-rloc  crude p r o t e i n  f e e d i n t a k e of b u l l o c k s on the  f i s h m e a l r e p l a c e d by DPW  I t was  concentrate  or  the c a r c a s s c h a r a c t e r i s t i c and meat B u c h o l t z e t a l . , 1971;  O l i p h a n t , 1974).  14  Bucholtz et_ a l . (1971) fed lactating dairy cows with concentrate mixtures containing up to 30% DPW.  Milk production and production persistency  from animals fed waste containing diets were normal and satisfactory compared with animals fed nitrogen from soybean meal or NPN from silage. feeding DPW  Studies on  to dairy cattle by the Agricultural Development and Advisory  Service of the U.K. Ministry of Agriculture (Blair and Knight, 1973b) showed that a ration including 20% DPW  and fed at the same rate as the control  ration gave a production equivalent to that of the control. When the  DPW  ration was fed a rate of 20% above the control, i t resulted in an increase of five percent more milk.  Bull and Reid (1971) observed that cows would  consume enough manure to meet their protein needs when itwas'the sole source of supplemental nitrogen in an otherwise low-nitrogen diet. suggested that DPW  These workers  could serve as the sole source of supplemental nitrogen for  cows producing up to 28 kg milk per day.  Furthermore, feeding DPW  did not  affect the milk quality and flavor or animal health. Lowman and Knight (1970) fed a range of diets in which DPW  replaced  barley at levels of 0-100%. They demonstrated that an equal combination of barley and DPW  can support medium to high rate of growth with sheep.  If the  cost of DPW was half of that of barley, 100% DPW was the cheapest feed for maintenance, and for liveweight gain 50% and 50% barley was the most economical combination.  Rodquiguez-Guedas (1966) reported that growth of lambs  fed pea straw, and concentrate containing 35% carob bean meal or DPW were similar. Zorita et a l .  (1966) fed ewes during the second half of gestation and  40 days of lactation with pelleted concentrate containing 60% DPW.  Birth  weights and daily weight gain of the lambs and weight pattern of ewes were considered normal.. In a latter study Zorita et a l . (1967) showed that milk  15  y i e l d and weight change of ewes fed concentrate w i t h 50% DPW were not d i f f e r e n t from the group fed standard concentrate. Hence, i t can be seen that the n u t r i t i v e values of l i t t e r and caged manure f o r the ruminants are s i m i l a r .  These e x c r e t i o n products can be an  economic sources of energy -as w e l l as nitrogen and minerals f o r ruminants.  C.  P o u l t r y wastes as feed f o r swine G e r i (1968) fed young pigs w i t h d i e t s containing 7-10% p o u l t r y manure to  replace some bran i n a balanced feed f o r 4 weeks.  Those fed manure containing  d i e t s had lower d a i l y weight gain and higher feed intake per kg gained.  The  younger pigs (17 kg) given manure were not as healthy as t h e , c o n t r o l (many developed d i a r r h e a ) . When a n t i b i o t i c s and vitamin B.^ were supplemented and the manure d i e t was given to older pigs (32 kg) d a i l y gain and feed e f f i c i e n c y were s l i g h t l y b e t t e r than the c o n t r o l .  Results obtained at the Harper Adams  A g r i c u l t u r a l College ( B l a i r and Knight, 1973b)indicated that f i v e percent  DPW  could be included i n swine r a t i o n s without i n f l u e n c i n g growth rate and feed efficiency.  There was a depression i n l i v e weight gain and feed e f f i c i e n c y  with 10% DPW  i n the feed.  Perez-Aleman et a l . (1971) and Denisov et a l .  (1975) c a l c u l a t e d a s i g n i f i c a n t l i n e a r r e l a t i o n s h i p between the amounts of manure added to the conventional d i e t on growth and feed e f f i c i e n c y .  Growth  was reduced by 0.02 kg/day, feed e f f i c i e n c y by 0.25 u n i t and k i l l i n g out percentage by 0.96%  f o r every 10% a d d i t i o n of manure.  concluded that i t might be economical  to include DPW  However, these workers at a l e v e l of 10% i n  the d i e t , which would save 3% of the conventional d i e t . In s p i t e of i t s adverse e f f e c t on growth, feeding manure decreased  the  backfat thickness and increased the meat:fat r a t i o which might improve the o v e r a l l grading of the carcasses (Perez-Aleman et a l . , 1971; Osterc,  1972;  16  Denisov  et a l . ,  1975).  ash and  t h e r e f o r e r e l a t i v e l y low d i g e s t i b l e energy,  t h a t the use of DPW  S i n c e the manure c o n t a i n s l a r g e amount of f i b r e  f o r f i n i s h i n g swine was  of  the r a t i o n to b a l a n c e i t s low energy  D.  P o u l t r y wastes as feeds f o r p o u l t r y  O s t e r c (1972) concluded  j u s t i f i e d but w i t h an  bean meal i n the b a s a l d i e t was growth was  C h i c k weight was  or  biodegraded  s u b s t a n t i a l l y l e s s when soy-  r e p l a c e d by 22% biodegraded  s l i g h t l y b e t t e r w i t h DPW  adjustment  value.  C a l v e r t e t a l . (1971) compared the n u t r i t i v e v a l u e o f DPW, hen manure w i t h soybean meal.  and  than c e l l u l o s e .  manure o r DPW  T h i s suggests  that  but DPW  does not seem to be of any v a l u e when s u b s t i t u t e d f o r soybean meal i n the chick d i e t .  Hodgetts  (1971) a l s o concluded  ment w i t h l a y i n g hens t h a t DPW f i c a n c e and merely  seems to have l i t t l e  a c t s as a f i l l e r  When l e v e l s o f DPW  up  from the r e s u l t s ebf the e x p e r i o r no n u t r i t i o n a l  signi-  or d i l u e n t i n the r a t i o n .  to 20% were f e d to b r o i l e r c h i c k s from  days R i n e h a r t e t a l . (1973) r e p o r t e d t h a t t h e r e was  7 to  28  a l i n e a r increase i n feed  consumption and a d e p r e s s i o n i n f e e d c o n v e r s i o n w i t h l i m i t e d e f f e c t on weight gain. ion  B r o i l e r f e c a l volume i n c r e a s e d i n a d i r e c t r e l a t i o n s h i p w i t h consumpt-  of DPW,  which suggested  Furthermore,  i t was  a low n u t r i e n t u t i l i z a t i o n of the m a t e r i a l .  shown t h a t the s u b s t i t u t i o n of 5 and 10% DPW  in a  low  p r o t e i n , low l y s i n e c o n t r o l d i e t p r e s e n t e d no amino a c i d type response. the m e t a b o l i z a b l e energy  c o n t e n t of DPW  was  These r e s u l t s t h e r e f o r e i n d i c a t e t h a t DPW  shown to be zero w i t h c h i c k s .  has no v a l u e f o r the young c h i c k .  S l o a n and Harms (1973) showed t h a t body weight and depressed  p r o g r e s s i v e l y as the l e v e l of DPW  b a s a l c o n t a i n i n g 24% p r o t e i n . of  5 and 10%  Also  was  f e e d c o n v e r s i o n were  i n c r e a s e d from 5-20%  in a  They compared the s u b s t i t u t i o n of sand a t l e v e l s  to the same l e v e l s of s u b s t i t u t i o n w i t h DPW.  Improved  results  17  were obtained using sand over DPW. presented in the DPW  The authors suggested that some factor is  (perhaps uric acid) that masks the bird's ability to  eat to meet i t s energy requirement, thus having a depressing effect upon growth and feed utilization. In spite of these findings, favorable results have been obtained by other workers.  Wehunt et a l . (1960) added broiler manure, hen manure and  soybean meal to provide additional 1.5 or 3% crude protein (N% x 6.25)  to  the basal containing 15% protein, with dextrose and cellulose in the diets being adjusted to equalize energy. ions.  Growth was improved by the supplementat-  However, the chicks receiving supplemental nitrogen from manure re-  quired more crude protein per unit gain in body weight than those received from soybean!meal suggesting the crude protein (or nitrogen) in the manure was less efficiently utilized than soybean meal.  Nevertheless, a l l lots  required about the same amount of true protein per gm. gain, indicating the true proteins in the manure were about equally efficient as compared with soybean meal. Similar growth responses from adding DPW  to diets which were sub-optimal  in protein or non-essential amino acids were obtained by McNab et a l . (1972), Lee and Blair (1972) and Lee and Blair (1973). 5-20% DPW  McNab et a l . (1972) added  to a basal diet, which contained suboptimal level of non-essential  amino acids but sufficient essential amino acids to meet the minimum requirement, and the diets were isocaloric.  Growth of the chicks fed the  DPW  diets were equal to chicks fed a standard broiler ration and consistently better than those fed the low-protein basal diet.  Similarly, adding 20%  DPW  to a semi-purified diet containing only 10% of the essential amino acids resulted in an improvement in growth, which was similar to the effect of adding an isonitrogenous amount of glutamic acid (Lee and Blair, 1972; 1973).  18  However, the feed conversion efficiency of the DPW diets was lower than that of diets supplemented with glutamic acid , showing that the amino acids of the protein i n the DPW were not utilized as efficiently as glutamic acid. In another study, Lee and Blair (1973) showed that the overall feed conversion efficiency of a broiler starter diet containing five percent DPW was better than that of an isonitrogenous-isocaloric control. This suggested that the true protein present in DPW can be utilized by the chick, and also some of the energy of DPW may have been utilized since the M.E. of DPW was assumed to be n i l when formulating the diets. Using an a r t i f i c i a l anus Yoshida and Hoshii (1968) showed that the digestibility of N i n the broiler excreta by hen was 52.8%. However, McNab et a l . (1974) using similar technique and fed with 99.5% DPW showed that true digestibility of the total N i n the DPW was 70.5%. The true protein i n the DPW was -64.2% digestible while the digestibility of uric acid was very high, up to 91%.  The digestibilities of amino acids were the lowest with valine  (24.7%) and highest with cystine and serine and an average value of 54.4%. Polin et a l . (1971) observed that only 34% of the total nitrogen in DPW was used as a protein source by laying hens. The primary deficiency in DPW is the low metabolizable energy content. Pryer and Connor (1964) showed that about 1/3 of the gross energy contained in feces could be utilized by the chicken (M.E. value of 1.09 - 1.11 kcal/gm D.M.). Polin et: a l . (1971) using white Leghorn chicks showed that the M.E. of DPW was 1.29 or 1.40 kcal/gm; depending on the mathematical approach used to evaluate the data.  Shannon et a l . (1972) reported that the M.E. values  of several samples of DPW varied from 0.64-1.27 kcal/gm D.M., with a mean of 0.97 kcal/gm.  From these M.E. values, i t is noted that the DPW nutrient  profile was quite similar to other fibrous feedstuffs, including bran and alfalfa meal.  19  Part of the variability in M.E. value can be attributed to the different formulation of the original diets fed to the birds and variations in the quantity of feed spillage in the manure. Presser and Ousterhout (1972) demonstrated that excreta produced from birds fed low fibre-high calorie diets were somewhat better utilized when recycled.  Young and Nesheim (1972) showed  that DPW from hens fed 19.8% wheat bran had a M.E. value of 0.18 kcal/gm as compared to 0.66 kcal/gm for DPW from hens fed a standard laying ration, which supports findings of Presser and Ousterhout (1972). Ousterhout and Presser (1971) showed that recycling manure resulted in a 25% utilization of the total dry matter nutrients in the manure. Young and Nesheim (1972) found that 30% of the dry matter was digested.  Shannon et^ a l .  (1972) demonstrated the digestibilities of organic matter and dry matter of DPW to be about 18.6 and 24.4%. These figures are close to the figure suggested by the M.E. value. The total carbohydrate content of DPW i s about 50% or less but only 1/7 is shown to be available to the bird (Blair, 1974). McNab e£ a l . (1974) reported that the apparent digestibilities of calcium and phosphorus varied widely with 1.2 - 45.3% for calcium and 7.5 - 46.2% for phosphorus.  Parker et^ a l . (1959).reported that the available phosphorus, as  determined by the method of the A.O.A.C. (1945), in broiler manure was 94% and i n hen manure was 88%. The low digestibility of the nutrients and available energy in the manure can be explained by the fact that in modern high-energy poultry rations, 70§80% of the energy yielding components and other nutrients of the diet are digestible and may be metabolized by poultry.  The remainder of the gross  energy, indigestible components of the diet, or dietary components not retained by the animal are found in the excreta.  The high fibre and ash, and  low fat and digestible carbohydrates contents in the excreta account for the  20  low M.E. value.  Nevertheless, the protein contained in the DPW  can be  utilized by the chicken. Non-protein nitrogen (NPN) in poultry excreta is 47 to 64% of the total nitrogen, of which 30 to 60% i s uric acid.  Davidson and Thomas (1969)  partitioned the total nitrogen into 19% as true protein, 5% as free and bound amino acids, 60% as uric acid, 9% as ammonia, 1.7% as urea and 1.2% as creatine and creatinine. Wiseman ^ t a l . (1956) noted that when chickens were fed f o l i c aciddeficient diets containing antibiotics, there was an increase i n numbers of f o l i c acid synthesizing coliform bacteria primarily Aerobacter species. Since the Aerobacter species found i n the intestinal contents were able to u t i l i z e uric acid, Wiseman proposed that.antibiotic supplement would result in better growth of chicks•through encouraging the increase in numbers and activity of bacteria so removing a potentially toxic substance, uric acid, from the intestine.  Results presented by Bare et ;al. (1964) gives support  to the above hypothesis.  Adding two percent uric acid to the basal diet  significantly depressed the growth  of the chicks and this growth depression  was alleviated by supplementing with antibiotics.  Chemical analysis of the  intestinal content revealed an increased degradation of uric acid in .the tract of the "uric acid-antibiotic" fed chicks. They proposed that uric acid depresses growth by acting as an irritant, since i t is an insoluble waste product that occurs in high level in the intestinal tract when ingested by the chick and thus, interferes with the absorption of nutrients from the intestine.  Concurrently, Lau and Wiseman (1964) showed that the addition  of uric acid to a synthetic medium reduced the in vitro production of riboflavin by cultures of bacteria isolated from the intestinal contents of rats and from human feces. Therefore, the growth depressing effect of uric acid  21  could result from the inhibition of the synthesis of vitamins or other unidentified nutritional factor for the chick by the intestinal microflora without affecting the bacterial growth. Lee and Blair (1972) supplemented the basal diet which contained crystalline essential amino acids only with uric acid and obtained no growth response; in fact a slight depression i n growth was observed.  Baker and Molitoris  (1974) showed that uric acid supplementation to a basal crystalline amino acid diet deficient in non-specific nitrogen did not e l i c i t e a growth response. On the other hand, Stapleton and Biely (1975) did not obtain a growth depression as Bare et a l . (1964) did when two percent of uric acid was added to a 20% protein chick diet.  They concluded that dietary uric acid was not, i n  i t s e l f , a factor i n depressing weight gain of chicks; yet i t is not utilized by the chick to any extent. Sullivan and Bird (1957) f i r s t demonstrated that the chick can use diammonium citrate and urea when fed low protein diets, provided adequate essential amino acids are present.  Using purified diets designed to supply a  balanced sufficiency but not an excess of essential amino acids the supplementation with diammonium citrate, triammonium citrate or urea resulted i n a growth response (Featherstone et a l . , 1962; Blair et a l . , 1972; Lee and Blair, 1972). Plasma amino acids levels were increased by the supplementations, and carcass composition studies showed that the additional weight gains by the birds receiving these nitrogen sources were accompanied by deposition of protein indicating, the chick is able to convert the nitrogen from these compounds to amino acids and proteins.  It is therefore concluded that  nitrogen from ammonium compounds or urea is likely to be useful in partially satisfying the non-essential amino acid requirement of the birds only when the diets contained a balanced sufficiency but not excess of essential amino  22  acid together with a deficiency of non-essential amino acids or non-specific nitrogen.  However, Allen and Baker (1974) showed that the organic ammonium  compounds and  urea were less efficacious than L-glutamic acid or a mixture  of dispensable amino acids. The use of non-protein nitrogen sources for growth by chicks on free amino acid diets is well established; but, the responses in a practical diet remain questionable.  Only Miller (1973) showed that supplementing the 12%  protein basal diet which contained fishmeal as the sole source of protein, with ammonium compounds or glutamic acid at level equivalent to 3% protein in most cases improved the growth of chicks.  According to Blair and Waring  (1969) chicks responded to diammonium" phosphate at the 1.5% dietary level supplemented to a practical diet which supplied a l l the essential amino acids at minimum required level and 19.5% protein, but not at the 3% level (equivalent to 2.3% protein). Other workers (Moran et a l . , 1967; McNab et a l . , 1972; Balloun and Kazemi, 1975; Trakulchang and Balloun, 1975a) showed that at low levels of inclusion (less than 3%) diammonium citrate might  not have  any effect on growth. At higher levels (5% or above) i t depressed growth, reduced feed consumption and nitrogen retention in most instances.  March  and Biely (1971)>in adding one or, two percent urea to diets containing 20, 22 or 24% protein obtained depression in growth of chicks from day old to 8 weeks of age.  Kazemi and Balloun (1972) showed that nitrogen retention  was markedly reduced when urea or diammonium citrate was included in the diet. Most of the published data have shown that the nitrogen from non-specific sources can be effectively utilized by the laying hens for egg production. Young £t a l . (1965) showed that the addition of diammonium citrate equivalent to three percent protein to a practical 13% protein diet improved egg production.  This was equal to that obtained with a 16% intact protein diet.  23  Reid e t a l . (1972) i n d i c a t e d t h a t supplementation o f the l o w - p r o t e i n d i e t s which c o n t a i n e d  basal  the e s s e n t i a l amino a c i d s to meet the requirement  with  n o n - s p e c i f i c n i t r o g e n such as ammonium s u l f a t e , diammonium phosphate or c i t r a t e improved egg p r o d u c t i o n and  the e f f i c i e n c y o f c o n v e r s i o n of e s s e n t i a l  amino n i t r o g e n i n t o egg p r o t e i n . Moran e t a l . (1967) d i d not o b t a i n an improvement i n egg p r o d u c t i o n  with  diammonium c i t r a t e s u p p l e m e n t a t i o n to the d i e t c o n t a i n i n g s u f f i c i e n t e s s e n t i a l amino a c i d s but d e f i c i e n t i n n i t r o g e n . diammonium c i t r a t e e q u i v a l e n t  I n another t r i a l , the a d d i t i o n o f  to 5% p r o t e i n i n a 10% p r o t e i n p r a c t i c a l l a y i n g  d i e t depressed egg p r o d u c t i o n s i g n i f i c a n t l y . obtained was  a depression  added to a 11.5%  contained  Fernandez et a l . (1973) a l s o  i n egg p r o d u c t i o n when diammonium c i t r a t e or phosphate p r o t e i n p r a c t i c a l d i e t or a s e m i - p u r i f i e d d i e t  that  a l l e s s e n t i a l amino a c i d s to meet the «iN.R.C. requirements but  inadequate i n n o n - e s s e n t i a l amino a c i d s or n o n - s p e c i f i c n i t r o g e n . The  e f f e c t s of u r e a s u p p l e m e n t a t i o n on egg p r o d u c t i o n are i n c o n c l u s i v e .  Chavez et _ a l . (1966) and Moran e^t a l . (1967) r e p o r t e d t h a t u r e a  supplementa-  t i o n had no e f f e c t on egg p r o d u c t i o n w h i l e Fernandez e t a l . (1973) showed a graded response i n egg p r o d u c t i o n to u r e a s u p p l e m e n t a t i o n a t 0.65  and  1.25%  levels. E a r l y s t u d i e s w i t h p o u l t r y manure i n d i c a t e d t h a t p o u l t r y f e c e s an u n i d e n t i f i e d growth f a c t o r f o r c h i c k s .  Rubin e t a l . (1946) r e p o r t e d  b r o i l e r c h i c k s from day o l d to 6 weeks of age f r e e hen  that  f e d d i e t s c o n t a i n i n g 5% u r i n e -  f e c e s i n p l a c e o f equal amount of c o r n i n the b a s a l showed improved  growth over those f e d the b a s a l .  Elam et_ a l . (1954) showed t h a t the a d d i t i o n  of f i s h s o l u b l e s , a n t i b i o t i c s or a u t o c l a v e d filtered  contained  through c h e e s e - c l o t h )  A d d i t i o n a l response was  poultry l i t t e r  suspension  (after  to the d i e t improved the c h i c k ' s growth.  o b t a i n e d when the l i t t e r  suspension  was  fed i n  24  combination with the antibiotics.  Hydrolysed poultry manure was demonstrated  to be as effective as or even superior to fish soluble or d i s t i l l e r ' s solubles in supplementing the chick diet with unidentified growth factors required by chicks for optimum growth (Fuller, 1956; Wehunt et a l . , 1960).  Rubin et a l .  (1946) believed that the factor was probably synthesized in the lower portion of the gut where absorption is not very good or perhaps in the voided feces. Flegal and Zindel (1971) observed that the body weight gain of White Leghorn chicks was not influenced when up to 20% of DPW was included in the diet.  The diets tested were similar in true protein content but no iso-  caloric.  Feed efficiency was inversely related to the level of DPW  diet indicating the energy dilution effect of DPW. could tolerate only 5% DPW feed efficiency.  in the  However, broiler chicks  in the diet without adverse effect on growth and  Growth and feed efficiency were improved by adding 4.5% to  a diet containing .20% of  DPW.  Biely et- al. (1972) indicated that DPW has a definite value as a broiler feed ingredient.  Inclusion of DPW  at 5-20%  levels could lower the cost per  pound of gain when compared to the control ration even though growth and feed efficiency of chicks on the DPW  diets were slightly depressed.  Bhargava and O'Neil (1975) demonstrated that by adjusting for the energy and protein content in diets DPW up to the 20% level had no adverse effect on growth to 8 weeks of age, edible meat ratio or carcass grade of broilers. The addition of lysine or methionine singly or in combination did not affect growth response.  In another study, when balanced for the amino acid content  of the diets by supplementing with lysine, methionine and arginine, Trakulchang and Balloun (1975b) showed that the additional protein from 10 to 20% to the diets effectively increased growth.  Cunningham and L i l l i c h (1975)  reported that only the group receiving 38.2% DPW had growth depression in a study  25  with various DPW  levels in isocaloric and iso-proteinous diets.  The dressing  percentage, carcass quality and meat flavor were not affected by feeding high levels of DPW.  Trakulchang and Balloun (1975b), however, showed that DPW at  10% of the diet did not affect the weight gain or feed efficiency but at 20% performance was significantly reduced even though the diets were isocaloric and iso-proteinous. i.  Trakulchang and Balloun (1975c) continued recycling the excreta from the chicks fed the DPW  diets.  Diets containing 0, 10 and 20% were originally  formulated to be equivalent in energy, portein, calcium and phosphorus content.  DPW recycling, at both 10 and 20% dietary levels significantly de-  pressed weight gain of birds 4 to 8 weeks of age.  As the number of recyclings  increased calcium content in the excreta decreased linearly so that the calcium : phosphorus ratio of the diet was decreased from a ratio of 1:1 during the f i r s t cycle to 0.34:1 after the 4th recycle.  This may be a factor  in the growth depression previously discussed. Quisenberry and Bradley (1969) were among the f i r s t to report that i n cluding 10 and 20% DPW  in the diets had no adverse effect on the egg pro-  duction, egg weight, feed efficiency and mortality of the laying hens. Flegal and Zindel (1971) showed no significant effect on egg production from the i n clusion of up to 30% DPW  in the diets without adjusting for the energy content;  but feed efficiency was inversely related to the level of DPW Including 40% DPW  in the ration.  in the diet significantly depressed the egg production,  which was not alleviated by the addition of fat, although i t improved the feed efficiency of the diet. BBirds receiving rations containing more than 10% DPW did not have body weight increases comparable to the control during the laying period.  Hodgetts (1971) added 10% DPW  in the basal and observed  no reduction in egg production and feed efficiency; however, the  feed cost  26  was reduced by the DPW  inclusion.  Flegal and Dorn (1971) reported that egg production of groups fed diets with 12.5 and 25% DPW  as a replacement for corn in the control was not  different from the control although feed intake was increased.  Young and  Nesheim (1972) also observed that egg production or egg weight was not affected by the inclusion of 22.5% DPW  in the diet but feed conversion and  body weight gain were adversely affected. It was noted that the laying hens increased food intake to achieve a constant daily metabolizable energy i n take.  Fecal volume increased directly in proportion to the level of DPW  energy content of the diets.  These authors concluded that DPW  and  is a low  energy, low protein material with an apparent utilization of not more than 30%.  At dietary levels up to 25% i t does not affect egg production.  Con-  versely, Trakulchang and Balloun (1975b) observed that DPW at these levels depressed egg production and feed efficiency and increased mortality even though diets were isocaloric and iso-proteinous. Blair and Lee (1973) supplemented the basal laying diet containing 11.5% protein with 9i7% autoclaved DPW.  Feed intake, egg production, total egg  mass, mean egg weight and Haugh score were increased by such supplementation. Rinehart et a l . (1973) showed that egg production was increased by 6.1% when DPW was added to the diet containing 80% of the amino acid requirement of the laying hen.. These reports illustrate that laying hens can u t i l i z e the amino acids and protein contained in the DPW.  Rinehart e_t a l . (1973) concluded that  DPW had 30-35% of the value of corn for laying hens. In general, egg size tended to decrease as the level of DPW layer diets. by feeding DPW  increased in  However, the shell thickness and Haugh units were not affected (Flegal and Zindel, 1971; York £t a l . , 1970).  The storage  quality, color, odor, taste and/or microbial content of eggs produced from  27  hens fed up to 30% DPW were not s i g n i f i c a n t l y d i f f e r e n t from the c o n t r o l ( F l e g a l et a l . , 1970; York et a l . , 1970). Ousterhout and Presser (1971) and Young and Nesheim (1972) c a l c u l a t e d that the r e c y c l i n g of DPW by no more than 25%.  i n l a y i n g r a t i o n could reduce the disposing problem  This would s t i l l leave 75% of the manure to be disposed  off by other means.  E.  E f f e c t of feeding p o u l t r y wastes on animal h e a l t h There are r i s k s due to residues i n the p o u l t r y excreta i n causing h e a l t h  hazards i n animal r e c e i v i n g r a t i o n s containing the waste m a t e r i a l . The i s the disease r i s k .  first  Freshly voided excreta, p a r t i c u l a r l y from caged stock,  can contain v i a b l e organisms such as C l o s t r i d i a , salmonella, corynebacteria and mycobacteria  (Alexander et a l . , 1968; K r a f t et a l . , 1969).  Many of these  b a c t e r i a are normal i n h i b i t a n t s of the i n t e s t i n e of p o u l t r y and w h i l e they are not pathogenic to p o u l t r y they are known to cause b l a c k l e g , gas gangrene and enterotoxemia i n c a t t l e .  However, the Salmonella and Arizona species are  not h i g h l y r e s i s t a n t to heat i n l i t t e r of normal moisture content and are unable to survive . i n b u i l t - u p l i t t e r or i n s i l a g e (Tucker, 1967; Alexander •• j et a l . , 1968; Messer et a l . , 1971).  Fontenot et a l . (1971) and Caswell et a l .  (1975) observed that a u t o c l a v i n g , dry heating at 100° C f o r up to 48 hours, or treatment w i t h B-propiolactone or ethylene oxide (though not able to comp l e t e l y s t e r i l i z i n g the l i t t e r ) was e f f e c t i v e i n p a s t e u r i z i n g the waste. Shannon jet a l . (1972) examined a range of p o u l t r y manure d r i e d by a v a r i e t y of commercial procedures and concluded that the number of organisms were so small that the r i s k of a disease i s low.  Furthermore, no disease problems  have been reported from the i n c l u s i o n of p o u l t r y wastes i n r a t i o n s f o r c a t t l e , sheep and p o u l t r y .  28  The main risk from residues in wastes i s from chemicals and drugs. Griel et a l . (1969) reported abortion i n cows fed dried l i t t e r from a roaster operation.  The roaster feed had 0.15-0.23 kg of 14% dienestrol diacetate  premix per ton and bioassay of the l i t t e r showed i t had extremely high estrogenic activity. A musty taint in eggs and broiler meat due to the presence of anisoles in l i t t e r has been reported by Curtis et a l . (1972).  The trouble was  attributed to the phenolic compounds added to timber as antifungal agents, which were subsequently converted microbiologically to anisoles in the l i t t e r . Therefore poultry l i t t e r which i s known to have originated from treated timber is probably not suitable for feeding to animal stock. Copper toxicity was observed in ewes fed poultry l i t t e r containing high levels of copper (Taylor, 1971; Webb et_ a l . , 1973).  However, in a study by  Lowman and Knight (1970), DPW with a copper content almost double that of barley (73 vs 48 ppm) showed a low digestibility of copper with sheep (24.2%). Hence, the available copper content of DPW could be equal to or lower than other feedstuffs.  Moreover, the copper problem w i l l not likely be as severe  in cattle since sensitivity to copper i s less than that in sheep. No marked levels of DDT, DDE or other pesticides were detected in poultry l i t t e r sampled from various locations (Fontenot et a l . , 1966; Messer et a l . , 1971; Fontenot et a l . , 1971).  Feeding DPW or broiler l i t t e r did not result i n  pesticide residues or chlorinated hydrocarbon compounds accumulation in liver and fat of fattening cattle (Fontenot et a l . , 1966; El-Sabban et a l . , 1970; Fontenot et a l . , 1971). No residues were detected in the various organs of lambs fed l i t t e r which was shown to contain amproleum and arsenic residues from the feed (Brugman er a l . , 1969).  Webb and Fontenot (1972) found residues of penicillin, Chlortetra-  29  cycline, nicarbazin and amproleum in broiler l i t t e r .  Steers fed as high as  50% of such l i t t e r for 121 or 198 days did not show an increase in amprolium, nicarbazin and chlortetracycline level in tissues. L i t t l e work has been reported for the effect of waste recycling on health problems in poultry. recycling DPW  Varghese and Flegal (1972) demonstrated that continous  to pullets did not alter the levels of arsenic, mercury, copper  and zinc in the tissues, eggs and feces. These data indicate that the medicinal and pesticide residues in poultry excreta do not appear to cause a serious  problem.  Besides, drug residues in  caged manure would probably be of l i t t l e consequence since laying hen rations contain l i t t l e , i f any drug additives.  F.  Effect of intestinal micro-organisms on nutrients utilization When young chicks were given fresh chicken feces or suspension of fresh  dropping, the growth rate may be lowered and mortality may  increase.  This  growth depression can be alleviated by the addition of antibiotics to the feed.  Heating at 100° C or autoclaving w i l l also eliminate the growth de-  pressing effect of fresh feces (Kratzer et a l . , 1951; Warden and Schaible, 1961; Yates and Schaible, 1961).  This indicates that the microorganisms  present in the feces may be responsible for the growth depression from feeding the feces.  Furthermore, the chick's requirement for phosphorus and magnesium  were higher when 0.5 or 1.0% fresh droppings was included in the feed or by administering orally a water suspension of feces.  Feeding sterilized chicken  feces did not affect the nutrient requirements (Edwards and Boyd 1963).  On  the other hand, many studies showed that feeding antibiotics might lower the requirement for several nutrients.  These studies suggest that the micro-  30  orgamisms i n the intestine interfere with the nutrient utilization and subsequently affect the growth. The influence of intestinal micro-organisms on host nutrition has been discussed quite thoroughly by Jayne-William and Fuller (1971). Comparison of the activities of intestinal proteases in germfree and conventional chickens shows that gut microflora exerts l i t t l e or no effect on the enzyme activities (Lepkovsky et a l . , 1964). However, many reports have shown that dietary antibiotics can improve protein utilization in chickens (Anderson et a l . , 1952, Machlin et a l . , 1952; Slinger et a l . , 1952; West and H i l l , 1955). When the protein content of the diet is below that required for maximum growth, growth of chickens is improved by : feeding antibiotics, which indicates that the intestinal micro-organisms compete with the host as the amount of protein available becomes limiting.  On the other hand, when fed  a diet containing ample readily digestible protein (26%) there is no difference between germ free and conventional birds in their efficiency of protein utilization (Miller, 1967). Young et a l . (1963) observed that fatty acids were absorbed better by chicks when reared i n a fumigated laboratory or fed antibiotic than i n a contaminated environment.  Furthermore, germfree environment appears to i n -  crease the retention of total fat by the chick (Boyd and Edwards 1967). The influence of the microflora on the absorption of fat and fatty acids depends pn the type of fatty acids.  Absorption of the saturated fatty acids,  palmitic and stearic acids, are lower in the conventional chicks than in germfree chick, but the absorption of the unsaturated fatty acids, oleic and linoleic acids, are not affected by the presence of microflora (Boyd and Edwards 1967, and Cole and Boyd 1967). Hence fats containing high proportions of saturated fatty acids, such as tallow, w i l l be affected to a greater extent  31  than those containing high proportion of unsaturated fatty acids, such as corn o i l , by the presence of the microflora. Intestinal micro-organisms do not seem to affect fat absorption by reducing the lipase activity since the lipase activity in the intestine was found to be similar between germfree and conventional chicks (Lepkovsky jet a l . 1964). Studies have shown that intestinal bacteria such as Clostridium welchii, Strepto-coecus faecalis and certain other bacteria, mostly s t r i c t anaerobes are able to split conjugated bile acids in taurine or choline and the cons t i t u t e d acid can be further degraded (Rosenberg 1969 and Flock et a l . 1972). This would severely affect the function of bile salt in fat digestion and absorption. The hydrolyzed products of lipolysis at the duodenum,i.e. monoglycerides and free fatty acids, are incorporated into micelles and then uptake and esterification of fats by the intestinal mucosal c e l l occur. obligatory for micelle formation.  Bile salts are  The function of bile salts in the duodenum  and jejunum depends not only on concentration but also on chemical form.  Free  bile acids are incapable of incorporating products of lipolysis into micelles. In vitro studies suggest that free bile acids may be inhibitory to several mucosal c e l l functions including active transport of sugars and amino acids and reesterification of fat in the mucosa (Rosenberg 1969 and Holt 1972). Therefore bacteria proliferate in the proximal intestine and free bile acids w i l l be formed.  Since free bile acids do not function as micelle forming  agents and the effective concentration of bile salts w i l l f a l l below those required for micelle formation, fat absorption w i l l be  impaired.  Lindblad et a l . (1954) and Simco and Stephenson (1961) showed that the addition of antibiotics to diets would e l i c i t greater growth response with diets containing 0.4 - 0.6% calcium and 0.2% phosphorus than with higher  32  l e v e l s of the minerals.  Body weight of chicks fed these low l e v e l s of calcium  and phosphorus w i t h a n t i b i o t i c s often were s i m i l a r to those fed 1% calcium and 0.2% phosphorus but without a n t i b i o t i c s .  The percent bone ash of chicks  fed the suboptimal l e v e l s of calcium was also increased by the a n t i b i o t i c feeding.  Kirchgessner and Friesecke (1965) showed that the r e t e n t i o n of  calcium and phosphorus was increased by feeding w i t h aureomycin.  However, the  e f f e c t of a n t i b i o t i c s on calciumandiphosphorus balance and r e t e n t i o n was not apparent when the d i e t s were adequate i n these minerals (Ahuja et a l . 1971). Hence, i t appears that the i n f l u e n c e of a n t i b i o t i c s on calcium and phosphorus u t i l i z a t i o n i n the chicks i s marked only when the d i e t s contain suboptimal or inadequate amount of these n u t r i e n t s .  33  METHODS AND MATERIALS Experiment 1. Effect of sodium hydroxide treatment on the chemical composition of DPW. A batch of DPW obtained from Fraser Valley Organic Ltd. was used to study the effect of sodium hydroxide treatment on the nutrient value of poultry waste.  The waste was collected from commercial broilers raised on heated con-  crete floor with no bedding materials and dried in a gas heated drum drying system.  Equal weights of water or 2, 3, 4, 5 and 7% sodium hydroxide solution  was added to the DPW, thoroughly mixed and dried under a heater (about 40°C) for 2 days.  The dried samples were ground and analysed for: acid-detergent  fibre content by a rapid micro-digestion method described by Waldern (1971); total nitrogen (using the macro Kjeldahl method - AOAC 1965); and uric acid content by a modified method described by Stapleton & Biely (1975).  The true  protein and non-protein nitrogen content of the DPW samples were determined by the procedure described by Hawk et a l. (1954) who adopted i t from Folin & Wu for the determination of non-protein nitrogen i n the serum. The method used was as followed: 1 gm of the DPW samples was weighed into a 50 ml Erlenmyer flask and 25 ml of 0.2 N sulfuric acid was added. The mixture was boiled gently on a water bath with occasional stirring for 30 minutes. The flask was removed from the water bath, 10 ml of 10% sodium tungstate solution was added and placed at room temperature for another 30 minutes with occasional stirring.  The solution was then filtered, the f i l t r a t e and the residue were  analysed for nitrogen by the macro-Kjeldahl method. in the residue was multiplied by a factor of 6.25.  The amount of nitrogen This is the true protein  in the sample while the amount of nitrogen in the f i l t r a t e i s the non-protein nitrogen content of the sample.  34  One sample of untreated DPW and the sample treated with 2% NaOH were hydrolyzed with 3N hydrochloric acid for 16 hours at 121°C.  The hydrolysate  was analysed for amino acid contents by an automatic amino acid analyser. The pH of the DPW samples and percentage of sodium hydroxide residual in the DPW were determined by stirring 1 gm of the sample i n 20 ml of dist i l l e d water and the pH of the solution was measured. It was then filtered and the f i l t r a t e was titrated with standard hydrochloric acid using phenol red as the indicator.  The sodium hydroxide equivalent present i n the DPW  sample was calculated arid expressed as the percentage of the original sodium hydroxide added to the DPW.  Experiment 2. Performance of broiler chicks fed of untreated DPW or DPW treated with various concentrations of sodium hydroxide and the M.E. values. Untreated DPW or DPW treated with 2, 3 and 5% sodium hydroxide solution were included in diets at levels of 10, 15 and 20%. A l l diets were formulated for equivalent true protein content. in Table 2.  The composition of the diets are shown  The DPW sample contained approximately 13% true protein and the  M.E. was estimated to be 1000 kcal/kg.  The control 1 diet contained 23% pro-  tein and a calculated M.E. value of 2959 kcal/kg., which was comparable to the diet containing 10% DPW;  The control 2 diet was formulated to provide  a-protein content and M.E. value similar to those diets containing 15 and 20% DPW. Broilerd chicks (five days of age) were used with each experimental diet fed to three replicates of eight birds each.  Birds were randomly assigned to  electrically heated battery brooders and feed and water were supplied ad, libitum.  Chicks were weighed at the begining of the test period and weekly  thereafter during the three week study.  Body weight gain and feed conversion  35  Table 2.  Composition of the diets in Experiment 2.  Ingredients (%) Ground wheat  Control 1  Control 2  61.5  30.0  Ground barley  —  DPW  —  2  Soybean meal  1  33.0 —  10% DPW 46.5 —  15% DPW 41.5 —  20%  DPW  1  36.5 —  10.0  15.0  20.0  27.0  27.5  28.0  28.0  28.0  Meat meal  3.0  3.0  3.0  3.0  3.0  Cereal grass  1.0  1.0  1.0  1.0  1.0  Tallow  4.0  2.0  8.0  8.0  8.0  Dicalcium phosphate  1.5  1.5  1.5  1.5  1.5  Ground limestone  1.0  1.0  1.0  1.0  1.0  Micronutrients^  1.0  1.0  1.0  1.0  1.0  Total  100  100  100  100  100  Calculated M.E. kcal/kg  2959  2754  2919  2805  2697  % True protein  23.01  22.96  22.85  22.83  22.83  L.  The same formulation was used i n Experiment 5, 6 and 7 for preparing the basal diets.  2. The DPW used was untreated or treated with 2, 3 or 5% sodium hydroxide. 3. The micronutrients supply per kg. of feed; Vit. A, 8800 I.U.; v i t . D , 880 ICU.; E, 22 I.U.; v i t . B , 13.2 ug.; 3  2  riboflavin, 6.6 ug.; calcium pantothenate, 8.8 mg.; niacin, 22 mg.; choline chloride, 220 mg.; amprolium, 500 mg.; ethoxyquin, 500 mg.; manganese sulfate, 308 mg., zinc oxide, 60.5. mg.; copper sulfate, 31 mg.; iodized salt, 0.25%. Unless otherwise stated, the premix also contained 11 mg. of zinc bactracin per kg. of feed.  36  ratios were calculated at weekly intervals; Broiler chicks (three weeks of age) were used to determine the M.E. of untreated DPW, and DPW treated with 2, 3 and 5% sodium hydroxide solution. ' DPW samples were substituted in the basal ration at 20% or 30% with 0.3% chromic oxide marker added to each diet. replicates with 8 birds each. days.  Each treatment consisted of three  The birds were fed the test diets for three  A sample of feces was collected on the 4th, 5th and 6th days from  each group, pooled together and freeze-dfied.  The feed and feces were analysed  for gross energy by oxygen bomb calorimetry, chromic oxide content by the method of Czarnocki et a l . (1961); and nitrogen content by the macro-Kjaldehl method.  The metabolizable energy values for the basal and DPW diets were  calculated according to the method of H i l l and Anderson (1958). E diet = combustible energy per gm of diet dry matter E excreta = combustible energy in excreta per gm of diet dry matter C^O^ per gm diet = combustible energy/gm excreta x 7  C*2®3 P  e r  £  m  e  x  c  r  e  t  a  N = Nitrogen retention per gm of diet dry matter Cr2C>3pper gm diet = N/gm diet - N/gm excreta x Cr^Og per gm excreta M.E. kcal/gm diet = E diet - E excreta - 8.22 N M.E. of DPW (kcal/gm) = »E./gm test diet - (M.E./gm basal diet x % basal i n test diet) M  % DPW in test diet  Experiment 3. Utilization of the non-protein nitrogen from the DPW or from the various nitrogenous compounds by broiler chicks. A basal diet (20% protein) was formulated to supply suboptimal level of protein for maximum growth of broiler chicks. Two DPW diets were prepared,  37  each containing 20% of untreated DPW or DPW treated with 2% NaOH solution. Non-protein nitrogen supplemented diets were prepared by substituting alphacel in the basal with uric acid, urea or diammonium citrate which was equivalent in nitrogen ,content to NPN i n the DPW diets.  The composition of the diets  are shown in Table 3. A l l diets were equivalent with respect to their true protein and calculated M.E. contents.  A high protein control diet containing  the same amount of metabolizable energy as the experimental diets but contained 23% protein was also used. Day old broiler chicks were used i n this experiment with each treatment consisting of five replicates with 5 birds each.  Chicks were randomly assigned  to in electrically heated raised floor battery brooder.  Experimental diets  were fed to chicks (4 weeks), with the body weight gain and feed consumption recorded weekly. When the chicks were 3 weeks old they were used for nitrogen retention determination.  Chicks of each treatment were starved for 16 hours, then fed  the experimental diet for 12 hours and starved again for 12 hours; afterwards they were returned to the ad-libitum feeding.  Feces were collected during  this 24 hours feed-and-fast period, freeze-dried and weighed. The feed consumption was also recorded.  The nitrogen content of the feed and feces was  determined according to macro-Kjeldahl method (A.O.A.C.); uric acid content of the DPW diets and the feces collected from each treatment were determined according to modified method described by Stapleton and Biely (1975).  Experiment 4. Availability of total nitrogen, true protein and minerals i n DPW and sodium hydroxide treated DPW. The availability (or true digestibility) of total nitrogen, protein, calcium, phosphorus and sodium i n the untreated DPW or DPW treated with 2, 3  38  Table 3. Composition of diets used in Experiment 3  Diets  Ingredients High Protein  Basal Control  Uric  Urea  DAC  DPW  Wheat  30.0  48.0  48.0  48.0  48.0  45.0  Barley  33.0  20.0  20.0  20.0  20.0  —  (%)  DPW  2  —  Soybean meal  —  1  20.Q  —  27.5  19.5  19.5  19.5  19.5  19.5  Meat meal  3.0  3.0  3.0  3.0  3.0  3.0  Cereal grass  1.0  l^O  1.0  1.0  1.0  1.0  Tallow  2.0  3.0  3.0  3.0  3.0  8.0  Alphacel  —  2.0  1.0  1.22  —  —  —  —  1.0  0.78  2.0  —  Dicalcium phosphate  1.5  1.5  1.5  1.5  1.5  1.5  Ground. limestone  1.0  1.0  1.0  1.0  1.0  1.0  Micro. 4 nutrients  1.0  1.0  1.0  1.0  1.0  1.0  Total  100  100  100  100  100  100  M.E. (kcal/kg)  2754  2825  2825  2825  2825  2765  True protein (%) Total N (%)  22.96  20.08  20.08  20.08  20.08  20.0  3.67  3.21  3.57  3.57  3.57  3 NPN sources  Calculated  1. 2. 3. 4.  3.57  Diammonium citrate. DPW used was untreated or treated with 2% NaOH. Non-protein nitrogen was supplied by uric acid, urea or diammonium citrate. The micronutrient premix used was same as i n Experiment 2.  39  or 5% NaOH solution was determined according to the method of Bragg et a l . (1969) with slight modification. According to the method of Bragg et a l . (1969) the birds were fed the marker diet immediately after feeding the purified diet or the test diet. However, i t was found i n a preliminary study, that some of the undigested material from the previous diet tended to mix up (in the intestine) with the ingesta from the marker diet as i t was fed immediately following the test diet.  Therefore, the procedure was modified to allow sufficient time for  evacuation of the excreta of the previous diet from the intestine before feeding the marker diet.  The marker diet was used to indicate the complete  excretion of the feces from the previous diet. The composition of the purified diet (nitrogen free-mineral free) used consisted of glucose 81.0%, alphacel 8.8%, corn o i l 10.0% and choline chloride 0.2%.  Each of the DPW samples was mixed with the purified diet at 1 : 1 ratio  in the test diets.  The marker diet used was a practical starter diet contain-  ing 0.3% ferric oxide. Sixty three week-old broiler chicks were used in the digestibility determinations.  Thestest birds were fed a commercial starter diet from one day to  21 days of age. They were then randomly assigned to 12 groups with 5 birds per group and three groups per dietary treatment. in each group was similar.  The total weight of birds  Chicks were housed in electrically heater batteries  with stainless steel feeders and waterers.  The birds were fed thetinarker diet  on the f i r s t day and the feed was withdrawn i n the afternoon (6 p.m.) of the second day. These birds were starved for 14 hours, followed by feeding the purified diet for four hours. fed the marker diet. oxide) were collected.  Birds were fasted again for four hours and  Excreta from the purified diet (containing no ferric The same procedure was repeated on the following day  40  with the t e s t d i e t s  (50% DPW + 50% p u r i f i e d d i e t )  E x c r e t a from the t e s t d i e t s were a g a i n c o l l e c t e d . consumed were measured.  replacing  the p u r i f i e d  Weight o f the t e s t  Water was l i m i t e d d u r i n g the s t a r v a t i o n  diet.  diets  period to  a v o i d e x c e s s i v e consumption o f water and consequently p r o d u c t i o n o f e x t r e m e l y wet  feces. The  feces c o l l e c t e d  i n d i v i d u a l l y measured. and  from each group were f r e e z e - d r i e d  and the weight was  The t e s t d i e t s , and the f e c e s from the p u r i f i e d  diet  t e s t d i e t s were a n a l y s e d f o r t o t a l n i t r o g e n by the A.O.A.C. method;  true p r o t e i n  as d e s c r i b e d b e f o r e ; and c a l c i u m and sodium c o n t e n t s by atomic  absorption spectrometry following  wet d i g e s t i o n  a c i d b y the method o f Johnson and U l r i c h  with p e r c h l o r i c  (1959).  and n i t r i c  The phosphorus c o n t e n t  of a l l samples was determined w i t h a spectrophotometer f o l l o w i n g  development  of c o l o r w i t h ammonium molybdate. The  a v a i l a b i l i t y o f each i n d i v i d u a l n u t r i e n t  to the f o l l o w i n g % nutrient Total =  availability  consumed - C t o t a l i n f e c e s from test diet  h y d r o x i d e were a l s o  x  , ... 100  consumed w i t h 2, 3 and 5% sodium  a n a l y s e d f o r p h y t a t e phosphorus and p h y t i c  to the method o f Wheeler and F e r r e l  The  t o t a l i n feces fed. the p u r i f i e d d i e t  f o u r samples o f u n t r e a t e d DPW o r DPW t r e a t e d  Experiment 5.  according  formula:  Total The  was c a l c u l a t e d  acid  according  (1971).  E f f e c t o f amino a c i d supplementation on the performance o f c h i c k s f e d d i e t s c o n t a i n i n g u n t r e a t e d DPW o r a l k a l i - t r e a t e d DPW.  amount o f a v a i l a b l e  t h r e o n i n e i n the c o n t r o l  lysine, arginine,  methionine" " c y s t i n e and 1  and DPW d i e t s used i n Experiment 2 were  calculated  41  and are shown i n Table 4.  The amino acids in the untreated DPW were assumed  to be 50% available while that of the alkali-treated DPW were about 70% available, and the amino acid compositions of the two samples of DPW determined i n Experiment 1 were used to calculate the amount of available amino acids contributed by the 20% DPW i n the diets.  It was noted that both of the control  diets (control 1 and 2) were suboptimal i n the sulfur-containing amino acids while the DPW diets contained higher levels of the sulfur-containing amino acids than the controls.  A l l diets were suboptimal i n available lysine as  compared to the level recommended by NRC (1971) nutrient requirements. In this experiment, three basal diets were prepared with the composition of Control diet 2 and 20% DPW diets as in Experiment 2 (see Table 2).  One of  the DPW diets contained untreated DPW while the other contained 3% sodium hydroxide treated DPW.  The basal diets were without ordwith 0.2% D-L methion-  ine, or with 0.2% D-L methionine + 0.1 % L-lysine or with 0.2% D-L methionine + 0.2% lysine supplement.  The high-energy control (Control)l)tsas i n Experi-  ment 2 but supplemented with 0.2% D-L methionine and 0.1% lysine was also used for comparing the performance of chicks fed the medium-high energy and low energy diets.  There were a total of 13 dietary treatments included i n  this study. Three hundred and ninety day-old broiler chicks were randomly assigned to electrically-heated battery brooders with 10 birds per replicate.  Three  replicates were used per dietary treatment.  The birds were given the test  diets and water ad libitum for four weeks.  Body weight and feed consumption  were measured weekly.  Experiment 6.  Effect of increasing the energy content of the diets with supplementary tallow on performance of chicks fed the diets containing untreated DPW or alkali-treated DPW.  42  Table 4. Available amino acid content of the diets (calculated )  Amino acid  N.R.C. Require ments  Levels i n Diets (%) Control j  Control 2  20% DPW untreated  20% DPW NaOH treated  2  Arginine  1.40  1.42  1.39  1.40  1.40  Lysine  1.25  1.16  1.20  1.20  1.19  Methionine + cystine  0.86  0.69  0.67  0.81  0.80  Threonine  0.80  0.82  0.81  0.78  0.79  Protein (true)  23.0  23.01  22.96  22.83  22.83  1. The available amino acid content of the ingredients was based on the figures provided by the Agricultural Extension Service, University of Arkansas, 1966. 2. The available amino acid content of the untreated DPW was estimated by multiplying the determined amino acid content of a sample of DPW by a factor of 50%. 3. The available amino acid content of the NaOH treated DPW was estimated by multiplying the determined amino acid content of the 2% NaOH treated DPW by a factor of 70%.  43  Three basal diets as i n the previous experiment containing a metabolizable energy value of approximately 2750 kcal/kg were prepared.  One of the  diets contained no DPW, while the other two contained either 20% untreated DPW or 20% alkali-treated (3% NaOH) DPW.  The energy content of these diets were  increased by approximate 100 kcal/kg by adding 2% animal fat to the diets with the soybean meal contents being adjusted so that a l l diets were equivalent i n the true protein contents.  No antibiotics were added to the diets.  A l l diets were supplemented with 0.2% D-L methionine and 0.1% lysine. The composition of the diets are shown in Table 5. Day old broiler chicks were randomly distributed to each of the battery brooders.  Three replicates of 10 chicks each were used per dietary treatment.  The test diets and water were supplied ad libitum for four weeks. Body weight and feed consumption of each group were measured at weekly interval. Sample of feces was collected from each replicate and freeze-dried when the chicks were seventeen days old.  Crude fat content by extracting the  sample with anhydrous diethyl ether for sixteen hours using the Soxphlet apparatus was determineddfor feed and feces.  The gross energy content of  the feed and feces were determined by bomb calorimetry using the Parr plain jacket oxgyen bomb and the nitrogen content was determined using the Kjeldahl method.  The acid insoluble ash content of the feed and feces was determined  according to the method described by Vogtmann et a l . (1975). The apparent digestibility of fat, metabolizable energy value and nitrogen retention of the diets were calculated usinghthe following formulas: A j• .,_ of <• fat <• _ = 1 •• - % Fat i n^excretax App. digestibility % Fat i n feed g/  A  % ash in feed % ash in excreta  M.E. = GE - GE x I ^ - 8.22^ - N % ash in feed F E % ash in excreta F E % ash in excreta' i n  f e e d  x  44  Table 5.  Composition of diets used in Experiment 6.  Ingredients (%)  Low-fat Basal Diets  Fat-supplemented Diets  Control  DPW  Control  DPW  Ground wheat  30.0  36.5  27.5  34.0  Ground barley  33.0  DPW  1  33.0  1  —  —  20.0  27.5  28.0  28.0  28.5  Meat meal  3.0  3.0  3.0  3.0  Cereal grass  1.0  1.0  1.0  1.0  Tallow  2.0  8.0  4.0  10.0  Dicalcium phosphate  1.5  1.5  1.5  1.5  Ground limestone  1.0  1.0  1.0  1.0  1.0  1.0  1.0  1.0  100  100  100  100  Soybean meal  2 Micronutrients Total  —  20.0  Calculated chemical composition M.E. (kcal/kg)  2755  2720  2844  2810  Protein (true) %  23.25  23.14  23.17  23.06  3.95  7.17  3.90  7.10  1.26  2.0  1.27  2.01  Crude fibre Calcium  %  %  1.  The DPW used was untreated or treated with 3% NaOH.  2.  The micronutrient premix used was same as in Experiment 2 except without zinc bacitracin and supplemented with 2 g. D-L methionine and 1 g. L-lysine monohydrochloride per kg. of feed.  45  where GE  r  = gross energy of the feed kcal/gm D.M.  GEg = gross energy of the excreta kcal/gm D.M. N„  = Amount of nitrogen per gm D.M. of feed  N^, = Amount of nitrogen per gm D.M. of excreta  m% N retention  = 1 -%•„•N in . excreta x % ash in feed % N i n feed % ash in excreta n  >T  Experiment 7. Effect of antibiotics supplementation on the performance of chicks fed with the DPW diets. The three basal diets containing no antibiotics from Experiment 6 were again used i n this experiment.  In addition, each of the three basal diets  was supplemented with zinc bacitracin at 44 mg/kg and procaine pencillin at 11 mg/kg to give the "antibiotic-fed" diets. Day old broiler chicks were allotted to groups of 10 chicks each in electrically-heated brooder batteries.  Each experimental diet was fed to  triplicate lots of chicks from day old to 4 week of age. The groups fed the antibiotic supplemented diets were kept separated from the control groups so as to avoid possible contamination between the dietary treatments.  Body  weight and feed consumption were measured weekly. Samples of feces from each lot were collected and freeze-dried on the 7th, 15th and 27th day. The feed and feces were analysed for crude fat content by extracting with anhydrous diethyl ether for four hours with the Goldfisch apparatus.  The gross energy content of the samples was determined by bomb  calorimetry and nitrogen by Kjeldahl method. The calcium content of the feed and feces were determined by atomic absorption spectrometry following wet digestion with perchloric and n i t r i c acid. The phosphorus content was  46  determined by the spectrophotometry  method as described before.  Acid i n s o l u b l e ash was used as the index substance f o r c a l c u l a t i n g the d i g e s t i b i l i t y c o e f f i c i e n t s and metabolizable energy values.  The apparent  f a t d i g e s t i b i l i t y , M.E. and percent n i t r o g e n r e t e n t i o n of the d i e t s fed to the chicks at 1, 2 and 4 week of age were c a l c u l a t e d according to the f o r mulas i n the previous experiment.  I n a d d i t i o n , calcium and phosphorus reten-  t i o n of the chicks at 2 week of age with the d i f f e r e n t d i e t a r y treatments were also  determined.  47  RESULTS AND DISCUSSION Experiment 1. Effect of sodium hydroxide treatment on the chemical composition of DPW. The chemical composition of the samples of DPW untreated or treated with various levels of sodium hydroxide solution are shown i n Table 6. Sodium hydroxide treatment slightly reduced the acid-detergent fibre (cellulose and lignin) content of DPW; however, a significant decrease was observed only at the 7% level of NaOH treatment.  The alkali treatment signi-  ficantly reduced the true protein content of the DPW at levels above 2%, and at 7% the effect was most pronounced showing a severe destruction of protein. The non-protein nitrogen and uric acid contents of the DPW were also reduced in relation to the level of sodium hydroxide used.  The destruction of true  protein, non-protein nitrogen and uric acid are apparent following treatment due to the strong odor of ammonia observed. The amino acid composition of a sample of untreated DPW and the sample treated with 2% sodium hydroxide solution i s shown in Table 7. Most of the amino acids were not affected by the treatment.  Lysine, arginine, serine,  proline, leucine and cystine showed slight reduction while alanine showed an increase with the treatment. When 2% sodium hydroxide was added to the DPW a l l of the sodium hydroxide had reacted with the material with only a slight increase i n pH of the sample.  Treatments with 3 to 5% NaOH significantly increased the NaOH  residue in the DPW sample.  Therefore, levels above 5% showed an undesirable  effect. DeGroot and Slump (1969) observed that treatment of food proteins with alkali might induce chemical changes which were attended with the occurrence  48  Table 6.  Effect of sodium hydroxide treatment on chemical composition of DPW  Chemical composition  Level of (%) Treatment v  0%  2%  Acid-detergent fibre  24.3  23.2  True protein  14.6  Non-protein, initrogen (% N x 6.25)  ki  5  7  23.6  23.4  23.5  22.1  13.5  10.7  10.7  10.5  9.7  11.7  10.5  10.1  10.1  10.2  9.6  Uric acid  3.5  3.2  3.1  3.0  2.4  2.0  Percent residual of sodium hydroxide  0  0  8.5  9.5  7.6  11.5  pH.  7.4  8.0  8.4  9.0  9.6  11.0  37-  49  Table 7. Amino acid composition of a sample of untreated DPW and the sample treated with 2% NaOH.  % in sample Amino Acid  Untreated DPW  Alkali-treated DPW  Lysine  0.48  0.38  Histidine  0.29  0.22  Arginine  1.11  0.88  Aspartic acid  1.0  0.95  Threonine  0.49  0.46  Serine  0.64  0.44  Glutamic acid  1.59  1.44  Proline  0.88  0.61  Glycine  0.93  0.94  Alanine  0.58  0.82  Valine  0.25  0.18  Cystine  1.49  1.31  Methionine  0.33  0.47  Isoleucine  0.54  0.44  Leucine  0.84  0.63  Tyrosine  0.33  0.34  Phenylalanine  0.51  0.54  50  of a new peptide, lysinoalanine, and with decreased content of cystine and to a lesser extent, lysine and serine. Cystine was decreased by 50% or more in samples of casein and isolated soy protein treated at pH 12.2 (0.2 M NaOH) and further decreased by raising the temperature above 40 C during drying. At lower NaOH concentrations (pH below 10) the effect on the amino acid content was not great.  In this study, the effect of NaOH treatment on the amino acdid  content of DPW is in agreement with results of DeGroot and Slump (1969). However, the degree of reduction is less than that observed by the above authors even though the concentration of NaOH used in this study is higher (2% vs 0.8% or 0.2 M). treated DPW.  There is an increase in alanine content in the NaOH  This may be due to the formation of the lysinoalanine during  the treatment followed by acid hydrolysis or other chemical changes. A primary change in proteins by alkali treatment, as proposed by DeGroot and Slump (1969), is the formation of dehydroalanine residues from cystine and serine residues.  This compound may react with the E-amino group of lysine  to give lysinoalanine.  Experiment 2. Performance of broiler chicks fed various levels of untreated DPW or DPW treated with various concentrations of sodium hydroxide and the M.E. values. The effects.of inclusion of untreated or sodium hydroxide treated DPW at levels of 10, 15 and 20% in the diets on the growth, feed consumption and feed conversion ratios are shown in Table 8. The growth and feed efficiency of chicks fed the control 2 diet, (low energy control) were significantly lower than those on control 1 (high energy control).  Including 10% DPW in the diet did not affect the performance of  chicks, although the feed conversion ratio was slightly higher than the high energy control. As the untreated DPW in the diet increased from 10% to 20%,  51  Table 8.  Effect of including untreated and sodium hydroxide treated DPW in diets on 3 weeks body weight gain, feed consumption and feed conversion ratio.  Level of NaOH Treatment  (%)  Body Weight Gain (g-) Control 1  Control 2  426.2 '  375.6  bcd  2:;  3  —  3:—  5V  1  10% DPW  15% DPW  cd  a  ,  20% DPW  „abc  402.0  432.9  —  470.4  de  486.9  —  434.8  Gd  441.7  —  457.6  de  427.5 °  6  Gde  b  d  388.l  ab  428.5  bcd  443.2  cde  484.5  e  Total Feed Consumption per bird (g.) 3 0.  683  693  a  ab  765°  780 869  2;  —  —  803  3:  —  —  772°  792  5>o  —  —  808  755  cd  Gd  Feed Conversion  747  cd  ? 7 2  6  cd  C  bc  bc  834  de  843  de  2  Ratio  3 0/',  1.67  a  1.84  cd  1.77  bGd  1.94  2.06  6  2%  —  —  1.70  ab  1.78  3  --  ZZ  l,77  b c d  1.79  5^1;  —  —  1.76  abc  bGd  bcd  1.76  abc  1.  Body weight gain = final body weight —  i n i t i a l body weight  2.  Feed conversion ratio = g. of feed/g. of gain.  3.  Different subscripts indicate significant difference (P < 0.05).  f  1.81  bcd  1.88  de  1.73  ab  52  growth of the chicks was progressively decreased.  Body weight gain of the  chicks fed the 15% DPW diet (402 g) was between those of the high-energy control (426.2 g) and low-energy control (375.6 g). to the calculated M.E.  This is directly related  content of the diet, which is below that of high-energy  control but above that of low-energy control. Body weight of chicks fed 20% DPW (388.1 g) was much below that of the high-energy control but Isimilar to those of low-energy control. Therefore, the poor growth of chicks fed the 20% untreated DPW diet, as compared with the high-energy control further supports the effect of dietary energy on growth. When compared to a similar energy control diet, addition of untreated DPW as high as 20% did not adversely affect growth. The feed conversion ratio progressively increased as the level of untreated DPW in the diet increased from 10-20% and was significantly greater at 20% DPW than that of the low-energy control, indicating that the diets containing high levels of untreated DPW were utilized less efficiently when compared to the control. However, higher feed consumption at the 15 and 20% DPW supported growth equal to or better than that of the low-energy control. A l l levels of sodium hydroxide treatment significantly improved the growth and feed conversion ratios of the chicks fed the diets containing high levels of DPW (above 10%).  Chicks fed the sodium hydroxide treated DPW grew  as well as those fed the high-energy control and in some cases had better growth. A l l NaOH treated DPW diets supported growth better than the lowenergy control. This is due to the increase in feed consumption with equal or better utilization of feed by the chicks fed NaOH treated diets compared to the low energy control. These results suggest that the NaOH treatment significantly improved the M.E. content of the DPW.  The improved energy level is,  further confirmed by the comparison of M.E. values for the untreated and sodium hydroxide treated DPW as shown in Table 9.  53  Table 9.  Effect of sodium hydroxide treatment on metabolizable energy value of  Level of NaOH treatment  DPW  Metabolizable Energy Value (kcal/kg) 20% inclusion in  30% inclusion in  (%)  the basal  the basal  07  725  930  827  1165  1145  1155  3'/  1200  1291  1245  5'-;  1300  1110  1205  Average  54  The M.E. values of 0, 2, 3 and 5% sodium hydroxide treated DPW were 827, 1155, 1245, and 1205 kcal/kg respectively.  Addition of 2% sodium hydroxide  significantly improved the M.E. of the DPW, but no further increase with higher NaOH dosage was observed.  The value of 1155 kcal/kg for the 2% NaOH  treated group is relatively low when compared to grains such  as barley and  oats eventhough these grains have a similar protein content compared to DPW. The high fibre content of the DPW reduces the available carbohydrate i n the DPW.  It is apparent that the sodium hydroxide treatment may degrade the  plant c e l l walls and increase the enzymatic digestion which resulted in an improvement in the utilization of nutrients contained in the DPW and in the M.E. content. Results of this study indicate that DPW added to the broiler diet at levels between 5 and 20% w i l l support broiler performance related to the dietary composition, especially energy.  Chemical treatment (NaOH) improved  the nutritive value of DPW in which the major improvement i s credited to increased available energy.  The treatment does not appear to have any adverse  effects on the bird with NaOH concentration up to five percent.  Experiment 3. Utilization of the non-protein nitrogen from the DPW or from the various nitrogenous compounds by broiler chicks. The body.weight gains, feed consumption and feed conversion efficiencies of the chicks fed the experimental diets for four weeks are shown i n Table 10. The body weight gains of chick fed the basal diet were not different from those fed the 23% protein diet.  Apparently, the chicks tended to consume more  feed so as to satisfy their protein requirement, as their food consumption was higher than those fed the high protein diet.  The growth rates of chicks  fed the diets containing 20% untreated DPW, alkali treated DPW or 1% uric  55  Table 10. Body weight gains, feed conversion ratio and feed consumption of chicks fed the different diets for 4 weeks in Experiment 3.  Diets  Body weight gains  Feed consumption  Feed Conversion  (g.)  per bird (g.)  ratio  c  1  High-protein  530  1012  Basal control  531°  1123  C  2.10  Uric acid  530°  1136°  2.12  Urea  497  b  1066  2.13  Diammonium citrate  394  a  893  Untreated DPW  521  1199  2.33  NaOH treated DPW  534°  1221  2.28  c  b  b  a  d  d  1.91  a  b  b  b  2.12  b  C  1. Different subscripts denote significant difference (P < 0,05).  C  56  acid were not significantly different from the control, while those fed the urea supplemented diet were significantly lowered.  Growth of chicks fed the .  diet supplemented with 2% diammonium citrate were greatly depressed.  Feed  consumption was increased by the inclusion of 20% untreated or alkali treated DPW i n the diets.  Addition of uric acid to the basal diet did not affect the  feed consumption of chicks, but addition of urea and diammonium citrate significantly depressed the feed consumption, with diammonium citrate producing the greatest effect.  Addition of the various NPN sources did not affect the feed  efficiency (g. feed/g. gain).  The DPW diets had poorer feed efficiencies when  compared with the control. Chicks fed the diet containing 20% NaOH treated DPW tended to have better growth and feed efficiency, though not statistically significant than those fed the diet containing untreated  DPW.  The percent nitrogen retention, g. N retained/100 g. of feed, and g. of uric acid excreted/100 g. of feed consumed of each treatment are shown i n Table 11.  The percent nitrogen retention of the DPW diets or the NPN  supplemented diets was lower than the control, but the amount N retained per 100 gm. of feed consumed by chicks fed these diets was not different from the control. Inclusion of DPW i n the diet or addition of the non-protein nitrogen to the basal diet increased the uric acid excretion. The control diet was suboptiomal i n protein content for maximum growth of broiler chicks.  If the chick can u t i l i z e the non-protein nitrogen for  synthesis of amino acids and protein, supplementation of such sources of nitrogen to the control should have stimulated a growth response.  However,  no favorable responses were obtained with the additional amount of nitrogen from the non-protein nitrogen fraction of the DPW or from the various nitrogenous compounds added to the diets.  The lack of response may be due  to two factors: f i r s t l y , the diets were low i n metabolizable energy, so  57  Table 11.  Effect of feeding DPW and non-protein nitrogen supplemented diets on nitrogen metabolism of the chicks.  Diets  N Retention •%  N (g.) retained  % uric  Uric acid (g.)  per 100 g.  acid in  excreted per  feed  feed.  100 g. feed  High-protein  40.5  1.42  4.35  Basal control  39.0  1.20  3.38  Uric acid  35.7  1.28  Urea  36.3  1.28  4.15  Diammonium citrate  37.0  1.22  4.36  Untreated DPW  36.6  1.30  0.98  4.30  NaOH treated DPW  36.1  1.27  0.87  4.11  1.02  4.33  58  that the chicks may have increased feed consumption to satisfy their energy needs, thereby consuming enough protein; secondly, the non—protein nitrogen may not be.utilized by the chick. Shannon and Blair (1969) and McNab et a l . (1974) using colostomised hens, showed that the percentage of absorption of diammonium citrate and uric acid were 99 and 91.2% respectively. Martindale (1975) also observed l i t t l e urate excretion i n feces of colostomised hens fed the 20% DPW diets.  These studies  show that NPN are completely available to the birds; yet the amount of nitrogen retained per 100 gm of feed consumed by chicks fed the non-protein nitrogen supplemented or DPW diets were not increased.  This indicates that  additional amount of nitrogen from NPN was not retained by the chick but simply excreted in the urine.  The increase i n uric acid excretion by  approximately the same amount of uric acid or equivalent consumed when fed NPN diets supports this suggestion.  Martindale (1975) also showed that urate  excretion was greater during DPW feeding by approximately the amount consumed. 14 When a dose of  C-urate was introduced into the crop of the bird 98.8% of the  radioactivity was recovered from the urine i n the f i r s t 24 hours with the remaining activity found in the feces.  Hence, results show that none of the  urate present i n DPW can be utilized by the growing chicks or by the laying hens. In vitro studies with chick liver homogenate, Lee and Blair (1972) showed that NH^  +  from the diammonium citrate can be incorporated into a-oxoglutaric  acid to form glutamic acid by means of glutamic dehydrogenase. However, i n vivo studies by Lee et a l . (1972) in which they supplementing 11.07% diammonium citrate to the basal diet containing essential amino acids as the sole source of nitrogen did not cause induction of glutamate dehydrogenase. Compared with the control, no increase in transaminases such as aspartate transaminase,  59  and alanine tranaminase was found in the livers of birds given the semisynthetic diets, suggesting that supplying non-essential nitrogen does not result in further induction of these enzymes. Literature results to date have shown that non-protein nitrogen sources were shown to be utilized successfully only i f the diets were deficient or lack non-specific nitrogen.  A  dietary inadequacy of non-essential nitrogen is improbable when ordinary feedstuffs are employed.  Therefore, though i t has the biochemical potential of  converting the nitrogen from non-specific nitrogen sources into amino acids, the chick does not seem to gain>.any benefit in vivo from the inclusion of non-protein nitrogen in protein-based diets. Feeding as low as 0.78% urea to the chick in this experiment was shown to have deleterious effect on chick's growth.  The toxic effects of urea  ingestion probably result from ammonia produced by hydrolysis of the urea by bacterial urease activity in the intestine.  Using different agents which were  able to suppress gastrointestinal urease activity in rats, chick and other simple stomach species, Visek (1962) and Visek (1968) showed that growth and feed utilization of the animals were significantly improved.  They suggested  that ammonia produced from urea hydrolysis affects cell regeneration as well as leads to profound histological changes on the intestine of some species. Antibiotics have been shown to be effective in suppressing the ureolytic activities in the intestine.  Dintzis and Hastings (1953) observed that high  dietary levels of penicillin, oxytetracycline and sulfaguanidine greatly reduced fecal bacterial count and at the same time completely suppressed urea hydrolysis.  Visek et a l . (1959) showed that 100 ppm of penicillin or  chlortetracycline in the diet could significantly reduce the ureolytic activities in the gastrointestinal tract of the rat. Harbers et a l . (1963) also showed that the addition of 100 ppm of chlortetracycline enhanced the  60  four week gains of chicks and lowered the urease a c t i v i t y and ammonia conc e n t r a t i o n i n the i n t e s t i n e .  In these experiments,  d i e t s contained 11  ppm  of zinc b a c i t r a c i n , however, no improvement i n growth was obtained w i t h t h i s l e v e l of a n t i b i o t i c s i n the urea supplemented d i e t . Olsen et^ a l . (1963) showed that the i n c l u s i o n of up to 12% diammonium c i t r a t e i n a semi-purified basal d i e t with i s o l a t e d soy-protein or casein as the sole p r o t e i n source r e s u l t e d i n progressive increases i n the concentration of glutamine and a s i g n i f i c a n t decrease i n glutamic a c i d i n the plasma.  The  observed decrease of plasma glutamic a c i d i s probably a r e f l e c t i o n of the use of glutamic a c i d f o r the formation of glutamine w i t h the d i e t a r y ammonia. Hence, the c h i c k , l i k e other species, u t i l i z e d glutamine as a c a r r i e r of ammonia i n the blood.  The l e v e l of glutamine i n the blood depends on the  balance between amount of ammonia ingested, the r a t e of formation of  glutamine,  the r a t e at which glutamine i s u t i l i z e d f o r u r i c a c i d or other s y n t h e s i s , and the r a t e of u r i c a c i d e x c r e t i o n . When the amount of nitrogen ingested, i n the form of p r o t e i n , diammonium c i t r a t e , urea or glutamic a c i d i s increased, u r i c a c i d e x c r e t i o n i s increased correspondently. Kazemi and Balloun 1972, Creek and V a s a i t i s 1961).  (Olsen et a l . 1963, However, when the intake  of nitrogen i s high enough that e x c r e t i o n rates approach or exceed the mean tubular secretory capacity of the kidneys, i t r e s u l t s i n a s i g n i f i c a n t i n crease i n plasma glutamine concentration and consequently ammonia i n the blood.  accumulation  of  T h i s , i n t u r n , adversely a f f e c t s the feed i n t a k e .  Indeed, chicks fed the d i e t s supplemented w i t h urea or diammonium c i t r a t e consumed l e s s feed than those fed the basal d i e t which may  e x p l a i n the  depression i n growth obtained w i t h these d i e t s . Olsen et a l . (1963) observed that the depression i n weight gain by d i e t s containing high l e v e l of diammonium c i t r a t e were not improved by the a d d i t i o n  61  of glutamic acid to these diets. These workers suggested that the decreased weight gain could not be attributed to a diversion of glutamic acid needed for protein synthesis that was diverted to glutamine formation.  On the other  hand, Bloomfield et a l . (1969) observed a significant protective effect of glycine and glycine + glucose against ammonia intoxication i n chicks.  These  protective agents exert their effect by enhancing uric acid sysnthesis.  They  suggested that the third step i n uric acid synthesis, that i s , formation of glycinamide ribotide from glycine and phosphoribosylamine may be the limiting step in chicks under stress from ammonia load.  The Agricultural Research  Council (1963) suggested that 1% glycine i s adequate i n practical-type diets. With higher dietary nitrogen levels the glycine requirement may be greater than 1%, which may be related to the involvement of glycine i n the detoxification of excess dietary nitrogen as uric acid.  In fact, Snetsinger and  Scott (1961) found that over 2% glycine was required to overcome the growth depression effect resulting from excesses of single amino acids.  Blair et a l .  (1972) found that increasing the glycine level i n the basal crystalline amino acids diet containing 10% diammonium citrate from 1% to 1.6% slightly improved the growth of the chicks though not reaching statistical significance. The amount of glycine contained i n the basal and the DPW diets was 1.17% and 1.25% respectively, although adequate according to NRC recommendation, may become limiting under ammonia load from the non specific nitrogen supplementation and consequently causing depression i n growth.  Experiment 4. Availability of total nitrogen, true protein and minerals i n DPW and sodium hydroxide treated DPW. The availabilities of total nitrogen, true protein, calcium, phosphorus and sodium i n the untreated DPW and i n the DPW samples treated with 2, 3 and  62  5% NaOH are shown in Table 12. The figures on the digestibilities of total nitrogen and true protein of the untreated DPW obtained with chicks in this study are in close agreement with those obtained by Yoshida and Hoshii (1968) and McNab et a l . (1974) although they determined availability with colostomized hens. The total nitrogen in the DPW showed higher digestibility than that of true protein, indicating the non-protein fraction of the total nitrogen i s more digestible than the true protein. The very low digestibility of the true protein i s expected.  The true  protein i n the DPW consist mainly of undigested protein residues, dead microorganisms, endogenous proteins (enzymes and dead cells ) from the bird and to a less extent of spilled feed and feather debris.  The undigested protein  residues can be partitioned into those that have escaped enzymatic attack during digestion and those that are truly indigestible with the enzymes. When these proteins are refed to the chicks most of them can be easily digested but the truly indigestible ones remain undigested. for the low digestibility of the true protein.in DPW.  This accounts  Davidson and Thomas  (1969) observed that about 55% of the true protein in the excreta from layers was soluble in phenol-acetate-water solution.  They suggested that this  portion may be the endogenous protein from sources such as the intestinal flora, tissue, secretion, etc. while the remaining portion which was contained in the residue represents the truly indigestible protein from the food. This offers an explanation for the 50% digestibility of protein in the DPW obtained in this study. As early as the beginning of this century workers have found that the digestibility of food proteins, especially those from plant origins, in the alimentary tract of monogastirc animals i s largely independent of the proteins  63  Table 12.  Availability of total nitrogen, true protein, calcium, phosphorus and sodium in untreated and NaOH treated DPW.  Level of NaOH  Availability (%)  1 to  Total N  *  Protein  *  *  Calcium  Phosphorus  Sodium  0  63.6  50.5  53.8  19.8  84.4*  2  83.2  66.1  42.3  18.4  42.8  3  83.3  70.2  44.7  16.8  41.7  5  90.4  72.2  52.6  18.6  48.3  Significant different (P < 0.05).  64  themselves but may be determined by the constituents of foods other than p r o t e i n , the c e l l w a l l components i n p a r t i c u l a r .  I t was postulated that since  the plant c e l l w a l l s are not always e a s i l y permeable to the d i g e s t i v e j u i c e s , i t renders the proteins comparatively  i n a c c e s s i b l e to the d i g e s t i v e j u i c e s ,  thus i n part explaining the p o s s i b i l i t y of poor u t i l i z a t i o n (Mendel and 1911).  Fine  In f a c t , Mendel and Fine showed that i s o l a t e d proteins from wheat,  corn and barley were u t i l i z e d much better than the same proteins i n the i n t a c t plant materials and were as thoroughly u t i l i z e d as the nitrogen components of f r e s h meat.  S e i d l e r et a l . (1964) observed that the d i g e s t i b i l i t y of  p r o t e i n i n oats with Leghorn cockerels was decreased with i n c r e a s i n g f i b r e content from 0 i l 4 % (dehusked) to 16.8%  i n the grains.  The sunflowers meals  containing increasing amount of c e l l u l o s e (from LO to 26%) were also shown to have a decreasing percentage of d i g e s t i b l e p r o t e i n (Sirbu et_ al_. 1972). observations  confirmed the above theory.  These  Furthermore, i n t h i s study, the  DPW  treated with various l e v e l s of sodium hydroxide showed a marked improvement i n the p r o t e i n d i g e s t i b i l i t y (50% f o r untreated vs 70% f o r a l k a l i - t r e a t e d ) , which gives f u r t h e r support to the above theory.  The a l k a l i - t r e a t m e n t i s  known to breakdown the c e l l w a l l components and s t r u c t u r e and increase the d i g e s t i b i l i t y of dry matter and n u t r i e n t s i n the roughage by ruminants (Chandra and Jackson, 1971;  Singh and Jackson, 1971; and Saxena, 1971).  The a l k a l i - t r e a t m e n t , therefore, by a c t i n g on the c e l l w a l l components increases the access of the substrates to the enzymatic or m i c r o b i a l a t t a c k and hence increases the d i g e s t i b i l i t y of the n u t r i e n t s . The c e l l w a l l components ( c e l l u l o s e and l i g n i n ) per se may an unfavorable  influence on the n u t r i e n t d i g e s t i b l i t y ,  also exert  that i s when i t cannot  be accused of rendering the n u t r i e n t s i n a c c e s s i b l e to the d i g e s t i v e agents. Piekarska (1964) and Rao and S u n d e r a v a l l i (1970) observed that rats- fed  65  semi-purified casein diets containing showed i n c r e a s e d  f e c a l nitrogen  10-20% f i b r e o r c r y s t a l l i n e c e l l u l o s e  e x c r e t i o n and hence the apparent p r o t e i n  d i g e s t i b i l i t y o f the c a s e i n i n the d i e t was reduced.  With c h i c k e n  a similar  adverse e f f e c t on the p r o t e i n d i g e s t i b i l i t y o f t h e d i e t s was observed when the d i e t s c o n t a i n e d  h i g h l e v e l s o f f i b r e , e i t h e r from powdered crude  from straws o r from o r c h a r d g r a s s and  V l c e k and Pazourek, 1970).  f i b r e i n the d i e t .  Since  lignin,  (Kibe e t a l . , 1964; Keys e t a l . , 1970; T h i s can be r e l a t e d t o the l a x a t i v e e f f e c t o f  the f i b r e i s g e n e r a l l y i n d i g e s t i b l e by the mono-  g a s t r i c a n i m a l , the i n c r e a s e d b u l k o f n o n - a s s i m i l a b l e  m a t e r i a l i n the l a r g e  i n t e s t i n e and p o s s i b l y i n the s m a l l i n t e s t i n e has an e f f e c t on t r a n s i t so t h a t t h e r e i s l e s s time f o r d i g e s t i o n and a b s o r p t i o n .  time  Mechanical f a c t o r s ,  such as p a r t i c l e s i z e o f the f i b r e s may a l s o i n f l u e n c e the r a t e o f passage through t h e i n t e s t i n e (Mendel and F i n e , 1911 and Morgan, 1934). A large proportion  o f the n i t r o g e n o u s m a t e r i a l o f normal f e c e s  could  be b a c t e r i a l s i n c e B e l l e t a l . (1959) found t h a t as much as one t h i r d o f the t o t a l s o l i d s o f human f e c e s i s b a c t e r i a . to have low d i g e s t i b i l i t y .  The b a c t e r i a l p r o t e i n s a r e known  I n v i t r o s t u d i e s , Baker (1943) showed t h a t the  i o d o p h i l e b a c t e r i a were r e s i s t a n t to d i g e s t i o n by p e p s i n  and v a r i e d i n degree  to t r y p s i n d i g e s t i o n depending on t h e s t r a i n s o f b a c t e r i a .  Reed est a l .  (1949), and McNaught et. a l . (1954) showed t h a t the t r u e d i g e s t i b i l i t y o f p r o t e i n s o f the b a c t e r i a l p r e p a r a t i o n w i t h growing r a t s .  from the rumen o f sheep was 63-74%  Kaufman e t a l . (1957) demonstrated t h a t the average  d i g e s t i b i l i t i e s o f d r i e d E . c o l i and L a c t o b a c i l l u s a r a b i n o s i s c e l l s were higher,  83.3 and 89% r e s p e c t i v e l y , b u t s t i l l below t h a t o f c a e s i n .  the r e l a t i v e l y low d i g e s t i b i l i t y o f b a c t e r i a l c e l l s can a l s o e x p l a i n of t h e low p r o t e i n d i g e s t i b i l i t y o f DPW.  The f i g u r e o f p r o t e i n  Therefore, part  digestibility  of DPW t r e a t e d w i t h a l k a l i i s comparable t o t h a t o f the b a c t e r i a l p r o t e i n .  66  This may indicate that the a l k a l i treatment did not effectively affect the bacterial c e l l wall.  Zalabak et a l . (1972) demonstrated that when a protein  preparation containing Bacillus megaterium was treated with small amounts of lysozyme or egg white, solubility of the protein and i t s digestion with trypsin was increased.  Therefore, apparently the bacterial c e l l wall has to  be lysed, either by mechanical means or by enzymes (lysozyme), before the proteins are readily available to the animal. The availability of calcium and.phosphorus in the DPW  samples determined  in this study .±si much lower than the values reported by Nwokolo and Bragg (1976) with soybean meal (SBM) , rapeseed meal (RSM), cottonseed meal (CSM) , and palm kernel meal (PKM) , as shown in Table 13.  This can be explained by  the high levels of crude fibre and phytic acid in the DPW  as compared with  the other feedstuffs. These two factors are known to affect the mineral availability dramatically. Moran (1934) found that ingestion of cellulose by test subjects caused increase  in the excretion of calcium and phosphorus in the feces.  Begin et  a l . (1960) and G r i f f i t h (1961) showed that the apparent calcium digestibility was decreased with increasing dietary cellulose levels from 3-12%. Nwokolo and Bragg (1976) in correlating the digestibility of calcium and. phosphorus with the crude fibre content in the feedstuffs, demonstrated a significant inverse relationship between crude fibre and calcium digestibility (r = -0.73) or phosphorus digestibility (r = -0.91).  Therefore, the i n -  fluence of fibre on calcium and phosphorus digestibility was well-illustrated. It is believed that the fibre affects the availability of minerals by similar mechanisms as discussed above. Phosphorus of plant origin has been generally considered poorly available.  A large proportion of the phosphorus in the plant materials, parti-  cularly cereals and cereal-by-products  exists as phytin, the calcium-magnesium  1  67  T a b l e 13.  E f f e c t o f crude f i b r e and p h y t i c a c i d content on c a l c i u m and phosphorus a v a i l a b i l i t y o f v a r i o u s f e e d s t u f f s .  Content  1  Feedstuffs  Crude f i b r e 3  SBM  RSM  CSM  PKM  DPW  6.5  12.0  13.6  17.5  27.0  0.85  1.92  1.92  1.42  3.34  Phytate-P  0.24  0.54  0.54  0.40  .0.94  Total P  0.87  1.25  1.20  0.80  1.36  Phytic  acid  4 Non-phytate P i n t o t a l P (%)  72.4  56.8  55.0  50.0  30.4  Calcium  0.39  0.85  0.26  0.36  2.39  Ca:P  0/.45:l  0.68:1  0.22:1  0.43:1  1.76:1  ratio  A v a i l a b i l i t y (%•) phosphorus  89,3  74.8  76.9  70.8  19.8  C"calcium  85.6  71.7  64.6  68.6  53.8  1.  Data taken from Nwokolo and Bragg (1976).  2.  The v a l u e s , o t h e r w i s e s t a t e d , a r e expressed  3.  Phytic acid  4.  Non-phytate P i n t o t a l P (%) = [ 1  i n percent i n the f e e s t u f f f s .  (%) = P h y t a t e P (%) x 3.55. p h y t a t e P (% i n f e e d s t u f f ) , total P (% i n f e e d s t u f f ) J  n X  n  68  s a l t of i n o s i t o l hexaphosphoric a c i d .  Nwokolo and Bragg (1976) found h i g h l y  s i g n i f i c a n t inverse r e l a t i o n s h i p between the phytate content and the calcium availability  (r = -0.93) or the phosphorus a v a i l a b i l i t y  (r = -0.93) of the  feedstuffs. The extent of the p h y t i n phosphorus that i s a v a i l a b l e f o r u t i l i z a t i o n by d i f f e r e n t species of animals at various ages s t i l l remains debatable. Certain authors have reported i t i s u t i l i z e d to a l i m i t e d extent. have considered i t i s h i g h l y a v a i l a b l e to animals.  Others  Ashton et ^al. (1960)  32 fed P  labeled calcium phytate and observed that approximately 20% of the  phytate phosphorus was retained by four-weeks o l d chicks.  Hence these  authors concluded that the chicks can u t i l i z e o n e — f i f t h of the phytate phosphate.  Temperton and Cassidy (1964) reported chicks retained approxi-  mately 60% of the phytate phosphate and only 50% of the non-phytate  phosphorus.  The wide disagreement that existed between i n v e s t i g a t o r s dn the a b i l i t y of the chick to u t i l i z e phytate phosphate, was explained by Nelson (1967) to be due to the v a r i a t i o n s i n the source of phytate phosphorus used, c r i t e r i a of response, age of the t e s t animals, and calcium and v i t a m i n  l e v e l s i n the  experimental d i e t s . Nelson (1967) i n a review showed that there i s no evidence showing that phytate i s absorbed and u t i l i z e d i n t a c t by any animal species. In order to be u t i l i z e d , p h y t i n phosphorus must be hydrolyzed to y i e l d inorganic phosphate. However, t h i s phosphorus compound cannot be hydrolysed by the normal enzymes of the d i g e s t i v e j u i c e s of animals.  The enzyme phytase, which i s present  i n c e r t a i n feed i n g r e d i e n t s and p o s s i b l y secreted by the i n t e s t i n e , s p e c i f i c a l l y hydrolyses i t to phosphate and i n o s i t o l . act only on soluble phytate (Taylor 1965).  Phytases from a l l sources  Hence, a v a i l a b i l i t y of phosphorus  from free p h y t i c a c i d and sodium phytate, both of which are h i g h l y s o l u b l e ,  69  was^; shown to be far greater than that of calcium phytate which i s insoluble (Maddaiah. et a l . , 1963; Waldroup et a l . , 1964 a). Therefore, the extent to which phytates are hydrolyzed depends largely on their solubility, which in I |  turn depends on the ions with which they are associated (mainly Ca ++ Mn  + ,K  | |  , Mg  ,  + and H  in natural phytates) and on the level of calcium or the  Ca : P ratio in the diet. Vandepopuliere et a l . (1961) reported that plant source phosphorus was readily available for growth in chicks when fed at an optimum Ca : P ratio of 1:1.  Waldroup et a l . (1964b) demonstrated that the combination of low  dietary calcium or low Ca : P ratio (0.8:1) significantly improved the u t i l i zation of calcium phytate by growing chicks. However, wider Ca : P ratios, apart from 1:1 would depress the utilization of phytic acid phosphorus or the calcium-phytate phosphorus (Harms et a l . , 1962; and Waldroup j 3 t a l . 1964b). Nott et a l . (1967) also reported that phytin phosphorus availability for laying hens was reduced by high levels of calcium in the diet.  Conversely,  diets high i n phosphate (inorganic) promote the breakdown of phytate.  This  may be brought about by increasing the solubility of the phytate by removing, as insoluble phosphate, calcium which would otherwise combine with and precipitate phytate. Assuming the phytate-phosphorus  i s completely unavailable and the non-  phytate phosphorus i s completely utillzable, then the percent availability of phosphorus in the feedstuff w i l l be equal to the percent of non-phytate phosphorus in total phosphorus. However, data presented by Nwokolo and Bragg show that availability of phosphorus from feedstuffs were always higher than the percent of non-phytate phosphorus in total phosphorus of the feedstuff by about 20% (see Table 13).  This indicates that at least 20% of the  available phosphorus was from the phytate source.  In this study, the DPW  70  contained 30% of t o t a l phosphorus as non-phytate phosphorus but has phosphorus a v a i l a b i l i t y of 20%, i n d i c a t i n g the phytate—phosphorus i n the DPW pletely unavailable.  was com-  This discrepancy can be explained by the d i f f e r e n c e i n  the calcium content of the m a t e r i a l s . DPW  contains considerably high l e v e l of  calcium (2.39%) and high Ca : P r a t i o (1.76:1) as compared w i t h the other f e e d s t u f f s although t h e i r phosphorus contents are s i m i l a r . of calcium i n the DPW  The high l e v e l  may render the phytate phosphorus u n a v a i l a b l e by the  mechanism mentioned above.  Furthermore,  the high f i b r e content of DPW  may  depress the a v a i l a b i l i t y of phosphorus. Calcium has been "shown to have an adverse e f f e c t on the a v a i l a b i l i t y of phytate phosphorus.  Conversely, the phytate molecule has been observed  reduce the a v a i l a b i l i t y of calcium.  Hoff-Jorgensen  (1946) observed  to  that  a d d i t i o n of p h y t i c a c i d to the d i e t s of dogs depressed both the absorption as w e l l as r e t e n t i o n of calcium.  Maddaiah at a l . (1963) also showed that  sodium phytate i n the d i e t reduced calcium r e t e n t i o n i n chicks and r a t s . Maddaiah e_t a l . (1964) i n v i t r o study, showed that at p h y s i o l o g i c a l —8 pH. range the phytate anion (H^phy  ) would be formed.  I t appears t h i s anion [ |  i s involved i n the complex formation with the cations such as Ca I| | j Mn  and Mg  i n the i n t e s t i n e and rendered them unavailable.  | [  , Zn  ,  On t h i s b a s i s ,  one mole of p h y t i c a c i d w i l l chelate 4 moles of calcium or 1% d i e t a r y phytate w i l l chelate 0.24%  d i e t a r y calcium i n the i n t e s t i n e .  Assuming the calcium not chelated to phytate i s completely a v a i l a b l e while the phytate calcium i s i n d i g e s t i b l e , and the p h y t i c acid i n the feeds t u f f s i s f u l l y chelated with calcium, then the a v a i l a b i l i t y of calcium i n soybean meal, rapeseed meal, cottonseed meal, palm k e r n a l meal are c a l c u l a t e d to be 49, 46, -77 and 6% r e s p e c t i v e l y . determined values while that of DPW  A l l of these are lower than the a c t u a l  i s 66%, s i m i l a r to the determined value.  71  This means that the phytic acid in the former four feedstuffs are only parti a l l y chelated with calcium, while the phytic acid in DPW i s completely chelated with calcium.  Therefore an attempt was made to calculate the  degree of saturation of the phytic acid with calcium in the feedstuffs.  As  14.4% of calcium in soybean meal is not available and soybean meal contains 0.39% calcium, the amount of phytate calcium in soybean meal i s 0.056% (14.4% x 0.39%).  Therefore 0.85% phytic acid in the soybean meal chelated  0.056% calcium or 1% to 0.066% calcium.  If the phytic acid is saturated with  calcium, 1% dietary phytic acid w i l l chelate 0.24%  calcium.  Therefore the  phytic acid in the soybean meal would be 36% (0.24% ^0.066%) saturated. Similarly, using the same procedure, phytic acid in rapeseed meal, cottonseed meal, palm-kernel meal and DPW are calculated to be 52, 20, 33 and 138% saturated. The degree of saturation of the phytic acid with calcium can be related 2+ to the relative abundance of calcium and other cations, Mg  in particular.  The calcium and magnesium contents i n the feedstuffs and their ratios are shown in Table 14.  It appears that the degree of saturation of phytic acid  correlates very well with the ratio of calcium to magnesium in the feedstuff. Cotton-seed meal has the lowest Ca : Mg ratio;., that i s , containing relatively more magnesium with respect to calcium shows the lowest degree of saturation of the phytic acid and vice versa.  Maddaiah et a l . (1964) found that the  stability of the complex formed between phytic acid and calcium was lower than that formed with magnesium. Therefore, in the presence of a comparatively excess amount of Mg  [ |  , i t w i l l successfully displace the Ca  | |  from chelation  with phytic acid, hence the degree of saturation of phytic acid with calcium is lower and more calcium is available.  Conversely, when calcium is abundant  i t w i l l successfully compete with Mg for chelation,.vas,. in DPW.  72  Table 14.  Calcium and magnesium contents of thefeedstuffs in relation to 1  the degree of chelation of phytic acid with calcium.  Feedstuffs  Calcium %  Magnesium %  Ca:Mg  % saturation  ratio  of phytic acid  SBM  0.39  0.41  0.95:1  36  RSM  0.85  0.47  1.80:1  52  CSM  0.26  0.56  0.46:1  20  PKM  0.36  0.44  0.81:1  33  DPW  2.39  0.42  5.69:1  138  1. Data taken from Nwokolo and Bragg (1976).  73  It is interesting to note that both rapeseed meal and cotton-seed meal contain the same amount of phytic acid yet the latter shows lower calcium availability than the former.  Suppose that a similar amount of calcium i s  chelated to the phytic acid in both feedstuffs and since cotton-seed meal contains a lower amount of calcium, then the proportion of total calcium that is chelated to phytic acid w i l l be higher in cotton-seed meal, which explains the lower calcium availability. In summary, the availability of calcium in the feedstuffs i s affected by the three factors; v i z . , the phytic acid content, degree of chelation of phytic acid with calcium and the calcium content.  With the same calcium  content, increasing the phytic acid content, and/or increasing the degree of chelation w i l l decrease the availability, while with the same phytic acid content, higher calcium content w i l l increase the availability. The calcium, phosphorus, phytate phosphorus and phytic acid content of the DPW and alkali-treated DPW samples are shown in Table 15.  The calcium and  phosphorus availabilities of the alkali-treated DPW were not significantly different from that of the untreated DPW, the replicates.  due to the high variability among  Since the alkali treatment did not affect the phytic acid  content of the material, i t is obvious i t could exert no effect on the calcium and phosphorus availability. The sodium in the DPW i s considered to be readily available.  However,  the percent availability of sodium in the alkali treated DPW were much lower. This is likely because most of the sodium hydroxide added to the DPW had reacted with the material to form complex compounds which were not available, so lowering the proportion of available sodium in these samples. In the previous experiment, when chicks were fed the 20% alkali-treated DPW diet, especially that treated with 5% sodium hydroxide, a considerably  74  Table 15.  Effect of sodium hydroxide treatment on the calcium, phosphorus and phytic acid contents of  Content  DPW.  Level of NaOH (%) Treatment  Calcium  2.39  2.39  2.38  2.33  Total P  1.36  1.35  1.33  1.30  Phytic acid  3.34  3.34  3.34  3.34  Phytate P  0.94  0.94  0.94  0.94  Phytate P in total P P availability Ca availability  (%)  69.2  69.6  70.7  72.3  19.8  18.4  16.8  18.6  53.8  42.3  44.7  52.6  75  higher quantity of sodium was consumed compared to the control. Normally with this quantity of sodium consumed i t may create stress on the chicks. However, no adverse effect on growth and health of feeding the alkali-treated DPW was observed.  diet  This is due to the low availability of the sodium in the  alkali-treated DPW,  hence, eventhough the chick has consumed the excessive  amount of sodium from these materials not a l l of them were available to the chicks sufficiently high enough to create the sodium stress.  Experiment 5.  Effect of amino acid supplementation on the performance of chicks fed diets containing untreated DPW or alkali-treated DPW.  Body weight gain, total feed consumption and feed conversion ratio of chicks fed the control and the DPW  diets with or without supplementation with  methionine alone or with methionine and lysine for four weeks are shown in Table 16. When the basal control 2 diet was supplemented with 0.2%-D-L methionine or 0.2% methionine + 0.1% lysine, growth of the chicks were improved (507 g, 582 g and 576 g, respectively). The improvement in growth was attained when 0.2% methionine was added to the diet.  Additional supplementation with  lysine did not result in additional improvement.  0.1%  Therefore, i t is suggested  that methionine is the c r i t i c a l essential amino acid in the control diet. Addition of 0.2% methionine to the control diet significantly increased the feed intake.  This is in accordance with the results obtained  by various investigators showing that deficiencies of single amino acids caused marked reductions in voluntary food intake (Baker 1974, review). Furthermore, the growth of chicks fed the supplemented control 2 diet was similar to that of the control 1 which contained a higher energy level. This indicates that  Table 16. Effect of amino acid supplementation on 4 week body weight gains, total feed consumption and feed conversion ratio of chicks fed the control and the DPW diets.  Average 4 week Body Weight Gains (g.) Supplementation  Control  Control  Untreated  1  2  DPW  0  —  506.6  0.2% met.  —  581.8  0.2% met + 0.1% lys. 02.% met + 0.2% lys.  544.4  a  576.3 —  cde  de  523.7  NaOH treated DPW 572.3  abc  604.6  ab  575.7  cde  541.8  552.9  bGd  533.l  e  abc  606.1  abc  606.7  s  e  Total Feed Consumption per b i r d 0  —  984  0.2% met  —  1055 1057  1006  0.2% + 0.2% lys  —  ab  997  (g.)  1123  Gd  1123  cd  ab  1049  ab  1154  cd  ab  1105  bc  1203  1107  bc  1177  a  0.2% + 0.1% lys  1  a  Feed Conversion Ratio  6  1  0  —  1.94  2.06°  1.97  0.2% met  —  1.80 •  2.04°  1.93  b  a  b  b  0.2% met + 0.1% lys  1.77  1.83  2.04°  1.98  0.2% met + 0.2% lys  —  1.80  2.07°  1.94  1.  a  a  a  Different subscripts indicate significant difference (P < 0.05).  b  b  de  Gde  77  without amino acid supplementation, the methionine deficiency in the lowenergy control diet (control 2) limited the chick's ability to consume enough feed to meet i t s energy requirement.  When the amino acids were balanced,  the chick was able to consume higher amounts of the lower energy diet (1055 g vs 1006 g in control 1) and hence resulted in corresponding growth. Feed efficiency of the non—supplemented that of the balanced control 1 diet.  control 2 diet was poorer than  This is because of the methionine  deficiency which lowered the protein or other amino acid utilization.  Supple-  menting this basal diet with methionine significantly improved the feed efficiency which was comparable to the high-energy control 1 diet. The control 2 diet was calculated to be suboptiomal in lysine with respect to the chick's requirement.  However, growth was improved by supple-  menting with 0.2% methionine only; adding 0.1% lysine to the methionine supplemented control diet did not resulted in further improvement in growth. This i s because of the lower energy content of the diet, which stimulated the feed consumption so that the chick had consumed enough amount of lysine to satisfy i t s need.  These results are in agreement with Harper and Rogers  (1965) finding that i f feed intake could be maintained in rats fed an imbalanced diet by adjusting the protein: calorie ratio of the diet growth would be improved and equivalent to that I; of control. Increasing the level of supplementation of lysine from 0.1 to 0.2% tended to reduce the body weight gain (575 g vs 553 g) and feed intake (1057 g vs 997 g) although differences were not statistically significant. This shows the signs of amino acid imbalance.  The diet containing 0.2% lysine  would be slightly in excess of lysine with respect ot other amino acids, particularly arginine.  Excess of dietary lysine i s shown to cause a reduction  in voluntary food intake, which explains the depression i n growth, as reported  78  by Baker (1974). Growth of chicks fed the basal DPW  (untreated or alkali-treated) diets  were higher than those fed the control 2 diet.  In addition, growth of the  chicks fed these diets were comparable to those fed the balanced high energy control diet.  This was expected because the DPW  diets contained higher levels  of the sulfur-containing amino acids than the control diet, hence, no amino acid deficiency effect was demonstrated.  Furthermore, the lower energy content  of these diets facilitated higher feed intake and consequently the chicks could consume enough of the amino acids to meet the requirements.  Therefore,  the addition of methionine and lysine to the diets containing untreated or alkali treated DPW,  did not result in additional growth. Moreover, these  supplementations did not increase the feed intake, further confirming that methionine was not deficient in the DPW  diets.  The chicks fed the untreated DPW diet, in general, grew slower than those fed the control diets or the alkali-treated diet.  The feed efficiency of  this diet was the lowest even though a l l diets were formulated to be similar in energy and true protein content.  This i s due to the low digestibility of  true protein (50%) in the untreated DPW as determined from the previous study. The DPW was calculated to furnish 2.6% true protein in the,diet, but actually i t contributed only 1.3% available protein.  Therefore the untreated  DPW  diet contained less than 21.7% available protein as compared to the 23% in the control. This explains the poorer growth and lower feed efficiency with the untreated DPW  diet.  availability of DPW  The alkali-treatment markedly improved the protein  (from 50 to 70%), which brought about the improvement in  growth and feed efficiency.  Nevertheless, the protein digestibility of  alkali—treated DPW was s t i l l below that of wheat and soybean meal, which generally are over 90% availability.  Thus the alkali-treated DPW  diet was  79  slightly suboptiomal in protein content. Although i t did not affect the growth, the.feed efficiency was reduced as compared with the balanced control. The feed consumption of chicks fed the DPW diets were higher than those fed the supplemented control 2 diets.  Since the diets are calculated to be  equivalent i n energy content, i t is probably because of the lower protein content i n the DPW diets which stimulated greater feed consumption.  There-  fore, the feed consumption of chicks i s influenced by dietary balance. In general, the amino acid profile of DPW is similar to that of the cereal grains such as wheat or barley.  When high levels of DPW are used to replace  wheat or corn i n the diets they are likely to be deficient i n lysine and methionine as i n the case of wheat or corn based diets.  In fact, in studies  by Stapletonn and Biely (1975), the supplementation of both the wheat and corn based control diet and the diet containing 20% DPW with lysine and methionine resulted i n improvements i n growth of similar magnitude. However, the sample of DPW used i n this study contained much higher level of methionine and cystine, about three times that of the DPW sample used by Stapleton andBiely or i n the wheat. Thus the DPW diets used i n this study contained relatively adequate level of the sulfur-containing amino acids as compared to the wheat-based control.  Supplementation of the DPW diets with methionine  did not result i n growth response, indicating the methionine i n the DPW was utilized by the chick for growth so that no deficiency was to be demonstrated. This i s i n accordance with thecfindings of Bhargava and O'Neil in which addition of methionine or lysine either singly or i n combination to the DPW diets, which calculated to contain sufficient methionine and lysine to meet the requirements, did not affect growth response.  Therefore, when balanced  for amino acid content inclusion of high level of DPW i n the diet does not affect .the growth.  80  DeGroot and Slump (1969) showed that severe treatment of isolated soyprotein with sodium hydroxide (pH 12.2) caused destruction of cystine and lysine which resulted in lowering the nutritive value of the protein.  Alkali  treatment also reduced the true digestibility of the proteins with rats. However, in' this study, the results from treating DPW with alkali were in opposite to that of DeGroot and Slump. digestibility of protein in the DPW.  The alkali treatment increased the  It also improved the nutritive value  of DPW even though i t had slight adverse effect on the cystine content of the DPW.  The differences in the response to alkali treatment can be attributed  to the difference in nature of the materials treated. When high protein materials are treated with the alkali, i t w i l l react directly with the proteins causing chemical and structural changes which may be undesirable. On the other hand, when materials containing high levels of fibres are treated with the alkali, i t reacts with the structural substances, bringing about changes which result in increased utilization of the materials.  Experiment 6.  Effect of increasing the energy content of the diets with supplementary 'fat (tallow) on performance of chicks fed the diets containing untreated DPW or alkali-treated DPW. f  The 2nd, 3rd and 4th week body weight gains of chicks fed the experimental diets are shown in Table 17.  The body weight gains of chicks fed the different  diets were similar during the f i r s t two weeks of- age.  At the end of the 3rd  week improvement in weight gain was observed with chicks fed the higher energy diets with 2% additional fat.  The growth response was more pronounced at  the end of the 4th week. Addition of 2% fat to the three basal diets improved weight gains by similar magnitude among the diets.  There was no  difference in growth among the diets with the same energy level.  81  Table 17. Effect of fat supplementation on body weight gains, feed consumption and feed conversion ratio of chicks fed the control and DPW diets.  Average Body Weight Gain (g .) 1  Low Fat Basal Diets .  Age (week))  Control  a  2  Untreated DPW  2  195  a  180  3  360  a  3 7 3  4  588  ab  Fat Supplemented Diets NaOH treated 191  a  ab  574  197  a  365  ab  598  a  Control  NaOH treated  190  194  a  376 625  b  Untreated DPW  ab  C  a  a  400°  385  621  631  c  bc  C  Total Feed Consumption per bird (g.) 1095  a  1169  b  1228°  1108  a  1255°  1209  Overall Feed Conversion Ratio 1.86  b  1.  2.04  d  2.06  d  i.80  a  2.03  d  1.95  Body weight gain = Body weight at the end of the week — day-old body weight '  2. Different subscripts on the same line indicate significant difference (P\<:0.05).  C  bc  82  Feed consumption and feed conversion ratios of chicks fed the different diets are also shown in Table 17.  With the exception of the untreated  diet, addition of 2% fat to the control or the alkali-treated DPW not affect the feed consumption but improved the feed efficiency. efficiency of the alkali-treated DPW (differed by 0.11  diets was  DPW  diet did The feed  improved to a greater extent  unit) than that of the control (differed by 0.06  Conversely, addition of 2% fat to the untreated DPW  unit).  diet increased the feed  consumption but did not affect the feed efficiency. The results obtained in this study are in agreement with the of many investigators  findings  in that addition of fat, both animal or vegetable,  improved body weight gain and feed efficiency (Potter et a l . , 1960;  Vermeersch  and Vanschoubroek 1968). However, Richardson et a l . (1958) showed that the addition of fat to the diets mainly improved the feed efficiency with l i t t l e effect on the growth. related to the M.E.  In fact, the growth responses to supplemental fat were  content of the diet.  Begin (1961) showed that with 22%  protein in the diet, a level of 2,970 kcal/kg. was required for maximum growth. With the M.E. kcal/kg) increasing  the minimum energy level  above this level (2970-3200  the energy content by adding fat did not result in an  increase in growth; whereas, with the dietary energy below this level, i n creasing the energy by adding fat would improve the growth. Feed efficiency was directly related with the energy content of the diets.  Therefore, the  three basal diets used in this study were suboptiomal in energy content, and increasing  the energy by adding 2% fat increased the caloric intake, which  resulted in higher growth. Although the dietary treatments were formulated to contain similar energy content at the two energy levels, the diets containing untreated DPW  or  alkali—treated DPW. always showed poorer feed efficiency than the control diet  83  a t t h e two energy l e v e l s .  T h i s i n d i c a t e s t h a t the n u t r i e n t s i n t h e d i e t ,  e s p e c i a l l y t h e energy were l e s s e f f i c i e n t l y u t i l i z e d by t h e c h i c k s when f e d w i t h DPW and may be a t t r i b u t e d to the h i g h e r  l e v e l o f crude f i b r e  i n t h e DPW d i e t s compared to t h e c o n t r o l ( 7 % v s 3.9%).  However, many a u t h o r s  have shown t h a t the o n l y d e l e t e r i o u s e f f e c t o f i n c l u d i n g h i g h i n the d i e t s was due to i t s energy d i l u t i o n p r o p e r t i e s .  contained  l e v e l of f i b r e  When t h e energy con-  t e n t o f t h e d i e t s c o n t a i n i n g h i g h l e v e l s o f f i b r e were compensated f o r by , adding f a t , growth and f e e d e f f i c i e n c y were n o t impaired 1958;  P o t t e r _et a l . , 1960; B e g i n , 1961).  f i b r e may be r e s p o n s i b l e  Therefore  f o r the lowering  (Richardson e t a l .  some.other f a c t o r  besides  i n the f e e d e f f i c i e n c y when f e d  w i t h DPW i n the d i e t s . Since f a t contributed  a s i g n i f i c a n t p o r t i o n o f t h e energy i n the DPW  d i e t s , any f a c t o r s t h a t a f f e c t the f a t ? u t i l i z a t i o n w i l l s i g n i f i c a n t l y a f f e c t the M.E. c o n t e n t o f the d i e t s as w e l l as t h e feed e f f i c i e n c y . apparent f a t d i g e s t i b i l i t y and M.E. v a l u e s shown i n T a b l e 18.  T h e r e f o r e the  o f t h e d i e t s were determined and  The apparent d i g e s t i b i l i t y o f crude f a t (mainly  tallow), i n the c o n t r o l d i e t s were between 75-78.8%. f i g u r e s , of 70-73% f o r t a l l o w o b t a i n e d  from  T h i s i s c l o s e to the  by Young (1961), March and B i e l y (1957),  and Vermeersch and Vanschoubroek (1968).  However, t h e apparent  digestibilities  of crude f a t i n t h e DPW d i e t s were markedly lower than t h a t o f the c o n t r o l d i e t s , w i t h the lowest i n t h e u n t r e a t e d  DPW d i e t s .  T h i s shows t h a t DPW im-  p a i r e d the d i g e s t i o n o f f a t i n t h e d i e t . S a i t o e_t a l . (1959) showed t h a t the d i g e s t i b i l i t y o f crude f a t tended to decrease from 87.2% w i t h no added c e l l u l o s e i n the d i e t ( c o n t a i n i n g 2.7% crude f i b r e ) to 84% w i t h 3.5% and 83% w i t h 9.5% c e l l u l o s e added.  B e g i n (1961) and  P o l i n e t a l . (1971) found t h a t f a t u t i l i z a t i o n was n o t a f f e c t e d by i n c l u d i n g various l e v e l s of t c e l l u l o s e i n the d i e t .  Therefore  the higher  l e v e l of  84  Table 18. Apparent fat digestibility, metabolizable energy values and nitrogen retention of the different diets in Experiment 6. Apparent Fat Digestibility (%) Low Fat Basal Diets Control  75.0  Fat Supplemented Diets  Untreated DPW.  NaOH treated  55.6  60.0  Control  78.8  Untreated DPW  NaOH treated  54.5  67.7  Metabolizable Energy Kcal/kg (as fed basis)  Formulated 2 Corrected Determined 3 Difference  2755  2720  2720  2844  2810  2810  2755  2561  2590  2844  2599  2738  2710  2561  2590  2892  2564  2744  45  169  147  246  66  40.7  42.1  ——  Nitrogen Retention (%)  45.7  38.7  38.0  54.5  1. The M.E. values of the diets were calculated using the figure of 7700 kcal/kg for the M.E. of tallow. 2. The M.E. values of the diets were calculated after correcting for the variation i n the fat digestibility of the diets. 3. The difference between the formulated value and the determined value.  85  f i b r e in. the DPW d i e t s cannot t o t a l l y e x p l a i n the marked reduction i n the f a t d i g e s t i b i l i t y , though i t may have some e f f e c t . Werner and Lutwak (1963) reported that f a t absorption from i n t e s t i n e of rat  diminished i n a l i n e a r fashion w i t h i n c r e a s i n g d i e t a r y calcium l e v e l s .  With chicks Fedde jat a l . (1959) observed that lowering the d i e t a r y calcium l e v e l to 0.33% increased the d i g e s t i b i l i t y of t a l l o w from 77% to 91%.  On  the other hand, when the d i e t a r y calcium l e v e l was increased to 3%, d i g e s t i b i l i t y of t a l l o w decreased to 71%. The e f f e c t of d i e t a r y calcium on f a t u t i l i zation appears to be i n r e l a t i o n to the kind of f a t i n the d i e t . . Calcium i n the d i e t was found to have no i n f l u e n c e on the d i g e s t i b i l i t y of low-melting f a t s while i t markedly decreased the d i g e s t i b i l i t y of high-melting f a t s and hydrogenated f a t s (Edwards et a l . , 1960).  However, Hakansson (1974) showed  that with l a y i n g hens, the d i g e s t i b i l i t y of a l l the f a t s was lower w i t h the higher calcium (4.34%) than w i t h the lower calcium (2.87%).  This decrease  a f f e c t e d a l l the f a t t y acids but e s p e c i a l l y s t e a r i c and p a l m i t i c a c i d s .  Since  tallow contains higher proportion of these saturated f a t t y acids in- the f a t as compared w i t h other vegetable o i l s (Renner and H i l l , 1961),, 'the d i g e s t i o n and absorption of t a l l o w i s l i k e l y to be a f f e c t e d to a greater extent by the d i e t a r y calcium l e v e l . March jhnd- Bie'Iy ( l g S ^ e ^ o b s e r ^  t a l l o w , only a  small percentage of the f e c a l f a t was i n the form of n e u t r a l f a t , i n d i c a t i n g the t a l l o w was r e a d i l y hydrolysed by the i n t e s t i n a l enzymes.  However, the  greater part of f a t excreted was i n the form of i n s o l u b l e soap and f r e e f a t t y acids.  This suggests that soaps formed from saturated f a t t y acids were not  absorbed.  Calcium probably i n t e r a c t s w i t h the f r e e saturated f a t t y acids  a f t e r h y d r o l y s i s i n the gut.  D i s s o c i a t i o n of the calcium-tallow complex,  i n v i t r o , was shown to occur between pH 4.8 and 6.4 (Hunt et a l . , 1961).  86  The pH of the duodenum and jejunum,where most of the calcium is absorbed, is between 5.6 and 6.3, and increases'thereafter to about 7.0 in the cecum. Therefore the calcium could have been absorbed in the duodenum without forming insoluble soap. However, with higher dietary calcium intake, the proportion of dietary calcium absorbed is reduced (Morrissey and Wasserman, 1971) so that more of the calcium w i l l be free to form insoluble soap in the. lower portions of the gut.  Hence, as the dietary calcium level is increased, more of the  saturated fatty acids from the tallow w i l l be converted into soaps and excreted, consequently the digestibility of these fats is decreased. The DPW diets were calculated to contain higher level of calcium (2.0%) compared to the control (1.26%) due to the high amount of calcium contributed by the DPW.  It i s reasonable to believe that the lower utilization of fat  (tallow) in the DPW  diets was caused by the higher dietary calcium level.  the contrary, Polin et a l . (1971) indicated that DPW did not affect the fat utilization of the diets. was used.  On  at 8 or 16% in the diet  In their study, corn o i l  Since corn o i l contains a very low level-of the saturated fatty  acids the utilization of corn o i l would not be affected nearly as much by the calcium level.  Therefore, no significant effect on fat utilization would  be anticipated from feeding DPW  together with .'.vegetable o i l s .  Fedde et_ a l . (1959) and Sibbald and Slinger (1963) found that the level of dietary inclusion of fat did not appear to affect the utilization of fats. Williams et a l . (1959) demonstrated that the digestibility coefficient of fat from the basal feed ingredients were lower than for added.fat. Hence, the increase in apparent digestibility coefficient of fat in the diet with increases in dietary fat levels as observed by Whitson et^ a l . (1943) and Williams et a l . (1959) is due to the higher utilization of the added fat. When corrected for the low digestibility of fat in the basal ration the added  87  fat was shown to be equally utilized at the various levels studied (Williams at a l . 1959)•  In this study, the apparent digestibility of the fat tended  to increase with the fat levels i n the diet, but the. increase was not large enough to have any significant effect. The M.E. values of the diets determined with chicks between 2 and 3 week of age are shown i n Table 18. The determined values for the control diets were close to the calculated values.  This indicates that the M.E. value of  tallow with 75% digestibility would be closed to the value of 7700 kcal/kg used in the formulation. With the higher fatn control .diet, the determined value was slightly higher than the calculated value.  This i s probably due to  the higher fat digestibility (78.8) as compared to that of the lower fat control (75%). The M.E. values of the DPW diets at both fat leyels were much lower than the calculated values.  The low fat digestibility appears to be  the major factor related to these low values. Assuming the M.E. value of the tallow was directly in proportion to i t s digestibility, then with 55.6% digestibility the M.E. value would be 5708 kcal/kg. Using this M.E. value, the M.E. of the untreated DPW diet containing 8% tallow would be 2561 kcal/kg. Similarly, the corrected calculated values for the untreated DPW diet with 10% fat, alkali-treated DPW diets with 8% fat or with 10% fat would be 2599, 2590 and 2738 kcal/kg respectively. value.  These values resemble the determined  Therefore the M.E. value of the diets were i n direct relationship  with the fat digestibility of the diets. n  Addition of 2% more fat to the diets increased the M.E. contents of  the diets, except with, the untreated DPW diet.  With the untreated DPW diet,  addition of 2% more fat to the diet resulted in only a very small increase in the M.E. content, which was due to the slight decrease in fat digestibility with the increased fat level.  88  The feed efficiencies of the diets, therefore, were directly related to the fat digestibility and the actual M.E.  content of the diets.  Due to the  lower fat digestibility and hence lowered M.E.  content, the feed efficiency  of the diets containing DPW would be reduced.  Increasing the fat digesti-  b i l i t y by specific factors or raising the M.E.  content by adding more fat  would improve the feed efficiency. Feed consumption of chicks fed the DPW diets at the two energy levels were higher than the control diets. contents of these diets.  This is probably due to the lower M.E.  In general, addition of 2% fat to the diets caused  a significant.lincrease in the M.E. no effect on the feed consumption.  content of the diets, but appeared to have This is similar to the finding by Begin  (1961) that the energy level of the diets had l i t t l e effect on the feed consumption.  As the cellulose level of the diet increased with a corresponding  decrease in energy level, the chicks did not appear to increase their feed intake to compensate for their energy needs.  The bulk alone was shown not to  be the limiting factor in feed intake since the diet containing  21% cellulose  promoted a volume intake that was significantly greater than any of the other cellulose diets (containing 3-18% cellulose).  This indicates that i t would  have been physically possible for these intermediate cellulose groups to have consumed more feed, yet they failed to do so. the energy level influence the feed intake.  Therefore factors other than Since the M.E.  content per unit  of volume was progressively reduced as cellulose was added to the diet, the decrease in caloric density could become a factor. In this study, the DPW diets had lower caloric density (due to higher bulk of the DPW)  compared to  the control diets which might have stimulated the greater feed consumption. The increase in energy content by adding 2% fat might not be high enough to overcome this effect.  89  The increase i n caloric intake may affect the protein utilization.  The  nitrogen retention of diets determined between the 2nd and 3rd week of age for the chicks are shown i n Table 18. In general, addition of 2% fat to the diets improved the N retention which was correlated with the metabolizable energy content of the diets. Various studies have shown that as the energy level of the diet increased the N retention also increased up to the optimal level of energy.  Additional increases in energy beyond this level would  result i n no further increase i n N retention and may decrease i t when the energy level was too high (Sanslone and Squibb, 1963; Farrell, 1974; and Velu, 1974).  Summer at a l . (1964) demonstrated that energy concentration of 3050  kcal/kg was the optimal level for maximum N utilization. used in this study were suboptimal i n energy.  Therefore the diets  It appears that about 3000  kcal/kg i s the optimal level of the energy i n the diet for maximum growth and nitrogen utilization. The chicks fed the DPW diets showed much lower N retention than those fed the control diets.  This can be attributed to the lower energy content of  the diets which impaired the N utilization, the low digestibility of protein in DPW and probably zero utilization of the non-protein nitrogen i n the diet. Assuming the protein i n the DPW was 50% digestible and the digestible protein contained i n the DPW diet was retained by the chick to the same extent as with the control diet (45.7% retention) while the non-protein nitrogen from the DPW was not utilized at a l l , then the N retention of the DPW diet was calculated to be 38%, which i s exactly the same as the determined value. Therefore, the proteins of the DPW diets were utilized as efficiently as that of the control diets provided the energy, levels were similar. This also indicates? that the protein in the DPW, aside from i t s low digestibility, the digestible portion i s well utilized by the chicks.  90  Because of the high calcium content in the DPW diets, utilization of the tallow in the diets was impaired and hence the M.E. contents of the diets were markedly lowered. efficiency were reduced.  As a result, the nitrogen utilization and feed If the utilization of the fat in the DPW diets was  improved then the performance of chicks fed such diets would be comparable to the control.  This leads to the objective of the next experiment.  Experiment 7.  Effect of antibiotics supplementation on the performance of chicks fed with the DPW diets.  The body weight gains of chicks fed the basal diets supplemented with antibiotics were always higher than those fed the basal diets at the end of 1, 2, 3 and 4 week of age (Table 19).  The antibiotic supplementation i n -  creased the weight gains of chicks at the end of the 4th week by 47, 54 and 57 g with the control, the untreated DPW diet and the alkali-treated DPW diet, respectively, or by an average of about,8.5%. Apparently, the antibiotic supplementation elicited a slightly greater growth response when fed with the DPW diets.  With or without the supplementation, weight gains of chicks fed  the DPW diets were higher than those fed the corresponding control diets at the end of the 4th week. The antibiotic supplemented alkali-treated DPW diet group showed the highest weight gain.  This i s probably due to the  higher feed consumption by these groups as seen in Table 20.  The total feed  consumption of the antibiotic-fed groups was not different from that of the controls.  The overall feed efficiency of the chicks on these diets was also  improved by the antibiotic supplementation.  The improvement in feed efficiency  was greater with the groups fed the DPW diet than with the control. The digestibilities of fat i n the diets with chicks at 1, 2 and 4 week of age are shown i n Table 21.  Irrespective of the antibiotic supplementation,  91  Table 19. Effect of antibiotics supplementation on body weight gains of chicks at 1, 2, i3and 4week of age.  Diets  Cumulative Body Weight Gain (g.) 1  <  Week 1 Control  3  1.  Week 4  70.7  a  197.9  378.5  565.0  Antibiotic  80.6  218.8  414.6  612.7  21.0  36.0  47.7  2  NaOH treated , DPW  Week 3  Basal  Difference Untreated DPW  Week 2  a  a  bc  10.0  b  b  a  b  Basal  70.8  195.5  393.9  608.8  Antibiotic  83.0°  214.l  433.2  663.4°  Difference  12.2  39.3  54.6  Basal  74.2  Antibiotic  82.9°  216.4°  427.4  676.6°  Difference  8.7  20.2  31.4  56.6  a  a  a  b  b  18.6 ab  196.6  a  •L  396.0  a  1_ b  b  620.0  b  Body weight gain = Body weight at the end ofthe week -day-old body weight  2. The difference in body weight gain between the antibiotic fed groups and the groups fed the basals. 3.  Different subscripts within the same column indicate at the 0.05 probability level.  significant difference  92  Table 20. Total feed consumption and feed conversion ratio of chicks fed diets for 4 weeks i n experiment 7.'  Diets  Control  Feed Consumption (g.) Basal  1030  1.80  Antibiotic  1059  1.74  a  a  3  Basal  1221  Antibiotic  1267  b  b  a  2.01  d  1.91° 0.10  Difference NaOH Treated DPW  b  0.06  Difference Untreated DPW  Feed Conversion Ratio'i  Basal  1235  1.99  Antibiotic  1250  1.87°  Difference  1. Overall feed conversion ratio  b  d  0.12  Total feed consumption for 4 weeks 4 week body weight gain  2. Difference subscripts i n thesame column indicate significant difference (P < 0.05). 3. The difference in feed conversion ratio between the antibiotic fed groups and the groups fed the basals.  93  Table 21.  Effects of age and antibiotics feeding on fat digestibility of the diets in Experiment 7.  Apparent Fat Digestibility (%)  Diets  Control  Week 1  Week 2  Week 4  Basal  42.5  64.2  78.7  Antibiotic  60.3  74.4  84.3  17.8  10.2  5.7  Basal  47.1  53.0  76.3  Antibiotic  62.7  76.9  84.1  Difference  15.6  23.9  7.8  Basal  43.1  57.8  84.1  Antibiotic  61.8  75.2  84.1  Difference  18.7  17.4  9.0  Difference Untreated DPW i  NaOH  1  treated DPW  1.  The difference in fat digestibility between the antibiotic fed groups and the groups fed the basals.  94  the digestibility of fat (mainly from tallow) increased with age of the chicks.  A marked increase i n fat digestibility was observed between the 1st  and 2nd week. Between the 2nd and 4th week there was s t i l l a gradual increase in fat digestibility.  This i s generally in agreement with the findings of  Fedde et a l . (1959), Renner and H i l l (1960), Carew et a l . (1972) and Hakansson (1974).  In reviewing the results obtained by these workers, i t .  was shown that the digestibility of tallow at one week of age was between 40-53% and increased to 70-79% at the 2nd week; at the 8th week the tallow digestibility was 76-82%. The results from this study indicate that maximum digestibility of tallow may be attained at the 4th week of age and beyond this age there would be l i t t l e increase i n the digestibility. The effect of age on fat digestibility varies with the kind of fat fed to the chicks.  With corn o i l or lard, the digestibility of fat only increased  slightly or showed no change from the 1st to 2nd week or with older age (Carew et al., 1972; Fedde et al., 1959;and Renner and H i l l 1960). Hakansson (1974) demonstrated that palmitic and stearic acids showed the largest i n creases in digestibility with age whereas the unsaturated fatty acids i n creased only slightly with age.  This may explain the differences i n the  effect of age on the various kind of fats.  The digestibility of vegetable  oils, which, contain lower proportion of the saturated fatty acids i s less affected by the age factor, and vice versa. During a period early in the l i f e of the chicks many workers (Pensack and Huhtanen, 1963; Eyssen and DeSomer, 1963 and Carew et a l . 1972) observed that the chicks consumed feed normally, but apparently developed a transitory syndrome of malabsorption of feed nutrients as expressed by reduction i n growth rate, impairment i n feed utilization and increased output of fecal material. Fat excretion, in terms of percent fat i n the excreta, was especially i n -  95  creased during this period, and reached the peak at 5-9 days of age. Spontaneous improvement in growth rate and intestinal absorption subsequently occurred after this i n i t i a l period.  These observations show that the newly-  hatched chick has not developed fully the physiological ability to absorb fat. life.  However,  this appears to develop rapidly after the f i r s t ten days of  The development of the ability for fat absorption seems to relate to  the type of fat ingested.  Carrew et a l . (1972) showed that with corn o i l ,  the quantity of fat excreted approached i t s minimal value almost immediately after the f i r s t week so that no difference was observed between 9-15 days of age.  With, tallow, the fat excretion tended to decline progressively until the  end of the 2nd week or further. When antibiotics were added to the diets, the fat digestibilities were increased at a l l ages. However, a marked increase in fat digestibility occurred at the 1st week, and thereafter the increase was more gradual and tended to-diminish with age.  This is in accordance with Pensack and Huhtanen (1963)  and Eyssen and DeSomer (1963) showing that antibiotic feeding reduced fecal fat excretion and resulted in increased weight gain and improved feed efficiency during the c r i t i c a l period of malasorption. Huhtanen and Pensack (1965a) found that enterococci, mainly  Streptococcus  faecalis predominated in the duodenum of the chicks at 3 days of age and were maximum at 6 days, then gradually decreased to 28 days of age, being largely replaced by anaerobic types.  Hence, the period during which the  chick was undergoing unutrient malabsorption appeared to coincide with the period of increase in numbers of Str. faecalis organisms in the duodenum, thus suggesting that this organism was involved in the malabsorption phenomenon. In fact, inoculation of germ—free chicks with Str. Faecalis was shown to cause a depression in growth and rise in fecal fat excretion but no such  96  e f f e c t s were observed w i t h other organisms such as l a c t o b a c i l l i and bacteriaceae.  entero-  A d m i n i s t r a t i o n of a n t i b i o t i c s was found to e l i m i n a t e the  organism and ameliorate the growth depression (Huhtanen and Pensack, 1965b; Eyssen and DeSomer, 1967).  Tortuero (1973) also observed that suppressing  the S t r . , f a e c a l i s population during the e a r l y period of the chick's l i f e by the implantation of L a c t o b a c i l l u s acidophilus or by a n t i b i o t i c feeding i n creased f a t d i g e s t i b i l i t y , and r e s u l t e d i n increased weight gain and b e t t e r feed e f f i c i e n c y .  Therefore a l l these f i n d i n g s i n d i c a t e that a n t i b i o t i c s  stimulate chick growth by t h e i r a c t i o n against micro-organisms which i n t e r fere w i t h the absorption of feed n u t r i e n t s , e s p e c i a l l y during the e a r l y part of the c h i c k i ' s s l i f e . Eyssen and DeSomer (1963) i n d i c a t e d that the growth-promoting e f f e c t of . a n t i b i o t i c s was r e s t r i c t e d to the c r i t i c a l period of a few days e a r l y i n the chick's l i f e .  However, i n t h i s study, the growth promoting e f f e c t of a n t i -  b i o t i c s and t h e i r e f f e c t on f a t d i g e s t i b i l i t y were s t i l l encountered up to 4 weeks of age.  Therefore, besides i n h i b i t i n g the undesirable organisms  during t h i s c r i t i c a l t r a n s i t i o n a l , period the a n t i b i o t i c s also acted i n the l a t e r stage to promote higher n u t r i e n t s absorption by the mechanisms as discussed i n the l i t e r a t u r e review. Although the f a t d i g e s t i b i l i t y was improved by the a n t i b i o t i c feeding, i t was f u r t h e r increased by i n c r e a s i n g age.  Thus the d i g e s t i b i l i t y of f a t  (tallow) was a f f e c t e d by the age as w e l l as by the m i c r o b i a l a c t i o n .  The  e f f e c t s of age and the a n t i b i o t i c feeding appeared to be a d d i t i v e . There was no d i f f e r e n c e i n the f a t d i g e s t i b i l i t y between the d i e t s (without a n t i b i o t i c s ) at the 1st week of age. and onward, the d i g e s t i b i l i t y of f a t i n the DPW lower than that of the c o n t r o l d i e t .  basal  However, at the 2nd week  d i e t s were again found to be  This d i f f e r e n c e tended to decrease  97  and became insignificant at the end of the 4th week. The effect of high calcium level on fat digestibility was not apparent at the f i r s t week probably because the chick's ability to absorb fat was limited.  At the older age (4th  week) the chick's ability to absorb fat was much improved and probably  was  able to overcome the insoluble-soap formation and absorb a larger amount of free fatty.acids.  Hence, i t is only between these two periods that the  effect of high calcium level on fat digestibility was demonstrated. A l l groups fed with antibiotics showed similar fat digestibility at the various ages.  This indicates that antibiotic feeding overcame the effect of high  calcium level on fat digestibility, probably by increasing the calcium absorption. The M.E. values of the diets determined at the various age (shown in Table 22) were correlated with the fat digestibility.  Hence at each age,  feeding antibiotics would increase the M.E. values of the diets and also increased with the age of the chicks.  Nelson et a l . (1963) observed  that when growth was stimulated by antibiotics an increase in M.E. diet was also obtained.  M.E.  of the  The authors attributed this effect to antibiotics  facilitating the absorption of calorigenic nutrients, which in this study proved to be the fat. At four week of age the M.E. values of the alkali-treated DPW diets (without or with antibiotics) were equivalent to the corresponding control diets.  However, the M.E. values of the untreated DPW diets were always lower  than the other diets, especially in comparison to the alkali-treated  DPW  diets even though treated DPW exhibited the same degree of fat digestibility. It is probably ,because of the low digestibility of nutrients in the untreated DPW and also the lower M.E. value of the untreated DPW of 1000 kcal/kg used in the formulation).  (lower than the value  This indirectly confirmed that the  98  Table  22. Effect of age and antibiotics feeding on the metabolizable energy values of the diets in Experiment 7.  Diets  M.E. kcal/kg Formulated  Control  NaOH treated DPW  Determined Week 1  Week 2  Week 4  Basal  2755  2510  2680  2723  Antibiotic  2755  2653  2786  2745  143  106  22  Difference Untreated DPW  (as fed basis)  1  —  Basal  2720  2008  2347  2523  Antibiotic  2720  2259  2520  2647  Difference  —  251  173  124  Basal  2720  2242  2574  2756  Antibiotic  2720  2480  2726  2799  Difference  —  238  152  43  99  a l k a l i - t r e a t m e n t improved the M.E. o f the DPW. The  n i t r o g e n , c a l c i u m and phosphorus r e t e n t i o n o f the d i e t s a r e shown i n  T a b l e 23.  I t was e v i d e n t t h a t a n t i b i o t i c s u p p l e m e n t a t i o n d i d not s i g n i f i c a n t l y  a f f e c t the u t i l i z a t i o n of these n u t r i e n t s i n the d i e t s . because the d i e t s c o n t a i n e d  T h i s i s presumably  adequate l e v e l s o f these n u t r i e n t s so t h a t no  b e n e f i c i a l e f f e c t s would be e x e r c i s e d by the a n t i b i o t i c s as d i s c u s s e d i n the l i t e r a t u r e review. The N r e t e n t i o n of t h e DPW  d i e t s were lower than t h a t o f the c o n t r o l  d i e t s , r e f l e c t i n g t h e lower u t i l i z a t i o n of n i t r o g e n i n the DPW the a l k a l i - t r e a t e d DPW  diets.  However,  showed b e t t e r n i t r o g e n u t i l i z a t i o n than the u n t r e a t e d  DPW. The p e r c e n t DPW  of c a l c i u m and phosphorus r e t a i n e d by the c h i c k s f e d the  d i e t s was lower than t h a t of the c o n t r o l .  d i g e s t i b i l i t y o f these m i n e r a l s of these m i n e r a l s  contained  i n the DPW  T h i s i s because of the low  and a l s o due to the h i g h  i n the d i e t s which reduced the m i n e r a l  ( M o r r i s s e y and Wasserman 1971).  The u n t r e a t e d  DPW  levels absorption  d i e t s c o n t a i n e d the  h i g h e r l e v e l of c a l c i u m and phosphorus (shown i n T a b l e 23) and showed lower r e t e n t i o n of these m i n e r a l s The  as compared w i t h  the a l k a l i - t r e a t e d DPW  f e e d e f f i c i e n c y o f the d i e t s ( r e p r e s e n t e d by the f e e d  r a t i o n s ) a t weekly i n t e r v a l s was s t u d i e d and shown i n T a b l e e f f i c i e n c y of the c o n t r o l d i e t was improved s i m i l a r l y experimental  period.  diets.  conversion  24.  The f e e d  throughout the e n t i r e  However, the f e e d e f f i c i e n c y of the DPW  d i e t s (un-  t r e a t e d or a l k a l i t r e a t e d ) were markedly improved a f t e r the second week, as shown by an i n c r e a s e i n d i f f e r e n c e i n the f e e d c o n v e r s i o n r a t i o s , between the a n t i b i o t i c f e d groups and the groups f e d the b a s a l s . improvement i n f a t d i g e s t i b i l i t y and M.E. c o n t e n t s  T h i s i s due to the marked  a f t e r t h i s age.  Although  the a n t i b i o t i c f e e d i n g s i g n i f i c a n t l y improved t h e f a t d i g e s t i b i l i t y and M.E.  100  Table 23. Effects of antibiotics feeding on nitrogen, calcium and phosphorus retention of chicks fed the experimental diets at 2 week of age.  Nitrogen Retention  Diets  %  Control  Untreated DPW  NaOH treated DPW  Phosphorus  Calcium %' i n diet  Retention %  % diet  Retention %  Basal  58.2  1.29  44.5  0.67  49.9  Antibiotics  55.7  1.29  43.1  0.67  50.0  Mean  57.0  Basal  49.2  2.49  16.9  0.97  29.6  Antibiotics  48.6  2.49  20.9  0.97  29.1  Mean  48.9  Basal  54.0  1.96  39.6  0.93  40.9  Antibiotics  49.5  1.96  43.6  0.93  38.8  Mean  51.8  50.0  43.8  29/4  18.9  41.6  39.8  101  Table 24. Feed conversion ratio of chicks fed the experimental diets at weekly intervals in Experiment 7.  Feed^Conversion Ratio (Weekly)  Diets  Control  0 -1  '1-2  2-3  3-4  Overall  Basal  1.26  1.71  1.81  2.08  1.80  Antibiotic  1.19  1.63  1.71  1.99  1.74  0.07  0.08  0.10  0.09  0.06  Basal  1.31  1.82  2.02  2.37  2.01  Antibiotic  1.28  1.79  1.92?  2.19  c 1.91  Difference  0.03  0.03  0.10  0.18  0.10  Basal  1.28  1.87  2.02  2.25  1.99  Antibiotic  1.23  1.82  1.87  2.09  c 1.87  Difference  0.05  0.05  0.15  0.16  0.12  3 Difference Untreated DPW  NaOH treated DPW  a  d  d  Total feed consumption for 4 weeks 4 week body weight gain  1.  Overall feed conversion ratio  2.  Different subscripts i n the same column indicate significant difference (P < 0.05).  3.  The difference i n feed conversion ratio between the antibiotic fed groups and the groups fed the basal.  1  content of the DPW  d i e t s to the l e v e l comparable to the c o n t r o l , the feed  e f f i c i e n c y of these d i e t s was  s t i l l i n f e r i o r to the c o n t r o l .  probably the low d i g e s t i b i l i t y of p r o t e i n i n the DPW f o r the lower feed e f f i c i e n c y of d i e t s containing i t .  I t was  that was responsible Therefore, the a n t i -  b i o t i c s markedly increased the f a t d i g e s t i b i l i t y , however there was no i n crease i n the d i g e s t i b i l i t y of p r o t e i n i n  DPW.  103  SUMMARY AND CONCLUSION Samples of DPW were treated with 2, 3, 4, 5 and 7% sodium hydroxide solution and their chemical compositions were determined.  Untreated DPW and  alkali-treated DPW were included at 10, 15 and 20% levels i n the chick diets and the performance of broiler chicks fed such diets were studied.  Feeding  trials in evaluating the utilization of non-protein nitrogen i n DPW by chicks and metabolic trials to determine the availability of protein and minerals i n DPW were performed.  Furthermore, the effects of supplementations of lysine  and methionine, dietary fat, and antibiotics on the performance of chicks fed the DPW diets and on the utilization of nutrients i n the diets were studied. The following results were observed. 1.  The alkali treatments had l i t t l e effect on the acid-detergent content of DPW except at the highest level (7%).  fibre  The true protein,  non-protein nitrogen and uric acid contents of DPW were reduced i n relation to the level of sodium hydoxide used. Most of the amino acids i n DPW were not affected by the 2% NaOH treatment except lysine, arginine, serine, proline and cystine which showed slight reduction while alanine showed an increase. 2.  DPW when added to the broiler diet at levels between 10-20% would support growth related to the dietary energy.  Inclusion of DPW i n  the diet did not affect growth but lowered the feed efficiency compared to the controls containing similar energy and protein contents. 3. Alkali treatment at various concentrations markedly improved the growth and feed efficiency of diets containing various levels of DPW. 4. The M.E. values of untreated DPW and DPW treated with 2, 3 and 5%  104  the growth, feed efficiency and nitrogen utilization indicating the poorer performance of chicks fed DPW diets was related to i t s energy dilution effect. 10.  In the absence of antibiotics, the dietary fat (tallow) utilization was impaired with the inclusion of DPW i n the diet.  The metaboliza-  ble energy of the diets were directly related to the fat utilization. Feeding of antibiotics completely ameliorated the adverse effect of DPW on fat utilization and markedly increased the M.E. of the diets, hence improved the growth and feed efficiency. 11.  Antibiotic supplementation had no effect on the nitrogen and minerals retention of the diets.  These studies showed that when balanced for amino acids and energy, inclusion of high levels of DPW i n the diets did not affect growth. However, feed efficiency of the diets containing DPW was impaired due toftielow digest i b i l i t y of protein i n the DPW and.reduced utilization of fat (tallow) in the diet i n the presence of DPW.  Nevertheless, the impaired fat utilization can  be ameliorated by the antibiotic feeding and the low digestibility of protein can be increased by sodium hydroxide treatment. The low M.E. value of DPW, low nutrient availabilities and variability in composition of the product may mean that i t has limited value as a source of nutrients. However, a low level of inclusion (about 10%) i s desirable since this may lower the cost of feed per unit gain and also increase the growth of chicks through stimulating feed intake due to i t s energy dilution effect. Treatment with sodium hydroxide significantly improved the nutritive values of DPW as a feed ingredient for chicks.  105  NaOH were determined to be 827, 1155, 1245 and 1205 kcal/kg  D.M.  "respectively. 5.  Supplementing the basal diet which was suboptimal in protein level (20%) with 2.25% protein equivalent from uric acid or from NPN in the DPW did not improve the growth of chicks.  Growth was depressed  by urea or diammonium citrate supplementation. Nitrogen retention was reduced and uric acid excretion was increased by the supplementation indicating that these nitrogen sources would not be utilized by the chicks. 6.  The availability of true protein of untreated DPW was found to be 50.5%.  Therefore, the low digestibility of protein in DPW  is res-  ponsible, in part, for the poorer feed efficiency of diets containing DPW  as compared to the controls.  The alkali treatments markedly  improved the protein digestibility (about 70%).  This explains the  improvement in performance of chicks obtained with the treatments. 7.  The availability of calcium and phosphorus in untreated DPW 53.8  a n  was  d 19.8% respectively. The alkali treatments did not affect  calcium and phosphorus availabilities significantly.  The availability  of sodium in untreated DPW was 84.4%, which was decreased to 41.848.3% by the alkali treatment. 8.  Growth of chicks fed the 20% DPW basal diets (untreated or a l k a l i treated) were higher than those fed the basal control diet. 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