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Factors affecting mineral availability from ingredients of animal origin with the chick Bulbul, Syed M. 1980

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FACTORS AFFECTING MINERAL AVAILABILITY FROM INGREDIENTS OF ANIMAL ORIGIN WITH THE CHICK • VJ^/ SYED M. BULBUL B . S c , East Pak i s tan A g r i c u l t u r a l U n i v e r s i t y , P a k i s t a n , 1963 M . S c , Texas A&M U n i v e r s i t y , U.S.A., 1965 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY THE FACULTY OF GRADUATE STUDIES Department o f P o u l t r y Sc ience We accept t h i s t h e s i s as conforming to the requ i red standard THE UNIVERSITY OF BRITISH COLUMBIA in A p r i l , 1980 © Syed Muhammed Bui Bui , 1980. In presenting th i s thesis in pa r t i a l fu l f i lment of the requirements for an advanced degree at the Univers ity of B r i t i s h Columbia, I agree that the Library shal l make i t f ree ly avai lable for reference and study. I further agree that permission for extensive copying of th i s thesis for scholar ly purposes may be granted by the Head of my Department or by his representatives. It i s understood that copying or publ icat ion of th i s thesis fo r f i nanc ia l gain sha l l not be allowed without my written permission. Department The Univers ity of B r i t i s h Columbia 2075 Wesbrook Place Vancouver, Canada V6T 1W5 Date . D E - 6 B P 7 5 - 5 1 1 E i i . ABSTRACT Chicks were u t i l i z e d in a study to estimate mineral (Ca, P, Mg, Mn, Cu and Zn) a v a i l a b i l i t y of 10 meat meal samples processed in 10 consecutive days. A balance procedure was used to determine a v a i l a b i l i t y in which a correction for endogenous mineral was u t i l i z e d . Results of th is study indicate that calcium and phosphorus are highly ava i lable from meat meals with values of 90% and 93.4% respec-t i v e l y . Magnesium, manganese, zinc and copper are also well u t i l i z e d with an average of 83.9%, 73.1%, 79.4% and 74%, respect ive ly. Variations in a v a i l a b i l i t y of minerals pa r t i cu l a r l y phosphorus, copper and zinc were observed among meat meal samples tested. This indicates that raw material used in day to day manufacturing of the meals are d i f f e ren t ; a l so, phosphorus might ex i s t in d i f fe rent forms from one meal to another. A v a i l a b i l i t y values observed in this study indicate that meat meal is an excel lent source of avai lable minerals. The important mineral (Ca, P, Mg, Mn, Cu and Zn) content was determined in blood meal, feather^meal, f i sh meal and meat meal. These a v a i l a b i l i t y studies u t i l i z e d the b ro i l e r chick (three weeks of age) in a mineral balance procedure. Results of mineral content showed a wide range in Ca (2.1-84.0 mg/g), P (1.9-54.0 mg/g), Mg (12.5-68.0 mg/kg), Cu (8.3-22.4 mg/kg) and.Zn (22.7-1 50 mg/kg). The range in concentration of Mg among samples was narrow (1.3-2.7 mg/g). Blood meal was the lowest in a l l minerals except Cu. Fish meal #1 and f i sh meal #2 or meat meal were the highest in these minerals. S i gn i f i cant var iat ion was observed in a v a i l a b i l i t y of each mineral among animal protein concentrates tested. 1 1 1 • Average a v a i l a b i l i t y of Ca, P, Mg, Mn, Cu and Zn was 88.3, 87.6, 80.8, 71.7, 73.2 and 76.8, respect ively. Studies were conducted with b ro i l e r chicks to compare the a v a i l -a b i l i t y of phosphorus from feather meal, blood meal, meat meal and f i sh meal using d i f fe rent assay techniques. A standard curve was drawn by p lo t t ing the growth rate and percentage of t i b i a ash obtained at various levels of added dicalcium phosphate (Reference d i e t ) . The b io log ica l a v a i l a b i l i t y of phosphorus for animal protein concentrates was calculated from the standard graph. When body weight was used as a c r i t e r i a the comparative a v a i l a b i l i t y of phosphorus from feather meal, blood meal, meat meal (L), meat meal (H) and f i sh meal was found to be 91%, 112%, 118%, 123% and 125%, respect ive ly. The comparative a v a i l a b i l i t y of phosphorus from feather meal, blood meal, meat meal (L), meat meal (H) and f i sh meal when percentage of t i b i a ash was used as a c r i t e r i a was found to be 84%, 98%, 112%, 121%, 121%, respect ive ly. The percentage of t i b i a ash obtained with test phosphate was divided by the percentage of t i b i a ash obtained with standard phosphate. When this method was used to calculate the comparative a v a i l a b i l i t y of phosphorus from feather meal, blood meal, meat meal (L) , meat meal (H) and f i s h meal, the calculated values were found to be 85%, 90.5%, 94.7%, 97.3% and 97.3%, respect ive ly. The a v a i l -a b i l i t y of phosphorus from feather meal, blood meal, meat meal (L), meat meal (H) and f i sh meal was calculated using mineral balance procedure and was found to be 72.5%, 88%, 92%, 95%, 95.3%, respect ive ly. This study indicates that var iat ion in the procedure used to determine phosphorus a v a i l a b i l i t y from animal protein sources may influence data. i v . TABLE OF CONTENTS Page ABSTRACT i i TABLE OF CONTENTS . . . . . i v LIST OF TABLES . v i LIST OF FIGURES v i i i LIST OF APPENDIX TABLES . . . i x ACKNOWLEDGEMENTS x GENERAL INTRODUCTION . . . .1 LITERATURE REVIEW . 3 A v a i l a b i l i t y of Minerals in Vegetable and Animal Protein Sources • • 3 Factors Af fect ing Mineral A v a i l a b i l i t y 5 Techniques for Estimating Mineral A v a i l a b i l i t y - • -21 EXPERIMENT 1. AVAILABILITY OF MINERALS IN MEAT MEAL TO THE GROWING CHICK 26 EXPERIMENTAL PROCEDURE . . . . 26 RESULTS AND DISCUSSION 30 Calcium 31 Phosphorus • • • • 31 Magnesium . . . . . . . . . . . . . 34 Manganese 35 Copper 36 Zinc 36 EXPERIMENT 2. AVAILABILITY OF MINERALS IN PROTEIN CONCENTRATE OF ANIMAL ORIGIN IN BROILER CHICKS 39 EXPERIMENTAL PROCEDURE 39 V . Page RESULTS AND DISCUSSION . 43 EXPERIMENT 3. COMPARISON OF ASSAY TECHNIQUES FOR PHOSPHORUS AVAILABILITY WITH THE CHICKS 50 EXPERIMENTAL PROCEDURE 51 RESULTS AND DISCUSSION . . 57 SUMMARY AND CONCLUSIONS .68 REFERENCES . . . .71 APPENDIX 84 v i . LIST OF TABLES Tab!e Page EXPERIMENT 1. AVAILABILITY OF MINERALS IN MEAT MEAL TO THE GROWING CHICK 1 Composition of synthetic mixture 28 2 Composition of test mixture 29 3 Proximate constituents of meat meal sample processed on 10 consecutive days (dry matter basis) 32 4 Mineral content of meat meal samples co l lected on TO consecutive days • • 33 5 A v a i l a b i l i t y of minerals from meat meals co l lected on 10 consecutive days 38 EXPERIMENT 2. AVAILABILITY OF MINERALS IN PROTEIN CONCENTRATE OF ANIMAL ORIGIN IN BROILER CHICKS 6 Composition of synthetic mixture 41 7 Composition of test mixture • • • • 42 8 Proximate constituents of blood meal, feather meal, f i sh meal #1, f i sh meal #2 and meat meal (dry matter basis) 44 9 The mineral content of blood meal, feather meal, f i sh meal #1, f i sh meal #2 and meat meal 45 10 A v a i l a b i l i t y of minerals in blood meal, feather meal, f i sh meal #1, f i sh meal #2 and meat meal . . . 49 v i i . Table Page EXPERIMENT 3. COMPARISON OF ASSAY TECHNIQUES FOR PHOSPHORUS AVAILABILITY WITH THE CHICKS 11 Composition of basal d iet . .52 12 Composition of the diet with d i f fe rent phosphorus levels supplemented in the dicalcium phosphate . 53 13 Composition of the test d iet containing (0.43% phosphorus) supplemented with animal protein concentrates 54 14 Premix composition of microingredients 55 15 Amino acid composition of the basal d iet 56 16 Body weight, t i b i a ash, feed e f f i c i ency and mortal i ty of four week old chicks as influenced by d i f fe rent phosphate levels in the diet 58 17 Body weight, t i b i a ash, feed e f f i c i ency and mortal i ty of four week old chicks fed (.43% phosphorus) supplemented by d i f fe rent animal protein concentrates with the basal d iet 59 18 ^Reta^yl^.^ a v a i l a b i l i t y of phosphorus in feather meal, blood meal, meat meal and f i sh meal when body weight used as a. c r i t e r i a for a va i l ab i l i t y 61 19 '.>ReTai:$ye7f,! a v a i l a b i l i t y of phosphorus in feather meal, blood meal, meat meal and f i s h meal when percentage of t i b i a ash'used as a c r i t e r i a for a v a i l a b i l i t y 63 20 Percentage of phosphorus a v a i l a b i l i t y in feather meal, blood meal, meat meal and f i sh meal 65 21 Percentage of phosphorus a v a i l a b i l i t y in feather meal, blood meal, meat meal and f i sh meal (Balance Procedure) 66 vi i i . LIST OF FIGURES Figure Page 1 Regression Tine of the body weight at d i f fe rent levels of dicalcium phosphate used for ca l cu l a t -ing comparative a v a i l a b i l i t y of phosphorus for animal protein concentrates 60 2 Regression l i ne of the percentage of t i b i a ash at d i f fe rent levels of dicalcium phosphate used for ca lcu lat ing comparative a v a i l a b i l i t y of phosphorus for animal protein concentrates . . . .62 I X . LIST OF APPENDIX TABLES Table Page 1 Analysis of variance for Ca a v a i l a b i l i t y of 10 meat meal samples (Experiment 1) £4 2 Analysis of variance for P a v a i l a b i l i t y of 10 meat meal samples (Experiment 1) 85 3 Analysis of variance for Mg a v a i l a b i l i t y of 10 meat meal samples (Experiment 1) 86 4 Analysis of variance for Mn a v a i l a b i l i t y of 10 meat meal samples (Experiment 1) 87 5 Analysis of variance for Cu a v a i l a b i l i t y of 10 meat meal samples (Experiment 1) -88 6 Analysis of variance for Zn a v a i l a b i l i t y of 10 meat meal samples (Experiment 1) 89 7 Analysis of variance for Ca a v a i l a b i l i t y of blood meal, feather meal, f i sh meal #1, f i sh meal #2, and meat meal (Experiment 2) 90 8 Analysis variance for P a v a i l a b i l i t y of blood meal, feather meal, f i s h meal #1, Fish meal #2, and meat meal (Experiment 2) . . . . .91 9 Analysis variance for Mg a v a i l a b i l i t y of blood meal, feather meal, f i s h meal #1, f i s h meal #2, and meat meal (Experiment 2) 92 10 Analysis of variance for Mn a v a i l a b i l i t y of blood meal, feather meal, f i sh meal #1, f i s h meal #2, and meat meal (Experiment 2) 93 11 Analysis of variance for Cu a v a i l a b i l i t y of blood meal, feather meal, f i sh meal #1, f i sh meal #2, and meat meal (Experiment 2) 54 12 . Analysis of variance for Zn a v a i l a b i l i t y of blood meal, feather meal, f i sh meal #1, f i sh meal #2, and meat meal (Experiment 2) 95 ACKNOWLEDGEMENTS I would l i k e to express my sincere appreciation to my research supervisor, Dr.D.B. Bragg, Professor and Chairman, Department of Poultry Science, for his valuable guidance, encour-agement and constructive c r i t i c i s m throughout the various aspects of th i s work. I am also grateful to other members of my Graduate Committee: B.E. March, Professor, Department of Poultry Science; Dr. R.C. Fitzsimmons, Associate Professor, Department of Poultry Science; Dr. C P . Krishnamurti, Professor, Department of Animal Science, for the i r advice and encouragement in the preparation and wr i t ing of th i s thes i s . The author wishes to express his appreciation to the B r i t i s h Columbia Feed Manufacturer's Association for f inanc ia l support that made this study possible. F i na l l y , I would l i k e to extend my hea r t - fe l t thanks to my parents and my fr iend C E . Duenas who constantly inspired me in completing this programme. Syed Muhammed Bui Bui 1. GENERAL INTRODUCTION In current pract ice, the nu t r i t i ve value of a rat ion is determined by the content of the various nutrients in the ingredients, and feed formulation is based on these values. Mineral content of rations is s im i l a r l y calculated on the sum of the various minerals in feed ingredients. Recent research has however indicated that what i s present i s not a l l ava i lab le and there i s a s i gn i f i can t difference between tota l content of nutrients and quantit ies ava i lab le . Minimum requirements and recommended levels of various minerals for d i f fe rent l ivestock have been determined using to ta l mineral content in mixed rat ions. This practice assumes that a l l minerals in the rat ion are highly ava i lab le . The use of meat meal in poultry diets has increased in recent years because of the high mineral content. But not much informa-t ion i s ava i lab le re l a t i ve to the a v a i l a b i l i t y of the n u t r i t i o n a l l y important minerals (Ca, P, Mg, Mn, Cu and Zn), from meat meal. Furthermore, meat meal derived from the processing of c a t t l e , sheep, swine and other animal species may d i f f e r in i t s composition. The product may contain by-products from predominately one species or varying proportions from a number of species. In addition to the var iat ion related to species, there may be d i f fe rent proportions of bone and other tissues, from one processing plant to another or from day to day in a s ingle processing plant. The influence of animal type and bone to t i ssue r a t i o w i l l influence the mineral composition and may af fect the d igest ion, absorption and u t i l i z a -t ion of meat meal by the animals. Therefore, i t i s necessary to determine the content of nu t r i t i o na l l y important minerals in a number of meat meal 2. samples and determine the v a r i a t i o n i n a v a i l a b i l i t y o f these minera l s among samples. L i t t l e i n fo rmat ion i s a v a i l a b l e i n the l i t e r a t u r e on the a v a i l -a b i l i t y of minera l s from other p r o te i n concentrates o f animal o r i g i n such as blood meal, f ea the r meal and f i s h meal which are used i n the pou l t r y d i e t as sources o f animal p r o t e i n . A l t h o u g h , l i t i s g ene r a l l y assumed tha t the minera l s in animal p r o te i n sources are h i gh l y a v a i l a b l e to the an ima l , f u r t h e r exper imental s tud ie s are needed i n view o f the observed v a r i a t i o n i n a v a i l a b i l i t y o f minera l s among i no r gan i c minera l supplements. Var ious methods have been used by many research workers to determine the a v a i l a b i l i t y o f phosphorus from d i f f e r e n t phosphate supp le -mented the c h i c k . I t was revea led i n the l i t e r a t u r e tha t con s ide rab le v a r i a t i o n i n the assay procedure employed has e x i s t e d . The purpose of t h i s study was to determine: 1) the v a r i a t i o n i n mineral composit ion o f meat meal from one process ing p l an t dur ing a 10-day per iod and the i n f l u e n c e o f d a i l y v a r i a t i o n i n meat meal on the a v a i l a b i l i t y o f minera l s (Ca, P, Mg, Mn, Cu and Zn) to the growing c h i c k s ; 2) to determine the a v a i l a b i l i t y o f minera l s (Ca, P, Mg, Mn, Cu and Zn) i n blood meal , f ea the r meal, f i s h meal and meat meal ; 3) to compare the phosphorus a v a i l a b i l i t y from p r o t e i n concen-t r a t e s , o f animal o r i g i n us ing d i f f e r e n t assay techniques and demonstrate the e f f e c t of technique on r e s u l t s . 3. LITERATURE REVIEW A v a i l a b i l i t y o f M inera l s i n Vegetable and Animal P r o t e i n Sources Var ious p r o t e i n sources have been reported to i n t e r f e r e w i th the a v a i l a b i l i t y of minera l s i n the d i e t . These i nc l ude peas (K ienho lz et a l . , 1959; K ienho lz et aT., 1962), i s o l a t e d soybean p r o t e i n (O ' De l l and Savage 1960), sesame meal (Lease et a j_. , 1960; Lease, 1 966), amino a c i d and case in d i e t s ( L i k u s k i and Forbes, 1964), s a f f l o w e r , cottonseed and soybean meals (Lease and W i l l i a m s , 1967a, 1967b). I s o l a ted soybean p r o t e i n reduces the a v a i l a b i l i t y o f molybdenum (Reid et aT., 1956), z i n c (O ' De l l and Savage, 1960), and manganese and copper (Davis et a]_., 1962). In these s t u d i e s , however, the minera l s were supplementary and not der i ved from the vegetable or animal feed s t u f f s . There are a number o f s tud ie s on the a v a i l a b i l i t y o f minera l s o f p l an t and animal o r i g i n to non-ruminants. Armstrong and Thomas (1952) est imated t ha t ca lc ium a v a i l a b i l i t y of l u ce rne , red c l o v e r and w i l d whi te c l o v e r was 84.89%, 83.11% and 79.95%, r e s p e c t i v e l y . In another s tudy, Armstrong et al_. (1 953) reported that a v a i l a b i l i t y o f ca lc ium i n three herbs o f g rass land ( b i nne t , c h i c o r y and narrow leaved p l a n t a i n ) was 80.38%, 87.73% and 95.28%, r e s p e c t i v e l y . The ca lc ium a v a i l a b i l i t y o f the three grasses ; t imothy , perenn ia l rye grass and cock s foo t , was 78.99%, 76.53% and 69.02%, r e s p e c t i v e l y (Armstrong £ t a l_ . , 1957). Devadatta and Appana (1954) repor ted the a v a i l a b i l i t y o f ca l c ium in amaranthus (74-78%), Sesbania g r a n d i f l o r a (85%) and Moringa o l e i f e r i a (69%). The a v a i l a b i l i t y o f phytate phosphorus has a l so been s t u d i e d . The committee on animal ' n u t r i t i o n (NAS-NRC, 1960) repor ted that approx imately 4. 30% o f the phosphorus i n p l an t ma te r i a l s could be u t i l i z e d by non-ruminants. Ashton et a]_. (1960) observed tha t four-week o l d ch ick s r e t a i ned app rox i -mately 20% o f phytate phosphorus wh i l e s ix-week o l d ch i ck s r e ta i ned 36% to 49%. Temperton and Cass idy (1964) reported t ha t ch ick s u t i l i z e d app rox i -mately 60% o f the phytate phosphorus and on ly 50% o f the non-phytate phosphorus. Salman and McGinnis (1968) observed tha t phosphorus u t i l i z a t i o n i n r a t i o n s con ta i n i ng 0.3% p l an t phosphorus was not s i g n i f i c a n t l y d i f f e r e n t from i t s u t i l i z a t i o n i n r a t i on s con ta i n i ng e i t h e r 0.6% p l an t phosphorus or 0.3% p l an t plus 0.3% i no rgan i c phosphorus. U t i l i z a t i o n o f phosphorus from p l an t ma te r i a l was t he re f o re h igh . There fo re , i t i s reasonable to be l i e ve tha t ch ickens can u t i l i z e g rea te r amounts o f phosphorus o f p lant o r i g i n than i s c u r r e n t l y suggested. Guenter and S e l l (1974) us ing i n t r a -28 muscular i n j e c t i o n o f r a d i o - a c t i v e Mg reported an a v a i l a b i l i t y va lue o f 61.2% f o r magnesium i n soybean meal. G i l l i s et a_l_. (1954) est imated b i o l o g i c a l a v a i l a b i l i t y o f ca lc ium and phosphorus from f i s h meal and found that the a v a i l a b i l i t y o f ca l c ium and phosphorus i n f i s h meals averaged 100.4%. O 'De l l et aj_. (1972) us ing the growth response o f ch i ck s eva luated the a v a i l a b i l i t y o f z i n c i n f e e d s t u f f s o f animal and p l an t o r i g i n and reported a v a i l a b i l i t y o f 57%, 67% and 75% f o r sesame meal , soybean meal and f i s h meal, r e s p e c t i v e l y . Nwokolo et a K (1 976) us ing a mod i f ied balance procedure eva luated the a v a i l a b i l i t i e s o f c a l c i um, phosphorus, magnesium, manganese, z i n c and copper from palm kernel meal , cottonseed meal , soybean meal and rapeseed meal. Results o f t h i s study i n d i c a t e d ca l c ium was we l l u t i l i z e d from palm kernel meal (68.8%), soybean meal (85.6%), cottonseed meal (64.6%) and rapeseed meal (71.1%). The average a v a i l a b i l i t y o f phosphorus was 78%. The magnesium was u t i l i z e d from the i n g red i en t s w i th 5. an average of 67.5% a v a i l a b i l i t y . Manganese, z i n c and copper showed g rea te r v a r i a t i o n i n a v a i l a b i l i t i e s . The range i n a v a i l a b i l i t y was 45.7% to 76.3% f o r manganese, 13.9% to 65.5% f o r z i n c and 42.2% to 62.2% f o r copper. The review o f l i e t e r a t u r e revea led that l i t t l e i n fo rmat ion has been reported on the a v a i l a b i l i t y o f minera l s from meat meals and other p r o t e i n concen-;, : t r a t e s of animal o r i g i n . Factors A f f e c t i n g Minera l A v a i l a b i l i t y The g a s t r o - i n t e s t i n a l ep i t he l i um i s r e l a t i v e l y - impe rmeab l e to ca lc ium and r e l a t e d a l k a l i n e ea r th ca t i on s under normal n u t r i t i o n a l c i rcumstances . Wilson (1962) has est imated that ca lc ium i s absorbed at a ra te o f about o n e - f i f t i e t h of that of sodium but at a r a te app rec i ab l y g reater than t ha t o f other d i v a l e n t c a t i o n s , such as Fe , Zn and Mn Absorpt ion i s i n f l uenced by severa l p h y s i o l o g i c a l and n u t r i t i o n a l f a c t o r s . The most prominent v a r i a b l e s are the o v e r a l l n u t r i t i o n a l s t a t e , age, the reproduct ion s ta tu s ( g e s t a t i o n , l a c t a t i o n ) , the abso lute l e v e l o f Ca i n -take, v i t amin D i n t a k e , and the presence of d i e t a r y agents tha t can form i n s o l u b l e complexes w i t h ca l c i um (N ico laysen et a l _ . , 1953; I r v i n g , 1957; Wasserman, 1963; Bronner, 1964). Ce r t a i n d i sease s t a t e s , f o r example, s t e a t o r r h e a , v i t amin D r e s i s t a n t r i c k e t s and malignancy o f the pa ra thy ro i d s , a l so d i r e c t l y or i n d i r e c t l y i n f l u e n c e ca l c ium ab so rp t i on . Lactose , the d i s accha r i de of mi lk o r i g i n , has been; l i nked w i th ca lc ium and bone metabolism f o r many years (Duncan, 1955; Atk inson et a l ., 1957; Dupuis and Fou rn i e r , 1963; Bronner, 1964). These experiments c l e a r l y show that the i n co rpo r a t i o n o f l a c t o se i n the d i e t s o f severa l spec ies 6. increases the absorpt ion and r e t e n t i o n o f ca lc ium (Bergeim, 1926; K l i n e et a l^ . , 1932). The extens i ve i n v e s t i g a t i o n s by Fou rn i e r , Dupuis and S u s b i e l l e of France demonstrated tha t the " l a c t o s e e f f e c t " was not s p e c i f i c f o r l a c t o s e . Other sugars, such as mannose, c e l l o b i o s e , r a f f i n o s e , , D- and L - xy l o se , D- and L -arab inose, and p o l y - a l c o h o l s , such as mann i t o l , s o r b i t o l , and i n o s i t o l , a l s o enhanced net ca lc ium absorpt ion and r e t e n t i o n when incorporated i n t o the d i e t o f r a t s . Some d i e t a r y sugars, such as g lucose and sucrose were i n e f f e c t i v e w i th r a d i o t r a c e r s s tud ie s o f ca lc ium and s t r on t i um. The same pat te rn was observed by Wasserman and Comar (1959). For example, the magnitude o f absorpt ion o f 45 85 o r a l Ca and/or Sr was enchanced by c e r t a i n sugars and not s i g n i f i c a n t l y a f f e c t e d by o the r s . The i n e f f e c t i v e sugars are those that are r a p i d l y absorbed by the upper small i n t e s t i n e . This i s the on ly d i s t i n g u i s h i n g fea tu re between e f f e c t i v e and i n e f f e c t i v e carbohydrates . The f a c t t ha t glucose can enhance Ca absorpt ion was shown by Vaughn and F i l e r (1960) when r a d i o a c t i v e Ca and g lucose were i n j e c t e d together d i r e c t l y i n t o the lumen of the r a t i l eum, by pass ing the s i t e o f ex tens i ve ab so rp t i on . Two types of exp lanat ions have been advanced fo r the e f f e c t of sugars on Ca ab so rp t i on . In one the sugars are thought to che l a t e or complex Ca and thereby enhance Ca ab so rp t i on . In the second the sugars are thought to exer t a n o n - s p e c i f i c e f f e c t on the metabo l i c machinery of the c e l l which i n tu rn leads to an inc reased pe rmeab i l i t y to Ca. The p r o t e i n s ta tus o f animals and humans i s a f a c t o r determin ing the degree of s k e l e t a l m i n e r a l i z a t i o n (McCanee et a l_ . , 1942; Frandsen et a l . , 1954). E s s en t i a l amino a c i d d e f i c i e n c i e s a l s o adver se l y a f f e c t ca lc ium 7. u t i l i z a t i o n p o s s i b l y a t the stage o f o s t eo i d synthes i s (Bavetta et a l . , 1954; Haggar et a l _ . , 1 955). Lehmann and Po l l o c k (1941-1942) noted tha t a amino ac ids increased the s o l u b i l i t y o f ca lc ium s a l t s , and, t h e r e f o r e , p red i c ted tha t the simultaneous presence o f both f a c t o r s i n the gut would a i d i n mineral ab so rp t i on . The enhancing e f f e c t o f var ious amino ac ids on the i n t e s t i n a l abso rp t ion o f Ca was f i r s t shown in the r a t (Wasserman et a l_ . , 1956). I t was noted that L - l y s i n e and L - a r g i n i ne were p a r t i c u l a r l y e f f e c t i v e , a lthough s i g n i f i c a n t increases in abso rp t ion were a l s o brought about by L - t ryptophane, L - l e u c i n e , L - h i s t i d i n e , L -meth ion ine, L - a s p a r t i c a c i d , h y d r o x y - L - p r o l i n e , L -g lutamic a c i d , and DL - t y r o s i ne . G l y c i n e , L-i s o l e u c i n e , L - v a l i n e , and L -pheny la lan ine were r e l a t i v e l y i n e f f e c t i v e . Perhaps l y s i n e and other amino ac ids can form s o l ub l e complexes wi th Ca at the pH o f i l e a l f l u i d which i s about 7.5 (Lehmann and P o l l a c k , 1941-1942; Wasserman, Lengemann, 1960). Lys ine a c t u a l l y i n h i b i t s Ca absorpt ion in the ch ick (Wasserman ejt aj_. , 1956), i n con t ra s t to the p o s i t i v e e f f e c t observed i n the r a t . The spec ies d i f f e r e n c e s t i l l remained unexp la ined. Phy t i c ac id ( I n o s i t o l hexaphosphoric ac id ) che la te s mineral e lements, reduc ing t h e i r a v a i l a b i l i t y i n whole or i n pa r t (Nelson e t a l . , 1967). Stud ies suggested t ha t i t probably che la ted to some ex ten t , a l l the ca t ions r equ i red by an ima l s . Bruce and Cal low (1934) i n an e a r l i e r r epo r t suggested t h a t i n d i e t s w i t h normal calcium-phosphorus r a t i o , the main a c t i o n o f phy t i c a c i d would be to render ca lc ium u n a v a i l a b l e . Phy t i c a c i d has been reported to render ca lc ium unava i l ab l e i n dogs (Hof f -Jorgensen, 1946), man (Bronner et a l . , 1954) and ch icks (Nelson et a l . , 1967). The i n a b i l i t y o f ch i ck s to u t i l i z e a s i g n i f i c a n t amount o f phytate phosphorus has been reported by G i l l i s e_t al_. (1 957) and i n a review by 8. Nelson (1967). In con t ra s t to t h i s , the a d d i t i o n o f phytate as bran (Roberts and Yudkin, 1961) or as a mixture o f pentacalc ium phytate and sodium phytate (Hof f - Jorgensen, 1946) was reported to inc rease a v a i l -a b i l i t y o f phosphorus from cerea l based r a t i o n s . Phy t i c a c i d has been repor ted to reduce a v a i l a b i l i t y o f i r o n (McCance e_t a l _ . , 1943), magnesium (Roberts and Yudk in, 1960), and z i n c (O 'De l l and Savage, 1960). K ra t ze r and Vohra (1966) suggested t ha t part o f the i n t e r f e r e n c e i n z i n c absorpt ion by phy t i c a c i d may be due to the format ion o f z i n c phosphate r a the r than z i n c phytate. Smith (1961) reported tha t net absorpt ion o f ca lc ium and magnesium decreased i n mi lk fed ca lves i n ge s t i n g high l e v e l s o f f i b r e as wood shav ings. Armstrong ejt al_. (1953) i n a study on the a v a i l a b i l i t y o f ca lc ium in three herbs o f g ra s s l and , observed evidence o f an inver se r e l a t i o n s h i p between ca lc ium a v a i l a b i l i t y and content of crude f i b r e . Southgate (1973) suggested t ha t i n man, d i e t a r y f i b r e acted as a weak ion exchanger which bound b i l e s a l t s and prevented t h e i r reabso rp t i on from the gut. Heaton (1973) a l so suggested that b ind ing o f l i t h o c h o l a t e i n the gut could account f o r reduced inc idence o f ga l l s t one s i n rats fed high f i b r e d i e t s . K r i t chev sky and Story (1974) demonstrated that d i e t a r y f i b r e exerted a b ind ing e f f e c t on b i l e s a l t s i n v i t r o . Vegetable f i b r e con s i s t s o f a heterogenous complex of po l y sacca r ide s and l i g n i n capable o f seques ter ing wate r , c a t i on s or anions depending on the chemis t ry o f the c o n s t i t u e n t macromolecu!es (Eastwood, 1973). I t appears ev ident that d i e t a r y f i b r e sequesters m i n e r a l s , render ing them unava i l a b l e . M i t c h e l l (1939) suggested that o x a l i c a c i d i n food would lead to poor ca lc ium u t i l i z a t i o n as a r e s u l t of format ion o f poor ly absorbable 9. ca lc ium o x a l a t e . Skorkowsk.a-Zieleniewska et aj_. (1974) us ing r a t s repor ted reduced ca l c i um, magnesium and i r o n absorpt ion from d i e t s con ta i n i ng o x a l i c a c i d . S i m i l a r r e s u l t s were reported f o r ca lc ium ( M u r i l l o et al_. 1973) and phosphorus (Compere, 1966). Brune and Bredehorn (1962) however observed tha t pigs u t i l i z e d ca lc ium oxa la te as e f f e c t i v e l y as o ther ca lc ium sources. Patel e t al_. (1 967) reported tha t most concentrates and vegetab le leaves had p r a c t i c a l l y no o x a l a t e s . I t would seem the re fo re that oxa la tes are not a major problem i n p r a c t i c a l d i e t s f o r non-ruminants. This view was a l so held by Fasset t (1966) who c r i t i c a l l y eva luated the l i t e r a t u r e p e r t a i n i n g to po s s i b l e oxa l a te i n t e r f e r e n c e w i th ca lc ium metabolism and came to the conc lu s ion tha t there was l i t t l e danger a s soc i a ted w i th i n ge s t i n g oxa l a te con ta i n i ng p l a n t s . In f luence o f c h e l a t i n g agents on minera l a v a i l a b i l i t y has been r epo r ted . K ra tze r et al_. (1959) observed recovery from z i n c d e f i c i e n c y symptoms i n turkey pou l t s when small amounts o f e t h y l e n e - d i a m i n e - t e t r a -a c e t i c a c i d (EDTA) were i nc luded i n i s o l a t e d soybean p r o t e i n d i e t . S i m i l a r e f f e c t s of EDTA have been observed i n chickens (O ' De l l e t a l . , 1964) and ra t s (Oberleas et a l_ . , 1966). Larsen et al_. (I960) reported that EDTA decreased i r o n a v a i l a b i l i t y to r a t s . Suso and Edwards (1968) 60 s tud ied the i n f l u e n c e o f var ious c h e l a t i n g agents on absorpt ion of Co, 59 54 65 'Fe, Mn and Zn by ch i ckens . They observed s i g n i f i c a n t inc reases i n 65 54 Zn absorpt ion and n o n - s i g n i f i c a n t increases i n Mn abso rp t ion w i th 59 i n c r ea s i n g l e v e l s o f EDTA. Add i t i o n of EDTA decreased abso rp t ion o f Fe fin and Co. Other c h e l a t i n g agents were not as e f f e c t i v e as EDTA i n improving z i n c a v a i l a b i l i t y (Vohra and K r a t z e r , 1964). 10. The amino ac ids c y s t e i ne and h i s t i d i n e which are natura l c h e l a t i n g agents , have b e n e f i c i a l e f f e c t s on the z i n c d e f i c i e n c y syndrome (N ie l sen et aj_. , 1966). In z i nc d e f i c i e n t ch i ck s fed i s o l a t e d soybean p r o t e i n , a supplement o f 0.5% c y s t e i ne a l l e v i a t e d a l l s igns of z i n c d e f i c i e n c y (N ie l sen e_t aj_. , 1966). They reported increased body weight , improved f e a t he r i n g and increased t i b i a z i n c c o n c e n t r a t i o n , po s s i b l y due to improved z i n c a v a i l a b i l i t y i n the d i e t . Supplementation o f h i s t i d i n e to a soybean d i e t a l l e v i a t e d the l eg abnormal i ty but d id not i nc rease growth, improve f e a t he r i n g or inc rease t i b i a z i n c c oncen t r a t i o n . A supplement of 2% a r g i n i n e hydroch lo r ide fed to z i n c d e f i c i e n t ch ick s aggravated both the leg abnormal i ty and the fea the r defects and tended to depress growth (Coleman et a l_ . , 1969). I t seems t ha t i n the c h i c k , c y s t e i n e , h i s t i d i n e and a r g i n i ne are po s s i b l e antagon i s t s o f z i n c i n some aspects of i t s metabol ism. The extent o f z i n c absorpt ion va r i e s w i th the l e v e l o f z i n c and wi th a range o f other d i e t a r y components. Methfesse l and Spencer (1974) observed a marked f a l l i n absorpt ion of z i n c from the duodenum with i n c r e a s -ing age in the r a t , but the evidence f o r an e f f e c t o f age or spec ies on z i n c 65 abso rp t ion i s c o n f l i c t i n g (Becker and Hoekstra (1971)). In a study of Zn absorpt ion i n bov ines, no evidence was found o f a d e c l i n e w i th age i n l a c t a t i n g cows, compared w i th two and s i x month o ld ca lves (Stake et aJL , 1975). Many of the f a c t o r s that i n f l u e n c e z i n c ab so rp t i on have been i n f e r r e d from the way they i n f l u e n c e s igns o f Zn d e f i c i e n c y or t o x i c i t y i n the an ima l . High Ca in takes po t en t i a t e the Zn d e f i c i e n c y syndrome or a f f e c t Zn u t i l i z a t i o n i n seve ra l spec ies (Becker and Hoekst ra , 1971), and they exer t a p r o t e c t i v e a c t i on aga ins t Zn t o x i c i t y i n pigs (Hsu et a l_ . , 1975). 11. These e f f e c t s r e s u l t l a r g e l y from an i n t e r f e r e n c e by Ca w i th z i n c absorp-t i o n and may be mediated by phy t i c a c i d ( L i k u s k i and Forbes, 1964; O ' De l l et a l_ . , 1964). Converse ly , low Ca in takes can a l l e v i a t e the e f f e c t s o f Zn d e f i c i e n c y (Tao and Hur ley , 1 975). High i no rgan i c P, as we l l as , high Ca in takes aggravate Zn d e f i c i e n c y i n r a t s . The i r e f f e c t appears to be a d d i t i v e and independent (Cabe l l and E a r l e , 1965). An independent a c t i o n o f phosphorus on Zn absorpt ion remains to be e s t a b l i s h e d . The chemical form i n which the Zn i s ingested a l so i n f l uence s ab so rp t i on , so t ha t d i e t s o f s i m i l a r Zn contents may d i f f e r i n amounts a v a i l a b l e to the an ima l . Thus Edwards (1959) found z i n c to be equa l l y we l l absorbed as the o x i d e , carbonate, s u l f a t e , whereas the Zn i n s p h a l e r i t e (mainly Zn ox ide) and f o r Trankl in i -te (oxides o f Zn, Fe, and Mn) was l a r g e l y unabsorbed judg ing by the c apac i t y o f these compounds to promote growth i n ch icks fed a Zn: -def ic ient d i e t . D i f f e r e n t p r o te i n sources vary i n t h e i r e f f e c t s on the Zn requirements o f r a t s , p i g s , c h i c k s , and p o u l t s , w i th d i e t s con ta i n i n g pro-t e i n of p lant seed o r i g i n r e q u i r i n g h igher l e v e l s o f d i e t a r y Zn than those con ta i n i ng p r o t e i n from animal sources. O 'De l l and Savage (1960) a t t r i b u t e d such d i f f e r e n c e s to the presence or absence of phytates which bind 'the z i n c i n a form from which i t i s not r e a d i l y re leased and absorbed. The a d d i t i o n o f phy t i c a c i d to case in d i e t s can reduce Zn r e t e n t i o n to tha t i n soybean p ro te i n d i e t s (Forbes, 1960; Oberleas , et a l_ . , 1 960) and Zn absorpt ion from combinations w i th phy t i c a c i d i s increased by au toc l a v i n g or by treatment w i th EDTA (K ra t ze r et a j_. , 1 959; O ' D e l l , 1960). The presence of phytate i s on l y one of the f a c t o r s a f f e c t i n g Zn a v a i l a b i l i t y from o i l s e e d meals (Lease and W i l l i a m s , 1967). Var ious c h e l a t i n g agents can improve the a v a i l a b i l i t y o f z i n c to ch ick s and pou l t s consuming soybean p r o t e i n d i e t s 12. (Nielsen.et , ; aJ_.., 1964; Vohra and K r a t ze r , 1964). Furthermore, c e r t a i n natura l feeds such as case in and l i v e r e x t r a c t conta in che la te s which improve Zn absorpt ion and u t i l i z a t i o n ( Scot t and Z e i g l e r , 1963). V itamin D has been reported to inc rease Zn abso rp t ion by some workers (K ienho lz et a l_ . , 1964; Whit ing and Bezeau, 1958) but not by others (Wasserman, 1962). From the work of (Becker and Hoekst ra , 1968) wi th r a t s , i t seems t ha t the increased Zn absorpt ion a t t r i b u t e d to v i tamin D i s not a d i r e c t e f f e c t o f the v i tamin but r e s u l t s from a homeostatic response to the increased need f o r z i n c which accompanies s t imu la ted s k e l e t a l c a l c i f i c a t i o n and growth. These workers have shown that bulk i s a f u r t h e r d i e t a r y f a c t o r a f f e c t i n g Zn absorpt ion (Becker and Hoekstra, 1971). Weanling r a t s were fed s e m i - p u r i f i e d c a s e i n -ce re lo se d i e t s con ta i n i ng graded l e v e l s o f c e l l u l o s e . Added c e l l u l o s e 65 decreased Zn ab so rp t i on , increased the ra te o f passage o f the i so tope 65 through the t r a c t , and decreased body Zn r e t e n t i o n . I t seems l i k e l y , as the authors suggest, t ha t by adding bulk to the d i e t , the r a te o f passage 65 through the d i g e s t i v e t r a c t i s enhanced and the Zn i s present at the s i t e s o f absorpt ion f o r a s ho r te r t ime, r e s u l t i n g i n decreased absorpt ion and a consequent s lower turnover o f t ha t which i s absorbed. The a v a i l a b i l i t y o f minera l s i n swine r a t i o n s i s improved by a d m i n i s t r a t i o n o f a n t i b i o t i c s (K i rchgessner e_t a l _ . , 1961, K i rchges sner , 1965). In e ighteen balance t r i a l s us ing pigs and p o u l t r y , the d a i l y r e ten t i on s o f c o b a l t and z i nc were more than doubled and copper r e t e n t i o n t r i p l e d by an a n t i b i o t i c supplement. They a l so reported increased manganese and i r on r e t e n t i o n i n animals r e c e i v i n g a n t i b i o t i c s . K i rchgessner et al_. (1961) us ing balance methods, showed t ha t r e t e n t i o n of s i l i c o n , 13. phosphorus, magnesium, c o b a l t , z i n c , copper, manganese and i r o n was increased i n young but not mature p i g s . The i n f l u e n c e o f v i t amin D on the absorpt ion o f var ious ca t i on s has been reported by e a r l i e r i n v e s t i g a t o r s . Me in tze r and Steenbock (1955) repor ted t ha t abso rp t ion o f magnesium was depressed i n r a t s fed low v i tamin D d i e t s . Sobel and Burger (1955) observed tha t v i tamin D increased the l e v e l s o f lead i n blood wh i l e Greenberg (1945) demonstrated an i nc rease i n s t ront ium absorpt ion due to v i t am in D a d m i n i s t r a t i o n . Wasserman (1962) extended the l i s t to i n c l ude coba l t and to a l e s s e r extent cesium but reported tha t sodium, potass ium, copper, i r o n and z i n c were not i n f l uenced by v i tamin D. Masuhara and Mig icovsky (1963) showed t ha t i r on and c o b a l t absorpt ion was enhanced by v i t amin D. A s l i g h t i nc rease i n phosphorus absorpt ion and no i nc rease i n copper absorpt ion were repor ted by Wasserman (1962). 54 I n jec ted Mn i s c l ea red from the bloodstream i n three phases (Borg and C o t z i a s , 1958). The f i r s t and f a s t e s t o f these i s i d e n t i c a l w i th a c learance r a te of other small i o n s , suggest ing the normal t r a n s -c a p i l l a r y movement; the second can be i d e n t i f i e d w i th the entrance o f Mn i n t o the mitochondr ia o f the t i s s u e s ; the t h i r d and s lowest components could i n d i c a t e the r a te o f nuc lear accumulat ion o f the me ta l . These i n t e r p r e t a t i o n s are supported by s t ud i e s demonstrat ing e a r l y and 54 p r e f e r e n t i a l accumulat ion of Mn i n the mitochondr ia r i c h organs o f the body, l o c a l i z a t i o n of Mn i n the mitochondr ia o f the c e l l , and high mi tochondr ia l and low nuc lear Mn turnover rates (Cotz ia s and Greenough, 1958). Loading the body w i th s t a b l e Mn, but not w i th other elements, 14. r a p i d l y e lu te s Mn from the body and r e d i s t r i b u t e s i t w i t h i n the t i s s ue s ( B r i t t o n and C o t z i a s , 1966; Cotz ia s and Greenough, 1958). The turnover 54 o f p a r e n t e r a l l y admin i s tered Mn has been d i r e c t l y r e l a t e d to the l e v e l o f s t a b l e Mn i n the d i e t o f mice over a wide range ( B r i t t o n and C o t z i a s , 1966). A l i n e a r r e l a t i o n s h i p between the r a t e o f e x c r e t i on of the t r a c e r and the l e v e l o f Mn i n the d i e t was observed and the concent ra t i on 54 o f Mn i n the t i s s ue s was d i r e c t l y r e l a t e d to the l e v e l o f s t a b l e Mn i n the d i e t . An inver se r e l a t i o n s h i p between d i e t a r y Mn and the percentage 54 of Mn taken up by the t i s s ue s o f ch i ck s has been demonstrated ( S e t t l e et aj_. , 1 969). The f i nd i ng s support the concept tha t v a r i a b l e e x c r e t i o n r a the r than v a r i a b l e absorpt ion i s the r e g u l a t o r o f manganese homeostasis. However, ( L a s s i t e r e t a_l_., 1 974) has provided evidence that d i e t a r y Mn l e v e l has a g reater e f f e c t on absorpt ion than on endogenous e x c r e t i o n , and that both v a r i a b l e e x c r e t i o n and absorpt ion p lay important r o l e s i n Mn 54 homeostasis. In an experiment w i th r a t s given a s i n g l e o r a l Mn dose, 54 l i v e r Mn was 15 times h igher a f t e r four hours i n those fed a d i e t con ta i n i n g 4 ppm Mn than those fed 1000 ppm Mn. Such a great d i f f e r e n c e i n d i c a t e s a major e f f e c t on ab so rp t i on . Howes and Dyer (1971) repor ted increased absorpt ion of manganese under cond i t i on s of low-Mn in takes and decreased absorpt ion at h igher Mn in takes i n c a l v e s . Manganese i s equa l l y we l l absorbed throughout the length o f the small i n t e s t i n e by a two-step mechanism i n v o l v i n g i n i t i a l uptake from the lumen and then t r a n s f e r across the mucosal c e l l s to the body. The two k i n e t i c processes operate s imu l taneous l y w i th Mn competing w i th Fe and Co f o r common b ind ing s i t e s i n both processes (Thomson e_t a l _ . , 1971). '<! . 15. In t h i s way one o f the metals exer t s an i n h i b i t o r y e f f e c t on the absorpt ion o f the o the r s . Thomson e_t a]_. (1971) showed t ha t the a d d i t i o n o f i r o n c o m p e t i t i v e l y i n h i b i t e d Mn absorpt ion i n F e - d e f i c i e n t r a t s . In pa t i en t s w i th va ry ing i r on s to res subjected to duodenal pe r fu s ion w i th Mn the r a te o f Mn absorpt ion was found to be inc reased i n i r o n d e f i c i e n c y and the enhanced Mn absorpt ion to be i n h i b i t e d by i r o n . Converse ly , high Mn in takes reduce i r o n absorpt ion in severa l s pec i e s . The absorpt ion mechanisms o f manganese and i r o n show many s i m i l a r i t i e s . Manganese a v a i l a b i l i t y i s f u r t h e r a f f e c t e d by excess d i e t a r y ca l c i um. In b i rd s the e f f e c t o f high d i e t a r y l e v e l s o f ca lc ium phosphate in aggravat ing Mn d e f i c i e n c y i s be l i e ved to be due to a reduct ion in s o l ub l e manganese ( Scha ib le and Bandemer, 1942; Wilgus and Pa t ton , 1939). Chemical forms as d i ve r se and va ry ing i n s o l u b i l i t y as o x i d e , carbonate, s u l f a t e , and c h l o r i d e were shown some years ago to be e q u a l l y va luab le as sources o f Mn i n pou l t r y r a t i on s ( S cha ib l e and Bandemer, 1942). D i f fe rences i n Mn a v a i l a b i l i t y among var ious i no r gan i c Mn sources have now been demonstrated us ing l e g abnormal i ty scores and bone Mn l e v e l s as the response c r i t e r i a (Watson e t a l_ . , 1971). The carbonate ore ( rhodochros i te ) and s i l i c a t e ore (rhodomite) are r e l a t i v e l y unava i l ab l e (Ga l lup and N o r r i s , 1939; Scha ib le and Bandemer, 1942). The f e ca l e x c r e t i o n o f p a r e n t e r a l l y 54 admin i s te red Mn i s h igher and l i v e r r e t e n t i o n much lower i n r a t s on a 1.0% than on a 0.6% Ca d i e t ( L a s s i t e r et a l_ . , 1969). I t appears t ha t ca lc ium can i n f l uence Mn metabolism by a f f e c t i n g r e t e n t i o n o f absorbed Mn as we l l as by a f f e c t i n g i t s a b s o rp t i on . Ethanol feed ing has been shown to inc rease hepat i c manganese (Barak et_ a]_. , 1971). 1 6 . This i s apparent ly due to a s i g n i f i c a n t e f f e c t on Mn ab so rp t i on , mediated by ethanol metabolism i n the gut (Schafer et a j_. , 1974). Manganese metabolism i s i n f l uenced by the e s t rogen i c hormones o f the ovary and by the adrenal c o r t i c a l hormones. The profound e f f e c t of estrogen on plasma Mn l e v e l s i n pou l t r y has a l so been shown by Panic et al_. (1974). The 54 a d m i n i s t r a t i o n o f g l u c o c o r t i c o i d hormones markedly a f f e c t s Mn d i s t r i b u t i o n i n the mouse. Copper occurs i n foods i n many chemical forms and combinations which a f f e c t i t s a v a i l a b i l i t y to the an ima l . Ea r l y work showed t ha t anemic r a t s are unable to u t i l i z e the copper o f copper s u l f i d e or porphyr in copper f o r hemoglobin s y n t h e s i s , whereas the o x i de , hydrox ide, i o d i d e , g lutamate, g l ycero phosphate, a s pa r t a t e , c i t r a t e , and pyrophosphate were we l l u t i l i z e d f o r t h i s purpose (Schul t ze et a l _ . , 1936). Pigs a l so absorb the copper o f c up r i c s u l f i d e much le s s e f f i c i e n t l y than that o f copper s u l f a t e (Bowland et aj_. , 1961). L a s s i t e r and B e l l (1960) s tud ied the 64 a v a i l a b i l i t y to sheep o f var ious compounds l a b e l l e d w i th Cu; The copper i n copper w i r e was l a r g e l y unav a i l a b l e and the copper i n copper ox ides le s s a v a i l a b l e than tha t i n water s o l ub l e s a l t s or the 64 carbonate. La te r Chapman and B e l l (1963) te s ted the uptake o f Cu from severa l i no rgan i c compounds by beef c a t t l e . The r e l a t i v e appearance o f 64 Cu i n the blood was i n the f o l l o w i n g o rde r : CuC0 3 > Cu (N0 3 ) 2 > CuS0 4 > C u C l 2 > Cu 2o > CuO(powder) > Cu (wi re) Changes i n the chemical forms o f copper i n p lants a f f e c t i n g a v a i l a b i l i t y must occur because f re sh green herbage i s l e s s e f f e c t i v e i n 17. promoting body copper s to res than hay or d r i e d herbage of equ i va l en t content (Hartmans; and Basman, 1970). Apparent ly changes i n the chemical forms o f the copper occur dur ing the cur ing or d ry ing process which improve t h e i r ab so rp t i on . M i l l s (1954, 1956) found that f re sh herbage conta ins the g reater o f i t s copper as neut ra l or a n i on i c complexes. These complexes induced a more r ap i d response and g rea te r Cu storage i n l i v e r than equ i va len t amounts of copper as copper s u l f a t e when fed to Cu d e f i c i e n t r a t s . M i l l s suggested tha t copper may be t ranspor ted through the i n t e s t i n a l mucosa both as i o n i c Cu and i n the form o f complexes such as those encountered i n herbage. Th is suggest ion rece i ved support from the work o f K i rchgessner and co-workers (K i rchgessner and Grassman, 1970; K i rchgessner , 1965). They showed that the a f f i n i t y o f Cu ions f o r i no rgan i c and organ ic l i gands i n the d i e t can reduce the r a t e o f ab so rp t i on , depending on the s i z e and s t a b i l i t y of r e s u l t i n g complexes. Small s t a b l e Cu complexes may be supe r i o r i n a b s o r b a b i l i t y to copper s u l f a t e . With s i n g l e amino ac ids as l i gands the r a te o f Cu absorpt ion depends on the type o f the amino a c i d , i t s c o n f i g u r a t i o n , and the degree of p o l y m e r i z a t i o n . D i f fe rences o f t h i s type may prov ide at l e a s t a p a r t i a l exp lana t i on o f the v a r i a t i o n s i n copper a v a i l a b i l i t y a r i s i n g from d i e t s con ta i n i n g d i f f e r e n t amounts and types, o f p r o t e i n (MacPherson and Hamingway, 1965; S u t t l e and M i l l s , 1966). Phytates form s t a b l e complexes w i th copper (Vohra et a j_. , 1965) and reduce the a s s i m i l a t i o n o f t h i s element (Davis et aj_. , 1962). High 64 l e v e l s o f a s co rb i c a c i d s i g n i f i c a n t l y depress Cu absorpt ion when placed i n t o a l i g a t e d segment o f the r a t i n t e s t i n e along w i th the r ad i o - coppe r . Whole body r e t e n t i o n s t ud i e s i n d i c a t e tha t the depress ing e f f e c t o f 18. a s co rb i c a c i d on Cu r e t e n t i o n i s achieved p r i m a r i l y by reduced i n t e s t i n a l absorpt ion (Van Campen and Grass, 1968). High d i e t a r y a s co rb i c a c i d has been shown to inc rease the s e v e r i t y o f Cu d e f i c i e n c y i n ch i ck s (Ca r l t on and Henderson, 1969; H i l l and S t a r che r , 1965). ' S tud ies on mineral i n t e r r e l a t i o n s h i p s date from e a r l y obser-vat ions tha t low ca lc ium r a t i o n s i n h i b i t e d phosphorus ba lance. La te r i n v e s t i g a t o r s revea led fundamental i n t e rdependence s between copper and molybdenum, z i n c and c a l c i u m , magnesium and phosphorus, ca lc ium and manganese, cadmium and z i n c ( H i l l ejt a j_. , 1963; Forbes, 1 963). A cons ide rab le degree of compet i t ion i s f o r a b ind ing s i t e i n or on the mucosal c e l l s and f o r others i t i s compet i t i on f o r c a r r i e r mo lecu les . The b i o l o g i c a l antagonism between copper and z i n c was demonstrated by Smith and Larson (1946). Van Reen (1953) showed tha t copper supp le -mentation a l l e v i a t e d the e f f e c t s o f z i n c t o x i c i t y wh i l e the reverse was reported by R i t c h i e ejt al_. (1963). Van Campen (1969) observed t ha t 65 copper- induced depress ion i n Zn abso rp t ion was mediated at the i n t e s t i n a l l e v e l p o s s i b l y due to d i r e c t compet i t ion betweeen z i n c and copper f o r a common c a r r i e r . K i rchgessner and Grassman (1969) repor ted tha t high l e v e l s of copper s u l f a t e supplementat ion i n p i g r a t i o n s pro-duced g rea te r r e t e n t i o n i f i r o n , z i n c , manganese and c o b a l t . D iet s high i n ca lc ium have a lower z i n c a v a i l a b i l i t y ( S u t t l e and M i l l s , 1966). Increased d i e t a r y ca lc ium was repor ted to enhance manganese abso rp t ion i n r a t s ( L a s s i t e r et aj_. , 1969) wh i l e Aleock and Mac lntyre (I960) observed that increased manganese i n the d i e t enhanced ca lc ium ab so rp t i on . Nugara and Edwards (1962) noted tha t high d i e t a r y phosphorus reduced magnesium r e t e n t i o n a t the abso rp t ion or e x c r e t i o n s i t e i n c h i c k s , wh i l e 19. O 'De l l et al_. (1960) showed w i th balance s tud ie s t ha t a high d i e t a r y phosphorus l e v e l decreased magnesium absorpt ion i n guinea p i g s . Forbes (1963) repor ted t h a t ca lc ium and phosphorus depressed magnesium absorp-t i o n and high ca lc ium l e v e l s d r a s t i c a l l y a f f e c t e d phosphorus absorpt ion i r r e s p e c t i v e o f magnesium l e v e l s i n the d i e t , wh i l e H i l l et^ aj_. (1963) showed t h a t there were copper, z i n c and i r o n components o f cadmium t o x i c i t y . The r e l a t i o n o f s i l v e r and mercury to copper uptake and u t i l i z a t i o n i s l e s s c l e a r than i s the r e l a t i o n o f z i n c , cadmium and i r o n . H i l l and co-workers (1964) repor ted t ha t s i l v e r , but not mercury, accentuated the e f f e c t s o f Cu d e f i c i e n c y i n c h i c k s , w h i l e mercury had an adverse e f f e c t on Cu adequate c h i c k s . Van Campen (1966), on the o the r hand, found that mercury produced a moderate, but not s i g n i f i c a n t , lower-ing o f ^ C u uptake from the i n t e s t i n e of the r a t , whereas s i l v e r had l i t t l e e f f e c t . Each o f these elements induced s i g n i f i c a n t and d i f f e r e n t changes i n the d i s t r i b u t i o n of the r e t a i ned Cu among the t i s s u e s o f the body. Further evidence o f a metabo l i c i n t e r a c t i o n between s i l v e r and copper has been presented by Jensen and co-workers (1964) who found t ha t the t o x i c e f f e c t s produced by adding 900 ppm Ag to p r a c t i c a l tu rkey pou l t d i e t s were complete ly prevented by 50 ppm of supplementary copper. The mechanisms which regu la te Cu abso rp t i on are not w e l l under-s tood, although i t now seems c l e a r tha t meta l - b i nd i ng components are i n vo l ved . The i n h i b i t i o n of Cu absorpt ion i s brought about by var ious metals r e s u l t s from compet i t ion f o r p r o t e i n meta l - b i nd i ng s i t e s . S ta rcher (1969) i d e n t i f i e d a s i n g l e meta l -b i nd ing p r o t e i n i n ch i ck duodenum and demonstrated t ha t the p r o t e i n would bind copper, as we l l as 20. cadmium and z i n c . Evans and Hahn (1974) found tha t o r a l l y admin i s te red copper becomes a s soc i a ted w i th a v a r i e t y of meta l - b i nd i ng l i gands and ..: t macro molecules i n the i n t e s t i n e o f the r a t . In the i n t e s t i n a l lumen copper was complexed w i th a p r o t e i n s i m i l a r to m e t a l l o t h i o n e i n , but whether t h i s compound i s a c t u a l l y i nvo l ved i n copper t r an spo r t from the i n t e s t i n e to the blood i s not ye t c l e a r . The r e s u l t s o f i n v e s t i g a t i o n s i n t o Menke's k inky h a i r d i sease i n c h i l d r e n (Danks e_t a l _ . , 1973), and a mouse mutant w i th d e f e c t i v e Cu metabolism (Hunt, 1974), i n d i c a t e the ex i s tence o f two d i f f e r e n t mechanisms. One invo l ves Cu t r an spo r t from the i n t e s t i n e lumen i n t o the mucosal c e l l s and the o ther from the musocal c e l l s to the plasma. In these two c o n d i t i o n s , copper r e a d i l y enters the mucosal c e l l s where i t bu i l d s up, but enters the blood stream i n inadequate q u a n t i t i e s due to an undef ined genet i c de fec t or defects in t h i s phase o f Cu ab so rp t i on . Some misce l laneous f a c t o r s have a l s o been l i n k e d to mineral a v a i l a b i l i t y . Davis et al_. (1 962) reported t ha t i s o l a t e d soybean p ro te i n conta ined a component which combined w i th z i ' nc , manganese and copper, caus ing ch i ck s to develop the r e spec t i v e d e f i c i e n c y symptoms because o f u n a v a i l a b i l i t y o f these m ine r a l s . The a d d i t i o n o f EDTA to such a d i e t reduced the c h i c k s ' requirement f o r these elements. Kiienholz (1962) presented evidence to i n d i c a t e the presence o f a f a c t o r (not phytate) i n peas which i n t e r f e r e d w i th the a v a i l a b i l i t y o f z i n c f o r ch ick growth. Au toc l av i ng the peas e l im ina ted the requirement f o r supplemental z i n c . This heat l a b i l e f a c t o r would l i k e l y be a p r o t e i n which i n t e r f e r e d w i th d i g e s t i o n or absorpt ion o f z i n c , reducing i t s a v a i l a b i l i t y . 21. Techniques f o r E s t imat ing Minera l A v a i l a b i l i t y The apparent d i g e s t i b i l i t y method measures the in take as we l l as f e c a l and u r i n a r y output o f the t e s t m i ne r a l s . Accord ing to M i t c h e l l (1964) i t was one of the more common methods o f determin ing mineral u t i l i z a t i o n . I t d id not account f o r the metabo l i c f e ca l and endogenous u r i na r y los ses and had a tendency to underest imate u t i l i z a t i o n of the t e s t m ine ra l s . This procedure assumed tha t endogenous minera l l o s ses were minimal and ignored them, s i nce the methods o f e s t imat i ng these losses were not e n t i r e l y s a t i s f a c t o r y . Ea r l y work on minera l a v a i l a b i l i t y i n ruminants was very s imp le . This requ i red on ly an est imate o f the i n take and f e c a l e x c r e t i on o f the minera l s t e s t e d . Rook and Campling (1962) observed that a l a rge amount of i n fo rmat ion publ i shed on magnesium a v a i l a b i l i t y f o r ruminants was obta ined i n balance s tud ie s i n which apparent d i g e s t i b i l i t y o f magnesium was c a l c u l a t e d as i n t ake l e s s f e ca l l o s s and expressed as a percentage o f i n t a k e . I t soon however, became ev ident that apparent d i g e s t i b i l i t y r e s u l t s were not i n d i c a t i v e o f the a v a i l a b i l i t y o f minera l s to l i v e s t o c k and a more p r e c i s e est imate was needed. The a v a i l a b i l i t y or t rue d i g e s t i b i l i t y method takes i n t o account the obse rva t ion tha t not a l l the mineral i n f e c a l or u r i n a r y e x c r e t i o n i s o f feed o r i g i n . E s t imat ion o f endogenous minera l e x c r e t i o n invo lves use o f p u r i f i e d mineral f r ee d i e t s or the use o f reg res s ions of r e t e n t i o n o f the element on i t s i n t a k e . The p u r i f i e d d i e t s are so formulated as to exclude minera l s being t e s t e d . Durat ion of the t e s t i s s ho r t , so as not to s u b s t a n t i a l l y d i s t u r b the minera l e q u i l i b r i u m of the 22. t e s t an imals . Because endogenous e x c re t i on i s taken i n t o account i n c a l c u l a t i n g t rue d i g e s t i b i l i t y , the r e s u l t s obta ined are u s u a l l y h igher than apparent d i g e s t i b i l i t y r e s u l t s and are a more r e a l i s t i c est imate o f mineral a v a i l a b i l i t y . The carcass a na l y s i s technique i nvo l ve s the use o f l i t t e r mates, some of which are s laughtered at the beginning o f the experiment to determine the r a t i o s o f body weight to the r e t e n t i o n o f t e s t m i ne r a l s . The other members o f the l i t t e r are fed a c o n t r o l l e d d i e t i n which the t e s t i n g r ed i en t i s the on ly source o f the minera l s under study. Feed ! i n take records are kept. At the end o f the exper imental p e r i o d , the t e s t animals are s l augh te red , ashed and mineral content determined. M inera l s r e t a i n e d , expressed as a f r a c t i o n o f minera l i n t a k e , i s an i n d i c a t o r o f a v a i l a b i l i t y . Armstrong and Thomas (1952) reported no s i g n i f i c a n t d i f f e r e n c e s between ca lc ium a v a i l a b i l i t y r e s u l t s obta ined by o ther methods or by the carcass a n a l y s i s method. The i so tope d i l u t i o n technique i nvo l ve s i n j e c t i n g i n t r a venou s l y , s i n g l e (Hansard et a l _ . , !1952; 1954) or m u l t i p l e (V isek e t a l _ . , 1953) doses o f r ad i o i s o tope s o f the t e s t element. At e q u i l i b r i u m , " i f there i s endogenous e x c r e t i o n o f the m i n e r a l , the s p e c i f i c a c t i v i t i e s o f the feces and plasma should be i d e n t i c a l . D i l u t i o n o f the t o t a l element i n the feces by endogenous e x c re t i on can be measured by d i f f e r e n c e i n the plasma and f e ca l s p e c i f i c a c t i v i t i e s . Pa i r s o f animals are used i n the comparative balance techn ique. One i s dosed o r a l l y w h i l e the o ther i s i n j e c t e d i n t r a venou s l y w i t h a r ad i o i s o t ope o f the t e s t element. I t i s assumed tha t the o r a l dose complete ly l a b e l s the d i e t a r y source o f the element. Endogenous e x c r e t i o n 23. i s est imated from the i n t r a venou s l y i n j e c t e d an ima l . True d i g e s t i b i l i t y can t he re f o re be c a l c u l a t e d . Aubert et a]_. (1 963) proposed a m o d i f i c a t i o n o f t h i s procedure, e l i m i n a t i n g the use o f pa i red animals by i n j e c t i o n of two d i f f e r e n t i sotopes o f the same element. A b i o l o g i c a l assay technique commonly used i n e s t imat i ng mineral a v a i l a b i l i t y i s the bone ash method o f G i l l i s et al_. (1 954). The assay i nvo l ve s the estab l i shment of a standard response curve us ing a s e m i - p u r i f i e d basal d i e t and graded l e v e l s o f an i no rgan i c s a l t of the t e s t element (assumed to be 100% u t i l i z e d a t low d i e t a r y l e v e l s ) . A p l o t of percent bone ash o f so l vent ex t r ac ted l e f t ch i ck dry f a t - f r e e t i b i a and ' the l oga r i thm o f the percentage d i e t a r y minera l was a s t r a i g h t l i n e . The t e s t i n g r ed i en t was s u b s t i t u t e d f o r a small f r a c t i o n o f the basal d i e t . B i o l o g i c a l a v a i l a b i l i t y was def ined as the r a t i o , expressed as a per -centage, of the amount o f the i no rgan i c s a l t to the amount o f t e s t i n g red i en t which produced the same bone ash when each was added to the basal d i e t . Percent bone ash i s the most commonly used t e s t f o r e s t imat i ng mineral a v a i l a b i l i t y i n feeds . Nelson (1967) noted tha t i t was one o f the most s e n s i t i v e , p r a c t i c a l c r i t e r i a f o r e va l ua t i n g the a v a i l a b i l i t y of d i e t a r y phosphorus. I t i s more accurate than body weight measurement and i s l i t t l e a f f e c t e d by other d i e t a r y v a r i a b l e s t ha t i n f l u e n c e growth (Nelson and Walker, 1964). Another b i o l o g i c a l assay technique which has been used i n e s t imat i ng minera l a v a i l a b i l i t y i s the body weight method o f O ' D e l l and co-workers (1972). Standard response curves are e s t a b l i s h e d by supplementing basal d i e t s w i th graded l e v e l s o f the t e s t element i n i no rgan i c form (100%). A p l o t o f weight or weight gain versus the 24. l oga r i thm of the supplemental element gives a l i n e a r response curve a t lower l e v e l s o f supplementat ion. The t e s t i n g red i en t s are analysed and subsequently s u b s t i t u t e d f o r carbohydrate i n the basal d i e t at low l e v e l s . The quan t i t y o f b i o l o g i c a l l y a v a i l a b l e mineral i s est imated from the standard curve and d i v i ded by the content of the t e s t mineral i n the i n g r e d i e n t . Nelson (1967) however observed t ha t body weight was not an accurate measure o f phosphorus u t i l i z a t i o n and i t s use has led to m i s lead ing conc l u s i on s . A number o f o ther b i o l o g i c a l assay techniques have been u t i l i z e d - i n e s t imat i ng mineral a v a i l a b i l i t y . A v a i l a b i l i t y o f i od i ne from var ious forms (d r i ed k e l p , i o d i z ed l i n s e e d meal, potassium i od i de ) have been s tud ied i n the l a y i n g hen by observ ing t h e i r e f f e c t s on the i od i ne content o f the egg (Wi lder et , 1933) : and i n a l b i no ra t s by prevent ion of enlargement o f the t h y r o i d gland ( M i t t l e r and Benham, 1954). A v a i l -a b i l i t y o f magnesium and i r o n has been s tud ied based on a b i l i t y to regenerate hemoglobin i n t e s t r a t s . Thompson and Raven (1959) est imated i r o n a v a i l a b i l i t y from d i f f e r e n t herbage spec ies by t h e i r a b i l i t y to regenerate hemoglobin i n anemic r a t s . K i rchgessner and Grassmann (1971) using r a t s a l so s tud ied a v a i l a b i l i t y o f copper us ing ce ru lop la smin as a t e s t enzyme. Re s to ra t i on o f ce ru lop la smin i n dep leted r a t s was taken as an i n d i c a t i o n o f copper a v a i l a b i l i t y . Baruah et al_. (1960) reported a method i n which the percentage t i b i a ash obta ined w i th t e s t phosphate was d i v i ded by the percentage t i b i a ash obta ined w i th the standard phosphate. B i r d et a]_. (1945) repor ted tha t percent o f phosphorus from var ious supplements s o l ub l e i n 0.25 percent h yd r o ch l o r i c a c i d was a f a i r l y good measure o f the a v a i l a b i l i t y to the ch i c k . The most conspicuous d i screpancy was Ca pyrophosphate whose s o l u b i l i t y was low (19.1%) but a v a i l a b i l i t y was n i l . Nwokolo e_t aj_. (1976) reported a balance procedure i n which r e t e n t i o n o f minera l was c a l c u l a t e d as mineral in take le s s f e ca l e x c r e t i o n co r rec ted f o r endogenous contaminat ion and expressed as percent o f i n t a k e . 26. EXPERIMENT 1. AVAILABILITY OF MINERALS IN MEAT MEAL TO THE GROWING CHICK The use o f meat meal i n p ou l t r y d i e t s has increased i n recent years because of the high minera l content . Meat meal der ived from the process ing o f c a t t l e , sheep, swine and o ther animal spec ies has a mixed compos i t ion. The product may con ta in by-products from predominately one spec ies or va ry ing proport ions of a number o f s pec i e s . In a d d i t i o n to the v a r i a t i o n r e l a t e d to spec ies there may be d i f f e r e n t p ropor t i on o f bone and t i s s u e from one process ing p lant to another or from day to day i n a s i n g l e process ing p l a n t . The i n f l u e n c e o f animal type and bone to t i s s u e r a t i o w i l l i n f l u e n c e the mineral composit ion and may a f f e c t the d i g e s t i o n , abso rp t ion and u t i l i z a t i o n of meat meal by the growing c h i c k s . The f o l l o w i n g study was designed to determine the v a r i a t i o n i n mineral compos i t ion o f meat meal from one process ing p lant dur ing a 10-day pe r iod and the i n f l u e n c e o f d a i l y v a r i a t i o n i n meat meal on the a v a i l a b i l i t y o f minera l s (Ca, P, Mg, Mn, Cu and Zn) to the growing c h i c k s . EXPERIMENTAL PROCEDURE Retent ion o f c a l c i um, phosphorus, magnesiurn, manganese, copper and z i n c was determined w i th three-week o l d b r o i l e r ch i ck s f o r 10 batches o f meat meal each processed on 10 consecut ive days. A balance procedure was used to determine the a v a i l a b i l i t y repor ted by Nwokolo et al_. (1976) i n which r e t e n t i o n o f mineral was c a l c u l a t e d as i n t ake l e s s f e ca l e x c r e t i o n co r rec ted f o r endogenous cpmponentL and expressed as percent 27. o f i n t a k e . The exper imental arrangement was a complete randomized design w i th four r e p l i c a t e s ( four ch i ck s each) per d i e t a r y t reatment. The t e s t b i rd s were fed a s t a r t e r d i e t con ta i n i ng known n u t r i t i o n a l requirements from one day to 20 days o f age. Chicks were mainta ined i n a ba t te r y brooder dur ing the f i r s t 19 days and t h e r e a f t e r groups o f four were t r a n s f e r r e d to metabolism cages w i th s t a i n l e s s s t e e l feeders and waterers,.. On the 21st day o f age, a l l ch icks were supp l i ed w i th feed ( s t a r t e r d i e t ) con ta i n i ng a 0.3% f e r r i c ox ide marker f o r four hours, fa s ted f o r 16 hours, fed a s y n t he t i c d i e t (Table 1) f o r a four -hour per iod and then returned to the s t a r t e r r a t i o n con ta in i ng the marker. Feces from the s y n t h e t i c d i e t were c o l l e c t e d ( s t a r t i n g a t the end o f the f i r s t batch of marked excreta and ending at the beginning o f the second batch o f marked e x c r e t a ) . -The same procedure was repeated a t 22 days o f age except t h a t the t e s t sample mixture (Table 2) rep laced the s y n t h e t i c d i e t . Feces were again c o l l e c t e d f o l l o w i n g the same procedure. Consumption o f both s y n t h e t i c and t e s t d i e t s was measured. Tota l marker - f ree feces were c o l l e c t e d and d r i e d at 85°C f o r 24 hours. The mineral content , except phosphorus, o f the feed i n g r e d i e n t , the t e s t r a t i o n , the feces from the s y n t h e t i c d i e t and from the t e s t d i e t were determined by atomic absorpt ion spectrophotometer f o l l o w i n g wet d i g e s t i o n w i th p e r c h l o r i c and n i t r i c ac ids by the method o f Johnson and U l r i c h (1959). The phosphorus content o f samples was determined on a Unicam SP 1800 spectrophotometer f o l l o w i n g development o f c o l o r w i th ammonium molybdate. Minera l content o f samples was expressed on a dry matter b a s i s . The f o l l o w i n g formula was used to c a l c u l a t e the percent minera l a v a i l a b i l i t y f o l l o w i n g ana l y s i s o f feed and e x c r e t a : Table 1. Composition o f s y n t he t i c m i x tu re . Ingredients g/kg Sucrose 700 C e l l u l o s e ( a l p h a - c e l l ) 200 Corn o i l 100 Table 2. Composition of t e s t mixture (g/kg). Meat Meal Mixture No. 1 2 3 4 5 6 7 8 9 10 Meat meal #1 300 - - - - - -Meat meal #2 - 313 - -Meat meal #3 309 _ _ _ _ _ _ _ Meat meal #4 - - - 318 _ _ _ _ _ _ Meat meal #5 314 Meat meal #6 _ _ _ _ _ 295 - - - -Meat meal #7 _ _ _ _ _ _ 303 - - -Meat meal #8 - - - - - - - 307 Meat meal #9 - - - - - - - - 320 -Meat meal #10 323 Syn the t i c D iet 700 687 691 682 686 705 697 693 680 577 A l l mixtures were i son i t rogenous (15.25 percent p r o t e i n ) . 30. Percent Minera l A v a i l a b i l i t y = T M I ~ ~ E F M E ) x 100 where TMI = t o t a l mineral i n take from i n g r ed i en t ( t e s t feed) TFME = t o t a l f e c a l minera l excreted EFME = endogenous f e c a l minera l excreted ( s yn the t i c d i e t exc re ta ) Ana l y s i s o f va r iance was c a r r i e d out to determine d i f f e r e n c e between the d i f f e r e n t meals i n the a v a i l a b i l i t y o f each element (Snedecor, 1956). D e t a i l o f the a n a l y s i s o f va r iance was shown in(Appendix Tables 1-6). D i f f e rence s among the means f o r a v a i l a b i l i t y was determined by the m u l t i p l e range t e s t (Duncan, 1955). C o r r e l a t i o n s were run between content and a v a i l a b i l i t y . RESULTS AND DISCUSSION Ten commerc ia l ly manufactured meat meals processed i n the same p l an t but on 10 consecut ive days were u t i l i z e d i n a study of v a r i a t i o n i n minera l content and a v a i l a b i l i t y . The proximate c on s t i t uen t s of meat meal samples (dry matter ba s i s ) i s shown i n Table 3. The minera l content of the 10 meat meals i s presented i n Table 4. These samples show a high l e v e l of c a l c i u m , phosphorus, magnesium and z i n c and a low l e v e l of manganese and copper. Cons iderable v a r i a t i o n i n the minera l content was observed p a r t i c u l a r l y i n c a l c i um, phosphorus and copper f o r the samples t e s t e d . Th i s i n d i c a t e s tha t the raw m a t e r i a l s used i n p roces s ing of the samples were d i f f e r e n t . The wide v a r i a t i o n i n ca lc ium (50 - 93 mg/g) and 31. phosphorus (32.7 - 55 mg/g) i s a good i n d i c a t i o n o f the amount of bone present i n samples on a day-to-day b a s i s . Resu l t s i n Table 5 show the a v a i l a b i l i t y o f each minera l i n the meals t e s t e d . Calcium (90.1% + 0.6) and phosphorus (93.4% + 1.3) were h i gh l y a v a i l a b l e i n a l l meals. Magnesium and z i n c were h i gh l y a v a i l a b l e w i t h cons ide rab le v a r i a t i o n i n the average (83.9% +1 .7 and 79.4% + 1.4 r e s p e c t i v e l y ) . Manganese and copper present i n meat meal showed lower a v a i l a b i l i t y than other minera l s te s ted (73.1% + 2.9 and 74.0% + 4.0 r e s p e c t i v e l y ) . Calcium Resu l t s (Table 5) i n d i c a t e t h a t ca lc ium i s h i gh l y a v a i l a b l e from the meat meal samples. The a v a i l a b i l i t y o f ca lc ium from meat meal #2 was s i g n i f i c a n t l y lower than from samples #1 and #4. Other meat meal samples were not s i g n i f i c a n t l y d i f f e r e n t i n ca lc ium a v a i l a b i l i t y compared to #2. These r e s u l t s i n d i c a t e t ha t d i f f e r e n c e s i n raw m a t e r i a l s u t i l i z e d i n p roces s ing meat meals may i n f l u e n c e a v a i l a b i l i t y . Cons iderable v a r i a -t i o n has been reported i n a v a i l a b i l i t y o f ca lc ium from i no r gan i c minera l supplements such as bone ash and d i c a l c i u m phosphate ( G i l l i s e t a l _ . , 1954). L i t t l e i n fo rmat ion was present i n the l i t e r a t u r e on a v a i l a b i l i t y o f ca lc ium from meat meal) . Phosphorus Phosphorus a v a i l a b i l i t y was h igher than other m inera l s t e s t ed i n meat meal (Table 5 ) . Cons iderab le v a r i a t i o n i n a v a i l a b i l i t y of Table 3. Proximate con s t i t uen t s of meat meal sample processed on 10 consecut i ve days (dry matter b a s i s ) . Sample* Dry Matter (%) Crude P ro te in (%) Crude F ib re («) Ether Ex t rac t (*) Ash (*) Meat meal #1 94.2 53.9 2.0 13.0 23.0 Meat meal #2 94.4 51 .7 2.0 13.5 21 .9 Meat meal #3 94.1 52.6 2.5 13.1 22.5 Meat meal #4 94.7 50.7 2.0 11 .4 28.8 Meat meal #5 94.8 51 .2 2.0 11.3 30.0 Meat meal #6 94.5 54.8 2.3 13.3 21 .4 Meat meal #7 94.2 53.5 2.5 11 .0 29.7 Meat meal #8 94.8 . 52.5 2.0 11 .0 29.0 Meat meal #9 94.5 50.4 2.0 11 .2 32.4 Meat meal #10 93.4 50.5 2.5 10.0 31 .8 Number i n d i c a t e s consecut i ve days o f process ing i n which sample was c o l l e c t e d . Table 4. M inera l content o f meat meal samples c o l l e c t e d on 10 consecut ive days. M inera l s Sample* Ca mg/g P mg/g Mg mg/g •Mn mg/kg Cu mg/kg Zn mg/ki Meat meal #1 63.0 33.3 2.0 16.6 12.5 95.3 Meat meal #2 51 .0 33.3 1.8 16.6 16.6 77.2 Meat meal #3 50.0 32.7 2.0 12.5 16.6 105.8 Meat meal #4 72.0 50.0 2.3 12.5 11 . 4 79.5 Meat meal #5 84.0 55.0 2.7 12.5 12.5 100.0 Meat meal #6 50.0 34.5 1 .8 16.6 14.5 100.0 Meat meal #7 81 .0 50.3 2.3 10.5 8.3 90.0 Meat meal #8 81 .0 52.0 2.3 10.5 8.3 100.0 Meat meal #9 93.0 55.0 2.8 11.1 12.5 102.0 Meat meal #10 93.0 50.7 2.8 11 .1 12.5 101 .0 Average - 71.8 " - 4 4 . 6 2.3 ... 13.1 12.6 95.1 SD 16.36 " 9.3 0.2 0.36 2.3 9.2 Number i n d i c a t e s consecut i ve days of process ing i n which sample was c o l l e c t e d . 34. phosphorus among meat meal samples was observed. A v a i l a b i l i t y of phosphorus from meat meal #6, #7, #8, #9 was s i g n i f i c a n t l y h igher than the a v a i l a b i l i t y o f the minera l from samples 1, 2, 3, 4 and 5; a l s o there was no d i f f e r e n c e between samples 2, 4 and 10. Meat meal #10 was s i g n i f i c a n t l y h igher than meat meal #1 and 3. No s i g n i f i c a n t d i f f e r e n c e was found between the samples #6, #7, #8, #9 and #10. The d i f f e r e n c e s i n a v a i l a b i l i t y o f phosphorus among the meat meal samples may be r e l a t e d to v a r i a t i o n i n the content of phosphorus (Table 4) i n which h igher l e v e l s appear to improve a v a i l a b i l i t y . The sources o f raw ma te r i a l used i n day-to-day p roces s ing may a l s o i n f l u e n c e a v a i l a b i l i t y . G i l l i s e t a]_. (1954), through b i o l o g i c a l s t u d i e s , est imated a v a i l a b l e phosphorus from bone meal , bone ash and d i c a l c i u m phosphate observ ing va lues o f 87%, 84% and 90% r e s p e c t i v e l y . Motzok ejt al_. (1956), through b i o l o g i c a l s tud ie s i n c h i c k s , demonstrated the v a r i a t i o n i n a v a i l a b i l i t y o f phosphorus from d i f f e r e n t phosphate supplements. Motzok e t aj_. (1956) d i d chromatography a n a l y s i s o f the d i f f e r e n t i no r gan i c phosphate supplements to determine the forms o f phosphorus i n the va r i ou s supplements and i t s r e l a t i o n s h i p to a v a i l a b i l i t y . They observed t h a t a v a i l a b i l i t y of phosphorus inc reased when present i n the orthophosphate form and decreased when i n a mixed form (o r tho , meta and paraform) or phosphorus w i th high molecu la r weight. Magnesium Resul ts i n d i c a t e t h a t magnesium i s h i gh l y a v a i l a b l e from the meat meal samples (Table 5 ) . The a v a i l a b i l i t y of magnesium i n meat meal #2 was s i g n i f i c a n t l y lower compared t o o ther meat meal samples i n which l i t t l e v a r i a t i o n was observed. Nwokolo e_t al_. (1976) eva luated the 35. a v a i l a b i l i t y o f magnesium from soybean meal , cottonseed meal , rapeseed meal and palm kernel meal and repor ted values were 77.4%, 74.5%, 61.1% and 56.4% r e s p e c t i v e l y . The h igher a v a i l a b i l i t y of t h i s element from meat meal over the vegetab le p r o t e i n may be due to the d i f f e r e n t forms i n the two d i f f e r e n t kinds of f e e d s t u f f s or the i n f l uence of o ther components such as phytate and f i b r e . Manganese Resu l t s (Table 5) i n d i c a t e t h a t manganese i s h i g h l y a v a i l a b l e i n meat meals f o r the ch i ck as compared to other p r o t e i n f e e d s t u f f s . The a v a i l a b i l i t y of manganese from meat meal #1 and #6 was s i g n i f i c a n t l y h igher than o the r meals. Meat meal #1 was s i g n i f i c a n t l y d i f f e r e n t from meat meal #8. No v a r i a t i o n i n a v a i l a b i l i t y of t h i s minera l was observed among the other samples. The h igher a v a i l a b i l i t y of manganese from meat meal #6 and meat meal #1 may again be r e l a t e d to a high content o f manganese (Table 4 ) . A s i g n i f i c a n t c o r r e l a t i o n was observed between concen t ra t i on and a v a i l a b i l i t y ( r = 0.67). Th i s i n d i c a t e s t ha t d i f f e r e n c e s i n source of raw ma te r i a l used f o r p repar ing the meat meal may i n f l u e n c e the content as we l l as a v a i l a b i l i t y o f the m i n e r a l . Ga l lup and No r r i s (1939) repor ted t ha t b i r d s have a high requirement f o r manganese due to poor absorpt ion o f the minera l i n the d i e t . The recommended manganese requirement i n p o u l t r y d i e t s i s 55 ppm (N.R.C.). Meat meal conta ins 23 ppm of a v a i l a b l e manganese and normal ly meat meal i s used as a secondary source of d i e t a r y p r o t e i n f o r p o u l t r y . A high supplemental l e v e l of manganese would be necessary i n d i e t s even though manganese from meat meal was e f f e c t i v e l y u t i l i z e d . 36. Copper Copper a v a i l a b i l i t y shows a range from 66.1% to 78.8% (Table 5 ) . The a v a i l a b i l i t y o f copper from meat meal #7 and meat meal #8 was s i g n i f i -c a n t l y lower than other meals t e s t e d . No s i g n i f i c a n t v a r i a t i o n i n a v a i l -a b i l i t y o f the mineral was observed between samples 1, 2, 3, 4, 5 and 6. A l s o , no d i f f e r e n c e was apparent between 1, 2, 5, 9 and 10. Low a v a i l -a b i l i t y o f copper f o r 7 and 8 may be due to low copper content as shown i n Table 4. There i s s i g n i f i c a n t c o r r e l a t i o n between content and a v a i l -a b i l i t y ( r = 0 .72) . Copper abso rp t ion and u t i l i z a t i o n can be a f f e c t e d by other mineral elements and d i e t a r y components (Underwood, 197,7). Large d i f f e r e n c e s i n copper a v a i l a b i l i t y have been repor ted by M i l l s (1954) and Fa r re r and Mi s t i 1 i s (1967). Phytate has been repor ted by Davis ejt a_l_. (1962) to reduce the absorpt ion and a s s i m i l a t i o n o f copper. Z inc A v a i l a b i l i t y o f z i n c was high i n meat meal samples t e s ted (Table 5 ) . The a v a i l a b i l i t y o f z i n c from meat meal #7 and meat meal #4 was s i g n i f i c a n t l y lower i n comparison to a v a i l a b i l i t y o f the same minera l from meat meal #3 and #10. Other meat meals showed no s i g n i f i c a n t v a r i a t i o n i n z i nc a v a i l a b i l i t y . The d i f f e r e n c e s i n a v a i l a b i l i t y o f z i n c i n these samples may a l so be due to v a r i a t i o n i n the content of z i n c , c o r r e l a t i o n c o e f f i c i e n t ( r = 0.58). O ' De l l e t a_l_. (1 972), us ing growth response in c h i c k s , eva luated the a v a i l a b i l i t y o f z i n c i n f i s h meal and reported the value of 75%. Zinc a v a i l a b i l i t y o f meat meals t e s ted were 79.4% which agrees wi th t ha t of f i s h meal (75%) reported by O 'De l l e t a l_ . , (1972) even though d i f f e r e n t techniques were u t i l i z e d to es t imate z i n c a v a i l a b i l i t y . Table 5. A v a i l a b i l i t y o f minera l s from meat meals c o l l e c t e d on 10 consecut ive days. Minera l s {%) Sample^ Ca P Mg Mn Cu Zn Meat meal #1 9 0 . 8 b c 91 . 2 a 82. ,o b 7 7 . 4b c 75. 1 bed 8 0 . 0 b c Meat meal #2 3 9 . 1 a 9 2 . 6 a b 79. ,2 a 7 1 . 6a b 74. 3bcd 7 8 . 6 a b c Meat meal #3 9 0 . 2 a b c 92 .2 a 83. ,8 b 7 2 . 1 a b 78. ,7d 80.7° Meat meal #4 91 .3° 9 2 . 7 a b 83. , l b 7 2 , 0a b 78. ,8 d 7 7 . 6 a b Meat meal #5 8 9 . 6 a b 91 . 8 a 82. ,9 b 7 2 . 0a b 76. 5bcd . 7 8 . 4 a b c Meat meal #6 8 9 . 8 a b C 94.5 C 82. ,7 b 80.0C 77. , 5 c d be 8 0 . 2 U Meat meal #7 9 0 . 3 a b c 94.5° 83. ,8 b 7 2 . 3a b 68. ,2 a 77 .0 a Meat meal #8 9 0 . 5 a b c 94.8° 84, .0 b 69.5a 66, . l a 8 0 . 2 b C Meat meal #9 9 0 . 1 a b c 94.9 C 84 . 3b 7 2 . 5 a b 72, . 5 b be Meat meal #10 9 0 . 1 a b c 9 4 . 3 b C 84 . l b 7 2 . 0a b 73 ^ be 81 . 2 C Average 90.1 93.4 83 .9. 73.1 74 .0 79.4 SD 0.6 1.3 1 .7 2.9 4 .0 1.4 Number i n d i c a t e s consecut ive days of process ing in which sample was c o l l e c t e d . Means w i th d i f f e r e n t s upe r s c r i p t s among meat meals on transformed data are s i g n i f i c a n t l y d i f f e r e n c e (P < 0.05). 39. EXPERIMENT 2. AVAILABILITY OF MINERALS IN PROTEIN CONCENTRATE:. OF : ANIMAL ORIGIN IN BROILER CHICKS A v a i l a b i l i t i e s of minera l s from d i f f e r e n t f e e d s t u f f s have been reported by many authors . The l i t e r a t u r e revea l s that research work on a v a i l a b i l i t y o f minera l s i s most ly on f e e d s t u f f o f vegetable o r i g i n w i th p a r t i c u l a r re fe rence to p h y t i n . Cereal gra ins are abundantly used i n pou l t r y and l i v e s t o c k feed i n which phosphorus i s present as p h y t i n , the a v a i l a b i l i t y o f minera l s i s o f g reate r concern. On the other hand l i t t l e i n fo rmat i on i s a v a i l a b l e i n the l i t e r a t u r e on the a v a i l a b i l i t y o f minera l s i n animal p r o t e i n sources (e .g . blood meal, f ea the r meal, f i s h meal and-meat meal) which are a l s o used i n the pou l t r y d i e t . Experimental s tud ie s are needed i n view o f the v a r i a t i o n among i no rgan i c mineral supplements ( G i l l i s e_t a l_ . , 1954; Grau and Zweigert , 1953) even though i t i s g ene r a l l y assumed that Ca and P i n animal p r o t e i n sources are h i gh l y a v a i l a b l e to the c h i c k s . The o b j e c t i v e of the f o l l o w i n g study was to determine the a v a i l -a b i l i t y o f important n u t r i t i o n a l minera l s (Ca, P, Mg, Mn, Cu and Zn) i n blood meal, fea ther meal, f i s h meal and meat meal. EXPERIMENTAL PROCEDURE Retent ion o f Ca, P, Mg, Mn, Cu and Zn was determined f o r blood meal, f ea the r meal, f i s h meal and meat meal w i th three-week o l d ch ick s us ing the balance procedure reported by Nwokolo et a]_. (1976). The experimental arrangement was a complete randomized design w i t h four 40. r e p l i c a t e s ( fou r ch i ck s each) per d i e t a r y t reatment. The four b i rd s i n each group were housed i n a s t a i n l e s s s t e e l metabolism cage wi th a s t a i n -le s s s t ee l feedersiand wate re r s . The t e s t b i rd s were fed a s t a r t e r d i e t con ta i n i ng known n u t r i t i o n a l requirements from one day to 21 days o f age. Chicks were mainta ined i n a ba t te r y brooder dur ing the f i r s t 18 days and t h e r e a f t e r groups of four were t r a n s f e r r e d to metabolism cages. On the 21st day o f age, a l l ch i ck s were fed a d i e t ( s t a r t e r d i e t ) c on ta i n i n g a 0.3% f e r r i c ox ide marker f o r four hours, fa s ted f o r 16 hours, fed a s y n t h e t i c d i e t (Table 6) f o r a four -hour per iod and then returned to the s t a r t e r d i e t con ta i n i ng the marker. Feces from the s y n t he t i c d i e t were c o l l e c t e d ( s t a r t i n g a t the end of the f i r s t batch o f marked excreta and ending at the beginning o f the second batch o f marked e x c r e t a ) . The same procedure was repeated except t ha t the t e s t feed (Table 7) rep laced the s y n t h e t i c d i e t . D i f f e r e n t l e v e l s o f f eed s t u f f s were u t i l i z e d to minimize the i n f l u e n c e o f d i e t a r y p r o t e i n . Feces were again c o l l e c t e d f o l l o w i n g the same procedure. Consumption of both s y n t h e t i c and t e s t d i e t s were measured. Tota l marker f ree feces were c o l l e c t e d and the feces were d r i ed at 85°C f o r 24 hours. The mineral contents (except P) o f the feed i n g r e d i e n t s , the t e s t r a t i o n , the feces from the s y n t h e t i c d i e t and from the t e s t d i e t were determined by atomic abso rp t ion s pec t r o -photometer f o l l o w i n g wet d i g e s t i o n w i th p e r c h l o r i c and n i t r i c ac ids by the method o f Johnson and U l r i c h (1959). The phosphorus content o f samples was determined on a Unicam 1800 Spectrophotometer f o l l o w i n g development of c o l o r w i th ammonium molybdate. Minera l content o f a l l samples was expressed on a dry matter b a s i s . Table 6. Composition o f s y n t h e t i c m i x tu re . Ingredients g/kg Sucrose 700 C e l l u l o s e ( a l p h a - c e l l ) 200 Corn O i l 100 Table 7. Composition of t e s t mixture (g/kg). Blood meal Feather meal F i sh meal F i sh meal Meat meal Ingred ients #1 #2 Blood meal 180 Feather meal - - 177 F i sh meal #1 - - - - 344 F i sh meal #2 - - - - - - 377 Meat meal - - - - - - - - 314 Syn the t i c d i e t 820 823 656 623 686 A l l mixtures are i son i t rogenous (15.5% p r o t e i n ) . 43. The f o l l o w i n g formula was used to c a l c u l a t e the percent mineral a v a i l a b i l i t y f o l l o w i n g a n a l y s i s of feed and e x c r e t a : Percent Minera l A v a i l a b i l i t y = T M 1 " ( ™ " E F M E ) x 100 where TMI = t o t a l mineral i n t ake from i n g red i en t ( t e s t feed) TFME = t o t a l f e c a l mineral excreted EFME = endogenous f e c a l mineral excreted ( s yn the t i c d i e t exc re ta ) Ana l y s i s of var iance was c a r r i e d out to determine d i f f e r e n c e s among the animal p r o t e i n concentrates i n the a v a i l a b i l i t y of each element (Snedecor, 1956). D e t a i l of the ana l y s i s of var iance was shown in(Appendix Tables 7-12). D i f f e r ence among the means f o r a v a i l a b i l i t y was determined by the m u l t i p l e range t e s t (Duncan, 1955). C o r r e l a t i o n s were run between content and a v a i l a b i l i t y . RESULTS AND DISCUSSION The proximate c o n s t i t u e n t s o f the blood meal , f ea the r mea l , f i s h meal #1, f i s h meal #2 and meat meal are shown i n Table 8. The mineral content o f the blood meal, f e a t he r meal, f i s h meal #1, f i s h meal #2 and meat meal t e s t e d i s presented i n Table 9. These meals show a cons ide rab le v a r i a t i o n i n content o f m ine ra l s . There i s a high l e v e l of Ca, P, and Mg and a low l e v e l of Mn, Cu and Zn. However, Zn content i s q u i t e high i n f ea the r meal and f i s h meal #2 i n comparison w i t h other meals. Resu l t s show (Table 10) the a v a i l a b i l i t y of t h e ' s i x minera l s i n Table 8. Proximate con s t i t uen t s o f blood meal, feather meal, f i s h meal #1 , f i s h meal #2 and meat meal (dry matter b a s i s ) . Dry Matter Grude P ro te in Crude F ibre Ether Ex t rac t Ash Sample (%) {%). {%) (%) (%) Blood meal 94.0 86.6 1.2 2.0 4.0 Feather meal 91.0 88.1 1.6 2.4 1.5 F i sh meal #1 94.0 45.3 1.3 8.0 13.3 F i sh meal #2 91.0 46.0 1.0 9.0 11.8 Meat meal 94.8 51.2 2.0 11.3 30.5 Table 9. The mineral content of blood meal, feather meal, f i s h meal #1 f i s h meal #2 and meat meal. M inera l s Ca P Mg Mn Cu Zn Ingredients mg/g mg/g mg/g mg/kg mg/kg mg/kg Blood meal 2.1 1.9 1.3 14.5 10.5 22.7 Feather meal 1.9 2.0 1.8 12.5 10.4 113.6 F i sh meal #1 21.0 22.0 1.3 16.6 8.3 68.8 F i sh meal #2 15.0 12.0 2.5 68.0 22.4 150.0 Meat meal 84.0 54.0 2.7 12.5 12.5 100.0 46. the f eed s t u f f s t e s t e d . No c o r r e l a t i o n was observed between the crude p r o t e i n content and a v a i l a b i l i t y o f any o f these m ine r a l s . Of course negat ive c o r r e l a t i o n was observed between the f i b r e content and a v a i l a b i l i t y of m i n e r a l . Average a v a i l a b i l i t y o f Ca was 88.3% w i th the lowest l e v e l o f u t i l i z a t i o n i n f ea the r meal (84.8%) and the h ighest l e v e l i n f i s h meal (90.1 and 89.8%) and meat meal (89.5%). These r e s u l t s i n d i c a t e that Ca i s h i gh l y a v a i l a b l e from the animal p r o t e i n sources t e s t e d . Reasonable v a r i a t i o n was observed i n the u t i l i z a t i o n o f ca lc ium from these sources (84.8 - 90.1%). Results i n d i c a t e a higher r e t e n t i o n o f Ca by the ch i ck from p r o t e i n of animal o r i g i n . G i l l i s e t al_. (1954), i n a study us ing b r o i l e r c h i c k s , est imated the a v a i l a b i l i t y o f P from bone meal , bone char and d i c a l c i um phosphate at 87, 86 and 90% r e s p e c t i v e l y . Nwokolo et_ al_. (1976) c a l c u l a t e d the a v a i l -a b i l i t y o f phosphorus from soybean meal , cottonseed meal, rapeseed meal and palm kernel meal at 89.3, 71.9, 74.8 and 70.8% r e s p e c t i v e l y . Phosphorus a v a i l a b i l i t y (Table 10)showed a t rend s i m i l a r to t ha t o f Ca. The average P a v a i l a b i l i t y f o r the p r o t e i n sources te s ted was 87.6%. Feather meal (72.5%) was low compared to f i s h meal (90 and 95.3%) and meat meal (92%). These values are s l i g h t l y h igher than r e s u l t s reported by G i l l i s et al_. (1954) f o r P a v a i l a b i l i t y from bone meal , bone cha r , bone ash and d i c a l c i um phosphate. However, r e s u l t s presented i n Table 10 f o r P are h igher than a v a i l a b i l i t y values reported f o r soybean meal , cottonseed meal , rapeseed meal and palm kernel meal (Nwokolo e t a l _ . , 1976). This d i f f e r e n c e i s expected due to the l i m i t e d i n f l u e n c e of f a c to r s such as phytate and f i b e r as i n d i c a t e d by Nwokolo and Bragg (1977) and Tay lor (1965). Salman and McGinnis (1968) observed that P u t i l i z a t i o n i n r a t i o n s 47. con ta i n i n g 0.3% p lant P was not s i g n i f i c a n t l y d i f f e r e n t from u t i l i z a t i o n i n r a t i o n con ta i n i n g e i t h e r 0.6% p l an t P or 0.3% p l an t plus 0.3% i no r gan i c P. , A v a i l a b i l i t y o f Mg i n blood meal , f ea the r mea l , f i s h meal #1, f i s h meal #2 and meat meal was 81.0%, 76.6%, 79.2% 85.0% and 82.2% r e s p e c t i v e l y . No i n fo rmat ion was found f o r Mg a v a i l a b i l i t y from f e e d s t u f f s o f animal p r o t e i n o r i g i n i n the l i t e r a t u r e rev iewed. Guenter and S e l l 28 (1974) us ing in t ramuscu la r i n j e c t i o n o f r a d i o a c t i v e . Mg showed that the a v a i l a b i l i t y o f Mg was 61.2% f o r soybean meal , whereas Nwokolo et a l . (1976) us ing balance s tud ies observed a v a i l a b i l i t y o f Mg of 77.4% f o r soy-bean meal. The a v a i l a b i l i t y o f Mg i n the d i f f e r e n t animal p r o te i n sources was s i g n i f i c a n t l y d i f f e r e n t . This suggests that the source of Mg has an i n f l u e n c e on d i g e s t i o n and ab so rp t i on . Resu l t s (Table 10) i n d i c a t e that Mn a v a i l a b i l i t y was 73.6% f o r blood meal, 71.2% f o r fea ther meal, 70.6% f o r f i s h meal #1, 71.1% f o r f i s h meal #2 and 71.9% fo r meat meal. There was no s i g n i f i c a n t d i f f e r e n c e i n a v a i l a b l e Mn among the sources t e s t e d . Ga l lup and Nor r i s (1939') and Wilgus and Patton (1939) reported that b i rd s have a high requirement f o r Mn due to poor absorpt ion o f the minera l i n the d i e t . However, p r o t e i n sources te s ted prov ide a supply of Mn that i s approx imate ly 70% a v a i l a b l e . The extent i n which each p r o t e i n w i l l a f f e c t the d i e t a r y Mn a l lowance i s , t h e r e f o r e , r e l a t e d to the d i e t a r y l e v e l o f each p r o t e i n source. Copper abso rp t ion and u t i l i z a t i o n can be markedly a f f e c t e d by severa l other mineral elements such as Mo and Zn (Underwood, 1977). D i f f e rences i n Cu a v a i l a b i l i t y have been repor ted by M i l l s (1954) and Fa r re r and M i s t i l i s (1967). The i n f l u e n c e of phytate i n decreas ing the absorpt ion 48. and a s s i m i l a t i o n o f Cu was reported by Davis et al_. (1 962). The copper i n f i s h meal #2 was 78.4% a v a i l a b l e wh i l e that o f f ea the r meal was 67.5% and a s i m i l a r value o f 67.7% was observed f o r f i s h meal #1. The lower a v a i l a b i l i t y of copper from feather meal and f i s h meal #1 may be r e l a t e d to lower content o f copper (Table 9) c o r r e l a t i o n c o e f f i c i e n t ( r = 0.69). The a v a i l a b i l i t y o f Cu from blood meal and meat meal was 76% and 76.5% r e s p e c t i v e l y . The l a rge d i f f e r e n c e between the two sources o f f i s h meal i s d i f f i c u l t to understand although s i m i l a r d i f f e r e n c e s were observed f o r Mg and Zn. The a v a i l a b i l i t y of Zn i n blood meal , f ea the r mea l , f i s h meal #1, f i s h meal #2 and meat meal was 73.2, 81.3, 71, 80 and 78.4% r e s p e c t i v e l y (Table 10). Blood meal and f i s h meal #1 was s i g n i f i c a n t l y lower than other sources t e s t e d . There i s s i g n i f i c a n t c o r r e l a t i o n between content and a v a i l a b i l i t y ( r = 0.79). O 'De l l et al_. (1972), us ing the growth response of c h i c k s , evaluated the a v a i l a b i l i t y o f Zn i n f e e d s t u f f s o f animal and p lant o r i g i n and reported values o f 57, 67 and 75% f o r sesame meal , soybean meal and f i s h meal r e s p e c t i v e l y . Nwokolo et al_. (1976) i n d i c a t e d tha t a v a i l a b i l -i t y of z i n c from vegetable concentrates was 13.9, 66.5, 38 and 60% f o r palm kernel meal, soybean meal, cottonseed meal and rapeseed meal r e s p e c t i v e l y . The phytate content o f the p l an t f e e d s t u f f s was imp l i c a t ed i n reducing the a v a i l a b i l i t y o f Zn by Lease et al_. (1 969), L i k u s k i and Forbes (1964), O 'De l l et a]_. (1972) and Nwokolo e t a]_. (1976). In format ion was l i m i t e d i n the l i t e r a t u r e regard ing the a v a i l a b i l i t y o f Zn from blood meal , f ea the r meal and meat meal. L i t t l e v a r i a t i o n was observed i n a v a i l a b i l i t y of Zn among concentrates used. Table 10. A v a i l a b i l i t y o f minera l s i n blood meal, feather meal, f i s h meal #1 , f i s h meal #2 and meat meal. M inera l s (%) Ingredi ents Ca P Mg Mn Cu Zn Blood meal 8 7 . 5 a 88 .0 b 81 .0 C 73.6 a 76.0 b 73.2 a Feather meal 84 .8 a 72 .5 a 76.6 a 71.2 a 67.5 a 81 , 3 b F i sh meal #1 9 0 . l a 95 .3 d 79 .2 b 70.6 a 67.7 a 71 . 0 a F i sh meal #2 89 .8 a 9 0 . 0 b c 8 5 . l d 71 . l a 78.4 b 80 .0 b Meat meal 89 .5 a 92.0° 82.2° 71 .9 a 76 .5 b 78.4 b Average 88.3 87.6 80.8 71 .7 73.2 76.8 Means wi th d i f f e r e n t s u p e r s c r i p t s among p ro te i n concentrates on transformed data are s i g n i f i c a n t l y d i f f e r e n t (P < 0.05). 50. EXPERIMENT 3. COMPARISON OF ASSAY TECHNIQUES FOR PHOSPHORUS AVAILABILITY WITH THE CHICKS Studies have been conducted by many research workers to e s t a b l i s h the comparative u t i l i z a t i o n of phosphorus from var ious supplements by ch icks ' . Nelson and Pee ler (1961) demonstrated a method i n which the standard curve was a reg re s s i on l i n e obta ined by p l o t t i n g the percentage o f bone ash obta ined a t the var ious l e v e l s of added r e f i n e d phosphorus and c a l c u l a t e comparative a v a i l a b i l i t y o f phosphorus from t e s t i n g r e d i e n t s . Baruah et a l . (1960) reported a method i n which the percentage t i b i a ash obta ined w i th t e s t phosphate was d i v i ded by the percentage t i b i a ash obta ined at standard phosphate. B i o l o g i c a l assay procedures f o r a v a i l a b i l i t y o f amino ac ids developed by Bragg et al_. (1969) were mod i f ied by Nwokolo (1976) f o r minera l a v a i l a b i l i t y s t u d i e s . Cons iderab le v a r i a t i o n e x i s t s i n the assay procedure employed by d i f f e r e n t r e sea rche r s . In c e r t a i n assays, constant Ca:p r a t i o s were used (Creech et^ a l_ . , 1 956; Nelson and P e e l e r , 1961), wh i l e i n others constant Ca l e v e l s of 1.0% or 1.2% were used (Ammerman ejt a l _ . , 1960). Problems i nvo l ved i n the development o f a b i o l o g i c a l assay f o r feed phos-phates were r e l a t e d to the compos i t ion o f these m a t e r i a l s . Among these was the quest ion o f ho ld ing the ca lc ium l e v e l constant or having a constant Ca:p r a t i o i n the assay d i e t and other d i e t a r y •. or metabo l i c e f f e c t s which i n f l u e n c e phosphorus a v a i l a b i l i t y (Nelson and P e e l e r , 1964). There fo re , the o b j e c t i v e s o f t h i s study were to compare: 1) the phosphorus a v a i l a b i l i t y from p r o t e i n concentrates o f animal o r i g i n us ing d i f f e r e n t assay techn iques ; 51: 2) The extent o f v a r i a t i o n i n phosphorus a v a i l a b i l i t y due to techn ique. EXPERIMENTAL PROCEDURE The basal d i e t used f o r t h i s study was composed o f sucrose, wheat, soybean meal, i s o l a t e d soybean p r o t e i n , t a l l o w , l imes tone , v i t amin and mineral premix (Table 11). This was found to con ta in 0.33% phosphorus and 0.84% ca l c i um. Two s e r i e s of exper imental d i e t s were formulated - a standard assay s e r i e s i n which d i c a l c i um phosphate ( con ta in i ng 24% ca lc ium and 18.5% phosphorus) was added to the basal d i e t to i nc rease the phosphorus l e v e l from 0.33% to 0.43%, 0.53%, 0.63%, 0.73% and l imestone was used to mainta in constant ca lc ium l e v e l o f 0.84% i n (Table 12). Another s e r i e s of t e s t d i e t s were made by supplementing d i f f e r e n t animal p r o t e i n concentrates to the basal d i e t and inc rease the phosphorus content from 0.33% to 0.43% and ma in ta in ing the ca lc ium l e v e l 0.84% us ing l imestone (Table 13). The d i e t s were kept i son i t rogenous and i s o c a l o r i c which conta in 23.2% p r o t e i n and approx imately 3142 kcal/kg o f metabo l i zab le energy. Premix composit ion o f m i c ro i ng red i en t s supp l ied to the d i e t i s shown i n Table 14. The amino ac id compos i t ion o f the basal d i e t i s shown i n Table 15. Four hundred randomly s e l e c ted day o ld b r o i l e r male ch i ck s were used to ca r r y out t h i s s tudy. The ch i ck s were d i v i ded equa l l y i n t o 10 treatment groups i n a randomized des ign w i th 10 ch i ck s i n each o f four r e p l i c a t e s . Cages were numbered and each treatment group i d e n t i f i e d . Feed and water were a v a i l a b l e to the ch i ck s ad 1 ib i tum and the groups were provided w i th normal care and management dur ing the exper imental pe r i od . Table 11. Composition o f basal d i e t . Ingred ient Percent Sucrose 10 - wheat 48 - soybean meal 29 I s o l a ted Soybean P ro te i n 5 - animal t a l l o w 5 l imestone 2 - v i t amin and mineral premix 1 100 P ro te i n 23.2% Metabo l i z ab le Energy 3142 kcal/kg Calcium 0.84% Phosphorus 0.33% Table 12. Composit ion of the d i e t con ta in i ng d i f f e r e n t l e v e l s of phosphorus supplemented w i th d i ca l c i um phosphate. Phosphorus (%) I ng red ient s 0.43 0.53 0.63 0.73 Sucrose Wheat Soybean meal I s o l a t ed Soybean P r o t e i n Ta l low Limestone D i ca l c ium phosphate V i tamin and Minera l Premix °/ D vn f o i n Metabo l i z ab l e Energy ( Kca l/kg % Calc ium 10.0 48.0 29.0 5.0 5.0 1.5 0.5 1.0 100.0 23.2 3142 0.84 10.0 48.0 29.0 5.0 5.0 1.0 1.0 1.0 100.0 23.2 3142 0.84 9.5 48.0 29.0 5.0 5.0 1.0 1.5 1.0 100.0 23.2 3140 0.84 9.5 48.0 29.0 5.0 5.0 0.5 2.0 1.0 100.0 23.2 3140 0.84 Table 13. Composit ion o f the t e s t d i e t conta in ing (0.43 phosphorus). Supplemented w i th Ingred ients Feather meal Blood meal Meat meal (L) Mean meal (H) F i sh meal Sucrose 15.5 15.5 9.5 10.0 9.0 Wheat 36.0 36.0 48.0 48.0 46.0 Soymean meal 38.0 38.0 29.0 29.0 31.0 I s o l a ted Soybean P r o t e i n 2.0 2.0 3.0 3.5 2.0 Ta i low 5.0 5.0 5.0 5.0 5.0 Limestone 2.0 2.0 1.5 1.5 2.0 Feather meal 0.5 - - _ Blood meal - 0.5 - _ _ Meat meal ( L ) 1 - - 3.0 _ Meal meal ( H ) 1 - - - 2.0 _ F i sh meal - - - - 4.0 V itamins & Minera l Premix 1.0 1.0 1.0 1.0 - 1.0 100.0 100.0 100.0 100.0 100.0 % P r o t e i n 23.3 23.3 23.2 23.2 23.2 Me tabo l i z ab le Energy Kcal/kg 3142 3143 3143 3142 3142 % Calc ium 0.84 0.84 0.84 0.84 0.84 Meat meal samples were low phosphorus (L - conta ins 3.33% phosphorus) and high phosphorus (H - conta ins 5.50% phosphorus). Table 14. Premix compos i t ion of m i c ro i ng red i en t s . Suppl ied per V i tamin Premix kg d i e t V i tamin A 1500 I.U V i tamin E 10 I.U V i tamin 400 I.U V i tamin K 0.5 mg Thiami ne 0.2 mg R i b o f l a v i n 3.6 mg Pantothenic Ac id 10 mg N i a c i n 27 mg Py r i dox ine 3 mg B i o t i n 0.09 mg Chol ine Ch lo r i de 1300 mg F o l i c Ac id 0.55 mg V i tamin B ^ 0.009 mg Suppl i e d per Minera l Premix kg d i e t Sodium Ch lo r i de 2 5 gm Magnesium Sulphate 0 5 gm Ferrous Sulphate 0 08 gm Manganese Sulphate 0 055 gm Zinc Carbonate 0 05 gm Copper Sulphate 0 004.gm Potassium Iodide 0 01 gm Sodium Molybdate 0 .01 gm Table 15. Amino a c i d composit ion of the basal d i e t . Percent Amino Ac id Percent of D iet Required-. Arg i ni ne 1 .6 1 -4 G l yc ine and Ser ine 2.0 1 .15 H i s t i d i n e 0.58 0.46 I s o l euc i ne 1 .0 0.86 Leucine 1 .8 1 .6 Lys ine 1 .3 1 .25 Methionine 0.69 0.46 Cy s t i ne 0.30 0.40 Pheny la lan i ne\ Tyros ine 1 .9 1 .5 Threonine 0.89 0.8 Tryptophan 0.30 0.23 Va l i ne 1 .2 1 .0 57. The du ra t i on o f the experiment was four weeks. The f o l l o w i n g records were kept f o r experimental p e r i o d . 1) body weight - i n i t i a l and weekly body weight was recorded by r e p l i c a t i o n and t reatment. 2) Feed consumption - weekly feed consumption was recorded by r e p l i c a t i o n and t reatment. 3) M o r t a l i t y was a l so recorded. On the 28th day o f the experiment three ch i ck s from each r e p l i c a t i o n (12 from each treatment) were s a c r i f i c e d , the l e f t t i b i a was removed and prepared f o r bone ash a n a l y s i s us ing the procedure descr ibed by the A.O.A.C. (1960). Bone ash was c a r r i e d out on i n d i v i d u a l samples. The average bone ash of 12 samples was used to c a l c u l a t e the percentage o f the bone ash per d i e t a r y t reatment. The phosphorus a v a i l a b i l i t y was a l s o determined f o l l o w i n g the balance procedure o u t l i n e d by Nwokolo et al_. (1976) i n which r e t e n t i o n of mineral was c a l c u l a t e d as mineral i n take l e s s f e ca l e x c r e t i o n co r rec ted f o r endogenous contaminat ion and expressed as percent o f i n t a k e . RESULTS AND DISCUSSION The average body we ight , percentage o.f t i b i a a sh , feed e f f i c i e n c y and m o r t a l i t y f o r 10 treatments are shown i n Tables 16 and 17. The comparative a v a i l a b i l i t y o f phosphorus from d i f f e r e n t animal p r o t e i n concentrates and d i c a l c i um phosphate was c a l c u l a t e d us ing body weight and t i b i a ash data i n Tables 16 and 17. The standard curve was a reg re s s i on Table 16. Body we ight , t i b i a ash, feed e f f i c i e n c y and m o r t a l i t y of four week o ld ch i ck s as i n f l uenced by d i f f e r e n t phosphate l e v e l s i n the d i e t . Ca P Body Weight T i b i a Ash Gain/Feed M o r t a l i t y Treatment (%) (%) (gm) (.%) Rat io [%) D i e t l 0.84 0.33 251.7 29.4 0.42 12 D iet 2 0.84 0.43 495.8 38.0 0.53 1 D iet 3 0.84 0.53 504.5 38.0 0.56 n i l . D iet 4 0.84 0.63 524.2 40.6 0.56 2 D iet 5 0.84 0.73 546.6 41.0 0.57 2 Table 17. Body weight , t i b i a ash, feed e f f i c i e n c y and m o r t a l i t y of four week o l d ch ick s fed (.43% phosphorus) supplemented by d i f f e r e n t animal p ro te in concentrates w i th the basal d i e t . Ca P Body Weight T i b i a Ash Gain/Feed M o r t a l i t y Treatment (%) (%) (gm) {%) Rat io {%) D ie t Feather meal 0.84 0.43 370.0 32.7 0.45 D ie t Blood meal 0.84 0.43 435.5 34.5 0.48 D ie t Meat meal ( L ) 1 0.84 0.43 457.0 35.0 0.50 D iet Meat meal ( H ) 1 0.84 0.43 465.1 37.0 0.51 D iet F i sh meal,. 0.84 0.43 467.5 37.0 0.52 •^Meat meal samples were low phosphorus (L) and high phosphorus (H) 600 580 560 5*01 1 510 < O 500 w r- w \ X 2 460 ul g 420 CD 400 380 3 . 0 340 F E A T H E R M E A L . F ISHMEAL * i MEATMEAL. *2 M E A T M E A L * t B L O O D M E A L 0.33 OM3 0.53 0.63 0.73 P E R C E N T DIETARY PHOSPHORUS i D ICALCIUM P H O S P H A T E ) Figure 1. Regress ion l i n e p l o t t e d from body weight at d i f f e r e n t l e v e l s o f d i c a l c i um phosphate. CTl o Table 18. R e l a t i v e a v a i l a b i l i t y of phosphorus i n feather meal, blood meal, meat meal , and f i s h meal when body weight 'used as c r i t e r i a fo r a v a i l a b i l i t y . A v a i l a b l e P Feeds tu f f (%) Feather meal 91 Blood meal 112 Meat meal ( L ) 1 118 Meat meal ( H ) 1 123 F i sh meal 125 Meat meal samples were low phosphorus (L) and high phosphorus ( H ) . 43 PERCENT DIETARY PHOSPHORUS CDICALCIUM PHOSPHATE) F i gu r e . 2 . Regress ion l i n e p l o t t e d from percentage of t i b i a ash at d i f f e r e n t l e v e l s of d i c a l c i um phosphate. Table 19. R e l a t i v e a v a i l a b i l i t y o f phosphorus in. feather meal, blood meal, meat meal, and f i s h meal when percentage o f t i b i a ash used as a c r i t e r i a fo r a v a i l a b i l i t y _ A v a i l a b l e P Feeds tu f f ( „ ) • " Feather meal 84 Blood meal 98 Meat meal ( L ) 1 112 Meat meal (H ) 1 121 F i sh meal 121 *Meat meal samples were low phosphorus (L) and high phosphorus (H). (Ti OJ 64. l i n e obta ined at the var ious l e v e l s o f added phosphorus. The b i o l o g i c a l a v a i l a b i l i t y o f phosphorus f o r d i f f e r e n t animal p r o t e i n concentrates was c a l c u l a t e d from the standard curve. F igure 1 was used f o r c a l c u l a t i n g comparative a v a i l a b i l i t y o f phosphorus f o r concentrates us ing body weight as a c r i t e r i a . The c a l c u l a t e d comparative a v a i l a b i l i t y of phosphorus from fea the r meal, blood meal, meat meal ( L ) , meat meal (H) and f i s h meal when body weight was used as a c r i t e r i o n was 91%, 112%, 118%, 123% and 125% r e s p e c t i v e l y i n Table 18. F igure 2 was used f o r c a l c u l a t i n g comparative a v a i l a b i l i t y o f phosphorus f o r concentrates us ing percentage of t i b i a ash as a c r i t e r i o n . The c a l c u l a t e d comparative a v a i l a b i l i t y of phosphorus from fea the r meal, blood meal, meat meal ( L ) , meat meal (H) and f i s h meal when percentage o f t i b i a ash was used as c r i t e r i a was 84%, 98%, 112%, 121% and 121% r e s p e c t i v e l y i n Table 19. The percentage t i b i a ash obta ined w i th the t e s t phosphate was d i v i ded by the percentage t i b i a ash obta ined w i th standard phosphate at the same phosphorus i n t ake . Using t h i s method, the comparative a v a i l a b i l i t y of the phosphorus from fea the r meal, blood meal, meat meal ( L ) , meat meal (H) and f i s h meal was 85%, 90.5%, 94.7%, 97.3% and 97.3% r e s p e c t i v e l y i n Table 20. The a v a i l a b i l i t y o f phosphorus was a l so determined f o l l o w i n g mineral balance procedure (Nwokolo ejt a l _ . , 1976). Using t h i s method the a v a i l a b i l i t y o f phosphorus was c a l c u l a t e d from d i f f e r e n t animal p r o t e i n concent rates . The a v a i l a b i l i t y o f phosphorus from fea the r meal, blood meal, meat meal ( L ) , meat meal (H) and f i s h meal was 72.5%, 88%, 92%, 95% and 95.3% r e s p e c t i v e l y i n Table 21. B i o l o g i c a l phosphorus a v a i l a b i l i t y values obta ined i n t h i s experiment are g rea te r than the a v a i l a b i l i t y values obta ined by mineral balance procedure (Nwokolo et_ a l_ . , • 1976). This d i f f e r e n c e i s probably Percentage of phosphorus a v a i l a b i l i t y i n feather meal, blood meal, meat meal, and f i s h meal. A v a i l a b l e P Feeds tu f f {%) Feather meal 86 Blood meal 90.5 Meat meal ( L ) 2 94.7 Meat meal (H ) 2 97.3 F i sh meal 97.3 Percent P a v a i l a b i l i t y = Percent t i b i a ash o f t e s t phosphorus Percent t i b i a ash o f standard phosphorus Meat meal samples were low phosphorus (L) and high phosphorus (H). Table 21. Percentage o f phosphorus a v a i l a b i l i t y i n feather meal, blood meal, meat meal, and f i s h meal. A v a i l a b l e P Feedstuf f (%) Feather meal 72.5 Blood meal 88.0 Meat meal ( L ) 2 92.0 Meat meal (H ) 2 95.0 F i sh meal : : 95.3 I TPI - (TFPE - EFPE) Percent P a v a i l a b i l i t y = TPI Meat meal samples were low phosphorus (L) and high phosphorus (H). C31 67. due to p r o t e i n e f f e c t of the animal concentrates used i n the d i e t or e f f e c t o f the i n t e r a c t i o n o f d i f f e r e n t n u t r i e n t s . The phosphorus a v a i l a b i l i t y determined from growth response i s d i f f e r e n t from that o f the phosphorus a v a i l a b i l i t y va lue obta ined from percent t i b i a a sh ; i t i s t he re f o re suggested that e i t h e r the requirement of phosphorus f o r growth i s d i f f e r e n t from tha t f o r bone c a l c i f i c a t i o n or that the metabolism o f phosphorus f o r these func t i on s i s d i f f e r e n t . D i f f e rences i n phosphorus a v a i l a b i l i t y between growth response and the percent bone ash has been reported by Motzok al_. (1 955). Body weights are not a s e n s i t i v e c r i t e r i o n of mineral a v a i l a b i l i t y as reported by Spandorf and Leon ?(]965). I t i s apparent from t h i s experiment that v a r i a t i o n i n the procedure used to determine phosphorus a v a i l a b i l i t y from phosphate sources may i n f l uence the r e s u l t s . The type of ca l c ium supplementat ion, r a t i o o f ca lc ium to phosphorus i n the d i e t , i n t e r p r e t a t i o n o f the data and v i tamin D^  l e v e l of the d i e t may be i n f l u e n c i n g f a c t o r s (Waldroup et a l . , 1963). 68. SUMMARY AND CONCLUSIONS Chicks were u t i l i z e d i n a study to es t imate minera l (Ca, P, Mg, Mn, Cu and Zn) a v a i l a b i l i t y o f 10 meat meal samples processed i n 10 consecut i ve days. A balance procedure was used to determine a v a i l a b i l i t y i n which a c o r r e c t i o n f o r endogenous minera l was u t i l i z e d . Resu l t s o f t h i s study i n d i c a t e t h a t ca lc ium and phosphorus are h i gh l y a v a i l a b l e from meat meals w i th values o f 90% and 93.4%, r e s p e c t i v e l y . Magnesium, manganese, z i n c and copper are a l so we l l u t i l i z e d w i th an average of 83.9%, 73.1%, 79.4% and 74%, r e s p e c t i v e l y . V a r i a t i o n i n a v a i l a b i l i t y o f m i n e r a l s p a r t i c u l a r l y phosphorus, copper and z i n c were observed among meat meal samples t e s t e d . This i n d i c a t e s tha t raw mate r i a l used i n day to day manufactur ing o f the meals were d i f f e r e n t , a l so phosphorus may e x i s t i n d i f f e r e n t forms from one meal to another. Resu l t s a l s o i n d i c a t e that concent ra t i ons o f i n d i v i d u a l minera l s appear to i n f l u e n c e a v a i l a b i l i t y . A v a i l a b i l i t y values observed i n t h i s study i n d i c a t e t ha t meat meal i s an e x c e l l e n t source o f a v a i l a b l e m i n e r a l s ; however, v a r i a t i o n was apparent among meals. The conc lu s ion o f these t e s t s show that every sample o f meat meal should be analyzed before being used i n the d i e t . The important d i e t a r y minera l content (Ca, P, Mg, Mn, Cu and Zn) was determined i n blood meal, fea ther meal, f i s h meal and meat meal. Resu l t s showed a wide range i n Ca (2.1-84.0 mg/g), P (1.9-54 mg/g), Mn (12.5-68 mg/ kg) , Cu (8.3-22.4 mg/kg) and Zn (22.7-150 mg/kg). The concen t ra t i on o f Mg among samples was narrow (1.3-2.7 mg/g). Blood meal was the lowest i n a l l minera l s except Cu ( f i s h meal #1) and f i s h meal or meat meal were the h ighest i n these m ine ra l s . 69. A v a i l a b i l i t y s tud ie s f o r the same minera l s u t i l i z e d the b r o i l e r ch ick ( three weeks o f age) i n a minera l balance procedure. S i g n i f i c a n t v a r i a t i o n was observed i n a v a i l a b i l i t y o f each mineral among animal p r o t e i n concentrate samples t e s t e d . Average a v a i l a b i l i t y of Ca, P, Mg, Mn, Cu and Zn was 88.3, 87.6, 80.8, 71.7, 73.2 and 76.8%, r e s p e c t i v e l y . The results. o f t h i s study i nd i c a te - ) that there i s v a r i a t i o n i n a v a i l a b i l i t y o f minera l s among the concentrates o f animal o r i g i n . Stud ies were a l so conducted wi th b r o i l e r ch i ck s to compare the a v a i l a b i l i t y o f phosphorus from feather meal, blood meal, meat meal and f i s h meal us ing d i f f e r e n t assay techn iques . A standard curve was drawn by p l o t t i n g the growth ra te and percentage o f t i b i a ash obta ined at var ious l e v e l s o f added d i c a l c i um phosphate ( re fe rence d i e t ) . The b i o l o g i c a l a v a i l a b i l i t y o f phosphorus f o r d i f f e r e n t animal p r o t e i n concentrates was c a l c u l a t e d from the standard curve. The c a l c u l a t e d comparative a v a i l a b i l i t y o f phosphorus from fea the r meal, blood meal, meat meal ( L ) , meat meal (H) and f i s h meal was 91%, 112%, 118%, 123% and 125%, r e s p e c t i v e l y , when body weight was used as. a c r i t e r i a . The comparative a v a i l a b i l i t y o f phosphorus from fea the r meal , blood meal, meat meal ( L ) , meat meal (H) and f i s h meal when percentage of t i b i a ash wasv used as a c r i t e r i a was 84%, 98%, 112%, 121% and 121%, r e s p e c t i v e l y . The percentage o f t i b i a ash obta ined wi th t e s t phosphate was d i v i ded by the percentage o f t i b i a ash obta ined w i th standard phosphate. Using t h i s method, the comparative a v a i l a b i l i t y o f the phosphorus from fea the r meal, blood meal , meat meal ( L ) , meat meal (H) and f i s h meal was 85%, 90.5%, 94.7%, 97.3% and 97.3%, r e s p e c t i v e l y . 70. 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In f luence of var ious c h e l a t i n g agents on absorpt ion o f 60co, 5 9 p 6 j 54^ n a n c | 65z n u y ch i cken . P o u l t r y S c i . 47: 1417-1425. S u t t l e , N.F. and C F . M i l l s . 1966. Studies on the t o x i c i t y of copper to p i g s . E f f e c t s of o r a l supplements of z i n c and i r o n s a l t s on the development o f copper t o x i c o s i s . Br. J . Nutr. 20: 135-148. Tao, S. and L.S. Hur ley. 1975. E f f e c t o f d i e t a r y ca lc ium d e f i c i e n c y dur ing pregnancy on z i n c m o b i l i z a t i o n i n t a c t and parathyro idec-tomized r a t s . J . Nutr . 105: 220-225. T a y l o r , T.G. 1965. The a v a i l a b i l i t y o f the ca l c ium and phosphorus o f p l an t ma te r i a l s f o r an imals . Proc. Nutr. Soc. 24: 105-112. Temperton, H. and J . Cass idy. 1964. Phosphorus requirements of p o u l t r y . The u t i l i z a t i o n o f phy t i n phosphorus by the ch i c k s as i n d i c a t e d by balance experiments. Br. 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The r e l a t i o n s h i p o f phosphorus, ca lc ium and v i tamin D3 " i n the d i e t o f b r o i l e r type c h i c k s . Pou l t r y S c i . 42: 982-988. Wasserman, R.H. 1962. Studies on v i t amin D3 and the i n t e s t i n a l absorpt ion of ca lc ium and o t h e r l o n s i n the r a c h i t i c c h i c k . J . Nutr . 77: 69-80. Wasserman, R.H. 1963. V i tamin D and the absorpt ion o f ca lc ium and s t ront ium i n v i v o . In "T ran s fe r o f Calcium and Stront ium Across B i o l o g i c a l Membranes". (R.H. Wasserman, e d . ) , p. 211. Academic P res s , New York. Wasserman, R.H. and C L . Comar. 1959. Carbohydrates and gastro i n t e s t i n a l ,absorpt ion of r ad i o s t r on t i um and r ad i oca l c i um i n the r a t . Proc. Soc. E x p t l . B i o l . Med. 101: 314. Wasserman, R.H., C L . Comar, and M.M. Nold. 1956. The i n f l u e n c e o f amino ac ids and other organ ic compounds on the gastro i n t e s t i n a l absorpt ion o f and s t r o n t i u m ^ i n the r a t . J . Nutr . 59: 371. Wasserman, R.H. and F.W. Lengemann. 1960. Further observat ions on l a c t o s e s t i m u l a t i o n o f the g a s t r o - i n t e s t i n a l absorpt ion of ca lc ium and s t ront ium i n the r a t . J . Nutr . 70: 377. Watson, L.T., C.B. Ammerman, S.M. M i l l e r and R.H. Harms. 1971. B i o l o g i c a l a v a i l a b i l i t y to ch i ck s of manganese from d i f f e r e n t i no rgan i c sources. Pou l t r y S c i . 50: 1693-1700. Wh i t i n g , F. and L.M. Bezeau. 1958. The c a l c i u m , phosphorus, and z i n c balance i n pigs as i n f l uenced by the weight of p i g and the l e v e l o f c a l c i um, z i nc and v i tamin D i n the r a t i o n . Can. J . Anim. S c i . 38: 109-117. W i l de r , O.H.M., R.M. Bethke and P.R. Record. 1933. The i od i ne content o f hens eggs as a f f e c t e d by the r a t i o n . J . N u t r i t i o n 6: 407-412. 83. Wi lgus, H.R., J r . and A.R. Pat ton . 1939. Factors a f f e c t i n g manganese u t i l i z a t i o n i n the ch i c ken . J . Nutr . 18: 35-45. Wi l son , T.H. 1962. " I n t e s t i n a l Ab so rp t i on . " Saunders, P h i l a d e l p h i a , Pennsy lvan ia . Appendix Table 1. Ana l y s i s of var iance fo r Ca a v a i l a b i l i t y o f 10 meat meal samples (Experiment 1 ) . Source D.F. Sum of Squares Mean Square 1 Treatment R e p l i c a t i o n E r ro r Total 27 39 0.042903 0.0029075 0.063767 0.10958 0.0047669 N.S. 0.00096917 N.S. 0.0023618 1 N.S. i n d i c a t e s no s i g n i f i c a n t d i f f e r e n c e ; at (P < 0.05). Appendix Table 2. Ana l y s i s of var iance f o r P a v a i l a b i l i t y of 10 meat meal samples (Experiment 1 ) . Source D.F. Sum of Squares 1 2 Mean Square '. Treatment R e p l i c a t i o n E r ro r Total 27 39 0.19401 0.0069800 0.10317 0.30416 0.021557* 0.0023267 N.S. 0.0038211 1 A s t e r i s k i n d i c a t e s s i g n i f i c a n t d i f f e r e n c e at (P < 0.05) 'N.S. i n d i c a t e s no s i g n i f i c a n t d i f f e r e n c e at (P < 0.05) Appendix Table 3. Ana l y s i s of var iance f o r Mg a v a i l a b i l i t y of 10 meat meal samples (Experiment 1 ) . Source D.F. Sum of Squares Mean Square 1,2 Treatment R e p l i c a t i o n E r r o r Tota l 27 39 0.26976 0.0034900 0.17926 0.45251 0.029973 0.0011633 N.S. 0.0066393 1 A s t e r i s k i n d i c a t e s s i g n i f i c a n t d i f f e r e n c e at (P < 0.05) "N.S. i n d i c a t e s no s i g n i f i c a n t d i f f e r e n c e at (P < 0.05). Appendix Table 4. Ana l y s i s of var iance f o r Mn a v a i l a b i l i t y of 10 meat meal samples (Experiment 1 ) . Source D.F. Sum of Squares Mean Square 1,2 Treatment R e p l i c a t i o n E r ro r Total 27 39 1 .1649 0.15905 1 .2383 2.5622 0.12943' 0.053016 N.S. 0.045862 •1 A s t e r i s k i n d i c a t e s s i g n i f i c a n t d i f f e r e n c e at (P < 0.05). 'N.S. i n d i c a t e s no s i g n i f i c a n t d i f f e r e n c e at (P < 0.05) Appendix Table 5. Ana l y s i s of var iance f o r Cu a v a i l a b i l i t y o f 10 meat meal samples (Experiment 1 ) . Source D.F. Sum of Squares Mean Square 1,2 Treatment R e p l i c a t i o n E r ro r Total 27 39 2.2732 0.045370 0.71958 3.0381 0.25257 0.0T5123 NVS. 0.026651 1 A s t e r i s k i n d i c a t e s s i g n i f i c a n t d i f f e r e n c e at (P < 0.05) "N.S. i n d i c a t e s no s i g n i f i c a n t d i f f e r e n c e at (P < 0.05) Appendix Table 6. Ana l y s i s o f var iance f o r Zn a v a i l a b i l i t y o f 10 meat meal samples (Experiment 1 ) . Source D.F. Sum of Squares Mean Square 1,2 Treatment R e p i i c a t i o n E r r o r Tota l 3 27 39 0.23735 0.066828 0.29600 0.60018 0.026373 0.002276 N.S, 0.010963 A s t e r i s k i n d i c a t e s s i g n i f i c a n t d i f f e r e n c e at (P < 0.05), "N.S. i n d i c a t e s no s i g n i f i c a n t d i f f e r e n c e at (P < 0.05) Appendix Table 7. Ana l y s i s of var iance f o r Ca a v a i l a b i l i t y of blood meal, feather meal, f i s h meal #1, f i s h meal #2, and meat meal (Experiment 2 ) . Source D.F. Sum of Squares Mean Square 1 Treatment R e p l i c a t i o n E r ro r Tota l 4 3 12 19 0.1762 0.028095 0.19618 0.40290 0.044655 N.S. 0.0093650 N.S, 0.016348 N.S. i n d i c a t e s no s i g n i f i c a n t d i f f e r e n c e at (P < 0.05). Appendix Table 8. Ana l y s i s o f var iance f o r P a v a i l a b i l i t y o f blood meal, feather meal, f i s h meal #1, f i s h meal #2 and meat meal (Experiment 2 ) . Source D . F . Sum of Squares Mean Square 1,2 Treatment Rep l i c a t i on E r ro r Tota l 4 3 12 19 3.8253 0.012895 0.12968 3.9679 0.95632 0.0042983 N.S. 0.010807 1 A s t e r i s k i n d i c a t e s s i g n i f i c a n t d i f f e r e n c e at (P < 0.05) [.S. i n d i c a t e s no s i g n i f i c a n t d i f f e r e n c e at (P < 0.05) Appendix Table 9. Ana l y s i s o f var iance f o r Mg a v a i l a b i l i t y of blood meal, fea ther meal, f i s h meal #1, f i s h meal #2 and meat meal (Experiment 2 ) . Source D.F. Sum of Squares Mean Square 1 ,2 Treatment Rep!i c a t i on E r r o r Tota l 4 3 12 19 0.50302 0.025880 0.052820 0.58172 0.12575 0.0086267 N.S, 0.0044017 A s t e r i s k i n d i c a t e s s i g n i f i c a n t d i f f e r e n c e at (P < 0.05). N.S. i n d i c a t e s no s i g n i f i c a n t d i f f e r e n c e at (P < 0.05). Appendix Table 10. Ana l y s i s o f var iance f o r Mn a v a i l a b i l i t y of blood meal, feather meal, f i s h meal #1, f i s h meal #2 and meat meal (Experiment 2 ) . Source D.F. Sum of Squares Mean Square 1 Treatment R e p l i c a t i o n E r ro r Tota l 12 19 0.073020 0.020575 0.19210 0.28569 0.018255 N.S. 0.0068583 N.S, 0.016008 N.S. i n d i c a t e s no s i g n i f i c a n t d i f f e r e n c e at (P < 0.05). Appendix Table 11. Ana l y s i s of var iance f o r Cu a v a i l a b i l i t y of blood meal, feather meal, f i s h meal #1, f i s h meal #2 and meat meal (Experiment 2 ) . Source D.F. Sum of Squares Mean Square 1,2 Treatment R e p l i c a t i o n E r ro r Tota l 4 3 12 19 1 .4833 0.16698 0.23597 1 .8862 0.37082 0.052660 N.S. 0.019664 A s t e r i s k i n d i c a t e s s i g n i f i c a n t , d i f f e r e n c e at (P < 0.05). "N.S. i n d i c a t e s no s i g n i f i c a n t d i f f e r e n c e at (P < 0.05) Appendix Table 12. Ana l y s i s of var iance f o r Zn a v a i l a b i l i t y of blood meal, fea ther meal, f i s h meal #1, f i s h meal #2 and meat meal (Experiment 2 ) . Source D.F. Sum of Squares Mean Square 1,2 Treatment R e p l i c a t i o n E r ro r Total 12 19 1 .0258 0.022440 0.15071 1 .1989 0.25644 0.0074800 N.S. 0.012559 1 A s t e r i s k i n d i c a t e s s i g n i f i c a n t d i f f e r e n c e at (P < 0.05) "N.S. i n d i c a t e s no s i g n i f i c a n t d i f f e r e n c e at (P < 0.05) 

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