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Interrelationship of Dietary Vitamin D3 with Zinc and Iron in Young Turkeys1,2
491
VITAMIN D 3 X K, N A AND MG IN POULT DIETS
stock ration. Am. J. Physiol. 92: 651-655. Meintzer, R. B., and J. Steenbock, 1956. Vitamin D and the magnesium absorption. J. Nutr. 56: 285-294. Richardson, J. A., W. D. Huffines and L. G. Welt, 1963. The effect of coincident hypercalcemia and potassium depletion on the rat kidney. Metabolism, 12: 560-569. Richardson, J. A., and L. G. Welt, 1965. The hypomagnesema of vitamin D administration. Proc. Soc. Exp. Biol. Med. 118: 512-514. Steel, R. G. D., and J. H. Torrie, 1960. Principles and Procedures of Statistics. McGraw-Hill Book Co., Inc., New York, Toronto, London. Wallach, S., and A. C. Carter, 1961. Metabolic and
renal effects of acute hypercalcemia in dogs. Am. J. Physiol. 200: 359-366. Wallach, S., J. V. Bellavia, J. Schorr and P. J. Camponia, 1966. Effect of vitamin D on the tissue distribution and transport of electrolytes 47Ca and 28 Mg. Endocrinology, 79: 773-782. Wasserman, R. H., 1962. Studies on vitamin D 3 and the intestinal absorption of calcium and other ions in the rachitic chick. J. Nutr. 77: 69-80. Worker, N. A., and B. B. Migicovsky, 1961. Effect of vitamin D on the utilization of beryllium, magnesium, calcium, strontium and barium in the chick. J. Nutr. 74: 409-494.
AYHAN AKSOY 3 AND T . W . SULLIVAN
Department of Poultry & Wildlife Sciences, University of Nebraska, Lincoln, Nebraska 68583 (Received for publication June 28, 1976)
ABSTRACT Three experiments were conducted with Large White turkeys to four weeks of age. The interrelationship of zinc and vitamin D 3 was studied in two experiments. Iron and vitamin D 3 were involved in one experiment. One group of ten male and one group of ten female poults were randomly assigned to each treatment within an experiment. All experiments involved a factorial arrangement of two dietary variables, D 3 and either zinc or iron. For example, all possible combinations of four zinc levels; 31, 46, 76 and 106 p.p.m. and three vitamin D 3 levels; 600, 1200, and 3600 I.C. units/kg. were fed in the second zinc experiment. Significant (P < 0.05) weight gain differences occurred among both zinc and D 3 levels in this experiment. Four week body weights were 356, 436, 459 and 444 g., respectively, for Zn levels; and 409, 410 and 452 g., respectively, for D 3 levels. Significant (P < 0.05) interactions occurred between dietary zinc and D 3 levels, and between iron and D 3 levels relative to body weight gain. Vitamin D 3 tended to increase tibia zinc levels in poults receiving higher zinc levels; the opposite occurred with lower levels of the element. Zinc level in feces was decreased with vitamin D 3 . Hemoglobin level was not influenced by D 3 but was increased by iron. POULTRY SCIENCE 56: 491-498, 1977
INTRODUCTION
T
HE literature shows considerable inconsistency and uncertainty as to the effect
of vitamin D on zinc metabolism. This might be due in part to the close relationships
between zinc and calcium, and between calcium and
vitamin
D. Wasserman
reported that duodenal absorption of
(1962) 64
Zn
in the chick was not enhanced by vitamin D3.
But, Martin and Patrick (1961) found
that addition of vitamin D 3 to a deficient diet decreased liver 65 Zn regardless of dietary
1. Published as paper number 5141, Journal Series, Nebraska Agricultural Experiment Station. 2. From a thesis submitted by the senior author in partial fulfillment of the requirements for the Ph.D. degree. 3. Present address: Animal Science Department, College of Agriculture, Ataturk University, Erzurum, Turkey.
Zn or Ca level. The presence of vitamin D 3 increased the
65
Zn level of the tibia when
the diet contained 1.0 percent calcium, and decreased the level in the presence of
1.6
percent calcium in both the zinc-adequate and deficient groups. A positive effect of vitamin D on zinc metabolism in the chicken was
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Interrelationship of Dietary Vitamin D 3 with Zinc and Iron in Young Turkeys 12
492
A. AKSOY AND T. W. SULLIVAN
Very few studies have been reported about the relationship of iron to vitamin D. According to Wasserman (1962), the duodenal absorption of 5 9 Fe was slightly increased by vitamin D 3 in chicks; however, this increase was not statistically significant. Masahura and Migicovsky (1963) reported that vitamin D increased the amount of 59 Fe in blood, liver and bone when the isotope was administered orally to chicks fed a low calcium diet. No effect was obtained when vitamin D was administered intraperitoneal^ with high dietary calcium, however. The purpose of this study was to investigate the effects of vitamin D 3 on the utilization of zinc and iron in starting turkeys. EXPERIMENTAL PROCEDURE Three experiments were conducted with Large White turkeys to four weeks of age.
Ten male and ten female poults were randomly assigned to each dietary treatment in all experiments. The possible interrelationships of zinc and vitamin D 3 was studied in two experiments. Iron and D 3 were involved in one experiment. A factorial arrangement of dietary treatments involving all combinations of three vitamin D 3 levels and four levels of zinc or iron was used in each experiment. All poults were maintained in thermostatically controlled, electrically heated battery brooders with raised wire floors throughout the experimental period. The ex-
TABLE 1.—Composition of the basal diet for zinc experiments' Ingredient
Per kg. diet
Dextrose sugar (cerelose) Isolated soybean protein Solka floe (wood flour) Corn oil Methionine-hydroxy-analog Glycine Ca3(P04)2 NaCl MgS04-7H20 FeC6H507-5H20 CuS04-7H20 KC1 MnS04H20 KI Choline chloride (50%) Myvamix (44 I.U. vit. E/g.) Vitamin A premix (5,000 I.U./g.) Vitamin B premix in sucrose 2 Penicillin-streptomycin, 1:3*
g463.00 370.00 40.00 45.00 5.00 2.00 40.00 5.00 4.80 0.60 0.04 8.00 0.38 0.04 5.00 1.00 3.00 5.00 0.50
'Calculated average composition: Protein, % 30.0 Metabolizable energy, Kcal./kg. 3046.0 Calcium, % 1.57 Phosphorus, % 1.05 2 Vitamin B premix provided the following per kg. of diet: 0.02 mg. vitamin B12,0.30mg. d-biotin, 4 mg. menadione, 8 mg. pyridoxine, 6 mg. folic acid, 10 mg. riboflavin, 30 mg. calcium pantothenate, 15 mg. thiamine HC1, 100 mg. niacin. *Pro-Strep (Merck and Company) contains 44 mg. of penicillin-streptomycin, 1:3 per gram.
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also indicated by the work of Kienholz et al. (1961). Their data showed that hens fed 7.0 p.p.m. of supplemental zinc would accumulate more zinc in the femur when the diet contained a higher level of vitamin D 3 . Worker and Migicovsky (1961) fed a single oral dose of vitamin D 3 to rachitic chicks and 36 hours later administered 65 Zn either orally or by subcutaneous injection. Chicks dosed orally with 65 Zn and with vitamin D had significantly more 65 Zn in the tibia at 24 hours post-administration than did vitamin D-depleted chicks not dosed with the vitamin. The same response was not obtained when 65 Zn was injected subcutaneously. These workers concluded that vitamin D increased the absorption of zinc from the intestinal tract of the chicken. Schisler and Kienholz (1967) reported that vitamin D 3 deficiency significantly reduced bone zinc and increased liver concentration in 48-week old pullets. There was no effect of supplemental zinc in vitamin D deficiency, but in the presence of vitamin D, high dietary zinc (356 p.p.m.) resulted in higher bone concentration of zinc than when low zinc (26 p.p.m.) was fed.
493
VITAMIN D 3 X ZN AND F E IN POULT DIETS
Zinc Experiments. Experiment 1. A purified diet was utilized and the composition of this diet is presented in Table 1. Chemical analysis indicated that this diet contained 31 p.p.m. zinc. Levels of supplemental zinc were 0, 15, 30 and 45 p.p.m.; supplemental levels of vitamin D 3 were 600, 1200 and 3600 I.C. units per kg. of diet. The source of supplemental zinc was Z n S 0 4 . 7 H 2 0 (A.R. grade). Feed and water troughs were coated with a plastic-type (phenolic modified polyester) finish to prevent the ingestion of unknown quantities of zinc. Experiment 2. The same basal diet and supplemental zinc source were used as in experiment 1. Levels of supplemental zinc were 0, 15, 45 and 75 p.p.m.; supplemental vitamin
TABLE 2.—Composition of dried skim-milk-casein basal diet1 Ingredient Dried skim milk Purified casein Dextrose sugar Corn oil Ca3(P04)2 NaCl ZnS04-7H20 MnS04 H 2 0 KI CuS04-5H20 Glycine Arginine • HC1 Choline • HC1 (50%) Vitamin A premix (5,000 I.U.) Myvamix (44 I.U. vit. E/g.) Vitamin premix in sucrose 2 Penicillin-streptomycin , 1:3*
Per kg. diet g600.00 100.00 205.00 50.00 15.00 4.00 0.30 0.30 0.08 0.04 6.00 6.00 4.00 3.00 1.00 5.00 0.5
1
Calculated Average Composition: Protein, % 28.30 Metabolizable energy, Kcal./kg. 2950 Calcium, % 1.30 Phosphorus, % 0.94 2 See footnote 2 of Table 1. *Pro-Strep (Merck and Company) contains 44 mg. of penicillin-streptomycin, 1:3 per gram.
D 3 levels were 600, 1200 and 3600 I.C. units per kg. of diet. Iron Experiment. Experiment 3. In this experiment a dried skim milk basal diet was used. Composition of this diet is presented in Table 2. The chemical analysis showed that the basal diet contained 16 p.p.m. of iron. The same precautions were taken to prevent the ingestion of unknown amounts of iron from the feed and water troughs as described in the zinc experiments. The levels of supplemental iron were 0, 10, 30, and 60 p.p.m.; levels of supplemental vitamin D 3 were 200, 400 and 800 I.C. units per kg. of diet. The source of supplemental iron was granular F e C 6 H 5 0 7 - 5 H 2 0 (iron citrate, U.S.P. grade). Blood samples were obtained by cardiac puncture from four poults in each
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perimental diet and distilled water were supplied ad libitum. Determination of zinc in basal diet, feces and tibia, and iron in basal diet were made by methods described by Hassan and Knudsen (1968). Hemoglobin and packed cell volume were determined by methods previously described by Al-Ubaidi and Sullivan (1963). Calcium and phosphorus levels in all basal diets were maintained somewhat higher than known requirements. It was hoped that moderate excesses of dietary Ca and P would minimize the effect of low D 3 levels on the absorption and metabolism of these elements and overall poult performance. All diets were supplemented with penicillin-streptomycin (1:3) to provide 22 p.p.m. of the antibiotics. Four-week body weight data were subjected to analysis of variance (Steel and Torrie, 1960) and Duncan's (1955) multiple range test. Individual bird data were used in these statistical procedures. Feed efficiency and survival data were not analyzed statistically because true replicates were not involved in the experiments. Tissue and fecal composition data were analyzed by analysis of variance and Duncan's multiple range test.
494
A. AKSOY AND T. W. SULLIVAN
experimental group when the experiment was terminated. RESULTS AND DISCUSSION Experiment 1. Data for body weight gain, efficiency of feed utilization, survival and tibiae and fecal zinc concentrations in poults are presented in Table 3. The D 3 x zinc effect on four week body weight was highly significant (P < 0.01). The body weight gain of poults receiving 31 p.p.m. of zinc was significantly less than the gain of poults receiving
the higher levels. Poults receiving the two higher levels of zinc (61 and 76 p.p.m.) gained significantly more than poults receiving the two lower levels (31 and 46 p.p.m.). Only the lowest level of vitamin D 3 significantly depressed body weight gain. Both survival and feed efficiency improved as the vitamin D 3 levels increased. Vitamin D 3 x zinc effect on zinc content of tibia was not statistically significant. Tibiae zinc levels increased significantly as dietary zinc levels were increased. The higher levels
600
Vitamin D 3 , I.C.units/kg. 3600 1200
Avg.
Zn, p.p.m. Avg. body wt. at 4 weeks, g.'
Feed/gain, 0-4 weeks
31 46 61 76
330 336 435 413
389 467 447 468
348 412 473 522
Avg.
378a
443b
439b
31 46 61 76
1.58 1.62 1.48 1.56 1.56
1.56 1.40 1.40 1.38 1.44
1.42 1.37 1.37 1.36 1.38
1.52 1.46 1.42 1.43
85 70 75 90 80
70 95 85 90 85
95 90 75 90 88
83 85 78 90
85 138 162 205 148
102 122 153 188 141
84 136 162 166 137
Avg.
31 46 61 76
Survival to 4 weeks, %
Avg. 2
Tibia Zn, p.p.m.
31 46 61 76 Avg.
Fecal Zn, p.p.m.3
31 46 61 76
356a 405b 452c 468c
90a 132b 159c 186d
125 136 145 138 292 188 235 224 280 308 269 264 398 381 366 378 Avg. 271 255 248 1 Each individual body weight value is the mean for survivors in two replicate groups of ten birds each. For either vitamin D 3 or Zn levels composite average values followed by the same letters are not significantly different from each other (P < 0.05). 2 Each tibia zinc value is the mean of six determinations (three samples from each of two replicate groups per treatment). 3 Each individual fecal value is the mean of two determinations per treatment.
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TABLE 3.—Body weight, feed efficiency, survival and tibiae and fecal zinc data from experiment 1
495
VITAMIN D 3 X ZN AND F E IN POULT DIETS
of vitamin D 3 tended to decrease the zinc content of tibiae. Martin and Patrick (1961) also reported a decreasing effect of vitamin D 3 on tibia zinc level in the presence of high calcium (1.6%). However, when the diet contained only 1.0 percent calcium, the presence of vitamin D 3 increased tibia zinc levels in chickens. Worker and Migicovsky (1961) using chicks and Schisler and Kienholz (1967) using 48-week old pullets found increased tibia zinc content in the presence of vitamin D 3 . However, in the latter study increased
tibia zinc content occurred only with a high level of dietary zinc (356 p.p.m.), and not with a low level (26 p.p.m.). There were no consistent differences among vitamin D 3 levels with regard to zinc content of feces. However, there was clearly an increase in zinc content of dried feces as the level of dietary zinc increased. Experiment 2. The D 3 x zinc effect on four-week body weight was again highly significant (P < 0.01). Poults receiving 3600 I.C.
Vitamin D 3 , I.C.units/kg.
600
1200
3600
Avg.
31 46 76 106
339 449 416 433
351 430 422 436
379 429 538 404
356a 436b 459b 444b
Avg.
409a
410a
452b
31 46 76 106
1.76 1.56 1.74 1.58 1.66
1.66 1.56 1.64 1.68 1.64
1.56 1.65 1.48 1.68 1.59
1.66 1.59 1.62 1.65
85 100 95 95 94
95 90 90 95 92
85 95 92 95
Avg.
75 95 90 95 89
31 46 76 106
86 157 178 182
87 147 188 184
140 182 197 192
104a 162b 188c 186c
Avg.
151a
152a
178b
Zn, p.p.m. Avg. body wt. at 4 weeks, g.1
Feed/gain, 0-4 weeks
Avg.
31 46 76 106
Survival to 4 weeks, %
Tibia Zn, p.p.m.2
3
148 170 137 138 240 299 201 220 431 392 430 472 715 617 926 602 Avg. 369 343 439 1 Each individual body weight value is the mean for survivors in two replicate groups of ten birds each. For either vitamin D3 or Zn levels, composite average values followed by the same letter are not significantly different from each other (P < 0.05). 2 Each tibia zinc value is the mean of six determinations (three samples from each of two replicate groups) per treatment. 3 Each individual fecal value is the mean of two determinations per treatment. Fecal Zn, p.p.m.
31 46 76 106
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TABLE 4.—Body weight, feed efficiency, survival, tibia and fecal zinc data from experiment 2
496
A. AKSOY AND T. W. SULLIVAN
units of dietary vitamin D 3 were significantly heavier than those receiving 600 and 1200 I.C. units of dietary vitamin D 3 per kg. of diet (Table 4). There was no significant interaction between dietary vitamin D 3 and zinc levels with regard to the tibia zinc content of four-week old poults in this experiment. But, highly significant differences occurred in tibia zinc content due to dietary zinc and vitamin D 3 levels. Tibia zinc data differed somewhat between
the first and second zinc experiments. The differences in dietary zinc levels between the experiments may have influenced these results. Significant interactions between dietary zinc and calcium in the chicken have been reported by other workers also (O'Dell et al., 1958, 1964; Forbes, 1960; Heth et al., 1966). In the present study the dietary calcium was the same in both experiments; however, zinc levels were somewhat higher in the
TABLE 5.—Body weight, feed efficiency, survival, hemoglobin (Hb) and packed-cell volume (p.c.v.) data from experiment 3 400
800
Avg.
Fe, p.p.m. 16 26 46 76 Avg.
311 366 356 349 346a
331 392 414 325 366ab
369 356 393 413 383b
337a 371b 388b 362ab
Feed/gain, 0-4 weeks
16 26 46 76 Avg.
2.58 2.38 2.22 2.36 2.38
2.18 2.38 2.14 2.43 2.28
2.36 2.30 2.24 1.97 2.22
2.37 2.35 2.20 2.25
Survival to 4 weeks, %
16 26 46 76 Avg.
75 80 90 85 83
100 85 95 90 93
80 100 85 95 90
85 88 90 90
Hb, g. per 100 ml. blood 2
16 26 46 76 Avg.
7.62 7.00 8.26 9.18 8.02
7.75 8.16 8.75 9.71 8.59
7.80 8.81 8.15 9.05 8.45
7.72a 7.99ab 8.39b 9.31c
p.c.v., % 3
16 26 46 76 Avg.
37.8 34.1 38.8 40.1 37.7
35.1 38.1 38.6 39.4 37.8
37.2 38.2 37.9 39.0 38.1
36.7 36.8 38.4 39.5
Avg. body wt. at 4 weeks, g.1
' Each individual body weight value is the mean for survivors in two replicate groups of ten birds each. For either vitamin D3 or Fe levels, composite average values followed by the same letter are not significantly different from each other (P < 0.05). 2 Each hemoglobin value is the mean of eight determinations (four samples from each of two replicate groups) per treatment. 3 Each percent p.c.v. value is the mean of eight determinations (four blood samples from each two replicate groups) per treatment.
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Vitamin D 3 , I.C. units/kg. 200
VITAMIN D 3 X ZN AND F E IN POULT DIETS
Experiment 3. Vitamin D 3 x iron effect on body weight gain to four weeks was highly significant (P < 0.01). Birds receiving 800 I.C. units of vitamin D 3 were significantly heavier than those receiving 200 I.C. units of vitamin D 3 (Table 5). The body weight gain of the poults receiving 16 p.p.m. of Fe was significantly less than the gain of the poults receiving 26 and 46 p.p.m. of iron. Vitamin D 3 did not significantly affect hemoglobin level of poults. However, highly significant differences in hemoglobin levels, among dietary iron levels were noted. Hemoglobin level in the blood of birds receiving only 16 p.p.m. of iron (the unsupplemented basal diet) was significantly less than in birds receiving 46 and 76 p.p.m. of dietary iron (Table 5). The hemoglobin value of birds receiving the lowest level of vitamin D 3 was slightly less than values for birds receiving the higher levels of D 3 . No significant interaction was noted between dietary iron and vitamin D 3 levels relative to packed cell volume. Packed cell volume data for either iron or D 3 levels followed trends very similar to those of hemoglobin. Recent research concerning the metabolic functions of vitamin D have been summarized by DeLuca (1971) and by Lawson and Emtage
(1974). The vitamin is currently believed to function in calcium absorption and transport through an active cation-oriented process involving a calcium binding protein a n d / o r a calcium ATPase. These functions are dynamically interrelated and involved in a complex system regulating plasma calcium and phosphate concentrations. Results from the present study agree with the current theory of vitamin D's metabolic functions. In the present study no evidence was obtained indicating a strong direct effect of vitamin D on either zinc or iron. However, it was apparent that vitamin D influenced the growth, feed utilization, and fecal and tissue contents of starting turkeys fed graded levels of both zinc and iron. These effects were apparently indirect and probably were mediated through the vitamin's primary role in calcium and phosphorus metabolism.
REFERENCES Al-Ubaidi, Y. Y., and T. W. Sullivan, 1963. Studies on the requirements and interactions of copper and iron in Broad Breasted Bronze turkeys to 4 weeks of age. Poultry Sci. 42: 718-725. DeLuca, H. F., 1971. Biological systems. The Vitamins. Edited by H. W. Sebrell and R. S. Harris. Academic Press, New York. Vol. 3: 240-247. Duncan, D. B., 1955. Multiple range and multiple F test. Biometrics, 11: 1-42. Forbes, R. M., 1960. Nutritional interactions of zinc and calcium. Fed Proc. 19: 643-647. Hassan, W. A. K., and D. Knudsen, 1968. Methods of Chemical Analysis of Plant, Soil and Water. Univ. of Nebr., College of Agriculture, Soil, Plant and Water Testing Service. Heth, D. A., and W. G. Hoekstra, 1963. Antagonistic effect of calcium on 65Zn absorption in rats. J. Animal Sci. 22: 837. Kienholz, E. W., M. L. Sunde, H. R. Bird and W. G. Hoekstra, 1961. The effect of dietary zinc level on the distribution of injected 65Zn in the eggs, excreta, and body parts of hens. Poultry Sci. 40: 1419-1420. Lawson, D. E. M., and J. S. Emtage, 1974. Molecular action of vitamin D in the chick intestine. Vitamins Hormones, 32: 277-298. Martin, W. G., and H. Patrick, 1961. Radionuclide mineral studies. The effect of feed and dietary zinc,
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second than in the first zinc experiment. This change, because of the close relationship between zinc and calcium, may have affected the results. Schisler and Kienholz (1967) obtained similar results in their experiment with 48-week old pullets. The interaction between dietary vitamin D 3 and zinc occurred only when the diet contained a high level of zinc (356 p.p.m.). Birds receiving the lowest level of vitamin D 3 (600) had the highest level of zinc in dried fecal matter (Table 4). Lower zinc excretion in the presence of higher levels of vitamin D 3 support the generally accepted hypothesis "that vitamin D might increase the retention of certain cations in the animal body."
497
498
A. AKSOY AND T.
calcium and vitamin D 3 on the retention of zinc in chicks. Poultry Sci. 40: 1004-1009. Masahura, T., and B. B. Migicovsky, 1963. Vitamin D and the intestinal absorption of iron and cobalt. J. Nutr. 80: 332-336. O'Dell, B. L., P. M. Newberne and J. E. Savage, 1958. Significance of dietary zinc for the growing chicken. J. Nutr. 65: 503-518. O'Dell, B. L., M. M. Yohe and J. E. Savage, 1964. Zinc availability in the chick as affected by-calcium and ethylendiamine tetraacetate. Poultry Sci. 43: 415-419.
W.
SULLIVAN
Schisler, D. K.,and E. W. Kienholz, 1967. Interactions of dietary zinc and vitamin D in laying hens. Poultry Sci. 46: 918-924. Steel, R. G. D., and J. H. Torrie, 1960. Principles and Procedures of Statistics. McGraw-Hill Book Co., Inc., New York, Toronto, London. Wasserman, R. H., 1962. Studies on vitamin D 3 and the intestinal absorption of calcium and other ions in the rachitic chick. J. Nutr. 77: 69-80. Worker, N. A., and B. B. Migicovsky, 1961. Effect of vitamin D on the utilization of zinc, cadmium and mercury in chick. J. Nutr. 75: 222-224.
D.
H.
BUSHMAN 2 AND G.
AKBAR JOYO
Poultry Research Institute, G.P.O. Box 125, Karachi,
Pakistan
(Received for publication June 29, 1976)
ABSTRACT A total of 288 Single Comb White Leghorn pullets were utilized to determine the practicality of phase feeding and the use of "low" protein diets in Pakistan. Dietary treatments consisted of feeding either a 19, 17 or 15% protein diet throughout 1 year of lay and of a stepwise reduction of the protein levels as follows: 19% to 15%; 17% to 13%; and 15% to 11%. The percentage of protein was reduced by 2% at the end of phases 1 and 2, each phase consisted of four, 28-day periods. Calculated values of lysine, methionine and methionine plus cystine were maintained at 4.5, 2.0 and 3.7% of the protein, respectively, in isocaloric diets containing 2,750 kcal. M.E. per kg. Average weekly high temperatures ranged from approximately 20° C. in the "winter" to 37° C. during the summer. Egg production and egg weight were directly related to protein consumption and it appeared that at least 17.5 g. of protein were required for maximum production in each of the three phases of production. Feed consumption during the warmer periods also appeared to be increased by feeding higher levels of protein regardless of the phase of production. This high protein requirement was thought to be due to low availability of essential amino acids in the local feed ingredients, especially in the fish meal. The problems encountered point out the extreme difficulty of trying to implement phase feeding and the use of low protein diets in developing countries where locally produced feed ingredients of unknown quality must be utilized. POULTRY SCIENCE 56: 498-505,
INTRODUCTION
T
H E use of low protein diets in a phase feeding program or throughout the laying cycle r e p r e s e n t s a potential m e a n s of increasing the efficiency of protein utilization. This
1. This work was conducted as part of a F.A.O.U.N.D.P. project and the results are published with the permission of the project manager. 2. Current address and address for reprints: American Soybean Association, Rio Sena 26-201, Col. Cuauhtemoc, Mexico 5 D.F. Mexico.
1977
is a very important aspect of poultry p r o d u c tion in view of the acute protein shortage being faced by third world countries. T h e r e is considerable evidence to indicate that the h e n ' s daily protein requirement during peak production is between 16 and 18 g. ( B e r g a n d B e a r s e , 1957; Milton and Ingram, 1957; H o c h r e i c h et al., 1973; T o u c h b u r n and N a b e r , 1962; Tonkinson et al., 1968; Nivas and S u n d e , 1967; Aitken et al., 1973). In t h e latter stages of production, the protein requirement may be reduced as evidenced by the successful results obtained in phase feed-
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Problems in Practical Implementation of Phase Feeding in Developing Countries'
VITAMIN D 3 X K, N A AND MG IN POULT DIETS
stock ration. Am. J. Physiol. 92: 651-655. Meintzer, R. B., and J. Steenbock, 1956. Vitamin D and the magnesium absorption. J. Nutr. 56: 285-294. Richardson, J. A., W. D. Huffines and L. G. Welt, 1963. The effect of coincident hypercalcemia and potassium depletion on the rat kidney. Metabolism, 12: 560-569. Richardson, J. A., and L. G. Welt, 1965. The hypomagnesema of vitamin D administration. Proc. Soc. Exp. Biol. Med. 118: 512-514. Steel, R. G. D., and J. H. Torrie, 1960. Principles and Procedures of Statistics. McGraw-Hill Book Co., Inc., New York, Toronto, London. Wallach, S., and A. C. Carter, 1961. Metabolic and
renal effects of acute hypercalcemia in dogs. Am. J. Physiol. 200: 359-366. Wallach, S., J. V. Bellavia, J. Schorr and P. J. Camponia, 1966. Effect of vitamin D on the tissue distribution and transport of electrolytes 47Ca and 28 Mg. Endocrinology, 79: 773-782. Wasserman, R. H., 1962. Studies on vitamin D 3 and the intestinal absorption of calcium and other ions in the rachitic chick. J. Nutr. 77: 69-80. Worker, N. A., and B. B. Migicovsky, 1961. Effect of vitamin D on the utilization of beryllium, magnesium, calcium, strontium and barium in the chick. J. Nutr. 74: 409-494.
AYHAN AKSOY 3 AND T . W . SULLIVAN
Department of Poultry & Wildlife Sciences, University of Nebraska, Lincoln, Nebraska 68583 (Received for publication June 28, 1976)
ABSTRACT Three experiments were conducted with Large White turkeys to four weeks of age. The interrelationship of zinc and vitamin D 3 was studied in two experiments. Iron and vitamin D 3 were involved in one experiment. One group of ten male and one group of ten female poults were randomly assigned to each treatment within an experiment. All experiments involved a factorial arrangement of two dietary variables, D 3 and either zinc or iron. For example, all possible combinations of four zinc levels; 31, 46, 76 and 106 p.p.m. and three vitamin D 3 levels; 600, 1200, and 3600 I.C. units/kg. were fed in the second zinc experiment. Significant (P < 0.05) weight gain differences occurred among both zinc and D 3 levels in this experiment. Four week body weights were 356, 436, 459 and 444 g., respectively, for Zn levels; and 409, 410 and 452 g., respectively, for D 3 levels. Significant (P < 0.05) interactions occurred between dietary zinc and D 3 levels, and between iron and D 3 levels relative to body weight gain. Vitamin D 3 tended to increase tibia zinc levels in poults receiving higher zinc levels; the opposite occurred with lower levels of the element. Zinc level in feces was decreased with vitamin D 3 . Hemoglobin level was not influenced by D 3 but was increased by iron. POULTRY SCIENCE 56: 491-498, 1977
INTRODUCTION
T
HE literature shows considerable inconsistency and uncertainty as to the effect
of vitamin D on zinc metabolism. This might be due in part to the close relationships
between zinc and calcium, and between calcium and
vitamin
D. Wasserman
reported that duodenal absorption of
(1962) 64
Zn
in the chick was not enhanced by vitamin D3.
But, Martin and Patrick (1961) found
that addition of vitamin D 3 to a deficient diet decreased liver 65 Zn regardless of dietary
1. Published as paper number 5141, Journal Series, Nebraska Agricultural Experiment Station. 2. From a thesis submitted by the senior author in partial fulfillment of the requirements for the Ph.D. degree. 3. Present address: Animal Science Department, College of Agriculture, Ataturk University, Erzurum, Turkey.
Zn or Ca level. The presence of vitamin D 3 increased the
65
Zn level of the tibia when
the diet contained 1.0 percent calcium, and decreased the level in the presence of
1.6
percent calcium in both the zinc-adequate and deficient groups. A positive effect of vitamin D on zinc metabolism in the chicken was
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Interrelationship of Dietary Vitamin D 3 with Zinc and Iron in Young Turkeys 12
492
A. AKSOY AND T. W. SULLIVAN
Very few studies have been reported about the relationship of iron to vitamin D. According to Wasserman (1962), the duodenal absorption of 5 9 Fe was slightly increased by vitamin D 3 in chicks; however, this increase was not statistically significant. Masahura and Migicovsky (1963) reported that vitamin D increased the amount of 59 Fe in blood, liver and bone when the isotope was administered orally to chicks fed a low calcium diet. No effect was obtained when vitamin D was administered intraperitoneal^ with high dietary calcium, however. The purpose of this study was to investigate the effects of vitamin D 3 on the utilization of zinc and iron in starting turkeys. EXPERIMENTAL PROCEDURE Three experiments were conducted with Large White turkeys to four weeks of age.
Ten male and ten female poults were randomly assigned to each dietary treatment in all experiments. The possible interrelationships of zinc and vitamin D 3 was studied in two experiments. Iron and D 3 were involved in one experiment. A factorial arrangement of dietary treatments involving all combinations of three vitamin D 3 levels and four levels of zinc or iron was used in each experiment. All poults were maintained in thermostatically controlled, electrically heated battery brooders with raised wire floors throughout the experimental period. The ex-
TABLE 1.—Composition of the basal diet for zinc experiments' Ingredient
Per kg. diet
Dextrose sugar (cerelose) Isolated soybean protein Solka floe (wood flour) Corn oil Methionine-hydroxy-analog Glycine Ca3(P04)2 NaCl MgS04-7H20 FeC6H507-5H20 CuS04-7H20 KC1 MnS04H20 KI Choline chloride (50%) Myvamix (44 I.U. vit. E/g.) Vitamin A premix (5,000 I.U./g.) Vitamin B premix in sucrose 2 Penicillin-streptomycin, 1:3*
g463.00 370.00 40.00 45.00 5.00 2.00 40.00 5.00 4.80 0.60 0.04 8.00 0.38 0.04 5.00 1.00 3.00 5.00 0.50
'Calculated average composition: Protein, % 30.0 Metabolizable energy, Kcal./kg. 3046.0 Calcium, % 1.57 Phosphorus, % 1.05 2 Vitamin B premix provided the following per kg. of diet: 0.02 mg. vitamin B12,0.30mg. d-biotin, 4 mg. menadione, 8 mg. pyridoxine, 6 mg. folic acid, 10 mg. riboflavin, 30 mg. calcium pantothenate, 15 mg. thiamine HC1, 100 mg. niacin. *Pro-Strep (Merck and Company) contains 44 mg. of penicillin-streptomycin, 1:3 per gram.
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also indicated by the work of Kienholz et al. (1961). Their data showed that hens fed 7.0 p.p.m. of supplemental zinc would accumulate more zinc in the femur when the diet contained a higher level of vitamin D 3 . Worker and Migicovsky (1961) fed a single oral dose of vitamin D 3 to rachitic chicks and 36 hours later administered 65 Zn either orally or by subcutaneous injection. Chicks dosed orally with 65 Zn and with vitamin D had significantly more 65 Zn in the tibia at 24 hours post-administration than did vitamin D-depleted chicks not dosed with the vitamin. The same response was not obtained when 65 Zn was injected subcutaneously. These workers concluded that vitamin D increased the absorption of zinc from the intestinal tract of the chicken. Schisler and Kienholz (1967) reported that vitamin D 3 deficiency significantly reduced bone zinc and increased liver concentration in 48-week old pullets. There was no effect of supplemental zinc in vitamin D deficiency, but in the presence of vitamin D, high dietary zinc (356 p.p.m.) resulted in higher bone concentration of zinc than when low zinc (26 p.p.m.) was fed.
493
VITAMIN D 3 X ZN AND F E IN POULT DIETS
Zinc Experiments. Experiment 1. A purified diet was utilized and the composition of this diet is presented in Table 1. Chemical analysis indicated that this diet contained 31 p.p.m. zinc. Levels of supplemental zinc were 0, 15, 30 and 45 p.p.m.; supplemental levels of vitamin D 3 were 600, 1200 and 3600 I.C. units per kg. of diet. The source of supplemental zinc was Z n S 0 4 . 7 H 2 0 (A.R. grade). Feed and water troughs were coated with a plastic-type (phenolic modified polyester) finish to prevent the ingestion of unknown quantities of zinc. Experiment 2. The same basal diet and supplemental zinc source were used as in experiment 1. Levels of supplemental zinc were 0, 15, 45 and 75 p.p.m.; supplemental vitamin
TABLE 2.—Composition of dried skim-milk-casein basal diet1 Ingredient Dried skim milk Purified casein Dextrose sugar Corn oil Ca3(P04)2 NaCl ZnS04-7H20 MnS04 H 2 0 KI CuS04-5H20 Glycine Arginine • HC1 Choline • HC1 (50%) Vitamin A premix (5,000 I.U.) Myvamix (44 I.U. vit. E/g.) Vitamin premix in sucrose 2 Penicillin-streptomycin , 1:3*
Per kg. diet g600.00 100.00 205.00 50.00 15.00 4.00 0.30 0.30 0.08 0.04 6.00 6.00 4.00 3.00 1.00 5.00 0.5
1
Calculated Average Composition: Protein, % 28.30 Metabolizable energy, Kcal./kg. 2950 Calcium, % 1.30 Phosphorus, % 0.94 2 See footnote 2 of Table 1. *Pro-Strep (Merck and Company) contains 44 mg. of penicillin-streptomycin, 1:3 per gram.
D 3 levels were 600, 1200 and 3600 I.C. units per kg. of diet. Iron Experiment. Experiment 3. In this experiment a dried skim milk basal diet was used. Composition of this diet is presented in Table 2. The chemical analysis showed that the basal diet contained 16 p.p.m. of iron. The same precautions were taken to prevent the ingestion of unknown amounts of iron from the feed and water troughs as described in the zinc experiments. The levels of supplemental iron were 0, 10, 30, and 60 p.p.m.; levels of supplemental vitamin D 3 were 200, 400 and 800 I.C. units per kg. of diet. The source of supplemental iron was granular F e C 6 H 5 0 7 - 5 H 2 0 (iron citrate, U.S.P. grade). Blood samples were obtained by cardiac puncture from four poults in each
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perimental diet and distilled water were supplied ad libitum. Determination of zinc in basal diet, feces and tibia, and iron in basal diet were made by methods described by Hassan and Knudsen (1968). Hemoglobin and packed cell volume were determined by methods previously described by Al-Ubaidi and Sullivan (1963). Calcium and phosphorus levels in all basal diets were maintained somewhat higher than known requirements. It was hoped that moderate excesses of dietary Ca and P would minimize the effect of low D 3 levels on the absorption and metabolism of these elements and overall poult performance. All diets were supplemented with penicillin-streptomycin (1:3) to provide 22 p.p.m. of the antibiotics. Four-week body weight data were subjected to analysis of variance (Steel and Torrie, 1960) and Duncan's (1955) multiple range test. Individual bird data were used in these statistical procedures. Feed efficiency and survival data were not analyzed statistically because true replicates were not involved in the experiments. Tissue and fecal composition data were analyzed by analysis of variance and Duncan's multiple range test.
494
A. AKSOY AND T. W. SULLIVAN
experimental group when the experiment was terminated. RESULTS AND DISCUSSION Experiment 1. Data for body weight gain, efficiency of feed utilization, survival and tibiae and fecal zinc concentrations in poults are presented in Table 3. The D 3 x zinc effect on four week body weight was highly significant (P < 0.01). The body weight gain of poults receiving 31 p.p.m. of zinc was significantly less than the gain of poults receiving
the higher levels. Poults receiving the two higher levels of zinc (61 and 76 p.p.m.) gained significantly more than poults receiving the two lower levels (31 and 46 p.p.m.). Only the lowest level of vitamin D 3 significantly depressed body weight gain. Both survival and feed efficiency improved as the vitamin D 3 levels increased. Vitamin D 3 x zinc effect on zinc content of tibia was not statistically significant. Tibiae zinc levels increased significantly as dietary zinc levels were increased. The higher levels
600
Vitamin D 3 , I.C.units/kg. 3600 1200
Avg.
Zn, p.p.m. Avg. body wt. at 4 weeks, g.'
Feed/gain, 0-4 weeks
31 46 61 76
330 336 435 413
389 467 447 468
348 412 473 522
Avg.
378a
443b
439b
31 46 61 76
1.58 1.62 1.48 1.56 1.56
1.56 1.40 1.40 1.38 1.44
1.42 1.37 1.37 1.36 1.38
1.52 1.46 1.42 1.43
85 70 75 90 80
70 95 85 90 85
95 90 75 90 88
83 85 78 90
85 138 162 205 148
102 122 153 188 141
84 136 162 166 137
Avg.
31 46 61 76
Survival to 4 weeks, %
Avg. 2
Tibia Zn, p.p.m.
31 46 61 76 Avg.
Fecal Zn, p.p.m.3
31 46 61 76
356a 405b 452c 468c
90a 132b 159c 186d
125 136 145 138 292 188 235 224 280 308 269 264 398 381 366 378 Avg. 271 255 248 1 Each individual body weight value is the mean for survivors in two replicate groups of ten birds each. For either vitamin D 3 or Zn levels composite average values followed by the same letters are not significantly different from each other (P < 0.05). 2 Each tibia zinc value is the mean of six determinations (three samples from each of two replicate groups per treatment). 3 Each individual fecal value is the mean of two determinations per treatment.
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TABLE 3.—Body weight, feed efficiency, survival and tibiae and fecal zinc data from experiment 1
495
VITAMIN D 3 X ZN AND F E IN POULT DIETS
of vitamin D 3 tended to decrease the zinc content of tibiae. Martin and Patrick (1961) also reported a decreasing effect of vitamin D 3 on tibia zinc level in the presence of high calcium (1.6%). However, when the diet contained only 1.0 percent calcium, the presence of vitamin D 3 increased tibia zinc levels in chickens. Worker and Migicovsky (1961) using chicks and Schisler and Kienholz (1967) using 48-week old pullets found increased tibia zinc content in the presence of vitamin D 3 . However, in the latter study increased
tibia zinc content occurred only with a high level of dietary zinc (356 p.p.m.), and not with a low level (26 p.p.m.). There were no consistent differences among vitamin D 3 levels with regard to zinc content of feces. However, there was clearly an increase in zinc content of dried feces as the level of dietary zinc increased. Experiment 2. The D 3 x zinc effect on four-week body weight was again highly significant (P < 0.01). Poults receiving 3600 I.C.
Vitamin D 3 , I.C.units/kg.
600
1200
3600
Avg.
31 46 76 106
339 449 416 433
351 430 422 436
379 429 538 404
356a 436b 459b 444b
Avg.
409a
410a
452b
31 46 76 106
1.76 1.56 1.74 1.58 1.66
1.66 1.56 1.64 1.68 1.64
1.56 1.65 1.48 1.68 1.59
1.66 1.59 1.62 1.65
85 100 95 95 94
95 90 90 95 92
85 95 92 95
Avg.
75 95 90 95 89
31 46 76 106
86 157 178 182
87 147 188 184
140 182 197 192
104a 162b 188c 186c
Avg.
151a
152a
178b
Zn, p.p.m. Avg. body wt. at 4 weeks, g.1
Feed/gain, 0-4 weeks
Avg.
31 46 76 106
Survival to 4 weeks, %
Tibia Zn, p.p.m.2
3
148 170 137 138 240 299 201 220 431 392 430 472 715 617 926 602 Avg. 369 343 439 1 Each individual body weight value is the mean for survivors in two replicate groups of ten birds each. For either vitamin D3 or Zn levels, composite average values followed by the same letter are not significantly different from each other (P < 0.05). 2 Each tibia zinc value is the mean of six determinations (three samples from each of two replicate groups) per treatment. 3 Each individual fecal value is the mean of two determinations per treatment. Fecal Zn, p.p.m.
31 46 76 106
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TABLE 4.—Body weight, feed efficiency, survival, tibia and fecal zinc data from experiment 2
496
A. AKSOY AND T. W. SULLIVAN
units of dietary vitamin D 3 were significantly heavier than those receiving 600 and 1200 I.C. units of dietary vitamin D 3 per kg. of diet (Table 4). There was no significant interaction between dietary vitamin D 3 and zinc levels with regard to the tibia zinc content of four-week old poults in this experiment. But, highly significant differences occurred in tibia zinc content due to dietary zinc and vitamin D 3 levels. Tibia zinc data differed somewhat between
the first and second zinc experiments. The differences in dietary zinc levels between the experiments may have influenced these results. Significant interactions between dietary zinc and calcium in the chicken have been reported by other workers also (O'Dell et al., 1958, 1964; Forbes, 1960; Heth et al., 1966). In the present study the dietary calcium was the same in both experiments; however, zinc levels were somewhat higher in the
TABLE 5.—Body weight, feed efficiency, survival, hemoglobin (Hb) and packed-cell volume (p.c.v.) data from experiment 3 400
800
Avg.
Fe, p.p.m. 16 26 46 76 Avg.
311 366 356 349 346a
331 392 414 325 366ab
369 356 393 413 383b
337a 371b 388b 362ab
Feed/gain, 0-4 weeks
16 26 46 76 Avg.
2.58 2.38 2.22 2.36 2.38
2.18 2.38 2.14 2.43 2.28
2.36 2.30 2.24 1.97 2.22
2.37 2.35 2.20 2.25
Survival to 4 weeks, %
16 26 46 76 Avg.
75 80 90 85 83
100 85 95 90 93
80 100 85 95 90
85 88 90 90
Hb, g. per 100 ml. blood 2
16 26 46 76 Avg.
7.62 7.00 8.26 9.18 8.02
7.75 8.16 8.75 9.71 8.59
7.80 8.81 8.15 9.05 8.45
7.72a 7.99ab 8.39b 9.31c
p.c.v., % 3
16 26 46 76 Avg.
37.8 34.1 38.8 40.1 37.7
35.1 38.1 38.6 39.4 37.8
37.2 38.2 37.9 39.0 38.1
36.7 36.8 38.4 39.5
Avg. body wt. at 4 weeks, g.1
' Each individual body weight value is the mean for survivors in two replicate groups of ten birds each. For either vitamin D3 or Fe levels, composite average values followed by the same letter are not significantly different from each other (P < 0.05). 2 Each hemoglobin value is the mean of eight determinations (four samples from each of two replicate groups) per treatment. 3 Each percent p.c.v. value is the mean of eight determinations (four blood samples from each two replicate groups) per treatment.
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Vitamin D 3 , I.C. units/kg. 200
VITAMIN D 3 X ZN AND F E IN POULT DIETS
Experiment 3. Vitamin D 3 x iron effect on body weight gain to four weeks was highly significant (P < 0.01). Birds receiving 800 I.C. units of vitamin D 3 were significantly heavier than those receiving 200 I.C. units of vitamin D 3 (Table 5). The body weight gain of the poults receiving 16 p.p.m. of Fe was significantly less than the gain of the poults receiving 26 and 46 p.p.m. of iron. Vitamin D 3 did not significantly affect hemoglobin level of poults. However, highly significant differences in hemoglobin levels, among dietary iron levels were noted. Hemoglobin level in the blood of birds receiving only 16 p.p.m. of iron (the unsupplemented basal diet) was significantly less than in birds receiving 46 and 76 p.p.m. of dietary iron (Table 5). The hemoglobin value of birds receiving the lowest level of vitamin D 3 was slightly less than values for birds receiving the higher levels of D 3 . No significant interaction was noted between dietary iron and vitamin D 3 levels relative to packed cell volume. Packed cell volume data for either iron or D 3 levels followed trends very similar to those of hemoglobin. Recent research concerning the metabolic functions of vitamin D have been summarized by DeLuca (1971) and by Lawson and Emtage
(1974). The vitamin is currently believed to function in calcium absorption and transport through an active cation-oriented process involving a calcium binding protein a n d / o r a calcium ATPase. These functions are dynamically interrelated and involved in a complex system regulating plasma calcium and phosphate concentrations. Results from the present study agree with the current theory of vitamin D's metabolic functions. In the present study no evidence was obtained indicating a strong direct effect of vitamin D on either zinc or iron. However, it was apparent that vitamin D influenced the growth, feed utilization, and fecal and tissue contents of starting turkeys fed graded levels of both zinc and iron. These effects were apparently indirect and probably were mediated through the vitamin's primary role in calcium and phosphorus metabolism.
REFERENCES Al-Ubaidi, Y. Y., and T. W. Sullivan, 1963. Studies on the requirements and interactions of copper and iron in Broad Breasted Bronze turkeys to 4 weeks of age. Poultry Sci. 42: 718-725. DeLuca, H. F., 1971. Biological systems. The Vitamins. Edited by H. W. Sebrell and R. S. Harris. Academic Press, New York. Vol. 3: 240-247. Duncan, D. B., 1955. Multiple range and multiple F test. Biometrics, 11: 1-42. Forbes, R. M., 1960. Nutritional interactions of zinc and calcium. Fed Proc. 19: 643-647. Hassan, W. A. K., and D. Knudsen, 1968. Methods of Chemical Analysis of Plant, Soil and Water. Univ. of Nebr., College of Agriculture, Soil, Plant and Water Testing Service. Heth, D. A., and W. G. Hoekstra, 1963. Antagonistic effect of calcium on 65Zn absorption in rats. J. Animal Sci. 22: 837. Kienholz, E. W., M. L. Sunde, H. R. Bird and W. G. Hoekstra, 1961. The effect of dietary zinc level on the distribution of injected 65Zn in the eggs, excreta, and body parts of hens. Poultry Sci. 40: 1419-1420. Lawson, D. E. M., and J. S. Emtage, 1974. Molecular action of vitamin D in the chick intestine. Vitamins Hormones, 32: 277-298. Martin, W. G., and H. Patrick, 1961. Radionuclide mineral studies. The effect of feed and dietary zinc,
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second than in the first zinc experiment. This change, because of the close relationship between zinc and calcium, may have affected the results. Schisler and Kienholz (1967) obtained similar results in their experiment with 48-week old pullets. The interaction between dietary vitamin D 3 and zinc occurred only when the diet contained a high level of zinc (356 p.p.m.). Birds receiving the lowest level of vitamin D 3 (600) had the highest level of zinc in dried fecal matter (Table 4). Lower zinc excretion in the presence of higher levels of vitamin D 3 support the generally accepted hypothesis "that vitamin D might increase the retention of certain cations in the animal body."
497
498
A. AKSOY AND T.
calcium and vitamin D 3 on the retention of zinc in chicks. Poultry Sci. 40: 1004-1009. Masahura, T., and B. B. Migicovsky, 1963. Vitamin D and the intestinal absorption of iron and cobalt. J. Nutr. 80: 332-336. O'Dell, B. L., P. M. Newberne and J. E. Savage, 1958. Significance of dietary zinc for the growing chicken. J. Nutr. 65: 503-518. O'Dell, B. L., M. M. Yohe and J. E. Savage, 1964. Zinc availability in the chick as affected by-calcium and ethylendiamine tetraacetate. Poultry Sci. 43: 415-419.
W.
SULLIVAN
Schisler, D. K.,and E. W. Kienholz, 1967. Interactions of dietary zinc and vitamin D in laying hens. Poultry Sci. 46: 918-924. Steel, R. G. D., and J. H. Torrie, 1960. Principles and Procedures of Statistics. McGraw-Hill Book Co., Inc., New York, Toronto, London. Wasserman, R. H., 1962. Studies on vitamin D 3 and the intestinal absorption of calcium and other ions in the rachitic chick. J. Nutr. 77: 69-80. Worker, N. A., and B. B. Migicovsky, 1961. Effect of vitamin D on the utilization of zinc, cadmium and mercury in chick. J. Nutr. 75: 222-224.
D.
H.
BUSHMAN 2 AND G.
AKBAR JOYO
Poultry Research Institute, G.P.O. Box 125, Karachi,
Pakistan
(Received for publication June 29, 1976)
ABSTRACT A total of 288 Single Comb White Leghorn pullets were utilized to determine the practicality of phase feeding and the use of "low" protein diets in Pakistan. Dietary treatments consisted of feeding either a 19, 17 or 15% protein diet throughout 1 year of lay and of a stepwise reduction of the protein levels as follows: 19% to 15%; 17% to 13%; and 15% to 11%. The percentage of protein was reduced by 2% at the end of phases 1 and 2, each phase consisted of four, 28-day periods. Calculated values of lysine, methionine and methionine plus cystine were maintained at 4.5, 2.0 and 3.7% of the protein, respectively, in isocaloric diets containing 2,750 kcal. M.E. per kg. Average weekly high temperatures ranged from approximately 20° C. in the "winter" to 37° C. during the summer. Egg production and egg weight were directly related to protein consumption and it appeared that at least 17.5 g. of protein were required for maximum production in each of the three phases of production. Feed consumption during the warmer periods also appeared to be increased by feeding higher levels of protein regardless of the phase of production. This high protein requirement was thought to be due to low availability of essential amino acids in the local feed ingredients, especially in the fish meal. The problems encountered point out the extreme difficulty of trying to implement phase feeding and the use of low protein diets in developing countries where locally produced feed ingredients of unknown quality must be utilized. POULTRY SCIENCE 56: 498-505,
INTRODUCTION
T
H E use of low protein diets in a phase feeding program or throughout the laying cycle r e p r e s e n t s a potential m e a n s of increasing the efficiency of protein utilization. This
1. This work was conducted as part of a F.A.O.U.N.D.P. project and the results are published with the permission of the project manager. 2. Current address and address for reprints: American Soybean Association, Rio Sena 26-201, Col. Cuauhtemoc, Mexico 5 D.F. Mexico.
1977
is a very important aspect of poultry p r o d u c tion in view of the acute protein shortage being faced by third world countries. T h e r e is considerable evidence to indicate that the h e n ' s daily protein requirement during peak production is between 16 and 18 g. ( B e r g a n d B e a r s e , 1957; Milton and Ingram, 1957; H o c h r e i c h et al., 1973; T o u c h b u r n and N a b e r , 1962; Tonkinson et al., 1968; Nivas and S u n d e , 1967; Aitken et al., 1973). In t h e latter stages of production, the protein requirement may be reduced as evidenced by the successful results obtained in phase feed-
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Problems in Practical Implementation of Phase Feeding in Developing Countries'