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Reinvestigation of the Vitamin A Requirements of Laying and Breeding Hens and Their Progeny
FEATHER MEAL PROCESSING AND SUPPLEMENTATION
Poultry Sci. 36: 1381-1382. Routh, J. I., 1942. Nutritional studies on powdered chicken feathers. J. Nutr. 24: 399-404. Sullivan, T. W., and E. L. Stephenson, 1957. Effect of processing methods on the utilization of hydrolyzed poultry feathers by growing chicks. Poultry Sci. 36: 361-365. Wilder, O. H. M., P. C. Ostby and B. R. Gregory, 1955. The use of chicken feather meal in feeds. Poultry Sci. 34: 518-524. Wisman, E. L., C. E. Holmes and R. W. Engel, 1958. Utilization of poultry by-products in poultry rations. Poultry Sci. 37: 834-838.
Reinvestigation of the Vitamin A Requirements of Laying and Breeding Hens and Their Progeny F. W. HILL, 1 M. L. SCOTT, L. C. NORRIS AND G. F. HETJSER2 Department of Poultry Husbandry, Cornell University, Ithaca, N. Y. (Received for publication November 4, 1960)
O
N THE basis of the available evidence from quantitative studies, the Committee on Animal Nutrition of the National Research Council (1954) has estimated the vitamin A requirements to be 1,200 U.S.P. units per pound of diet for growing chickens, and 2,000 U.S.P. units per pound of diet for laying and breeding hens. The results of individual studies on which these estimates are based have varied widely. The sources of vitamin A activity used in the various studies on requirement were fish oils, alfalfa meals and/or yellow corn, all of which were unstable to some degree, especially after mixture in the experimental diets. Even with the precaution of frequent diet mixing, the instability of the vitamin or its precursors introduced considerable uncertainty into the quantitative estimates of requirement.
1 Present address: Department of Poultry Husbandry, University of California, Davis, California. 2 Present address: 608 Hillside Drive, Lakeland, Florida.
Recently, efforts in industry have been directed toward the development of vitamin A preparations which are highly stable in diet mixtures and under adverse conditions of storage. Reinvestigation of the vitamin A requirements of hens and their progeny using one of these "stabilized" vitamin A preparations was considered appropriate because of the uncertainties concerned in earlier work and the wide variations in estimates derived from the different experiments. One of the abnormalities associated with vitamin A deficiency in hens is the production of eggs with a high incidence of blood spotting of the yolk (Bearse et al., 1960). This egg defect normally occurs in low incidence among commercial strains of chickens, but is known to be an inherited trait (Lerner et al., 1951). The studies to be described were undertaken to investigate the requirement of hens and their progeny for vitamin A, using a stabilized source of vitamin A and strains of chickens differing widely in their
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Mangold, E., and J. Dubski, 1930. The digestion of keratin, especially the horny material of birds' feathers, by fowls and mammals. Wiss. Arch. Landw., Abt. B, Tierernahr. Tierzucht 4: 200221. McKerns, K. W., and E. Rittersporn, 1958. The nutritional significance of processed keratin in poultry feeding. Poultry Sci. 37: 433-436. Naber, E. C , and C. L. Morgan, 1956. Feather meal and poultry meat scrap in chick starting rations. Poultry Sci. 35: 888-895. Rosenberg, H. R., J. T. Baldini and C. I. Tollefson, 1957. Histidine requirement of the growing chick.
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TABLE 1.—Composition of basal vitamin A deficient diet for laying hens
%
Ground white corn Ground wheat Soybean oil meal (50% protein) Fish solubles Dried brewers' yeast Dried whole whey Dicalcium phosphate Limestone Salt (iodized) Manganese sulfate Vitamin mixture
49.5 20.0 18.5 1.0 2.0 2.0 2.5 4.0 0.5 0.025 0.15 100.175
Vitamin mixture supplied, mg. per kg. of diet: 22 niacin, 11 calcium pantothenate, 4.4 riboflavin, 3.3 pyridoxine hydrochloride, 2.2 thiamine chloride, 0.66 folacin, 1.1 menadione, 0.11 biotin, 750 I.C.U. vitamin D3, in a sucrose carrier. Added separately from this mixture were vitamin B12, 8.8 meg., and 11 mg. alpha-tocopheryl acetate.
propensity to produce blood spotting in eggs. PROCEDURE AND RESULTS The vitamin A requirement of laying and breeding hens. Two experiments were conducted in successive years to determine the vitamin A requirements of Single Comb White Leghorn hens. The basal diet used in both experiments had the composition shown in Table 1. It was typical of rations used in practice excepting that it contained white corn as the major cereal base, lacked any source of carotenoid pigments, and was supplemented with a mixture of vitamins to insure against deficiency of any known factor other than vitamin A. The only component of the basal diet which contained any appreciable amount of vitamin A was the fish solubles; on the basis of chemical analysis, it contributed less than 100 USP units of vitamin A per pound of diet. The vitamin A source used in the experimental diets was a commerciallyprepared product based on synthetic vitamin A palmitate in a beaded gelatin
In the first experiment, the experimental diets contained 800; 1,200; 1,600; 2,000; and 5,000 USP units of vitamin A per pound, supplied by the synthetic vitamin A palmitate supplement. In addition, to determine whether an additional antioxidant would be of benefit, the combination of 1,200 USP units of vitamin A plus .0125% diphenyl p-phenylene diamine (DPPD) was used. Each diet was fed to two duplicate lots of 20 pullets each. The strain of White Leghorns chosen for this experiment was characterized by generally superior performance in egg production, viability, egg size and other production characteristics as shown by its record in the New York State Random Sample Test (1954-1955), and
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Component
carrier containing an antioxidant mixture to further enhance stability. The preparations used in the two respective experiments contained 360,000 and 371,000 USP units per gram by spectrophotometric analysis (Association of Official Agricultural Chemists, 1955). Each experimental lot contained 20 Single Comb White Leghorn pullets 6-7 months old at the beginning of each experiment. The lots were housed in pens approximately 6X12 feet in size with raised wire screen floors. The pens were provided with thermostatically controlled, steam-heated radiators to maintain the temperature above a minimum of 50° F. Each experiment began at the on-set of egg production, which was approximately by November 1 and continued for eleven 28-day periods. The experimental diet, water, flaked oyster shell, and granite grit were supplied to each lot ad libitum. Day length was maintained at 14 hours by providing incandescent electric light when necessary. In order to produce fertile eggs, two White Leghorn cockerels were used in each pen, and they were shifted among the pens at weekly intervals, in rotation.
VITAMIN A REQUIREMENTS OF HENS
TABLE 2.—The effect of vitamin A level on egg production (Experiment 1) Average rate of egg production 1 Vitamin A level USP units/lb. 800
Periods 1-5
Periods 6-8
%
%
75 73 72 73
56 49
76 74
61 36
57 54
74 70
48 62 43
56 52 58
72
33
51
76 5,000
27 39
59 43
79 73
46
45
71 2,000
48 44
43 47
74 67
38
53
75 1,600
34 42 48
73 1,200+DPPD
%
48 47 74
1,200
Periods 9-11
53 50 46
55
48
1 Hen-day basis. Underlined figures are averages of the data from individual lots shown to the left.
TABLE 3.—The ejfect of vitamin A level on egg production (Experiment 2)
Vitamin A level
Periods 1-5
USP units/lb. 800 1,200 2,000 3,600 5,000 10,000 1
Periods 6-8
Periods 9-11
%
%
%
70 76 79 70 76 74
43 68 63 51 54 64
22 44 42 41 52 43
Hen-day basis.
blood spot incidence, body weight, mortality, vitamin A content of egg yolk, vitamin A content of hen liver at the conclusion of the experiment, and the effect of maternal vitamin A nutrition on the requirements of progeny for vitamin A. Data from the first experiment (Table 2) show the effect of vitamin A level on egg production rate. During the first five 28-day periods of the experiment, little difference in egg production was apparent between the various treatments. In the next three periods, and also in the final three periods, egg production rate was markedly lower in the groups receiving diets containing 800 units and 1,200 units plus DPPD. The performance of the lots receiving 1,200 units without the added antioxidant was apparently as good as the lots receiving any higher level of vitamin A. These data are interpreted to indicate that 1,200 units per pound was a marginal level of vitamin A, and that the minimum requirement for egg production was satisfied by 1,600 USP units per pound. This was confirmed in the second experiment, the results of which are shown in Table 3. During the first five 28-day periods of this experiment, little difference in egg production rate was noted. In the next six periods, egg production was
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by one pronounced defect. This defect was the production of a much higher than normal proportion of eggs with blood spots. This characteristic was sought in order to make a critical evaluation of the possible relationship between vitamin A nutrition and the blood spot problem. In the second experiment another strain of White Leghorns, also possessing generally superior characteristics in production traits but showing the normal moderate incidence of blood spots, was used. Because of limitations of space, it was necessary to use single lots of 20 pullets each fed diets containing 800; 1,200; 2,000; 3,600; 5,000; and 10,000 USP units of vitamin A per pound of diet. In both experiments, observations were made on egg production, hatchability,
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H I L L , M.
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T A B L E 4.—Body weight and mortality Experiment 1 Level of vitamin A
Experiment 2
Average weight Average weight ——————— Mor- ——— ——— MorInitial Final tality Initial Final tality gm. 1,884 1,889 1,880 1,879 1,876
gm. 1,869 1,966 1,873 1,992 2,055
— —
2,009
1,873
— —
% 28 19 11 13 19 0
gm. 1,856 1,807
gm. 1,908 1,968
— — 1,833
— — 2,033
1,831 1,865 1,827
1,991 2,099 1,975
% 0 3
10 .1
19 0
markedly reduced in the lot receiving 800 USP units per pound, but was supported at a normal rate by 1,200 units and was not improved by feeding higher levels of vitamin A. I t should be mentioned here t h a t the performance of the stock used in the second experiment was not entirely satisfactory, due evidently to the influence of a respiratory disease during the growing period. This resulted in an unusually high incidence of unproductive pullets which were easily identified in the early stages of the experiment through their trapnest records. These pullets were removed from the experiment, so the production rates summarized in Table 3 represent the performance of the remaining pullets. The number of functional pullets ranged from 12 to 19, and was approximately 15 in most of the lots. D a t a on body weight and mortality in the two experiments are summarized _in Table 4. In both experiments, body weight was not maintained as well at the 800 unit level as at higher levels of vitamin A supplementation. I t appeared in the first experiment t h a t the 1,200 unit level was marginal, and t h a t satisfactory weight maintenance required approximately 1,600 units of vitamin A per pound. Excepting possibly for the relatively high mortality at the lowest level of vitamin A in experiment 1, the mortality pattern was not clearly indicative of
HEUSER
vitamin A nutrition. None of the hens which died showed any gross evidence of vitamin A deficiency, such as xerophthalmia or kidney damage. The incidence of blood spots in the eggs in both experiments is shown in Table 5. This was determined in experiment 1 by breaking out all eggs produced on three successive days in each period. Blood spots were classified as large (one-eighth inch or more in diameter) or small; eggs with profuse evidence of blood were included in the category of large spots. During the first five periods in experiment 1, the incidence of blood spots showed no relationship to vitamin A nutrition. The incidence was high, as expected from previous experience with this strain. In the last five periods of the experiment the incidence was generally higher, and was highest in the groups receiving 800 and 1,200 units of vitamin A per pound. The lowest incidence was shown by the lots receiving 1,600 units per pound, and no further improvement was achieved by feeding higher levels. The increased incidence of blood spots in eggs from hens suffering from vitamin A deficiency was confirmed in the second experiment. Observations in this experiment were restricted to three sampling times in
TABLE 5.—Effect of vitamin A level on incidence of blood spots in eggs of two different strains of White Leghorn hens Incidence of blood spots1 Experiment 1 Level of vitamin A
USP units/lb. 800 1,200 1,200+DPPD 1,600 2,000 3,600 5,000 10,000
Experiment 2
Periods 6-11 No. eggs Periods 6,7,8 No. eggs examexamTotal Large ined Total Large ined
% % 38 34 28 22 28
19 13 It 9 7
— — 24 9 — —
626 677 669 703 627
— —
728
% 12 4
% 7 1
— — — — 2 0 6 6 1
1 4 0
91 73
— — 97 81 82 113
1 Strain of hens used in Experiment 1 had a high genetic propensity for blood spots; those used in Experiment 2 did not.
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Units/lb. 800 1,200 1,200+DPPD 1,600 2,000 3,600 5,000 10,000
data
C. N O R M S AND G. F.
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VITAMIN A REQUIREMENTS OF HENS
TABLE 6.—Effect of dietary vitamin A on the vitamin A content of egg yolk Dietary level USP units/lb. 800 1,200 1,200+DPPD 1,600 2,000 3,600 5,000 10,000
Vitamin A per gram yolk Exp. 1
Exp. 2
USP units 0.9 3.7 2.9 4.2 6.3
USP units 0.7 8.9
—
12.7
—
— —
6.9 10.6 12.5 16.3
Experiment 1 data are averages for four determinations made in periods 8-11. Experiment 2 data are averages for three determinations made in periods 3, 5 and 6.
TABLE 7.—The effect of vitamin A level on hatchability Vitamin A level USP units/lb. 800
1,200
1,200+DPPD
Hatchability of fertile eggs Experiment 1
Experiment 2
%
%
84 92 88
66
84
78
83 84 90 83 86
1,600
2,000
79 74
76
73 85 79
71
3,600 5,000
84 83 84
10,000
70
71 77
Experiment 1: average of 3 hatches, in periods 5, 7 and 8. Experiment 2: average of 10 hatches, in periods 3-11.
A. In general, the vitamin A content of egg yolk tended to increase as the dietary level of vitamin A increased. Agreement between the two experiments was generally good, excepting at the 1,200 unit level which, as indicated by other performance characteristics, appeared to be marginal and subject to considerable variation. The hatchability of eggs was unrelated to vitamin A nutrition, as shown in Table 7. Hatchability was maintained at satisfactory levels in experiment 1; performance was less satisfactory in experiment 2, due possibly to the same factors which influenced egg production performance as discussed above. Fertility was
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periods 6, 7 and 8. Blood spots were reduced to an essentially normal level by feeding 1,200 units per pound, and no consistent further reduction was produced by feeding higher levels of vitamin A. These data support the conclusion that the requirement for vitamin A to minimize the incidence of blood spots is approximately the same as the level required for maximum egg production and maintenance of body weight. These data also indicate that the high incidence of blood spotting characteristic of the strain used in experiment 1 was not due to an unusually high requirement for vitamin A, but must have had some other physiological basis. The relationship between the vitamin A content of the diet and the vitamin A content of egg yolk is summarized in Table 6. Observations in experiment 1 were based on egg samples taken in each of the four final 28-day periods; in experiment 2, egg samples were taken in periods 3, 5 and 6. Determinations of vitamin A content were made on extracts of saponified egg yolk by spectrophotometric analysis. Confirmatory values were obtained by the antimony trichloride method for determination of vitamin
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TABLE 8.—Composition of basal vitamin Adeficient chick diet Components
42.6 10.0 35.0 2.5 2.5 2.5 2.0 1.5 0.25 1.0 0.2 100.05
Vitamins and minerals added, per kg. diet: 3 mg. thiamine chloride, 5 mg. riboflavin, 10 mg. calcium pantothenate, 5 mg. pyridoxine hydrochloride, 26 mg. niacin, 1 mg. folacin, 0.1 mg. biotin, 0.01 mg. vitamin Bi 2 , 1 mg. menadione, 1 gm. choline chloride, 400 I.C.U. vitamin D 3 , 20 I.U. alpha-tocopheryl acetate, 3.5 gm. K 2 HP0 4 , 1.2 gm. MgS0 4 , 0.15 gm. MnSO 4 ,0.28gm. FeS0 4 -7H 2 0, 7.8mg.CuSO 4 -5H 2 0, 1.3 mg. Nal.
satisfactory throughout both experiments. The vitamin A requirement of chicks. Two experiments were conducted with the progeny of the hens of experiment 1 to determine the relationship between maternal vitamin A nutrition and the requirement of the chick for vitamin A. The composition of the basal chick diet is shown in Table 8; the same source of supplementary vitamin A was used in the chick experiments as had been employed in the hen experiments. Data for the first experiment are shown in Table 9. Lots of 19-20 male chicks from the progeny of each of the maternal treatments, were fed chick diets containing 200, 600, or 1,200 USP units of vitamin A per pound of diet. All the chicks fed 200 units of vitamin A per pound of diet showed poor growth, excepting the progeny of the hens fed 5,000 units per pound. Increasing the level of vitamin A in the maternal diet from 800 to 2,000 USP units per pound did not materially improve the performance of chicks fed the deficient diet. In
TABLE 9.—Effect of vitamin A in maternal and chick diets on growth of progeny (Experiment C 1) Level of vitamin A Maternal diet
Chick diet
USP units/lb. 800 200 1,200 200 1,200+DPPD 200 1,600 200 2,000 200 5,000 200
USP units/lb.
Response of c:hicks Avg. Ataxia weight inci- Mor4 weeks dence tality gm.
%
%
226 233 270 242 258 320
75 56 60 55 80 10
40 69 45 40 20 0
800 1,200 1,200+DPPD 1,600 2,000 5,000
600 600 600 600 600 600
319 322 332 324 322 346
0 0 0 0 0 0
5 0 5 0 0 0
800 1,200 1,200+DPPD 1,600 2,000 5,000
1.200 1,200 1,200 1,200 1,200 1,200
322 333 345 328 327 342
0 0 0 0 0 0
0 0 0 0 5 0
Data show averages of single lots of 19-20 male chicks each, except progeny of 1,200 USP units maternal diet which had 15-16 chicks per lot.
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Glucose (Cerelose) Ground wheat Soybean oil meal (50% protein) Ether-extracted fish meal Dried brewer's yeast Dried whole whey Dicalcium phosphate Limestone Salt Hydrogenated shortening (Hydora) DL-methionine
%
addition to poor growth, the deficient chicks showed high mortality and a high incidence of an ataxia similar to that described by Adamstone (1947). Increasing the level of vitamin A in the chick diet to 600 or 1,200 USP units per pound of diet resulted in normal growth and survival of all progeny, and freedom from ataxia. A tendency was evident for the progeny of hens fed 5,000 units per pound of diet to grow somewhat more rapidly than the progeny of the other maternal groups. It was considered possible that the ataxia observed in the chicks fed 200 units per pound of diet in the first chick experiment might have been due in part to marginal vitamin E nutrition or to other influences preventable by the addition of an antioxidant. Therefore, the experiment
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VITAMIN A REQUIREMENTS OF HENS
TABLE 10.—Effect of vitamin A in maternal and chick diets on growth of progeny (Experiment C 2) Level of vitamin A Maternal diet
Chick diet1
USP units/lb. 800 200 1,200 200 1,200+DPPD 200 1,600 200 2,000 200 5,000 200
USP units/lb.
Respor ise of chicks2 Avg. Ataxia Morweight mci- tality 4 weeks dence gm.
%
%
282 248 290 314 275 334
44 50 55 60 50 0
19 35 5 15 0 0
800 1,200 1,200+DPPD 1,600 2,000 5,000
400 400 400 400 400 400
252 293 296 322 306 350
25 0 0 0 0 0
19 5 0 5 5 0
800 1,200 1,200+DPPD 1,600 2,000 5,000
600 600 600 600 600 600
316 305 310 312 324 350
0 0 0 0 0 0
13 0 0 0 0 0
1 Chick diet supplemented with antioxidant (0.01% DPPD) and 9 I.U. each of d-alpha tocopheryl acetate and d-alpha-tocopherol per pound of diet. 2 Data show averages of single lots of 20 male chicks each, except progeny of 800 and 5,000 USP units maternal lots which had 16 chicks each.
TABLE 11.—Effect of vitamin A in maternal and chick diets on growth of progeny (Experiments C3 and C4) Average weight at 4 weeks Vitamin A in maternal diet
Vitamin A in chick diet, USP units/lb. 600
1,200
5,000
USP units/lb. 800 1,200 2,000 3,600 5,000 10,000
gm. 170' 302> 269' 282' 295' 2871
gm. 2681 346 305 319 314 323
gm. 257 324 319 302 320 311
gm. 282 339 312 315 319 320
288
321
315
325
Average (1,200-10,000)
Average (6005,000)
269 336 314 312 320 320
i Ataxia observed. D a t a are averages of 2 experiments, each using 9-12 male chicks per treatment.
per pound, normal growth was obtained in all progeny, regardless of hen treatments. Also included in this experiment, but not shown in Table 10, were groups fed 200 and 400 USP units of vitamin A per pound without the added antioxidant and/or vitamin E. The incidence of ataxia and the growth rate of these chicks were no different from those fed the vitamin E plus the antioxidant. Therefore, it was concluded that the ataxia which was observed in these two experiments was due entirely to vitamin A deficiency. As was observed in the first experiment, the progeny of hens fed 5,000 USP units of vitamin A per pound tended to grow more rapidly than the progeny of the other maternal lots. A systematic study of the influence of maternal vitamin A nutrition on the requirement of progeny for vitamin A was continued in the second year of work. The range of maternal vitamin A levels was extended to 10,000 units per pound to determine whether any consistent advantage in the performance of progeny could be achieved by feeding very high maternal levels as suggested by the results in the previous year. Two experiments were conducted in which the progeny of each of
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was repeated using levels of 200, 400 and 600 USP units of vitamin A per pound of chick diet in the presence of an added antioxidant (.01% DPPD) and 9 I.U. each of d-alpha-tocopheryl-acetate and d-alpha-tocopherol per pound of diet. The results of this experiment are shown in Table 10. With the lowest level of vitamin A in the chick diet, ataxia was present in all chicks excepting the progeny of hens fed 5,000 USP units per pound. When the chick diet contained 400 units per pound, ataxia and poor growth were observed only in the progeny of hens fed the lowest vitamin A level (800 units) and growth was essentially normal in all other lots. When the chicks were fed 600 USP units
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TABLE 12.—Effect of dietary vitamin A on the vitamin A content of the liver of the hen Vitamin A level of layer diet
Experiment 1 Experiment 2 USP units/gm. USP units/gm. 2 16 18 17 2
70 21
—
1,540
—
— —
9 330 600 3,100
1
Hen data obtained at conclusion of each experiment, using 6 hens per treatment in experiment 1 and 3 hens per treatment in experiment 2. All hens contained approximately 500 USP units of vitamin A per gram of liver at the start of the experiments. 2 No detectable vitamin A.
the maternal groups were fed chick diets containing 200, 600, 1,200 and 5,000 USP units of vitamin A per pound. The two experiments gave results in close agreement, so the data have been combined for presentation in Table 11. Growth of the progeny of hens fed 800 USP units per pound of ration was sub-normal, regardless of the level of vitamin A supplied in the chick ration. This was in contrast to the results of the previous year, in which essentially normal growth was obtained when sufficient vitamin A was fed to chicks from deficient hens. The data in Table 11 also show that 200 USP units per pound in the chick ration produced sub-normal growth in all progeny, regardless of the maternal level of vitamin A. Ataxia was observed in all of the chicks fed the deficient chick diet. The progeny of all hens receiving 1,200 units of vitamin A or more per pound, when fed chick diets containing 600 units of vitamin A or more per pound, showed normal growth rate. In contrast to results obtained the previous year, there was no evidence in this experiment that high levels of vitamin A in the maternal diets produced more
DISCUSSION
The experimental results presented in this report support the conclusion that the minimum requirement for vitamin A by the laying hen is approximately 1,2001,600 USP units of vitamin A per pound of diet when this is supplied by a stable source of the vitamin. This is substantially less than has been found in most other experiments on vitamin A requirement and is explainable on the basis of the greater stability of the source of vitamin A employed in the present studies. It may also be related in part to differences in
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USP units/lb. 800 1,200 1,200+DPPD 1,600 2,000 3,600 5,000 10,000
Vitamin A in hen liver1
rapid chick growth. These data, therefore, are interpreted to show that normal performance of the progeny required a minimum of 1,200 USP units of vitamin A per pound in the maternal diet and 600 USP units of vitamin A per pound in the chick diet. Liver storage of vitamin A. At the conclusion of each of the experiments with hens, representative hens were sacrificed to determine the concentration of vitamin A in the liver. Similar analyses at the beginning of the experiment showed an initial level of approximately 500 USP units of vitamin A per gram of liver. The data in Table 12 show that relatively low levels of vitamin A were present in the livers of hens fed 2,000 USP units of vitamin A per pound or less. The vitamin A concentration in the liver was markedly increased with higher levels of vitamin A. At the lower levels of dietary vitamin A, there was no close relationship between the vitamin A content of the liver and the productive performance of the hen or the ability to transfer vitamin A to the egg yolk. The lower levels of vitamin A which were adequate for normal productive performance were evidently sufficient to meet tissue requirements but not sufficient to produce high liver storage levels.
VITAMIN A REQUIREMENTS OF HENS
The data obtained in these studies on the relation between maternal nutrition and chick requirement for vitamin A showed that the minimum maternal requirement for vitamin A leaves little or no vitamin A reserves in the newlyhatched progeny of these hens. In the second study, the progeny from hens fed the lowest level of vitamin A were so deficient that it was not possible to achieve normal growth by feeding high levels of vitamin A in the chick ration. In our first study, however, feeding an adequate level of vitamin A in the chick ration overcame the influence of maternal deficiency, due possibly to a less severe deficiency in that study. In any case, it appears clear that when a stabilized source of the vitamin is
used, a level of 600 USP units of vitamin A in the chick ration is sufficient to produce normal growth and development provided that the maternal ration contains at least 1,200 USP units of the vitamin A per pound. In the first experiment, a high maternal level of vitamin A (5,000 units per pound) tended to improve growth of progeny, even when the level of vitamin A in the chick diet was ample. However, this did not occur the second year; further work would be necessary to show whether this apparent discrepancy between the experiments is meaningless, or indicative of a strain difference in response to vitamin A reserves. The definition of quantitative need for vitamin A (as with all nutritive factors) depends on the criteria of adequacy which are employed. From the point of view of supporting survival, freedom from gross symptoms of deficiency, weight maintenance, productive output, minimum incidence of blood spotting in eggs, hatchability, and normal development of healthy progeny, the minimum requirement of the hen under good environmental conditions was 1,200-1,600 USP units of vitamin A per pound in the type of experimental diet employed in this work. To provide appreciable storage of the vitamin in the liver of the hen, a dietary level of more than 2,000 USP units per pound was necessary. Progeny of hens fed 1,200 USP units per pound of diet or higher levels of vitamin A required approximately 600 USP units per pound of chick starter diet under the conditions of these experiments. SUMMARY
The quantitative requirement of mature hens and their progeny for vitamin A was studied in two long term experiments using a stable preparation of vitamin A palmitate, strains of chickens differing in incidence of production of blood spotting
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the efficacy of carotenes to meet the vitamin A requirement under various circumstances, since much of the early work on vitamin A requirement was conducted using alfalfa meal and yellow corn as sources of vitamin A activity. In both experiments, vitamin A deficiency increased the incidence of blood spots in eggs. The data obtained show clearly that the requirement for vitamin A to achieve minimum incidence of blood spotting in eggs is approximately the same as the minimum required for normal productive performance. This was shown using a strain characterized by a high incidence of blood spotting and relatively similar results were also obtained with a strain showing the normal moderate incidence of this defect. Although it is clear that vitamin A deficiency increases blood spotting incidence, the strain in which high incidence of this defect occurred did not show an unusually high requirement for vitamin A. The requirement of 1,2001,600 USP units of vitamin A per pound of diet to minimize incidence of blood spots is in agreement with the findings of Bearse et al. (1960)
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Normal growth and development of progeny required t h a t chicks be fed 600 USP units of vitamin A per pound of diet, and t h a t the maternal diet contain at least 1,200 USP units per pound. In one experiment, chicks produced by hens fed 800 USP units per pound were unable to achieve normal growth in early life, even when fed chick diets very high in vitamin A. Chicks fed deficient diets (less than 400 USP units per pound) showed a characteristic ataxia. Ataxia was also observed
in chicks from deficient hens, when the chick diet contained a minimal level of vitamin A (400-600 USP units per pound). Thus, the minimum requirement for normal, healthy progeny of hens fed adequate vitamin A is approximately 600 USP units of vitamin A per pound of diet using a "stabilized" vitamin A product. ACKNOWLEDGEMENTS
The authors wish to t h a n k Dr. T. S. Nelson (present address: International Minerals and Chemical Corp., Skokie, 111.) and Mr. H. E. Butters (present address: Eaton Labs., Norwich, N . Y.) for technical assistance in conducting these experiments. We also are indebted to Hoffman La Roche, Inc., Nutley, N. J. for financial assistance and for the vitamin A preparation, Rovimix A-325, used in these studies; and to Distillation Products Industries, Rochester, N . Y. for financial assistance and the vitamin E preparations used. REFERENCES Adamstone, F. B., 1947. Histologic comparison of the brains of vitamin A-deficient and vitamin Edeficient chicks. Arch. Path. 43: 301-312. Association of Official Agricultural Chemists, 1955. Official Methods of Analysis, 8th edition, p. 812. Washington, D. C. Bearse, G. E., C. F. McClary and H. C. Saxena, 1960. Blood spot incidence in chicken eggs and vitamin A level of the diet. Poultry Sci. 39: 860865. Lerner, I. M., L. W. Taylor and D. C. Lowry, 1951. Selection for increased incidence of blood spots in White Leghorns. Poultry Sci. 30: 748-757. National Research Council, 1954. Nutrient requirements for poultry. A report of the Committee on Animal Nutrition. Publication 301.
F E B R U A R Y 9-11. A N N U A L F A C T F I N D I N G
CONFERENCE,
T H E I N S T I T U T E OF A M E R I C A N P O U L T R Y I N D U S T R I E S , M U N I C I P A L A U D I T O R I U M , KANSAS C I T Y M I S S O U R I
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in eggs, and a diet of natural materials low in vitamin A and carotenoids. The minimum requirement of laying; hens for maximum egg production, maintenance of body weight and health, and minimum incidence of the blood spotting defect was 1,200-1,600 USP units of vitamin A per pound of diet. The lower level of vitamin A appeared marginal for these functions, but was not improved by the incorporation of an additional antioxidant in the diet. The vitamin A requirement to minimize incidence of blood spotting in eggs was no higher than the: requirement to achieve maximum productive performance in other respects. A strain of chickens characterized by a high incidence of blood spotting of egg yolk showed no higher requirement for vitamin A than a strain which had a normal moderate incidence of this defect. Although deficiency of vitamin A clearly increased the incidence of this abnormality, the high incidence genetically characteristic of one of the strains used in this work was not due to an unusually high requirement for vitamin A.
HEUSER
Poultry Sci. 36: 1381-1382. Routh, J. I., 1942. Nutritional studies on powdered chicken feathers. J. Nutr. 24: 399-404. Sullivan, T. W., and E. L. Stephenson, 1957. Effect of processing methods on the utilization of hydrolyzed poultry feathers by growing chicks. Poultry Sci. 36: 361-365. Wilder, O. H. M., P. C. Ostby and B. R. Gregory, 1955. The use of chicken feather meal in feeds. Poultry Sci. 34: 518-524. Wisman, E. L., C. E. Holmes and R. W. Engel, 1958. Utilization of poultry by-products in poultry rations. Poultry Sci. 37: 834-838.
Reinvestigation of the Vitamin A Requirements of Laying and Breeding Hens and Their Progeny F. W. HILL, 1 M. L. SCOTT, L. C. NORRIS AND G. F. HETJSER2 Department of Poultry Husbandry, Cornell University, Ithaca, N. Y. (Received for publication November 4, 1960)
O
N THE basis of the available evidence from quantitative studies, the Committee on Animal Nutrition of the National Research Council (1954) has estimated the vitamin A requirements to be 1,200 U.S.P. units per pound of diet for growing chickens, and 2,000 U.S.P. units per pound of diet for laying and breeding hens. The results of individual studies on which these estimates are based have varied widely. The sources of vitamin A activity used in the various studies on requirement were fish oils, alfalfa meals and/or yellow corn, all of which were unstable to some degree, especially after mixture in the experimental diets. Even with the precaution of frequent diet mixing, the instability of the vitamin or its precursors introduced considerable uncertainty into the quantitative estimates of requirement.
1 Present address: Department of Poultry Husbandry, University of California, Davis, California. 2 Present address: 608 Hillside Drive, Lakeland, Florida.
Recently, efforts in industry have been directed toward the development of vitamin A preparations which are highly stable in diet mixtures and under adverse conditions of storage. Reinvestigation of the vitamin A requirements of hens and their progeny using one of these "stabilized" vitamin A preparations was considered appropriate because of the uncertainties concerned in earlier work and the wide variations in estimates derived from the different experiments. One of the abnormalities associated with vitamin A deficiency in hens is the production of eggs with a high incidence of blood spotting of the yolk (Bearse et al., 1960). This egg defect normally occurs in low incidence among commercial strains of chickens, but is known to be an inherited trait (Lerner et al., 1951). The studies to be described were undertaken to investigate the requirement of hens and their progeny for vitamin A, using a stabilized source of vitamin A and strains of chickens differing widely in their
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Mangold, E., and J. Dubski, 1930. The digestion of keratin, especially the horny material of birds' feathers, by fowls and mammals. Wiss. Arch. Landw., Abt. B, Tierernahr. Tierzucht 4: 200221. McKerns, K. W., and E. Rittersporn, 1958. The nutritional significance of processed keratin in poultry feeding. Poultry Sci. 37: 433-436. Naber, E. C , and C. L. Morgan, 1956. Feather meal and poultry meat scrap in chick starting rations. Poultry Sci. 35: 888-895. Rosenberg, H. R., J. T. Baldini and C. I. Tollefson, 1957. Histidine requirement of the growing chick.
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TABLE 1.—Composition of basal vitamin A deficient diet for laying hens
%
Ground white corn Ground wheat Soybean oil meal (50% protein) Fish solubles Dried brewers' yeast Dried whole whey Dicalcium phosphate Limestone Salt (iodized) Manganese sulfate Vitamin mixture
49.5 20.0 18.5 1.0 2.0 2.0 2.5 4.0 0.5 0.025 0.15 100.175
Vitamin mixture supplied, mg. per kg. of diet: 22 niacin, 11 calcium pantothenate, 4.4 riboflavin, 3.3 pyridoxine hydrochloride, 2.2 thiamine chloride, 0.66 folacin, 1.1 menadione, 0.11 biotin, 750 I.C.U. vitamin D3, in a sucrose carrier. Added separately from this mixture were vitamin B12, 8.8 meg., and 11 mg. alpha-tocopheryl acetate.
propensity to produce blood spotting in eggs. PROCEDURE AND RESULTS The vitamin A requirement of laying and breeding hens. Two experiments were conducted in successive years to determine the vitamin A requirements of Single Comb White Leghorn hens. The basal diet used in both experiments had the composition shown in Table 1. It was typical of rations used in practice excepting that it contained white corn as the major cereal base, lacked any source of carotenoid pigments, and was supplemented with a mixture of vitamins to insure against deficiency of any known factor other than vitamin A. The only component of the basal diet which contained any appreciable amount of vitamin A was the fish solubles; on the basis of chemical analysis, it contributed less than 100 USP units of vitamin A per pound of diet. The vitamin A source used in the experimental diets was a commerciallyprepared product based on synthetic vitamin A palmitate in a beaded gelatin
In the first experiment, the experimental diets contained 800; 1,200; 1,600; 2,000; and 5,000 USP units of vitamin A per pound, supplied by the synthetic vitamin A palmitate supplement. In addition, to determine whether an additional antioxidant would be of benefit, the combination of 1,200 USP units of vitamin A plus .0125% diphenyl p-phenylene diamine (DPPD) was used. Each diet was fed to two duplicate lots of 20 pullets each. The strain of White Leghorns chosen for this experiment was characterized by generally superior performance in egg production, viability, egg size and other production characteristics as shown by its record in the New York State Random Sample Test (1954-1955), and
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Component
carrier containing an antioxidant mixture to further enhance stability. The preparations used in the two respective experiments contained 360,000 and 371,000 USP units per gram by spectrophotometric analysis (Association of Official Agricultural Chemists, 1955). Each experimental lot contained 20 Single Comb White Leghorn pullets 6-7 months old at the beginning of each experiment. The lots were housed in pens approximately 6X12 feet in size with raised wire screen floors. The pens were provided with thermostatically controlled, steam-heated radiators to maintain the temperature above a minimum of 50° F. Each experiment began at the on-set of egg production, which was approximately by November 1 and continued for eleven 28-day periods. The experimental diet, water, flaked oyster shell, and granite grit were supplied to each lot ad libitum. Day length was maintained at 14 hours by providing incandescent electric light when necessary. In order to produce fertile eggs, two White Leghorn cockerels were used in each pen, and they were shifted among the pens at weekly intervals, in rotation.
VITAMIN A REQUIREMENTS OF HENS
TABLE 2.—The effect of vitamin A level on egg production (Experiment 1) Average rate of egg production 1 Vitamin A level USP units/lb. 800
Periods 1-5
Periods 6-8
%
%
75 73 72 73
56 49
76 74
61 36
57 54
74 70
48 62 43
56 52 58
72
33
51
76 5,000
27 39
59 43
79 73
46
45
71 2,000
48 44
43 47
74 67
38
53
75 1,600
34 42 48
73 1,200+DPPD
%
48 47 74
1,200
Periods 9-11
53 50 46
55
48
1 Hen-day basis. Underlined figures are averages of the data from individual lots shown to the left.
TABLE 3.—The ejfect of vitamin A level on egg production (Experiment 2)
Vitamin A level
Periods 1-5
USP units/lb. 800 1,200 2,000 3,600 5,000 10,000 1
Periods 6-8
Periods 9-11
%
%
%
70 76 79 70 76 74
43 68 63 51 54 64
22 44 42 41 52 43
Hen-day basis.
blood spot incidence, body weight, mortality, vitamin A content of egg yolk, vitamin A content of hen liver at the conclusion of the experiment, and the effect of maternal vitamin A nutrition on the requirements of progeny for vitamin A. Data from the first experiment (Table 2) show the effect of vitamin A level on egg production rate. During the first five 28-day periods of the experiment, little difference in egg production was apparent between the various treatments. In the next three periods, and also in the final three periods, egg production rate was markedly lower in the groups receiving diets containing 800 units and 1,200 units plus DPPD. The performance of the lots receiving 1,200 units without the added antioxidant was apparently as good as the lots receiving any higher level of vitamin A. These data are interpreted to indicate that 1,200 units per pound was a marginal level of vitamin A, and that the minimum requirement for egg production was satisfied by 1,600 USP units per pound. This was confirmed in the second experiment, the results of which are shown in Table 3. During the first five 28-day periods of this experiment, little difference in egg production rate was noted. In the next six periods, egg production was
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by one pronounced defect. This defect was the production of a much higher than normal proportion of eggs with blood spots. This characteristic was sought in order to make a critical evaluation of the possible relationship between vitamin A nutrition and the blood spot problem. In the second experiment another strain of White Leghorns, also possessing generally superior characteristics in production traits but showing the normal moderate incidence of blood spots, was used. Because of limitations of space, it was necessary to use single lots of 20 pullets each fed diets containing 800; 1,200; 2,000; 3,600; 5,000; and 10,000 USP units of vitamin A per pound of diet. In both experiments, observations were made on egg production, hatchability,
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H I L L , M.
L. SCOTT, L.
T A B L E 4.—Body weight and mortality Experiment 1 Level of vitamin A
Experiment 2
Average weight Average weight ——————— Mor- ——— ——— MorInitial Final tality Initial Final tality gm. 1,884 1,889 1,880 1,879 1,876
gm. 1,869 1,966 1,873 1,992 2,055
— —
2,009
1,873
— —
% 28 19 11 13 19 0
gm. 1,856 1,807
gm. 1,908 1,968
— — 1,833
— — 2,033
1,831 1,865 1,827
1,991 2,099 1,975
% 0 3
10 .1
19 0
markedly reduced in the lot receiving 800 USP units per pound, but was supported at a normal rate by 1,200 units and was not improved by feeding higher levels of vitamin A. I t should be mentioned here t h a t the performance of the stock used in the second experiment was not entirely satisfactory, due evidently to the influence of a respiratory disease during the growing period. This resulted in an unusually high incidence of unproductive pullets which were easily identified in the early stages of the experiment through their trapnest records. These pullets were removed from the experiment, so the production rates summarized in Table 3 represent the performance of the remaining pullets. The number of functional pullets ranged from 12 to 19, and was approximately 15 in most of the lots. D a t a on body weight and mortality in the two experiments are summarized _in Table 4. In both experiments, body weight was not maintained as well at the 800 unit level as at higher levels of vitamin A supplementation. I t appeared in the first experiment t h a t the 1,200 unit level was marginal, and t h a t satisfactory weight maintenance required approximately 1,600 units of vitamin A per pound. Excepting possibly for the relatively high mortality at the lowest level of vitamin A in experiment 1, the mortality pattern was not clearly indicative of
HEUSER
vitamin A nutrition. None of the hens which died showed any gross evidence of vitamin A deficiency, such as xerophthalmia or kidney damage. The incidence of blood spots in the eggs in both experiments is shown in Table 5. This was determined in experiment 1 by breaking out all eggs produced on three successive days in each period. Blood spots were classified as large (one-eighth inch or more in diameter) or small; eggs with profuse evidence of blood were included in the category of large spots. During the first five periods in experiment 1, the incidence of blood spots showed no relationship to vitamin A nutrition. The incidence was high, as expected from previous experience with this strain. In the last five periods of the experiment the incidence was generally higher, and was highest in the groups receiving 800 and 1,200 units of vitamin A per pound. The lowest incidence was shown by the lots receiving 1,600 units per pound, and no further improvement was achieved by feeding higher levels. The increased incidence of blood spots in eggs from hens suffering from vitamin A deficiency was confirmed in the second experiment. Observations in this experiment were restricted to three sampling times in
TABLE 5.—Effect of vitamin A level on incidence of blood spots in eggs of two different strains of White Leghorn hens Incidence of blood spots1 Experiment 1 Level of vitamin A
USP units/lb. 800 1,200 1,200+DPPD 1,600 2,000 3,600 5,000 10,000
Experiment 2
Periods 6-11 No. eggs Periods 6,7,8 No. eggs examexamTotal Large ined Total Large ined
% % 38 34 28 22 28
19 13 It 9 7
— — 24 9 — —
626 677 669 703 627
— —
728
% 12 4
% 7 1
— — — — 2 0 6 6 1
1 4 0
91 73
— — 97 81 82 113
1 Strain of hens used in Experiment 1 had a high genetic propensity for blood spots; those used in Experiment 2 did not.
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Units/lb. 800 1,200 1,200+DPPD 1,600 2,000 3,600 5,000 10,000
data
C. N O R M S AND G. F.
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VITAMIN A REQUIREMENTS OF HENS
TABLE 6.—Effect of dietary vitamin A on the vitamin A content of egg yolk Dietary level USP units/lb. 800 1,200 1,200+DPPD 1,600 2,000 3,600 5,000 10,000
Vitamin A per gram yolk Exp. 1
Exp. 2
USP units 0.9 3.7 2.9 4.2 6.3
USP units 0.7 8.9
—
12.7
—
— —
6.9 10.6 12.5 16.3
Experiment 1 data are averages for four determinations made in periods 8-11. Experiment 2 data are averages for three determinations made in periods 3, 5 and 6.
TABLE 7.—The effect of vitamin A level on hatchability Vitamin A level USP units/lb. 800
1,200
1,200+DPPD
Hatchability of fertile eggs Experiment 1
Experiment 2
%
%
84 92 88
66
84
78
83 84 90 83 86
1,600
2,000
79 74
76
73 85 79
71
3,600 5,000
84 83 84
10,000
70
71 77
Experiment 1: average of 3 hatches, in periods 5, 7 and 8. Experiment 2: average of 10 hatches, in periods 3-11.
A. In general, the vitamin A content of egg yolk tended to increase as the dietary level of vitamin A increased. Agreement between the two experiments was generally good, excepting at the 1,200 unit level which, as indicated by other performance characteristics, appeared to be marginal and subject to considerable variation. The hatchability of eggs was unrelated to vitamin A nutrition, as shown in Table 7. Hatchability was maintained at satisfactory levels in experiment 1; performance was less satisfactory in experiment 2, due possibly to the same factors which influenced egg production performance as discussed above. Fertility was
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periods 6, 7 and 8. Blood spots were reduced to an essentially normal level by feeding 1,200 units per pound, and no consistent further reduction was produced by feeding higher levels of vitamin A. These data support the conclusion that the requirement for vitamin A to minimize the incidence of blood spots is approximately the same as the level required for maximum egg production and maintenance of body weight. These data also indicate that the high incidence of blood spotting characteristic of the strain used in experiment 1 was not due to an unusually high requirement for vitamin A, but must have had some other physiological basis. The relationship between the vitamin A content of the diet and the vitamin A content of egg yolk is summarized in Table 6. Observations in experiment 1 were based on egg samples taken in each of the four final 28-day periods; in experiment 2, egg samples were taken in periods 3, 5 and 6. Determinations of vitamin A content were made on extracts of saponified egg yolk by spectrophotometric analysis. Confirmatory values were obtained by the antimony trichloride method for determination of vitamin
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TABLE 8.—Composition of basal vitamin Adeficient chick diet Components
42.6 10.0 35.0 2.5 2.5 2.5 2.0 1.5 0.25 1.0 0.2 100.05
Vitamins and minerals added, per kg. diet: 3 mg. thiamine chloride, 5 mg. riboflavin, 10 mg. calcium pantothenate, 5 mg. pyridoxine hydrochloride, 26 mg. niacin, 1 mg. folacin, 0.1 mg. biotin, 0.01 mg. vitamin Bi 2 , 1 mg. menadione, 1 gm. choline chloride, 400 I.C.U. vitamin D 3 , 20 I.U. alpha-tocopheryl acetate, 3.5 gm. K 2 HP0 4 , 1.2 gm. MgS0 4 , 0.15 gm. MnSO 4 ,0.28gm. FeS0 4 -7H 2 0, 7.8mg.CuSO 4 -5H 2 0, 1.3 mg. Nal.
satisfactory throughout both experiments. The vitamin A requirement of chicks. Two experiments were conducted with the progeny of the hens of experiment 1 to determine the relationship between maternal vitamin A nutrition and the requirement of the chick for vitamin A. The composition of the basal chick diet is shown in Table 8; the same source of supplementary vitamin A was used in the chick experiments as had been employed in the hen experiments. Data for the first experiment are shown in Table 9. Lots of 19-20 male chicks from the progeny of each of the maternal treatments, were fed chick diets containing 200, 600, or 1,200 USP units of vitamin A per pound of diet. All the chicks fed 200 units of vitamin A per pound of diet showed poor growth, excepting the progeny of the hens fed 5,000 units per pound. Increasing the level of vitamin A in the maternal diet from 800 to 2,000 USP units per pound did not materially improve the performance of chicks fed the deficient diet. In
TABLE 9.—Effect of vitamin A in maternal and chick diets on growth of progeny (Experiment C 1) Level of vitamin A Maternal diet
Chick diet
USP units/lb. 800 200 1,200 200 1,200+DPPD 200 1,600 200 2,000 200 5,000 200
USP units/lb.
Response of c:hicks Avg. Ataxia weight inci- Mor4 weeks dence tality gm.
%
%
226 233 270 242 258 320
75 56 60 55 80 10
40 69 45 40 20 0
800 1,200 1,200+DPPD 1,600 2,000 5,000
600 600 600 600 600 600
319 322 332 324 322 346
0 0 0 0 0 0
5 0 5 0 0 0
800 1,200 1,200+DPPD 1,600 2,000 5,000
1.200 1,200 1,200 1,200 1,200 1,200
322 333 345 328 327 342
0 0 0 0 0 0
0 0 0 0 5 0
Data show averages of single lots of 19-20 male chicks each, except progeny of 1,200 USP units maternal diet which had 15-16 chicks per lot.
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Glucose (Cerelose) Ground wheat Soybean oil meal (50% protein) Ether-extracted fish meal Dried brewer's yeast Dried whole whey Dicalcium phosphate Limestone Salt Hydrogenated shortening (Hydora) DL-methionine
%
addition to poor growth, the deficient chicks showed high mortality and a high incidence of an ataxia similar to that described by Adamstone (1947). Increasing the level of vitamin A in the chick diet to 600 or 1,200 USP units per pound of diet resulted in normal growth and survival of all progeny, and freedom from ataxia. A tendency was evident for the progeny of hens fed 5,000 units per pound of diet to grow somewhat more rapidly than the progeny of the other maternal groups. It was considered possible that the ataxia observed in the chicks fed 200 units per pound of diet in the first chick experiment might have been due in part to marginal vitamin E nutrition or to other influences preventable by the addition of an antioxidant. Therefore, the experiment
1251
VITAMIN A REQUIREMENTS OF HENS
TABLE 10.—Effect of vitamin A in maternal and chick diets on growth of progeny (Experiment C 2) Level of vitamin A Maternal diet
Chick diet1
USP units/lb. 800 200 1,200 200 1,200+DPPD 200 1,600 200 2,000 200 5,000 200
USP units/lb.
Respor ise of chicks2 Avg. Ataxia Morweight mci- tality 4 weeks dence gm.
%
%
282 248 290 314 275 334
44 50 55 60 50 0
19 35 5 15 0 0
800 1,200 1,200+DPPD 1,600 2,000 5,000
400 400 400 400 400 400
252 293 296 322 306 350
25 0 0 0 0 0
19 5 0 5 5 0
800 1,200 1,200+DPPD 1,600 2,000 5,000
600 600 600 600 600 600
316 305 310 312 324 350
0 0 0 0 0 0
13 0 0 0 0 0
1 Chick diet supplemented with antioxidant (0.01% DPPD) and 9 I.U. each of d-alpha tocopheryl acetate and d-alpha-tocopherol per pound of diet. 2 Data show averages of single lots of 20 male chicks each, except progeny of 800 and 5,000 USP units maternal lots which had 16 chicks each.
TABLE 11.—Effect of vitamin A in maternal and chick diets on growth of progeny (Experiments C3 and C4) Average weight at 4 weeks Vitamin A in maternal diet
Vitamin A in chick diet, USP units/lb. 600
1,200
5,000
USP units/lb. 800 1,200 2,000 3,600 5,000 10,000
gm. 170' 302> 269' 282' 295' 2871
gm. 2681 346 305 319 314 323
gm. 257 324 319 302 320 311
gm. 282 339 312 315 319 320
288
321
315
325
Average (1,200-10,000)
Average (6005,000)
269 336 314 312 320 320
i Ataxia observed. D a t a are averages of 2 experiments, each using 9-12 male chicks per treatment.
per pound, normal growth was obtained in all progeny, regardless of hen treatments. Also included in this experiment, but not shown in Table 10, were groups fed 200 and 400 USP units of vitamin A per pound without the added antioxidant and/or vitamin E. The incidence of ataxia and the growth rate of these chicks were no different from those fed the vitamin E plus the antioxidant. Therefore, it was concluded that the ataxia which was observed in these two experiments was due entirely to vitamin A deficiency. As was observed in the first experiment, the progeny of hens fed 5,000 USP units of vitamin A per pound tended to grow more rapidly than the progeny of the other maternal lots. A systematic study of the influence of maternal vitamin A nutrition on the requirement of progeny for vitamin A was continued in the second year of work. The range of maternal vitamin A levels was extended to 10,000 units per pound to determine whether any consistent advantage in the performance of progeny could be achieved by feeding very high maternal levels as suggested by the results in the previous year. Two experiments were conducted in which the progeny of each of
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was repeated using levels of 200, 400 and 600 USP units of vitamin A per pound of chick diet in the presence of an added antioxidant (.01% DPPD) and 9 I.U. each of d-alpha-tocopheryl-acetate and d-alpha-tocopherol per pound of diet. The results of this experiment are shown in Table 10. With the lowest level of vitamin A in the chick diet, ataxia was present in all chicks excepting the progeny of hens fed 5,000 USP units per pound. When the chick diet contained 400 units per pound, ataxia and poor growth were observed only in the progeny of hens fed the lowest vitamin A level (800 units) and growth was essentially normal in all other lots. When the chicks were fed 600 USP units
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TABLE 12.—Effect of dietary vitamin A on the vitamin A content of the liver of the hen Vitamin A level of layer diet
Experiment 1 Experiment 2 USP units/gm. USP units/gm. 2 16 18 17 2
70 21
—
1,540
—
— —
9 330 600 3,100
1
Hen data obtained at conclusion of each experiment, using 6 hens per treatment in experiment 1 and 3 hens per treatment in experiment 2. All hens contained approximately 500 USP units of vitamin A per gram of liver at the start of the experiments. 2 No detectable vitamin A.
the maternal groups were fed chick diets containing 200, 600, 1,200 and 5,000 USP units of vitamin A per pound. The two experiments gave results in close agreement, so the data have been combined for presentation in Table 11. Growth of the progeny of hens fed 800 USP units per pound of ration was sub-normal, regardless of the level of vitamin A supplied in the chick ration. This was in contrast to the results of the previous year, in which essentially normal growth was obtained when sufficient vitamin A was fed to chicks from deficient hens. The data in Table 11 also show that 200 USP units per pound in the chick ration produced sub-normal growth in all progeny, regardless of the maternal level of vitamin A. Ataxia was observed in all of the chicks fed the deficient chick diet. The progeny of all hens receiving 1,200 units of vitamin A or more per pound, when fed chick diets containing 600 units of vitamin A or more per pound, showed normal growth rate. In contrast to results obtained the previous year, there was no evidence in this experiment that high levels of vitamin A in the maternal diets produced more
DISCUSSION
The experimental results presented in this report support the conclusion that the minimum requirement for vitamin A by the laying hen is approximately 1,2001,600 USP units of vitamin A per pound of diet when this is supplied by a stable source of the vitamin. This is substantially less than has been found in most other experiments on vitamin A requirement and is explainable on the basis of the greater stability of the source of vitamin A employed in the present studies. It may also be related in part to differences in
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USP units/lb. 800 1,200 1,200+DPPD 1,600 2,000 3,600 5,000 10,000
Vitamin A in hen liver1
rapid chick growth. These data, therefore, are interpreted to show that normal performance of the progeny required a minimum of 1,200 USP units of vitamin A per pound in the maternal diet and 600 USP units of vitamin A per pound in the chick diet. Liver storage of vitamin A. At the conclusion of each of the experiments with hens, representative hens were sacrificed to determine the concentration of vitamin A in the liver. Similar analyses at the beginning of the experiment showed an initial level of approximately 500 USP units of vitamin A per gram of liver. The data in Table 12 show that relatively low levels of vitamin A were present in the livers of hens fed 2,000 USP units of vitamin A per pound or less. The vitamin A concentration in the liver was markedly increased with higher levels of vitamin A. At the lower levels of dietary vitamin A, there was no close relationship between the vitamin A content of the liver and the productive performance of the hen or the ability to transfer vitamin A to the egg yolk. The lower levels of vitamin A which were adequate for normal productive performance were evidently sufficient to meet tissue requirements but not sufficient to produce high liver storage levels.
VITAMIN A REQUIREMENTS OF HENS
The data obtained in these studies on the relation between maternal nutrition and chick requirement for vitamin A showed that the minimum maternal requirement for vitamin A leaves little or no vitamin A reserves in the newlyhatched progeny of these hens. In the second study, the progeny from hens fed the lowest level of vitamin A were so deficient that it was not possible to achieve normal growth by feeding high levels of vitamin A in the chick ration. In our first study, however, feeding an adequate level of vitamin A in the chick ration overcame the influence of maternal deficiency, due possibly to a less severe deficiency in that study. In any case, it appears clear that when a stabilized source of the vitamin is
used, a level of 600 USP units of vitamin A in the chick ration is sufficient to produce normal growth and development provided that the maternal ration contains at least 1,200 USP units of the vitamin A per pound. In the first experiment, a high maternal level of vitamin A (5,000 units per pound) tended to improve growth of progeny, even when the level of vitamin A in the chick diet was ample. However, this did not occur the second year; further work would be necessary to show whether this apparent discrepancy between the experiments is meaningless, or indicative of a strain difference in response to vitamin A reserves. The definition of quantitative need for vitamin A (as with all nutritive factors) depends on the criteria of adequacy which are employed. From the point of view of supporting survival, freedom from gross symptoms of deficiency, weight maintenance, productive output, minimum incidence of blood spotting in eggs, hatchability, and normal development of healthy progeny, the minimum requirement of the hen under good environmental conditions was 1,200-1,600 USP units of vitamin A per pound in the type of experimental diet employed in this work. To provide appreciable storage of the vitamin in the liver of the hen, a dietary level of more than 2,000 USP units per pound was necessary. Progeny of hens fed 1,200 USP units per pound of diet or higher levels of vitamin A required approximately 600 USP units per pound of chick starter diet under the conditions of these experiments. SUMMARY
The quantitative requirement of mature hens and their progeny for vitamin A was studied in two long term experiments using a stable preparation of vitamin A palmitate, strains of chickens differing in incidence of production of blood spotting
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the efficacy of carotenes to meet the vitamin A requirement under various circumstances, since much of the early work on vitamin A requirement was conducted using alfalfa meal and yellow corn as sources of vitamin A activity. In both experiments, vitamin A deficiency increased the incidence of blood spots in eggs. The data obtained show clearly that the requirement for vitamin A to achieve minimum incidence of blood spotting in eggs is approximately the same as the minimum required for normal productive performance. This was shown using a strain characterized by a high incidence of blood spotting and relatively similar results were also obtained with a strain showing the normal moderate incidence of this defect. Although it is clear that vitamin A deficiency increases blood spotting incidence, the strain in which high incidence of this defect occurred did not show an unusually high requirement for vitamin A. The requirement of 1,2001,600 USP units of vitamin A per pound of diet to minimize incidence of blood spots is in agreement with the findings of Bearse et al. (1960)
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F. W. H I L L , M. L. SCOTT, L.. C. N O R R I S AND G. F.
Normal growth and development of progeny required t h a t chicks be fed 600 USP units of vitamin A per pound of diet, and t h a t the maternal diet contain at least 1,200 USP units per pound. In one experiment, chicks produced by hens fed 800 USP units per pound were unable to achieve normal growth in early life, even when fed chick diets very high in vitamin A. Chicks fed deficient diets (less than 400 USP units per pound) showed a characteristic ataxia. Ataxia was also observed
in chicks from deficient hens, when the chick diet contained a minimal level of vitamin A (400-600 USP units per pound). Thus, the minimum requirement for normal, healthy progeny of hens fed adequate vitamin A is approximately 600 USP units of vitamin A per pound of diet using a "stabilized" vitamin A product. ACKNOWLEDGEMENTS
The authors wish to t h a n k Dr. T. S. Nelson (present address: International Minerals and Chemical Corp., Skokie, 111.) and Mr. H. E. Butters (present address: Eaton Labs., Norwich, N . Y.) for technical assistance in conducting these experiments. We also are indebted to Hoffman La Roche, Inc., Nutley, N. J. for financial assistance and for the vitamin A preparation, Rovimix A-325, used in these studies; and to Distillation Products Industries, Rochester, N . Y. for financial assistance and the vitamin E preparations used. REFERENCES Adamstone, F. B., 1947. Histologic comparison of the brains of vitamin A-deficient and vitamin Edeficient chicks. Arch. Path. 43: 301-312. Association of Official Agricultural Chemists, 1955. Official Methods of Analysis, 8th edition, p. 812. Washington, D. C. Bearse, G. E., C. F. McClary and H. C. Saxena, 1960. Blood spot incidence in chicken eggs and vitamin A level of the diet. Poultry Sci. 39: 860865. Lerner, I. M., L. W. Taylor and D. C. Lowry, 1951. Selection for increased incidence of blood spots in White Leghorns. Poultry Sci. 30: 748-757. National Research Council, 1954. Nutrient requirements for poultry. A report of the Committee on Animal Nutrition. Publication 301.
F E B R U A R Y 9-11. A N N U A L F A C T F I N D I N G
CONFERENCE,
T H E I N S T I T U T E OF A M E R I C A N P O U L T R Y I N D U S T R I E S , M U N I C I P A L A U D I T O R I U M , KANSAS C I T Y M I S S O U R I
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in eggs, and a diet of natural materials low in vitamin A and carotenoids. The minimum requirement of laying; hens for maximum egg production, maintenance of body weight and health, and minimum incidence of the blood spotting defect was 1,200-1,600 USP units of vitamin A per pound of diet. The lower level of vitamin A appeared marginal for these functions, but was not improved by the incorporation of an additional antioxidant in the diet. The vitamin A requirement to minimize incidence of blood spotting in eggs was no higher than the: requirement to achieve maximum productive performance in other respects. A strain of chickens characterized by a high incidence of blood spotting of egg yolk showed no higher requirement for vitamin A than a strain which had a normal moderate incidence of this defect. Although deficiency of vitamin A clearly increased the incidence of this abnormality, the high incidence genetically characteristic of one of the strains used in this work was not due to an unusually high requirement for vitamin A.
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