Phosphorus Metabolism and Requirements of Hens1

PHOSPHORUS REQUIREMENTS or HENS Bird, S., 1948. Quantitative determination and segregation of breast conformation in poultry. Poultry Sci. 27:506-508. Broadbent, M., and H. W. Bean, 1952. The yield of edible meat from turkeys, ducklings and differend market classes of chickens. Poultry Sci. 3 1 : 447-450. Brown, P. B., and H. W. Bean, 1952. The yield of edible meat from different market classes of chickens. Poultry Sci. 31: 232-234. Essary, E. O., S. J. Mountney and O. E. Goff, 1951. Conformation and performance in standardbred and crossbred broilers. Poultry Sci. 30: 552-557. Frischknecht, C. D., and M. A. Jull, 1946. Amount of breast meat and live and dressed grades in relation to body measurements in twelve week old purebred and crossbred chickens. Poultry Sci. 25: 330-344. Gilbreath, J. C , and C. W. Upp, 1952. The growth pattern of the Cornish fowl. Louisiana Agr. Exp. Sta. Bui. 464. Hathaway, H. E., 1953. Comparing processing yields of various broiler strains (Preliminary report). The Southeastern Poultryman 6: (1) 39, 113-115. Hathaway, H. E., 1952. Test shows possibilities of improving meat yields. Birds from 1951 National C.O.T. used in Louisiana experiment. Broiler Growing, 3(10): 46-48. Henderson, E. W., 1950. Breed differences in meat type score and weight of twelve week old

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cockerels. Michigan Agr. Exp. Sta. Quart. Bui. 32: 507-512. Jaap, R. G., M. M. Renard and R. D. Buckingham, 1950. Dressed and eviscerated meat yields from chickens at twelve weeks of age. Poultry Sci. 29: 874-880. Jull, M. A., and W. A. Maw, 1923. Determination of the dressed, drawn and edible percentages of various kinds of domestic birds. Sci. Agr. 3: 329338. Jull, M. A., R. E. Phillips and C. S. Williams, 1943. Relation between cut-up chicken proportions and prices. U. S. Egg Poultry Mag. 49: 122-124. Lowe, B., 1941. Edible meat from two weights of roasters comparing yields from forty-three to forty-seven pound and forty-eight to fifty-four pound classes of roasters. U. S. Egg Poultry Mag. 47: 95-102. Maw, W. A., 1939. Poultry meat studies at MacDonald College. Canadian Soc. Tech. Agr. Review (June): 60-64. McNally, E. H., and N. H. Spicknall, 1949. Meat yield from live, dressed and eviscerated Rhode Island Red males of broiler, fryer and light roaster weights. Poultry Sci. 28: 562-567. Stotts, C. E., and M. I. Darrow, 1953. Yields of edible meat from Cornish crossbreds, non-Cornish crossbreds and purebred broilers. Poultry Sci. 32: 145-150.

Phosphorus Metabolism and Requirements of Hens 1 M. B. GILLIS, 2 L. C. NORRIS AND G. F. HEUSER Agricultural Experiment Station and School of Nutrition, Cornell University, Ithaca, New York (Received for publication March 5, 1953)

T

HE phosphorus requirement of laying hens has not been adequately defined. Earlier work at this Station indicated that 0.5 percent of phosphorus in the ration was insufficient to maintain egg production and egg shell strength but 1 Supported in part by a grant-in-aid from the International Minerals and Chemical Corporation, Chicago, Illinois. A preliminary report of this work was made at t h e Ninth World's Poultry Congress, Paris, 1951. 2 Present address: Central Research Laboratory, International Minerals and Chemical Corporation, Skokie, Illinois.

that 0.75 percent was adequate for these purposes (Norris, Heuser, Wilgus and Ringrose, 1933). Miller and Bearse (1934) obtained greater egg production with a ration containing approximately 0.8 percent phosphorus than with one containing 0.6 percent of this element. Evans and Carver (1942) reported that 0.8 percent of phosphorus gave better results than 0.6 or 1.2 percent when the ration contained 2.5 percent calcium. However, they found little difference between 0.6 and 0.8 percent phosphorus in a ration containing only 1.5 percent cal-

978

M. B. GILLIS, L. C. NORRIS AND G. F. HEUSEB.

cium. Evans, Carver and Brant (1944) reported that 0.8 percent phosphorus gave more consistently satisfactory egg shell quality than 0.6 percent phosphorus. In the case of young chicks and poults, it has been shown that the organic phosphorus of phytin is not as efficiently metabolized as the more usual sources of inorganic phosphorus (Gillis, Norris and Heuser, 1948, 1949; Singsen 1948). Common (1939) obtained evidence which indicated that a considerable portion of phytic acid in the diet of laying hens remains unhydrolyzed during its passage through the digestive tract. A considerable portion of the phosphorus in the ration previously employed by Norris et al. (1933) in studies with laying hens was in the form of phytin. It seemed desirable, therefore, to study the phosphorus requirements of laying hens under conditions where varying amounts of the total phosphorus was supplied by phytin. The experiments reported in this paper were carried out for this purpose.

TABLE 1.—Low-phosphorus, purified-type diet used in experiment 1 Ingredient Dried blood fibrin Ground cellophane Liver fraction " L " B-vitamin premix Fish liver oil (3,000A, 400D) Soybean oil Mineral mixture Defluorinated phosphate Calcium phytate Calcium carbonate

White Leghorn hens in their first year of production were used in all experiments. They were housed in wire-floored laying pens and individually trap-nested during the experiments. Feeding was ad libitum. The hens were weighed individually and physically examined at approximately monthly intervals. Each experimental lot consisted of fifteen or sixteen hens at the beginning of the experiments. The experimental rations and other details of management will be described for each experiment. Experiment 1. The objective of this experiment was to compare the efficiency of isolated phytate with an inorganic phosphate. The experiment covered the period of November 25, 1948 to May 21, 1949.

20.0 3.0 1.0 0.5 0.5 2.0 1.2 * * *

Corn starch, sufficient to make 100% * Used in amounts required to supply the percentages of calcium, phytin phosphorus, and inorganic phosphorus indicated for the various lots in Table 2.

The low-phosphorus basal ration is given in Table 1; it consisted largely of refined ingredients selected for low phosphorus content. Supplementary phosphorus was supplied by defluorinated TABLE 2.—Experimental outline and results'obtained by varying the percentages of phytin and inorganic phosphorus Lot No.

EXPERIMENTAL

%

Calcium, % Phytin P, % Inorganic P, %

1

2.00 0.70 0.05

2

2.00 0.50 0.25

3

2.00 0.25 0.50

Wt. change during +24 experiment, gm. -137 +143 60 7 13 Mortality, % Egg production, % 72 75 79 Dec. 65 69 68 Jan., Feb., Mar. 42 58 60 April, May Inorg, plasma P, mg. percent (March) 2.35 3.47 4.09 Bone ash, tibiae, % 56.2 60.5 60.3 Shell breaking strength, kg. 3.78** 4 . 1 9 " 4.01

4*

2.00 0.00 0.75

— — 71 70

— 4.39

—.

4.48

* Discontinued after 4th month. ** The larger number of soft-shelled and broken eggs produced by these hens is not reflected in this statistic.

phosphate and/or isolated calcium phytate 3 . Four lots of hens were used. The diet of each lot contained a total of 0.75 percent phosphorus, but the two phosphorus supplements were supplied in varying proportions so that the amount of phytin phosphorus received by different 3

Produced by Corn Products Refining Company.

PHOSPHORUS REQUIREMENTS OF HENS

lots varied from 0.0-0.70 percent of the ration. The scheme of supplementation and the results obtained are presented in Table 2. During the course of the experiment (fourth month), blood samples were taken from the hens and the amount of inorganic phosphorus in the plasma was determined. The breaking strength of egg shells was also determined at intervals. I t was observed, however, that hens in lots 1 and 2 which received the largest amounts of phytin laid the greatest number of softshelled and cracked eggs. It was obviously impossible to use such eggs in our determinations. The values for shell strength of lots 1 and 2 in Table 2, therefore, undoubtedly reflect a more favorable condition than actually existed. Due to the high cost of the experimental ration, lot 4 was discontinued after it became relatively certain that the level of inorganic phosphorus which it was receiving was above the minimum required. Data for this lot, therefore, are confined to the first four months of the experiment. At the conclusion of the experiment, representative hens from each lot were sacrificed for bone ash determinations. The tibiae were removed, the fat was extracted and the ash determined in the fat-free dry bone. The results of the experiment are presented in Table 2. These data show that the purified calcium phytate was less efficiently utilized than the inorganic phosphorus of defluorinated phosphate. The addition of 0.7 percent phytin phosphorus to the basal ration which contained 0.05 percent inorganic phosphorus did not provide an adequate amount of this element. Hens in this lot suffered 60 percent mortality and the survivors lost weight. Egg production in this lot was significantly less than in lots receiving more inorganic phosphorus. The ash con-

979

tent of bones from this lot was reduced, indicating that some decalcification had taken place. The inorganic phosphorus in the plasma of hens fed this level of phytin was quite low. Hens which received the combination of 0.50 percent phytin phosphorus and 0.25 percent inorganic phosphorus produced approximately as many eggs as hens which received a larger proportion of their phosphorus in inorganic form. They did not give quite as satisfactory performance, however, with respect to weight gained, quality of egg shells produced, and level of inorganic phosphorus in blood plasma. The combination of 0.25 percent phytin phosphorus and 0.50 percent inorganic phosphorus appeared to be quite satisfactory. After four months under experimental observation, this lot did not differ significantly from the lot which received 0.75 percent inorganic phosphorus. It appeared from these results that when the ration contained a total of 0.75 percent phosphorus, the hens required between 0.25 and 0.50 percent inorganic phosphorus. Although the hens made less efficient use of phytin phosphorus, it is apparent that this form of the element was at least partially metabolized. Several months were required to produce observable symptoms of deficiency due to the feeding of phytin. This is in contrast to the young chick which is quickly and drastically affected by rations containing phytin as the only source of phosphorus, (Gillis, Norris and Heuser, 1948,1949). Experiment 2. The objective of this experiment was to compare the utilization of phytin and inorganic phosphorus when the phytin was supplied by natural ingredients. It was realized that the isolated phytate supplied in Experiment 1 might not be utilized to the same extent as

980

M. B. GILLIS, L. C. NORMS AND G. F. HEUSER

TABLE 3.—Practical-type ration used in experiment 2 to study availability of phytin in natural feedstuffs Ingredient

%

Wheat bran Wheat middlings Soybean meal Alfalfa leaf meal Dried brewers' yeast Liver fraction " L " Fish oil (3,000A, 400D) Salt Calcium carbonate Defluorinated phosphate

20.0* 10.0 20.0 2.0 3.0 1.0 0.5 0.5

** **

Yellow corn meal, sufficient to make 100% * For Lot 1 (high phytin) untreated bran was used; for Lot 2 (low phytin) the phytin was largely removed by soaking in dilute acid. ** Added in the amounts necessary to provide the percentages of calcium and inorganic phosphorus shown in Table 4.

was superior to the ration containing only 0.21 percent inorganic phosphorus by nearly all comparisons. This was true despite the fact that both rations contained the same amount of total phosphorus. There was an advantage in egg production for the lot which received supplementary inorganic phosphorus. This advantage increased as the experiment progressed. The results confirm those of Experiment 1 to the effect that the hens utilized phosphorus from an inorganic source more effectively than that from phytin. The isolated and refined calcium phytate and the naturally occurring material thus exhibited similar nutritional properties. TABLE 4.—Results obtained by partial substitution of inorganic phosphate for phytin in natural feed ingredients

phytin in common feedstuffs. The experiment was run concurrently with ExperLot No. 1 2 iment 1 and under identical conditions of management. The experimental ration Calcium, % 2.00 2.00 Phytin P, % 0.53 0.29 is shown in Table 3. Inorganic P, % 0.21 0.45 The experimental treatments and rechange during experisults are presented in Table 4. Lot 1 re- Wt.ment, gm. -141 -52 ceived the basal ration without additional Mortality, % 7 7 production, % inorganic phosphorus. Lot 2 received the Egg Dec. 79 77 same ration except that the phytin in Jan., Feb., Mar. 63 69 April, May 64 75 wheat bran was mostly extracted and an Inorg. plasma P, mg. percent 4.83 5.63 equivalent amount of inorganic phos- Bone ash, tibiae, % 57.9 59.3 4.23 4.67 phorus from defluorinated phosphate was Shell breaking strength, kg. added to the diet. Removal of phytin was accomplished by soaking bran in warm Experiment 3. The previous experdilute acid (pH 5.5) for several hours. iments showed an advantage for available Under these conditions, phytin is hydro- forms of inorganic phosphorus over phytin lyzed enzymatically by phytase present phosphorus for hens. They gave no direct in the bran. The amount of treated bran evidence, however, concerning the total fed was equivalent to 20 percent of the un- quantitative requirement of the hen for treated material. In this manner, it was this element. The objectives of this experpossible to feed two rations nearly iden- iment, therefore, were to determine the tical except for their contents of phytin quantitative requirement for phosphorus and inorganic phosphorus. and to make further comparisons of inThe effects of the two treatments on the organic and phytin phosphorus. The criteria under consideration are shown in experiment covered the period from JanTable 4. The practical-type ration con- uary 12, to September 14, 1950. Two basal rations of the compositions taining 0.45 percent inorganic phosphorus

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PHOSPHORUS REQUIREMENTS or HENS

shown in Table 5 were used in this experiment. Ration 1 was designed to furnish phosphorus mostly in inorganic form, while Ration 2 furnished a higher proportion of phytin phosphorus. Both were formulated to provide approximately 0.5 percent total phosphorus and 2.0 percent calcium on the basis of initial analyses of ingredients. Analyses of each subsequent batch mixture of each diet showed, however, that during the experiment Ration 1 supplied an average of approximately 0.49 percent total phosphorus and 1.90 percent calcium, while Ration 2 supplied approximately 0.47 percent total phosphorus and 1.87 percent calcium. The scheme of supplementation and the results are given in Table 6. One lot of hens received each basal ration. Additional lots received 0.15 and 0.30 percent inorganic phosphorus added to each basal ration. In this experiment the inorganic phosphorus was supplied by means of c.p. dicalcium phosphate. The basal ration containing 0.39 percent inorganic phosphorus and 0.49 percent total phosphorus was as satisfactory for maintenance of weight and egg production as the same ration supplemented

TABLE 5.- -Experimental

rations used in experiment 3

Ingredient

Ration 1

Ration 2

50.0% 26.1

50.0% 6.3 13.0 21.0

Yellow corn meal Corn starch Wheat bran Soybean meal Fish meal Crude casein Alfalfa leaf meal Dried brewers' yeast Fish oil (3,000A, 400D) A.P.F. concentrate Iodized salt Calcium carbonate Manganese sulfate

8.0 7.5 2.0 2.0 0.3 0.5 3.6 0.022

2.0 2.0 0.3 0.2 0.5 4.7 0.022

1.91 .49 .10 .39

1.87 .47 .32 .15

Calcium, % Total P, % Phytin Inorganic

with additional inorganic phosphorus. The decline in production between the first and third quarterly periods was nearly identical for each of the three lots which received the ration low in phytin. The breaking strength of egg shells from the three lots was the same. However, the addition of supplementary inorganic phosphorus caused a trend toward higher plasma phosphorus values and definitely maintained higher percentages of bone ash. If value is placed on the latter cri-

TABLE 6.—Experimental outline and results, experiment 3 Basal ration

1

1

1

Lot No.

1A

IB

IC

Added CaHP0 4 , % Total Ca, % Total P, % Phytin P Inorganic P

0.0 1.91 .49 .10 .39

0.67 1.91 .64 .10 .54

1.33 1.91 .79 .10 .69

Wt. change, gm. Mortality, % Egg production, % 1-12 wks. 13-24 wks. 25-35 wks. Change in production Inorg. plasma P mg. percent Bone ash, tibiae, % Egg shell brk. str., kg.

'2

2

2

2A

2B

2C

0.0 1.87 .47 .32 .15

0.67 1.87 .62 .32 .30

1.33 1.87 .77 .32 .45

+92 12

+111 37

+26 6

-76 31

-174 6

+28 31

80 71 53 -27

73 62 42 -31

77 70 49 -28

79 65 48 -31

75 69 52 -23

72 77 64 -8

3.66 59.5 3.77

3.82 63.9 3.70

3.94 64.1 3.77

3.88 60.0 3.55

3.82 59.8 3.87

4.24 61.6 3.86

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M. B. GILLIS, L. C. NORRIS AND G. F. HEUSER

teria, it would appear that 0.39 percent inorganic phosphorus was not quite optimum in this experiment. On the other hand, the high-phytin basal ration which contained 0.15 percent inorganic and 0.47 percent total phosphorus was considerably improved by added inorganic phosphorus. After the initial period of three months there was an advantage in egg production for the lots receiving 0.15 and 0.30 percent supplementary phosphorus. The decline in egg production from the first to the last period was 31, 23, and 8 percent respectively for the basal, basal plus 0.15 percent inorganic phosphorus, and basal plus 0.30 percent inorganic phosphorus. Weight maintenance was also better in the lot which received 0.45 percent inorganic plus 0.32 percent phytin phosphorus than in the lots which received 0.15 and 0.30 percent inorganic phosphorus. There was also a slight advantage for this lot in level of inorganic plasma phosphorus and bone ash values. No improvement in egg shell breaking strength was obtained by increasing the inorganic phosphorus in the ration beyond 0.3 percent. In this experiment it appeared that the total phosphorus requirement for maintenance of body weight and egg production was approximately 0.5 percent of the ration when the phosphorus was nearly all inorganic. However, a higher level of approximately 0.65 percent phosphorus gave better results with respect to maintenance of blood phosphorus and prevention of decalcification of bone. When phytin comprised an appreciable portion of the total phosphorus in the diet (Lots 2A, 2B, 2C), however, a total phosphorus allowance of 0.77 percent gave more favorable results than 0.47 or 0.62 percent of this element. It is estimated from the limited data available that

roughly fifty percent of the phytin phosphorus in ordinary feed ingredients was utilized by the hens in this experiment. DISCUSSION The experiments reported above show that laying hens have considerably more ability to utilize the phosphorus of phytin than do young chicks. Several months were required to produce serious symptoms of deficiency by feeding hens rations containing phosphorus mostly in the form of phytin. Under similar conditions high mortality occurs in chicks within a few days (Gillis el al., 1949). Adult birds, of course, are not rapidly building skeletal or soft tissue, both of which require large amounts of phosphorus. Their requirements are mostly for replacement of phosphorus deposited in eggs and other normal catabolic losses. Furthermore hens are able to draw upon their skeletal stores for a limited amount of phosphorus, thus probably delaying the effects of a dietary deficiency of this element. In spite of these facts, however, phytin or a combination of phytin and inorganic phosphorus were not as efficiently utilized as were defluorinated phosphate or dicalcium phosphate. There is a strong suggestion in these experiments that phytin was approximately one-half as effective as the inorganic phosphates in supplying phosphorus. For example in Experiment 3 (Table 6) we have assumed that the minimum amount of phosphorus needed in Ration 1 was that received by Lot IB. This lot received a total of 0.64 percent dietary phosphorus. However, in Ration 2 it appeared that the minimum total phosphorus necessary for optimum results was that received by Lot 2C, or 0.77 percent. There is thus a discrepancy of 0.13 percent in the phosphorus requirement of these two lots of hens receiving different rations. If, however, the phos-

PHOSPHORUS REQUIREMENTS OF HENS

phorus in phytin is only one half as available as that in dicalcium phosphate there is good agreement as to the requirement on either of these rations. Using this assumption Lot IB received 0.54 percent phosphorus from dicalcium phosphate and 0.05 percent "available" phosphorus from phytin, or a total of 0.59 percent "available" phosphorus. On the same basis Lot 2C received 0.45 percent phosphorus from dicalcium phosphate and 0.16 percent "available" phosphorus from phytin or a total of 0.61 percent total "available" phosphorus. The results of Experiments 1 and 2 are also compatible with the conclusions that approximately 0.6 percent available phosphorus is required and that phytin is one half as available as inorganic phosphate in meeting the requirement. In Experiment 1 (Table 2) we have concluded that on the basis of all available criteria Lot 3 received the minimum amount of phosphorus necessary for optimum performance. This lot received 0.50 percent inorganic phosphorus and 0.12 percent "available" phosphorus from phytin if our assumption of one-half availability for phytin is correct. The minimun requirement for "available" phosphorus in this experiment was, therefore, 0.62 percent, a value in good agreement with the values of 0.59 and 0.61 calculated from Experiment 3. In Experiment 2 (Table 4) it was concluded that the phosphorus allowance of Lot 2 was more nearly optimum than that of Lot 1. If the same calculations are applied to these two lots it is determined that the allowance of Lot 2 was 0.60 percent "available" phosphorus while that of Lot 1 was only 0.48 percent. Thus in three experiments utilizing four different diets optimum performance was secured in lots of hens which received respectively 0.59, 0.60, 0.61, and 0.62 percent of

983

"available" phosphorus. The term "available" in this case would imply that the phosphorus was used with the same degree of efficiency as that in c.p. dicalcium phosphate or a high grade defluorinated phosphate. The present experiments strongly indicated that the requirement of the laying hen for phosphorus was less than that suggested by earlier work. This discrepancy is undoubtedly due in large part to past failure to recognize the difference in availability between inorganic and phytin phosphorus. The calculated inorganic phosphorus content of the ration used by Norris et al. (1933) was 0.45-0.50 percent and that reported by Miller and Bearse (1934) to give optimum results was 0.500.60 percent. I t appears, therefore, that the phosphorus requirements determined by these workers are in substantial agreement with our conclusions when allowance is made for the difference in availability between inorganic and phytin phosphorus. From the present work it appeared that in some instances as little as 0.5 percent total phosphorus was adequate for egg production and maintenance of weight if supplied mostly in readily available inorganic form. However, this level did not prevent some decalcification of bone and did not maintain the plasma phosphorus content quite as well as approximately 0.60 percent of readily available phosphorus. In the formulation of practical rations for laying hens it will generally be necessary to include ingredients which contain appreciable quantities of phytin phosphorus. Under such conditions due account should be taken of the poor availability of phytin. The total phosphorus provided in Such a diet should exceed the 0.6 percent minimum requirement by the amount necessary to provide at least this amount in "available" form.

984

C. W. CARLSON, D. G. JONES, W. KOHLMEYER AND A. L. MOXON SUMMARY

REFERENCES

Experiments with White Leghorn pullets have shown that phosphorus in phytin is not as satisfactory as that from inorganic phosphorus supplements in meeting the requirements of laying birds. This was found to be true of both purified calcium phytate and the phytin found in common feedstuffs of plant origin. From the data available it is estimated that the hens in these experiments utilized phytin phosphorus approximately one-half as effectively as they utilized defluorinated phosphate or dicalcium phosphate. Under the conditions of these experiments, it appeared that 0.5 percent of inorganic or "available" phosphorus was required for egg production and maintenance of weight. For the maintenance of optimum blood levels of phosphorus and prevention of decalcification of bone, however, the requirement was approximately 0.6 percent phosphorus.

Common, R. H., 1939. Phytic acid and mineral metabolism in poultry. Nature, 143: 379-380. Evans, R. J., and J. S. Carver, 1942. The calcium and phosphorus requirements of single comb White Leghorn pullets. Poultry Sci. 21: 469. Evans, R. J., J. S. Carver and A. W. Brant, 1944. Influence of dietary factors on egg shell quality. I. Phosphorus. Poultry Sci. 23: 9-15. Gillis, M. B., L. C. Norris and G. F. Heuser, 1948. The utilization by the chick of phosphorus from different sources. J. Nutrition, 35:195-208. Gillis, M. B., L. C. Norris and G. F. Heuser, 1949. The effect of phytin on the phosphorus requirement of the chick. Poultry Sci. 28: 283-288. Miller, M. W., and G. E. Bearse, 1934. Phosphorus requirements of laying hens. Washington Agr. Exp. Sta. Bui. 306. Norris, L. C , G. F. Heuser, H. S. Wilgus, Jr., and A. T. Ringrose, 1933. The calcium and phosphorus requirements of laying hens. New York State College of Agr. 46th Ann. Rept. 137-138. Singsen, E. P., 1948. The phosphorus requirements of the chicken with special reference to the availability of phytin phosphorus. Storrs Agr. Exp. Sta. Bui. 260.

The Effects of Vitamin Bi2 and Aureomycin on Reproductive Performance in Turkeys 1 C. W. CARLSON, D. G. JONES, WM. KOHLMEYER AND A. L. MOXON 2 South Dakota Agricultural Experiment Station, College Station (Received for publication March 9, 1953)

T I T T L E information is available con-*—' cerning the need for vitamin B i 2 for hatchability of turkey eggs. Based on studies conducted for three hatching seasons, Kratzer (1952) has reported that turkey hens on an animal protein deficient ration performed as well with regard to hatchability of fertile eggs as hens on a practical ration. However, poults from 1 Published by permission of the Director of the S. Dak. Agric. Exp. Sta. as Paper No. 265 of the Journal Series. 2 Present Address: Ohio Agricultural Experiment Station. Wooster, Ohio.

such depleted hens responded to feeding or injection of crystalline vitamin B12 while poults from hens fed normal rations gave no response. Antibiotics elicited comparable growth responses, regardless of the source of the poults. There is also little information available concerning the possible value of antibiotics in the turkey breeder diet. Work at this station (Carlson, Kohlmeyer and Moxon, 1951; and Carlson, unpublished results, 1951) has indicated that supplements containing vitamin B12 and aureomycin, when added to diets deficient in animal protein, have