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The Pantothenic Acid Requirement of Turkey Hens
The Pantothenic Acid Requirement of Turkey Hens F. H. KRATZER, P. N. DAVIS, B. J. MARSHALL AND D. E. WILLIAMS Department of Poultry Husbandry, University of California, Davis (Received for publication April 5, 1954)
"EXPERIMENTS
trate containing 12.5 mg. per pound was added in the third year. The fish meal was washed two times with water and then dried at 60°C. The ground wheat and corn were heated at 110°C. for 30 hours. The basal rations were found to contain 3.3, 2.8 and 3.5 mg. of pantothenic acid per kilogram in successive years by the method of Skeggs and Wright (1944) using Lactobacillus arabinosus as the assay organism. Calcium-d-pantothenate was used as a supplement to give diets of various pantothenic acid content. Spring-hatched Bronze turkey hens were reared on practical turkey rations until they were divided into groups and were fed the experimental rations. There were 10, 15 and 14 hens per group respectively in the successive seasons. The experiments were started on February 6th, January 23rd and December 21st in the three years. The hens were housed in pens approximately 12X20 feet with raised wire floors. Natural mating was used the first year but the fertility was not as satisfactory as desired. Toms were placed in pens the second year, but developed lameness and had to be removed early in the season. Artificial insemination with 1/40 ml. of mixed semen was used every 2 weeks in both the second and third years.
on the pantothenic
>
-•- acid requirement of poults with an extracted type of ration indicated that the need for optimum growth was definitely higher than for chicks (Lepkovsky el al., 1945). Later work with a heated diet showed that, when it was properly supplemented, it could be used satisfactorily for pantothenic acid studies (Kratzer and Williams, 1948) whereas the heated diet had proven unsatisfactory earlier (Jukes, 1938). Symptoms of a deficiency in poults were dermatitis, poor growth and high mortality. Work with chicken hens has demonstrated the need for pantothenic acid for hatchability and good liveability in chicks (Gillis et al., 1948). In the present study, the need for pantothenic acid in the diet of turkey breeder hens was investigated in experiments extending over three breeding seasons. EXPERIMENTAL
The basal ration deficient in pantothenic acid contained the following: waterwashed fishmeal, 13.0 g.; heated ground corn, 50.0 g.; heated ground wheat, 33.0 g.; ground limestone, 2.0 g.; fish oil (2,250 A, 300 D), 1.0 g.; salt, 0.5 g.; choline chloride, 0.2 g.; manganese sulfate, 0.0125 g.; vitamin E concentrate (44 units/g.), 0.11 g.; niacin, 0.0055 g.; menadione, 0.0011 g.; riboflavin, 0.00066 g.; thiamine hydrochloride, 0.00066 g.; pyridoxine hydrochloride, 0.00044 g.; folic acid, 0.00022 g.; and biotin, 0.000022 g. Half of the fish oil was replaced by dry vitamin A and D supplements in the second and third years and 0.1 percent of a vitamin B12 concen-
RESULTS
Effect on hatchability. In the first year of the experiment, eggs for the first hatch were set on February 14th, 8 days after the breeder hens were started on the experiment. Successive hatches were set at 2 week intervals. Hatchability for the basal group was satisfactory for the first 68
69
PANTOTHENIC ACID REQUIREMENT OF TURKEYS
3 hatches but dropped to 18 percent in the fourth hatch and to zero in the 5th hatch (Table 1). TABLE 1.—Effect of duration of feeding pantothenic acid deficient diet upon hatchability Hatch number
Number of fertile eggs
Percent hatchability
1 2 3 4 5 6 7 8
7 11 12 28 29 22 13 4
57 82 58 18 0 5 0 0
In summarizing the data for the 3 years, hatchability was calculated only for hatches 4 to 8, 5 to 8 and 4 to 9 respectively for the various years. I t was felt that by then the hens had become depleted in pantothenic acid and that hatchability would be directly related to the level of the vitamin in the diet. In the first year (Figure 1), hatchability increased as pantothenic acid was added until approximately 16.5 mg. of pantothenic
acid per kg. was included in the ration. In the second year, however, the highest level of the vitamin (20.4 mg./kg.) produced the best hatchability. It was thought advisable to determine the relation of dietary pantothenic acid to hatchability again, especially at high levels of supplementation. In the third experiment 19.8 mg. of pantothenic acid per kg. gave slightly better hatchability than 14.3 mg./kg. while 25.2 mg. and 30.6 mg. per kg. produced progressively poorer hatchability. Since 20.9 mg./kg. produced lower hatchability than 16.5 mg./kg. in one experiment and 19.8 mg./kg. caused only slightly better hatchability than 14.3 mg./kg. in another trial, it seems probable that under most conditions approximately 16 mg. of pantothenic acid per kilogram of ration is adequate for optimum hatchability. Effect on egg production. Egg production for the experimental periods (Table 2) showed no consistent relationship to the pantothenic acid content of the ration. In both the first and third seasons the groups fed the lowest levels of pantothenic TABLE 2.—Effect of pantothenic acid in the ration upon egg production in turkey hens Pantothenic acid in feed (mg./kg.)
Total eggs per hen (February to May)
3.3 7.7 12.1 16.5 20.9
42.6 33.4 35.9 34.5 36.2
Second Year
2.8 ' 7.2 11.6 16.0 20.4
23.3 28.2 21.3 28.5 22.6
Third Year
3.5 14.3 19.8 25.2 30.6
30.0 29.0 22.6 25.8 24.9
•5C-
;«First Year t30
|-20
0
5
»
* = First year
o
o = Second year
•
• = Third year
10 15 20 25 PANTOTHENIC ACID IN RATION (mg./Kg.)
^
30
FIG. 1. Effect of pantothenic acid in the ration of turkey breeder hens upon the hatchability of fertile eggs.
70
F. H. K R A T Z E R , P. N . D A V I S , B. J. M A R S H A L L AND D. E. W I L L I A M S
acid laid more eggs than the other groups while in the second season the production of the basal group was intermediate as compared to the other groups. Effect on embryos. Eggs which failed to hatch were opened and examined during the first 2 years of the experiment. M a n y embryos from the pantothenic acid-low groups were noted to have a type of stiff and wiry down (Figure 2) which is not usually found in embryos in unpipped eggs from hens fed adequate rations, except possibly a t a very low incidence. Practically all of these embryos with abnormal down also had abnormalities of the legs, particularly a bending of the tarsometatarsus. Most of the abnormal embryos were from hens fed rations containing 2.8 or 3.3 mg. of pantothenic acid per kilogram whereas much fewer were from those on the next level (7.2 or 7.7 mg./kg.). T h e
higher levels of pantothenic acid used were apparently adequate to prevent the abnormality observed. Pantothenic acid in eggs. Free p a n t o thenic acid was determined in eggs from each group of hens in the second and third years. All eggs for analysis were taken during the second half of the breeding season so that their content would reflect the dietary level. Two eggs from each group were pooled and were sampled for each analysis according to the procedure described b y Gillis el al. (1948). A total of six eggs per group were analyzed in the second year and eight per group in the third year. T h e results (Figure 3) show a consistent rise in the free pantothenic acid in turkey eggs as the level in the diet was increased. T h e dietary requirement for optimum hatchability, or about 16 mg. per kilogram of ration corresponds to ap-
FIG. 2. Embryos on right from hens fed ration low in pantothenic acid compared with embryo from hen fed adequate ration.
PANTOTHENIC ACID REQUIREMENT OF TURKEYS ""i
"
r
1
1
1
1
_
ACID IN EGG (meg. 5 w
3.
.-
o
HEN
sf^ «
jg? Sv
3
PAN
e*
«« Second yeor
o - — ^ • Third year
1
~0
5
1
i
i
i
i
10
15
20
25
30
-
PANTOTHENIC ACID IN RATION Img./Kg.)
FIG. 3. Relation of pantothenic acid in the ration of turkey breeder hens to the free pantothenic acid in their eggs.
proximately 11 micrograms of free pantothenic acid per gram of egg. Survival of poults. In the second season of the experiment representative poults from each group were placed in a battery and fed a ration deficient in pantothenic acid. The length of time which these poults would survive was determined. Survival was greatly influenced by the level of the vitamin in the breeder ration (Table 3). Sixteen milligrams of pantothenic acid per kilogram of ration was the minimum level to give optimum survival. Effect on poult weight. Weight of poults was recorded in the third year of the experiment. The data indicate (Table 4) TABLE 3.—Effect of pantothenic acid in the diet of breeder hens upon the survival of their poults fed a pantothenic acid-low diet
Date hatched
April 27
May 24
Pantothenic acid in breeder ration (mg./kg.)
Number of poults
Average survival (days)
2.8 7.2 11.6 16.0 20.4
2 10 10 10 10
1.5 5.3 8.9 11.3 10.5
7.2 11.6 16.0 20.4
6 1 6 6
7.5 12.0 13.2 14.3
71
TABLE 4.—Effect of pantothenic acid in turkey breeder ration upon weight of poults at hatching Pantothenic acid in breeder ration (mg./kg.)
Number of poults
Average weight (grams)
3.5 14.3 19.8 25.2 30.6
65 128 92 109 98
47.6 50.9 50.1 51.1 51.1
that poult weight was decreased by the lowest level of pantothenic acid in the breeder ration, but there was no effect at levels above 14.3 mg. per kg. DISCUSSION Pantothenic acid has been found to be required for hatchability in turkeys. It required approximately 5 weeks to deplete the hen's stores of vitamin to the point where hatchability was affected. Approximately 16 mg. of pantothenic acid was required per kilogram of ration to maintain optimum hatchability. This is somewhat higher than has been reported to be needed by chicken hens since Gillis et al. (1948) determined their need to be between 7.5 and 10.0 milligrams per kilogram. This requirement is also somewhat higher than the poult requirement which was found to be approximately 10.5 milligrams per kilogram to produce optimum growth (Kratzer and Williams, 1948). The results indicate a depression in hatchability at levels of 25 milligrams of pantothenic acid and higher. No explanation can be offered for this adverse effect which was noted in the last year in which the study was conducted. Maximum hatchability in the 3 experiments was not as high as was desired. However, the hatchability results did not include the early hatches of each season, and a decline in overall hatchability as the season progresses is commonly noted. The
72
POULTRY SCIENCE INDEX
hatchability of adequately supplemented groups compared favorably with hatchability of eggs from hens on practical rations which were set concurrently in the same incubators. The level of pantothenic acid in the eggs varied directly with the levels in the ration. This indicates that intestinal synthesis of the vitamin by microorganisms or the eating of droppings containing the vitamin was not a factor in supplying pantothenic acid to the bird. These results also indicate that about 11 micrograms of free pantothenic acid must be present per gram of egg for proper development of the embryo. The level of pantothenic acid in the breeder ration also influences the survival of poults hatched from their eggs when the poults are fed a ration somewhat deficient in the vitamin. A wiry down condition noted in the embryos which failed to hatch may be analogous to the dermatitis which occasionally develops in poults deficient in pantothenic acid (Kratzer and Williams, 1948). Poults from hens fed the lowest level of pantothenic acid were smaller than those from other groups. Egg production of the breeder hens was not influenced by the level of pantothenic acid in their rations. There were also no gross symptoms which could be observed in the hens during the course of the experiment. This is similar to the observations made by Gillis et al. (1948) with chicken hens. SUMMARY
Hatchability in turkeys was greatly reduced when the breeder hens were fed a
ration deficient in pantothenic acid for about 5 weeks. Approximately 16 milligrams of pantothenic acid per kilogram of ration was required to maintain optimum hatchability. Egg production was unaffected even at the lowest levels of pantothenic acid fed. The level of pantothenic acid in the eggs and the survival of poults from deficient hens were directly related to the level in the ration. Wiry down in the embryos which failed to hatch and smaller poults were noted from hens in groups fed low levels of pantothenic acid. ACKNOWLEDGEMENT
We are grateful to Lederle Laboratories Division, American Cyanamid Co., Pearl River, New York for the folic acid and to Merck and Company, Rahway, New Jersey for the vitamin Bi2 used in these studies. We are indebted to Dr. V. S. Asmundson for examination of the embryos. REFERENCES Lepkovsky, S., F. H. Bird, F. H. Kratzer and V. S. Asmundson, 1945. The comparative requirements of chicks and turkey poults for pantothenic acid. Poultry Sci. 24: 335-339. Kratzer, F. H., and D. E. WilUams, 1948. The pantothenic acid requirement of poults for early growth. Poultry Sci. 27: 518-523. Jukes, T. H., 1938. The vitamin G requirements of young poults. Poultry Sci. 17: 227-234. Gillis, M. B., G. F. Heuser and L. C. Norris, 1948. Pantothenic acid in the nutrition of the hen. J. Nutrition, 35:351-363. Skeggs, H. R., and L. D. Wright, 1944. The use of Lactobacillus arabinosus in the microbiological. determination of pantothenic acid. J. Biol. Chem. 156: 21-26.
POULTRY SCIENCE INDEX A subject matter index of volumes 1 to 20 inclusive, is available from C. B. Ryan, SecretaryTreasurer, Poultry Science Association, Texas
A and M College System, College Station, Texas, at $1.00 per copy.
"EXPERIMENTS
trate containing 12.5 mg. per pound was added in the third year. The fish meal was washed two times with water and then dried at 60°C. The ground wheat and corn were heated at 110°C. for 30 hours. The basal rations were found to contain 3.3, 2.8 and 3.5 mg. of pantothenic acid per kilogram in successive years by the method of Skeggs and Wright (1944) using Lactobacillus arabinosus as the assay organism. Calcium-d-pantothenate was used as a supplement to give diets of various pantothenic acid content. Spring-hatched Bronze turkey hens were reared on practical turkey rations until they were divided into groups and were fed the experimental rations. There were 10, 15 and 14 hens per group respectively in the successive seasons. The experiments were started on February 6th, January 23rd and December 21st in the three years. The hens were housed in pens approximately 12X20 feet with raised wire floors. Natural mating was used the first year but the fertility was not as satisfactory as desired. Toms were placed in pens the second year, but developed lameness and had to be removed early in the season. Artificial insemination with 1/40 ml. of mixed semen was used every 2 weeks in both the second and third years.
on the pantothenic
>
-•- acid requirement of poults with an extracted type of ration indicated that the need for optimum growth was definitely higher than for chicks (Lepkovsky el al., 1945). Later work with a heated diet showed that, when it was properly supplemented, it could be used satisfactorily for pantothenic acid studies (Kratzer and Williams, 1948) whereas the heated diet had proven unsatisfactory earlier (Jukes, 1938). Symptoms of a deficiency in poults were dermatitis, poor growth and high mortality. Work with chicken hens has demonstrated the need for pantothenic acid for hatchability and good liveability in chicks (Gillis et al., 1948). In the present study, the need for pantothenic acid in the diet of turkey breeder hens was investigated in experiments extending over three breeding seasons. EXPERIMENTAL
The basal ration deficient in pantothenic acid contained the following: waterwashed fishmeal, 13.0 g.; heated ground corn, 50.0 g.; heated ground wheat, 33.0 g.; ground limestone, 2.0 g.; fish oil (2,250 A, 300 D), 1.0 g.; salt, 0.5 g.; choline chloride, 0.2 g.; manganese sulfate, 0.0125 g.; vitamin E concentrate (44 units/g.), 0.11 g.; niacin, 0.0055 g.; menadione, 0.0011 g.; riboflavin, 0.00066 g.; thiamine hydrochloride, 0.00066 g.; pyridoxine hydrochloride, 0.00044 g.; folic acid, 0.00022 g.; and biotin, 0.000022 g. Half of the fish oil was replaced by dry vitamin A and D supplements in the second and third years and 0.1 percent of a vitamin B12 concen-
RESULTS
Effect on hatchability. In the first year of the experiment, eggs for the first hatch were set on February 14th, 8 days after the breeder hens were started on the experiment. Successive hatches were set at 2 week intervals. Hatchability for the basal group was satisfactory for the first 68
69
PANTOTHENIC ACID REQUIREMENT OF TURKEYS
3 hatches but dropped to 18 percent in the fourth hatch and to zero in the 5th hatch (Table 1). TABLE 1.—Effect of duration of feeding pantothenic acid deficient diet upon hatchability Hatch number
Number of fertile eggs
Percent hatchability
1 2 3 4 5 6 7 8
7 11 12 28 29 22 13 4
57 82 58 18 0 5 0 0
In summarizing the data for the 3 years, hatchability was calculated only for hatches 4 to 8, 5 to 8 and 4 to 9 respectively for the various years. I t was felt that by then the hens had become depleted in pantothenic acid and that hatchability would be directly related to the level of the vitamin in the diet. In the first year (Figure 1), hatchability increased as pantothenic acid was added until approximately 16.5 mg. of pantothenic
acid per kg. was included in the ration. In the second year, however, the highest level of the vitamin (20.4 mg./kg.) produced the best hatchability. It was thought advisable to determine the relation of dietary pantothenic acid to hatchability again, especially at high levels of supplementation. In the third experiment 19.8 mg. of pantothenic acid per kg. gave slightly better hatchability than 14.3 mg./kg. while 25.2 mg. and 30.6 mg. per kg. produced progressively poorer hatchability. Since 20.9 mg./kg. produced lower hatchability than 16.5 mg./kg. in one experiment and 19.8 mg./kg. caused only slightly better hatchability than 14.3 mg./kg. in another trial, it seems probable that under most conditions approximately 16 mg. of pantothenic acid per kilogram of ration is adequate for optimum hatchability. Effect on egg production. Egg production for the experimental periods (Table 2) showed no consistent relationship to the pantothenic acid content of the ration. In both the first and third seasons the groups fed the lowest levels of pantothenic TABLE 2.—Effect of pantothenic acid in the ration upon egg production in turkey hens Pantothenic acid in feed (mg./kg.)
Total eggs per hen (February to May)
3.3 7.7 12.1 16.5 20.9
42.6 33.4 35.9 34.5 36.2
Second Year
2.8 ' 7.2 11.6 16.0 20.4
23.3 28.2 21.3 28.5 22.6
Third Year
3.5 14.3 19.8 25.2 30.6
30.0 29.0 22.6 25.8 24.9
•5C-
;«First Year t30
|-20
0
5
»
* = First year
o
o = Second year
•
• = Third year
10 15 20 25 PANTOTHENIC ACID IN RATION (mg./Kg.)
^
30
FIG. 1. Effect of pantothenic acid in the ration of turkey breeder hens upon the hatchability of fertile eggs.
70
F. H. K R A T Z E R , P. N . D A V I S , B. J. M A R S H A L L AND D. E. W I L L I A M S
acid laid more eggs than the other groups while in the second season the production of the basal group was intermediate as compared to the other groups. Effect on embryos. Eggs which failed to hatch were opened and examined during the first 2 years of the experiment. M a n y embryos from the pantothenic acid-low groups were noted to have a type of stiff and wiry down (Figure 2) which is not usually found in embryos in unpipped eggs from hens fed adequate rations, except possibly a t a very low incidence. Practically all of these embryos with abnormal down also had abnormalities of the legs, particularly a bending of the tarsometatarsus. Most of the abnormal embryos were from hens fed rations containing 2.8 or 3.3 mg. of pantothenic acid per kilogram whereas much fewer were from those on the next level (7.2 or 7.7 mg./kg.). T h e
higher levels of pantothenic acid used were apparently adequate to prevent the abnormality observed. Pantothenic acid in eggs. Free p a n t o thenic acid was determined in eggs from each group of hens in the second and third years. All eggs for analysis were taken during the second half of the breeding season so that their content would reflect the dietary level. Two eggs from each group were pooled and were sampled for each analysis according to the procedure described b y Gillis el al. (1948). A total of six eggs per group were analyzed in the second year and eight per group in the third year. T h e results (Figure 3) show a consistent rise in the free pantothenic acid in turkey eggs as the level in the diet was increased. T h e dietary requirement for optimum hatchability, or about 16 mg. per kilogram of ration corresponds to ap-
FIG. 2. Embryos on right from hens fed ration low in pantothenic acid compared with embryo from hen fed adequate ration.
PANTOTHENIC ACID REQUIREMENT OF TURKEYS ""i
"
r
1
1
1
1
_
ACID IN EGG (meg. 5 w
3.
.-
o
HEN
sf^ «
jg? Sv
3
PAN
e*
«« Second yeor
o - — ^ • Third year
1
~0
5
1
i
i
i
i
10
15
20
25
30
-
PANTOTHENIC ACID IN RATION Img./Kg.)
FIG. 3. Relation of pantothenic acid in the ration of turkey breeder hens to the free pantothenic acid in their eggs.
proximately 11 micrograms of free pantothenic acid per gram of egg. Survival of poults. In the second season of the experiment representative poults from each group were placed in a battery and fed a ration deficient in pantothenic acid. The length of time which these poults would survive was determined. Survival was greatly influenced by the level of the vitamin in the breeder ration (Table 3). Sixteen milligrams of pantothenic acid per kilogram of ration was the minimum level to give optimum survival. Effect on poult weight. Weight of poults was recorded in the third year of the experiment. The data indicate (Table 4) TABLE 3.—Effect of pantothenic acid in the diet of breeder hens upon the survival of their poults fed a pantothenic acid-low diet
Date hatched
April 27
May 24
Pantothenic acid in breeder ration (mg./kg.)
Number of poults
Average survival (days)
2.8 7.2 11.6 16.0 20.4
2 10 10 10 10
1.5 5.3 8.9 11.3 10.5
7.2 11.6 16.0 20.4
6 1 6 6
7.5 12.0 13.2 14.3
71
TABLE 4.—Effect of pantothenic acid in turkey breeder ration upon weight of poults at hatching Pantothenic acid in breeder ration (mg./kg.)
Number of poults
Average weight (grams)
3.5 14.3 19.8 25.2 30.6
65 128 92 109 98
47.6 50.9 50.1 51.1 51.1
that poult weight was decreased by the lowest level of pantothenic acid in the breeder ration, but there was no effect at levels above 14.3 mg. per kg. DISCUSSION Pantothenic acid has been found to be required for hatchability in turkeys. It required approximately 5 weeks to deplete the hen's stores of vitamin to the point where hatchability was affected. Approximately 16 mg. of pantothenic acid was required per kilogram of ration to maintain optimum hatchability. This is somewhat higher than has been reported to be needed by chicken hens since Gillis et al. (1948) determined their need to be between 7.5 and 10.0 milligrams per kilogram. This requirement is also somewhat higher than the poult requirement which was found to be approximately 10.5 milligrams per kilogram to produce optimum growth (Kratzer and Williams, 1948). The results indicate a depression in hatchability at levels of 25 milligrams of pantothenic acid and higher. No explanation can be offered for this adverse effect which was noted in the last year in which the study was conducted. Maximum hatchability in the 3 experiments was not as high as was desired. However, the hatchability results did not include the early hatches of each season, and a decline in overall hatchability as the season progresses is commonly noted. The
72
POULTRY SCIENCE INDEX
hatchability of adequately supplemented groups compared favorably with hatchability of eggs from hens on practical rations which were set concurrently in the same incubators. The level of pantothenic acid in the eggs varied directly with the levels in the ration. This indicates that intestinal synthesis of the vitamin by microorganisms or the eating of droppings containing the vitamin was not a factor in supplying pantothenic acid to the bird. These results also indicate that about 11 micrograms of free pantothenic acid must be present per gram of egg for proper development of the embryo. The level of pantothenic acid in the breeder ration also influences the survival of poults hatched from their eggs when the poults are fed a ration somewhat deficient in the vitamin. A wiry down condition noted in the embryos which failed to hatch may be analogous to the dermatitis which occasionally develops in poults deficient in pantothenic acid (Kratzer and Williams, 1948). Poults from hens fed the lowest level of pantothenic acid were smaller than those from other groups. Egg production of the breeder hens was not influenced by the level of pantothenic acid in their rations. There were also no gross symptoms which could be observed in the hens during the course of the experiment. This is similar to the observations made by Gillis et al. (1948) with chicken hens. SUMMARY
Hatchability in turkeys was greatly reduced when the breeder hens were fed a
ration deficient in pantothenic acid for about 5 weeks. Approximately 16 milligrams of pantothenic acid per kilogram of ration was required to maintain optimum hatchability. Egg production was unaffected even at the lowest levels of pantothenic acid fed. The level of pantothenic acid in the eggs and the survival of poults from deficient hens were directly related to the level in the ration. Wiry down in the embryos which failed to hatch and smaller poults were noted from hens in groups fed low levels of pantothenic acid. ACKNOWLEDGEMENT
We are grateful to Lederle Laboratories Division, American Cyanamid Co., Pearl River, New York for the folic acid and to Merck and Company, Rahway, New Jersey for the vitamin Bi2 used in these studies. We are indebted to Dr. V. S. Asmundson for examination of the embryos. REFERENCES Lepkovsky, S., F. H. Bird, F. H. Kratzer and V. S. Asmundson, 1945. The comparative requirements of chicks and turkey poults for pantothenic acid. Poultry Sci. 24: 335-339. Kratzer, F. H., and D. E. WilUams, 1948. The pantothenic acid requirement of poults for early growth. Poultry Sci. 27: 518-523. Jukes, T. H., 1938. The vitamin G requirements of young poults. Poultry Sci. 17: 227-234. Gillis, M. B., G. F. Heuser and L. C. Norris, 1948. Pantothenic acid in the nutrition of the hen. J. Nutrition, 35:351-363. Skeggs, H. R., and L. D. Wright, 1944. The use of Lactobacillus arabinosus in the microbiological. determination of pantothenic acid. J. Biol. Chem. 156: 21-26.
POULTRY SCIENCE INDEX A subject matter index of volumes 1 to 20 inclusive, is available from C. B. Ryan, SecretaryTreasurer, Poultry Science Association, Texas
A and M College System, College Station, Texas, at $1.00 per copy.