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Reproductive Ability of Chickens Implanted at Nine Weeks of Age with Estrogen Pellets1
Reproductive Ability of Chickens Implanted at Nine Weeks of Age with Estrogen Pellets1 AHMET C. AKPINAR 2 AND C. S. SHAFFNER Poultry Department, University of Maryland, College Park (Received for publication July 7, 1951)
B
ECAUSE of the rather widespread use of estrogen implantation as a fattening agent and because estrogen will temporarily decrease the pugnaciousness of cockerels, this experiment was conducted to determine the effect of such treatment on the future reproductive ability of birds. Asmundson (1931) injected estrogen into laying pullets without apparent effect on egg weight, egg shells, or number of eggs produced. Turner (1948) concluded that a low level of estrogen helped to maintain egg production during the normal autumn decline. The effect of estrogens on ovulation, egg production, oyster shell consumption, feed consumption and body weight was studied by Adams, McGibbon and Casida (1950). They fed the orally effective estrogens diansylhexene and dienestrol diacetate at levels ranging from .01 to .04 percent of the diet to White Leghorn pullets. The .04 percent level of either estrogen severely depressed egg production and there were indications of a disturbance of calcium metabolism. The effect of large dosages of estrogen in decreasing testis size by depressing the production of the gonadotropic hormones is rather well accepted. Much of this work has been summarized by Skaller and Grigg (1950) who point out that estrogens 1
Scientific Paper No. A375. Contribution No. 2382 of the Maryland Agricultural Experiment Station (Department of Poultry Husbandry). 2 Present Address: University of Istanbul, Istanbul, Turkey.
at low levels may stimulate gonadotropic hormone production. Bird et al. (1947) found that when estrogens are administered, secondary sex characters suffer regression more readily than the testis, indicating that hormone production is stopped before the testis begins to atrophy. Kumaran and Turner (1949) found that spermatogenesis did not progress beyond the spermatogonial stage when diansylhexene was fed at the level of 4 gms. per 100 lbs. of feed. METHODS AND MATERIALS
Sixty male and 60 female chickens were selected from a pen-reared flock of 9week-old birds. Thirty of each sex were implanted with a 15 mg. pellet of stilbestrol in the upper neck region, and the remaining 30 of each sex maintained as controls. When the birds were 10 weeks of age, they were moved to range shelters and reared together in the conventional manner. The females were moved to laying batteries when they were 180 days of age. Changes in body weight and comb size, egg production, egg size, and specific gravity of eggs were recorded. Specific gravity was determined by submerging the eggs in salt solutions with specific gravities varying from 1.066 to 1.102. When the males were 240 days of age, a random sample of 5 treated and 5 control males were selected and moved to individual cages in a heated building. They were then subjected to 14 hours of light daily. These males were used for semen evaluation studies. 119
120
AHMET C. AKPINAR AND C. S. SHAFFNER
RESULTS AND DISCUSSIONS
(1) Growth and comb size. In Figure 2, the effect of the estrogen implantation on growth is presented. It will be noted that the treatment did not exhibit a marked effect on body weight. The treated and untreated groups tended to vary together rather consistently and any marked changes are thought to be due to the environment. To determine the effectiveness of treat55
production of the testis was permanently depressed by estrogen treatment in early life. (2) Egg production. Since the administration of exogenous estrogen is known to cause a marked suppression of the gonadotropic production of the pituitary, it was expected that sexual maturity of the treated females would be somewhat delayed. This did not prove to be the case. The average age at first egg was 179.5 +
Control d1
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^Treated ?
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130
140
1 150 160 170 Days after treatment
i
180
190
200
FIG. 1. Effect of estrogen implantation on comb growth.
ment in depressing the production of the male sex hormone, comb sizes were recorded. In the male in particular the effect of implantation on comb size remained noticeable for more than 150 days. The treatment had little effect on the comb size of the female. Apparently the females had largely overcome the effect of the treatment before the comb exhibited much growth. Comb sizes for the two groups are shown in Figure 1. It would appear that in the male androgen
3.5 days for the controls and 182.5 + 3.5 days for the treated pullets. The effect of the estrogen administered when the birds were 63 days of age apparently had been mostly overcome. Egg production was recorded for the first four months following sexual maturity. During this period the average production of the birds of the control and treated groups was 72.2 and 63.9 percent, respectively. I t would thus appear likely that treating young pullets with estrogen has a slightly
121
ESTROGEN AND REPRODUCTIVE ABILITY
detrimental effect on future egg production. The average weights of the eggs laid by the control and treated birds were 54.9+1.0 and 50.0 + 0.7 grams, respectively. The difference between these two groups is statistically significant. Since the size of the egg is known to be normally influenced most by the size of the yolk
indicating that the egg shells of the treated birds were thinner than those from the controls was found in the fact that less than 1 percent of the eggs laid by the control groups were soft-shelled while more than 2.5 percent of those laid by the treated groups were soft-shelled. Similar results were previously recorded by Adams et al. (1951).
3500
80 IOO 120 Days offer treatment
140
160
180
200
FIG. 2. Effect of estrogen implantation on body growth.
liberated by the ovary, it is assumed that the estrogen treatment had some residual effect in decreasing size of yolk. The specific gravity of the eggs was determined to ascertain whether or not the treatments had had any effect in altering calcium metabolism. The specific gravity of the eggs laid by the control birds was consistently greater than that of the eggs produced by the treated birds. The average specific gravities of the eggs laid by the control and treated groups were 1.087 + 0.004 and 1.081 + 0.001, respectively. Further evidence
(3) Semen production. The effect of estrogen implantation on the subsequent reproductive ability of the males was studied by making bi-weekly semen collections from treated and untreated males. These collections were started 210 days after the estrogen implantation. The treated cockerels were found to be delayed in sexual maturity and produced smaller amounts of semen than the control males. At the end of the collection period the average volume of the ejaculate of the control males was 0.41 ml. while for the treated group the volume was
122
H. L. ALMQUIST
0.12 ml. It was not determined whether this reduction in volume was due to testicular damage or to the depressive effect of the estrogen on the gonadotropic production of the pituitary. The earlier literature on this subject has been reviewed by Kumaran and Turner (1949). Semen from both groups of males was used for insemination and proved to be equally effective in inducing fertility. It would thus appear that the volume of semen was more seriously affected than the quality of the cells produced. SUMMARY
The effect of a single 15 mg. diethylstilbestrol pellet implanted into male and female chickens 63 days of age on their subsequent reproductive ability was studied. Changes in body weight and comb size were recorded as well as egg production, egg size, and specific gravity of the eggs produced. The semen quantity and quality of the males was also recorded. The results indicated that the implantation had little permanent effect on the ultimate body size of either sex and that the ultimate comb size of the female was not affected while the combs of the treated males remained permanently smaller than those of the untreated males. The days to sexual maturity for the females was unchanged by the treatment, but the egg production, egg weight,
and specific gravity of the eggs produced by the treated females were noticeably decreased. The date of sexual maturity of the males appeared to be increased and semen quantity decreased by the treatment; however, the treated males produced some semen of good quality. In general, it appeared that the treatment was much more noticeable on the males than on the females. REFERENCES Adams, J. L., W. H. McGibbon and L. E. Casida, 1950. The effect of orally administered synthetic estrogen on Single Comb White Leghorn pullets. Poultry Sci. 29: 666-671. Adams, J. L., W. H. McGibbon and L. E. Casida, 1951. Some characteristics of eggs from estrogenfed pullets. Poultry Sci. 30: 694-700. Asmundson, V. S., 1931. Effect of hormones on the formation of the hen's egg. Poultry Sci. 10: 157165. Bird, S., L. I. Pugsley and M. O. Klotz, 1947. The quantitative recovery of synthetic estrogens from tissues of the birds (Gallus domesticus) the response of the birds' testis, comb and epidermis to estrogen and of humans to ingestion of tissue from treated birds. Endocrinology 41:282-294. Kumaran, J. D. S., and C. W. Turner, 1949. The endocrinology of spermatogenesis in birds. Effect of estrogen and androgen. Poultry Sci. 28: 593602. Skaller, F. S., and G. W. Grigg, 1950. The effect of orally administered synthetic estrogen (hexoestrol) on the male fowl. Australian J. Agr. Res. 1:496-516. Turner, C. W., 1948. Feeding estrogen (diansylhexene) to laying hens. Poultry Sci. 27: 593-600.
Evaluation of Vitamin Requirement Data H. J. ALMQUIST The Grange Co., Modesto, Calif. (Received for publication July 14,1952)
T
HE fact that the logarithm of the intake level of a nutrient, such as a vitamin, shows a linear relation to a corresponding growth or other biological response is not new or strange. For example,
Almquist et al. (1938) reported a linear relation between the logarithm of vitamin K. intake of the chick and blood clotting power. This relation can be derived from a few simple assumptions and the reaction
B
ECAUSE of the rather widespread use of estrogen implantation as a fattening agent and because estrogen will temporarily decrease the pugnaciousness of cockerels, this experiment was conducted to determine the effect of such treatment on the future reproductive ability of birds. Asmundson (1931) injected estrogen into laying pullets without apparent effect on egg weight, egg shells, or number of eggs produced. Turner (1948) concluded that a low level of estrogen helped to maintain egg production during the normal autumn decline. The effect of estrogens on ovulation, egg production, oyster shell consumption, feed consumption and body weight was studied by Adams, McGibbon and Casida (1950). They fed the orally effective estrogens diansylhexene and dienestrol diacetate at levels ranging from .01 to .04 percent of the diet to White Leghorn pullets. The .04 percent level of either estrogen severely depressed egg production and there were indications of a disturbance of calcium metabolism. The effect of large dosages of estrogen in decreasing testis size by depressing the production of the gonadotropic hormones is rather well accepted. Much of this work has been summarized by Skaller and Grigg (1950) who point out that estrogens 1
Scientific Paper No. A375. Contribution No. 2382 of the Maryland Agricultural Experiment Station (Department of Poultry Husbandry). 2 Present Address: University of Istanbul, Istanbul, Turkey.
at low levels may stimulate gonadotropic hormone production. Bird et al. (1947) found that when estrogens are administered, secondary sex characters suffer regression more readily than the testis, indicating that hormone production is stopped before the testis begins to atrophy. Kumaran and Turner (1949) found that spermatogenesis did not progress beyond the spermatogonial stage when diansylhexene was fed at the level of 4 gms. per 100 lbs. of feed. METHODS AND MATERIALS
Sixty male and 60 female chickens were selected from a pen-reared flock of 9week-old birds. Thirty of each sex were implanted with a 15 mg. pellet of stilbestrol in the upper neck region, and the remaining 30 of each sex maintained as controls. When the birds were 10 weeks of age, they were moved to range shelters and reared together in the conventional manner. The females were moved to laying batteries when they were 180 days of age. Changes in body weight and comb size, egg production, egg size, and specific gravity of eggs were recorded. Specific gravity was determined by submerging the eggs in salt solutions with specific gravities varying from 1.066 to 1.102. When the males were 240 days of age, a random sample of 5 treated and 5 control males were selected and moved to individual cages in a heated building. They were then subjected to 14 hours of light daily. These males were used for semen evaluation studies. 119
120
AHMET C. AKPINAR AND C. S. SHAFFNER
RESULTS AND DISCUSSIONS
(1) Growth and comb size. In Figure 2, the effect of the estrogen implantation on growth is presented. It will be noted that the treatment did not exhibit a marked effect on body weight. The treated and untreated groups tended to vary together rather consistently and any marked changes are thought to be due to the environment. To determine the effectiveness of treat55
production of the testis was permanently depressed by estrogen treatment in early life. (2) Egg production. Since the administration of exogenous estrogen is known to cause a marked suppression of the gonadotropic production of the pituitary, it was expected that sexual maturity of the treated females would be somewhat delayed. This did not prove to be the case. The average age at first egg was 179.5 +
Control d1
50
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•
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.*•• E 45
Tr
O
""
,*"""
/'
" 40
•
O t_ O
Qi
|
•
35
L
o o
S 30 o «u
k-^"
5
25
Control -J
20
•"""
0 120
-8~~
~-—=-6
^Treated ?
1
130
140
1 150 160 170 Days after treatment
i
180
190
200
FIG. 1. Effect of estrogen implantation on comb growth.
ment in depressing the production of the male sex hormone, comb sizes were recorded. In the male in particular the effect of implantation on comb size remained noticeable for more than 150 days. The treatment had little effect on the comb size of the female. Apparently the females had largely overcome the effect of the treatment before the comb exhibited much growth. Comb sizes for the two groups are shown in Figure 1. It would appear that in the male androgen
3.5 days for the controls and 182.5 + 3.5 days for the treated pullets. The effect of the estrogen administered when the birds were 63 days of age apparently had been mostly overcome. Egg production was recorded for the first four months following sexual maturity. During this period the average production of the birds of the control and treated groups was 72.2 and 63.9 percent, respectively. I t would thus appear likely that treating young pullets with estrogen has a slightly
121
ESTROGEN AND REPRODUCTIVE ABILITY
detrimental effect on future egg production. The average weights of the eggs laid by the control and treated birds were 54.9+1.0 and 50.0 + 0.7 grams, respectively. The difference between these two groups is statistically significant. Since the size of the egg is known to be normally influenced most by the size of the yolk
indicating that the egg shells of the treated birds were thinner than those from the controls was found in the fact that less than 1 percent of the eggs laid by the control groups were soft-shelled while more than 2.5 percent of those laid by the treated groups were soft-shelled. Similar results were previously recorded by Adams et al. (1951).
3500
80 IOO 120 Days offer treatment
140
160
180
200
FIG. 2. Effect of estrogen implantation on body growth.
liberated by the ovary, it is assumed that the estrogen treatment had some residual effect in decreasing size of yolk. The specific gravity of the eggs was determined to ascertain whether or not the treatments had had any effect in altering calcium metabolism. The specific gravity of the eggs laid by the control birds was consistently greater than that of the eggs produced by the treated birds. The average specific gravities of the eggs laid by the control and treated groups were 1.087 + 0.004 and 1.081 + 0.001, respectively. Further evidence
(3) Semen production. The effect of estrogen implantation on the subsequent reproductive ability of the males was studied by making bi-weekly semen collections from treated and untreated males. These collections were started 210 days after the estrogen implantation. The treated cockerels were found to be delayed in sexual maturity and produced smaller amounts of semen than the control males. At the end of the collection period the average volume of the ejaculate of the control males was 0.41 ml. while for the treated group the volume was
122
H. L. ALMQUIST
0.12 ml. It was not determined whether this reduction in volume was due to testicular damage or to the depressive effect of the estrogen on the gonadotropic production of the pituitary. The earlier literature on this subject has been reviewed by Kumaran and Turner (1949). Semen from both groups of males was used for insemination and proved to be equally effective in inducing fertility. It would thus appear that the volume of semen was more seriously affected than the quality of the cells produced. SUMMARY
The effect of a single 15 mg. diethylstilbestrol pellet implanted into male and female chickens 63 days of age on their subsequent reproductive ability was studied. Changes in body weight and comb size were recorded as well as egg production, egg size, and specific gravity of the eggs produced. The semen quantity and quality of the males was also recorded. The results indicated that the implantation had little permanent effect on the ultimate body size of either sex and that the ultimate comb size of the female was not affected while the combs of the treated males remained permanently smaller than those of the untreated males. The days to sexual maturity for the females was unchanged by the treatment, but the egg production, egg weight,
and specific gravity of the eggs produced by the treated females were noticeably decreased. The date of sexual maturity of the males appeared to be increased and semen quantity decreased by the treatment; however, the treated males produced some semen of good quality. In general, it appeared that the treatment was much more noticeable on the males than on the females. REFERENCES Adams, J. L., W. H. McGibbon and L. E. Casida, 1950. The effect of orally administered synthetic estrogen on Single Comb White Leghorn pullets. Poultry Sci. 29: 666-671. Adams, J. L., W. H. McGibbon and L. E. Casida, 1951. Some characteristics of eggs from estrogenfed pullets. Poultry Sci. 30: 694-700. Asmundson, V. S., 1931. Effect of hormones on the formation of the hen's egg. Poultry Sci. 10: 157165. Bird, S., L. I. Pugsley and M. O. Klotz, 1947. The quantitative recovery of synthetic estrogens from tissues of the birds (Gallus domesticus) the response of the birds' testis, comb and epidermis to estrogen and of humans to ingestion of tissue from treated birds. Endocrinology 41:282-294. Kumaran, J. D. S., and C. W. Turner, 1949. The endocrinology of spermatogenesis in birds. Effect of estrogen and androgen. Poultry Sci. 28: 593602. Skaller, F. S., and G. W. Grigg, 1950. The effect of orally administered synthetic estrogen (hexoestrol) on the male fowl. Australian J. Agr. Res. 1:496-516. Turner, C. W., 1948. Feeding estrogen (diansylhexene) to laying hens. Poultry Sci. 27: 593-600.
Evaluation of Vitamin Requirement Data H. J. ALMQUIST The Grange Co., Modesto, Calif. (Received for publication July 14,1952)
T
HE fact that the logarithm of the intake level of a nutrient, such as a vitamin, shows a linear relation to a corresponding growth or other biological response is not new or strange. For example,
Almquist et al. (1938) reported a linear relation between the logarithm of vitamin K. intake of the chick and blood clotting power. This relation can be derived from a few simple assumptions and the reaction