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Effect of Thyroprotein-Feeding on the Gland and Organ Weights of Two-Year-Old White Leghorn Hens*
Effect of Thyroprotein-Feeding on the Gland and Organ Weights o f T w o Year-Old White Leghorn Hens* C. W. TURNER Department of Dairy Husbandry, University of Missouri, Columbia (Received for publication August 27, 1947)
of groups of normal White Leghorn hens obtained in another experiment are presented.
URING the past five years a group of White Leghorn hens have been fed a ration containing sufficient thyroprotein to induce a mild degree of hyperthyroidism (10 gm. per 100 lbs. of feed). Until the present year (6th laying year) the control group and those fed thyroprotein have laid about equal numbers of eggs during the fall and winter each year. However, during the spring and summer, the thyroprotein-fed group maintained egg production at a higher level. With advancing age, the yearly egg production of the thyroprotein-fed group has declined far less than the control group. (Turner and Kempster, 1947). The question has been raised as to the effect of continuous thyroprotein-feeding upon the body composition and gland and organ weight. Data was presented on the gland and organ weights of a limited number of Rhode Island Red hens fed thyroprotein for two consecutive years in comparison with normal hens (Turner et al. 1946). The object of the present study was to determine the progressive effect of feeding thyroprotein during a period of a year upon the glands and organs of White Leghorn hens similar to the hens on the longtime experiment. For comparison, the average weight of the glands and organs
Information on the selection of the fowls used in this experiment is presented in the preceding paper (Turner, 1948). A group of about 75 birds were selected at random from the control group and placed in a separate pen. They were fed the control ration to which thyroproteinf at the rate of 10 gm./lOO lbs. of feed was added. The sample of thyroprotein used in this study contained 2.7 percent thyroxine as determined by the method of Reineke et al. (1945). This sample of material has been used in the experiment upon the effect of continued feeding of thyroprotein to laying hens (Turner, et al. 1946). It had been bioassayed on growing chickens by Schultze and Turner (1945). The thyroprotein feeding was begun in August 1945. The first group of 10 birds was sacrificed in September after about 30 days of treatment. Each succeeding group was sacrificed following two months additional thyroprotein feeding until Sept. 1946. This latter group consisted of the 5 remaining birds. Each bird to be included in each bimonthly group was selected upon the
* Contribution from the Department of Dairy Husbandry, Missouri Agricultural Experiment Station, Journal Series No. 1060.
t The thyroprotein under the trade name of protamone was supplied by the Cerophyl Lab. Inc., Kansas City, Missouri.
EXPERIMENTAL METHODS
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EXPERIMENTAL RESULTS
Since the individual birds selected to constitute each group of 10 hens were picked out of the larger groups of controls and thyroprotein-fed hens, the differences in body weight are only indicative of the success or failure of selecting birds of representative average weight (Table 1). The seasonal variation in the body weights of the same hens in the long time feeding experiment indicated that the feeding of thyroprotein had little effect on the average body weight in the Leghorn breed (Turner et al. 1945-46). It is not surprising, therefore, that the amount of body fat in the two groups with the advance of thyroprotein-feeding did not change significantly. Examination of the weights of the various body parts, endocrine glands, organs or digestive system from month to month with the advance of the time that the birds were fed upon thyroprotein indicate little cumulative effect of this mild degree of hyperthyroidism upon any part except the thyroid gland. This suggests that the amount of thyroprotein required to maintain higher spring and summer egg production in the White Leghorn breed does not place an excessive burden upon the body sufficient to cause enlargement of the heart, kidney, liver or upon the digestive system.
EFFECT OF THYROPROTEIN-FEEDING UPON THE THYROID GLAND
The continued feeding of thyroprotein causes a gradual but consistant decline in the average weight of the thyroid glands (Fig. 1). This would be expected when exogenous thyroid hormone is administered in excess of that normally secreted by the birds own thyroid. The reason for this becomes clear from an examination of the normal mechanism of control of thyroid hormone secretion rate by the pituitary as illustrated by the technique of measurement employed in the preceding paper (Turner, 1947). As an example let us consider a normal hen secreting 12 micrograms (7) of d, 1thyroxine equivalent each day. She has a thyroid gland weighing 140 mg. Her pituitary is secreting sufficient thyrotrophic hormone to maintain that sized thyroid gland. If less thyrotrophic hormone is secreted by the pituitary, then the bird's thyroid decreases in size and secretes less thyroxine. If more thyrotrophic hormone is secreted then the thyroid is enlarged and more thyroxine is secreted. It has been discovered that the rate of secretion of thyrotrophic hormone by the pituitary is regulated in part by the amount of thyroid hormone either secreted or administered (by injection or feeding) to the bird. Thus if the normal rate of thyroid secretion is reduced or completely stopped by feeding thiouracil, then the pituitary secretes more thyrotrophic hormone and the thyroid gland enlarges. On the other hand, if 6 micrograms of thyroxine were injected daily into the hen, there would then be 18 micrograms present. This would immediately cause the pituitary to decrease the secretion of thyrotrophic hormone about § and the thyroid in turn would soon secrete only § as much thyroxine or 6 micrograms. Thus in a few days following the administration of J the normal thyroxine secretion rate, the hen
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same basis of body weight as the birds selected in the previous experiment with representative numbers of each weight class in each group. The feed was removed about 24 hours before satrifice and the body weight included was the weight of bird after the fast at the time of sacrifice. The birds were decapitated. The blood volume was determined by the drain-out method. The glands and organs were dissected relatively free of fat and connective tissue and weighed on appropriate balances.
157
THYROPROTEIN-FEEDING TO LEGHORN H E N S
• o
200
O 150 i
0
Y ^
* ^ ^
" ^ \ ^
a.
> i tu
o
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50
O—O CONTROLS •
SEPT
•
THYROPROTEIN
I NOV
1
1 DEC
MAR
1 MAY
1 JULY
SEP
MONTHS FIG. 1. The effect of feeding thyroprotein to two-year-old White Leghorn hen for a period of a year upon the thyroid gland weight. It will be noted that there is a gradual decline in weight due to the fact that in the presence of an excess of thyroid hormone, the birds own thyroid ceases to function.
would be back- to the normal effective amount of thyroxine but her own glands would be furnishing \ and the injected thyroxine would be furnishing \. Thus it will be seen that the injection or feeding of thyroid material when less than or equal to the normal thyroxine secretion rate is without beneficial effect to the bird since that amount will simply depress the animals own thyroid secretion rate a corresponding amount. When, as in the present case, an amount of thyroprotein is fed which is in excess of the normal thyroxine secretion rate, then the birds own thyroids stop thyroxine secretion completely because, the excessive thyroxine in the blood causes the pituitary to cease entirely the secretion of the thyrotrophic hormone. Consequently, the thyroids steadily decrease in size due to the complete inactivity of the glands and the depletion in the glands of stored colloid in the lumen of the alveoli (Fig. 1).
DISCUSSION
The development of methods in this laboratory by which iodinated casein becomes highly thyroactive (Reineke and Turner, 1945) provides a cheap source of synthetic thyroprotein. The question arises whether such a product incorporated into the ration of domestic animals would (1) have favorable effects upon the growth rate, reproduction, egg production, milk production and other productive processes; and if so (2) would it unfavorably influence the continued ability of such animals to produce due to overstimulation of the vital organs thereby shortening the animal's life or reducing production after a limited period of "over stimulation." At the outset of our investigations it seemed desirable to determine if some degree of mild hyperthyroidism induced by the feeding of thyroprotein would favoraby influence the growth rate of fowls. In
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TABLE I.—Comparison of the gland and organ weights of control and thyroprotein-fed White Leghorn Hens
Normal feed
Difference**
Thyroprotein
304.9 4.9 -22.8 -14.7 0.9 9.5 7.8 1.7
2,138.0 899.4 90.5 228.5 51.2 63.6 16.9 46.7
—
— 5.4 137.9 16.9 177.5 1.3 41.8 4.4
8.4 7.0 33.5 37.2 13.9 1.4
-
Difference
2,043.0 980.0 195.2 286.2 57.7 53.7 8.8 44.9 57.8
2,025.0 994.9 129.2 284.3 57.2 59.9 9.8 50.1 67.7
-18.0 14.9 -66.0 - 1.9 - 0.5 6.2 1.0 5.2 9.9
6.3 155.7 19.2 120.1 2.4 23.3 4.6
7.6 115.9 18.3 158.4 2.3 22.0 4.2
1.3 -39.8 - 0.9 38.3 - 0.1 - 1.3 - 0.4
0.6 0.7 2.3 0.3 3.2 1.5
6.1 8.1 13.3 2.3 33.6 22.0
6.4 9.2 14.4 2.3 36.1 25.2
0.3 1.1 1.1 0 2.5 3.2
2.5 0.1 0.9 1.9 3.1 0.2
8.1 7.3 36.3 35.9 14.8 1.8
7.9 7.2 40.2 35.1 14.2 1.5
Difference
1,925.0 939.7 136.8 294.0 56.8 54.2 5.7 48.5 62.9
64.0 1.9 25.6 1.8 0.2 0.5 0.1 0.4 0.9
0.2 -65.0 - 2.5 -52.5 1.0 - 0.3 0
6.8 142.0 13.4 149.0 3.4 3.6 4.6
0.7 0.6 1.6 0.2 2.6 21.4
7.4 10.1 11.8 2.9 33.1 8.4
6.8 9.4 14.1 3.2 36.3 6.9
0.3 0.2 4.4 0.4 1.2 0
8.5 6.9 37.0 37.1 18.7 1.0
11.0 6.8 36.1 39.0 21.8 0.8
1.1 0.4 2.4 49.0 - 1.4 16.6 0.1 -
1,861.0 937.8 111.2 295.8 56.6 54.7 5.8 48.9 62.0
Thyroprotein
Thyroprotein
6.6 207.0* 15.9 201.5 2.4 3.9 4.6
-
6.7 8.7 13.9 2.5 32.1 51.7
Normal feed
-
-
-
Normal feed
-
0.2 0.1 3.9 0.8 0.6 0.3
TABLE I.—(continued)
Normal feed
Total Body Wt., gms. 2,007.0 N e t Carcass Wt., gms. 880.6 Body F a t , gms. 158.5 Skin & Feathers, gms. 280.4 Shank, gms. 49.2 Head, gms. 64.5 Comb, gms. 16.5 Head without Comb, gms. 48.0 Blood, drained out, cc. 72.6 Endocrine Glands Pituitary, m g . 7.9 Thyroid, mg. 150.3 Parathyroid, mg. 27.2 166.9 Adrenal, mg. Thymus, gm. 0.5 Ovary, g m . 53.1 Pancreas, gm. 3.8 Organs Heart, g m . 6.8 Lungs, gm. 8.2 Kidney, g m . 14.1 Spleen, g m . 1.6 Liver, gm. 40.2 55.7 Oviduct, gm. Digestive System Crop, g m . 8.5 Proventriculus, gm. 6.9 Edible Gizzard, gm. 36.4 36.7 E m p t y Small Intestines, gm. E m p t y Large Intestines, g m . 18.7 Bile, cc. 1.1
Thyroprotein
July, 1946
May, 1946
March, 1946 Glands a n d organs
Difference**
Normal feed
Thyroprotein
Difference
Normal feed
Thyroprotein
Difference
1,984.0 869.6 125.0 279.9 51.1 67.2 18.7 48.5 68.4
-23.0 -11.0 -33.5 - 0.5 1.9 2.7 2.2 0.5 - 4.2
2,043.0 874.5 110.4 260.8 51.4 71.8 22.5 49.3 72.2
2,052.0 872.8 75.9 243.6 53.2 74.9 27.7 47.2 72.1
9.0 - 1.7 -34.5 -17.2 1.8 3.1 5.2 - 2.1 - 0.1
1,725.0 784.5 57.4 230.5 55.4 64.2 18.7 45.5 67.9
1,634.0 762.9 69.5 239.6 51.3 67.1 21.2 45.9 57.5
-91.0 -21.6 12.1 9.1 - 4.1 2.9 2.5 0.4 -10.4
9.9 113.2 30.9 143.2 0.6 44.4 3.4
2.0 -37.1 '3.7 -23.7 0.1 - 8.7 - 0.4
9.3 150.4 33.5 158.7 0.7 62.7 4.3
9.1 92.0 33.7 170.9 1.1 51.9 4.6
- 0.2 -58.4 0.2 12.2 0.4 -10.8 0.3
9.6 122.5 54.5 144.6 0.8 37.6 3.8
9.7 69.7 37.7 137.9 1.1 15.6 3.1
0.1 -52.8 -16.8 - 6.7 0.3 -22.0 - 0.7
6.9 9.8 14.1 1.8 35.2 54.2
0.1 1.6 0 0.2 5.0 1.5
7.5 8.3 16.5 1.8 49.1 66.3
6.9 7.4 13.3 1.5 34.5 57.5
- 0.6 - 0.9 - 3.2 - 0.3 -14.6 - 8.8
6.7 8.1 13.6 2.4 40.4 44.8
6.1 8.1 11.9 1.9 34.2 22.6
- 0.6 0 - 1.7 - 0.5 - 6.2 -22.2
0.6 0.3 0.7 3.7 3.4 0.1
8.8 7.8 37.1 44.6 14.3 1.2
9.6 6.6 30.9 32.9 12.6 1.5
0.8 - 1.2 - 6.2 -11.7 - 1.9 0.3
6.5 7.6 34.2 39.1 21.1 1.3
7.1 7.0 32.2 35.5 15.3 1.3
-
7.9 7.2 35.7 33.0 15.3 1.0
-
* The average thyroid gknd weight appears too high. **Minus sign indicates that the thyroprotein-fed group were less in weight than the controls.
0.6 0.6 2.0 3.6 5.8 0
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T o t a l Body W t , gms. 1,833.1 894.5 N e t Carcass Wt., gms. 113.3 Body F a t , gms. 243.2 Skin & Feathers, gms. Shank, gms. 50.3 Head, gms. 54.1 Comb, gms. 9.1 45.0 H e a d without Comb, gms. Blood, drained out, cc. 58.1 Endocrine Glands 6.5 Pituitary, mg. 137.5 Thyroid, mg. 14.5 Parathyroid, mg. 128.5 Adrenal, m g . 2.7 T h y m u s , gm. 25.2 Ovary, gm. 4.3 Pancreas, g m . Organs 6.0 Heart, g m . 9.3 Lungs, g m . 12.3 Kidney, g m . 2.3 Spleen, g m . 29.5 Liver, g m . 30.3 Oviduct, gm. Digestive System 8.1 Crop, g m . 6.8 Proventriculus, gm. 37.9 Edible Gizzard, gm. 36.8 E m p t y Small Intestines, gm. 12.7 E m p t y Large Intestines, g m . 1.4 Bile, cc.
Jan., 1946
Nov., 1945
Sept:, 1945 Glands a n d organs
THYROPROTEIN-FEEDING TO LEGHORN H E N S
represents a decreased tolerance of thyroprotein with advancing age, it may represent a decreased normal thyroxine secretion rate as indicated in the preceding paper (Turner, 1948). The data presented in the present paper is interpreted as indicating that a degree of hyperthyroidism can be induced by the feeding of thyroprotein which will favorably influence productive processes such as egg production and which at the same time is so mild in character that the glands and organs (other than the thyroid gland) are unaffected and remain normal in weight. Thus the influence of mild hyperthyroidism having favorable physiological effects upon growth and reproduction should not be confused with the effects of marked hyperthyroidism induced in the past by the administration of high levels of thyroid or thyroxine which exceeded the normal thyroid secretion rate many fold. SUMMARY
A group of about 75 White Leghorn hens at the beginning of their second laying year were fed thyroprotein at the rate of 10 gm./lOO lbs. complete ration beginning in August 1945. Each two months for a period of a year a representative group of 10 birds were sacrificed and the various glands and organs were weighed and compared with the same glands and organs of a group of control birds. The thyroid glands of these birds gradually declined in weight in comparison with the controls. This decline in weight is interpreted as being due to the administered thyroprotein inhibiting the secretion of the pituitary thyrotrophic hormone and in turn the secretion of thyroxine. With no further thyroxine secretion, the glands gradually become depleted of stored colloid. Examination of the average weights of
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several studies where variable amounts of thyroprotein were fed it was observed that slightly greater growth was frequently obtained. (Parker, 1943; Irwin et al. 1943; Turner et al. 1944). The favorable influence of mild hyperthyroidism was especially apparent in the stimulation of feather growth. With the development of methods of synthesizing thyroprotein containing about 3 percent of thyroxine as determined by chemical methods, a number of practical trials have indicated stimulation of greater body and feather growth than observed in the controls by the feeding of about 0.04 percent (18 gm. /100 lbs. feed) of thyroprotein in the starter feed. As much as 0.1 percent (54 gm./lOO lbs. feed) has been fed to White Rocks without depressing growth significantly below the weight of the control group. With the development of methods of determining the thyroxine secretion rate of fowls (Schultze and Turner, 1945) it was discovered that the feeding of 0.009 percent of thyroprotein equaled the thyroid secretion rate of both White Rock and White Leghorn chickens. It thus appeared that the degree of hyperthyroidism induced by the feeding of slightly more than four times the amount of thyroprotein required by birds to equal their thyroid hormone secretion rate was most effective in stimulating growth. Further these birds could tolerate by feeding without detrimental effect upon growth about 30 times their normal thyroid hormone secretion. In the case of the laying hens, the addition of thyroprotein at the rate of 10 gm./lOO lbs. of complete feed was observed to be most effective in sustaining summer egg production. This is at a level only slightly more than twice the thyroxine secretion rate of growing birds. However, rather than consider that this
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C. W. TURNER
REFERENCES
Irwin, M. R., E. P. Reineke, and C. W. Turner, 1943. Effect of feeding thyroactive iodocasein on growth, feathering, and weights of glands of young chicks. Poultry Sci. 22:374-380. Parker, J. E., 1943. Influence of thyroactive iodocasein on the growth of chicks. Proc. Soc. Exp. Biol, and Med. 52:234-236. Reineke, E. P., and C. W. Turner, 1945. The effect of manganese compounds and certain other factors on the formation of thyroxine in iodinated casein. J. Biol. Chem. 161:613-619.
Reineke, E. P., C. W. Turner, G. O. Kohler, R. D. Hoover, and M. B. Beezley, 1945. The quantitative determination of thyroxine in iodinated casein having thyroidal activity. J. Biol. Chem. 161:599-611. Schultze, A. B., and C. W. Turner, 1945. The determination of the rate of thyroxine secretion by certain domestic animals. Mo. Agr. Exp. Sta. Res. Bui. 392. Turner, C. W., 1948. Effect of age and season on the thyroxine secretion rate of White Leghorn hens. Poultry Sci. 27:146-154. Turner, C. W., M. R. Irwin, and E. P. Reineke, 1944. Effect of feeding thyroactive iodocasein to Barred Rock cockerels. Poultry Sci. 23: 242-246. Turner, C. W., M. R. Irwin, and E. P. Reineke, 1945. Effect of the thyroid hormone on egg production of White Leghorn hens. Poultry Sci. 24: 171-180. Turner, C. W., and H. L. Kempster, 1947. Effect of mild hyperthyroidism on seasonal and yearly egg production of fowls with advancing age. Am. J. Physiol. 149:383-388. Turner, C. W., H. L. Kempster, and N. M. Hall, 1946. Effect of continued thyroprotein feeding on egg production. Poultry Sci. 25:562-569. Turner, C. W., H. L. Kempster, N. M. Hall, and E. P. Reineke, 1945. The effect of thyroprotein on egg production. Poultry Sci. 24:522-533.
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the various body parts, endocrine glands, organs or digestive systems from month to month indicated no cumulative hypertrophy or other changes which might be considered to be due to the continued feeding of thyroprotein. It was concluded that a degree of hyperthyroidism could be maintained by the continued feeding of thyroprotein at the rate of 10 gm./lOO lbs. of complete feed which would be effective in sustaining summer egg production yet was so mild in character that the glands and organs other than the thyroid would be unaffected.
of groups of normal White Leghorn hens obtained in another experiment are presented.
URING the past five years a group of White Leghorn hens have been fed a ration containing sufficient thyroprotein to induce a mild degree of hyperthyroidism (10 gm. per 100 lbs. of feed). Until the present year (6th laying year) the control group and those fed thyroprotein have laid about equal numbers of eggs during the fall and winter each year. However, during the spring and summer, the thyroprotein-fed group maintained egg production at a higher level. With advancing age, the yearly egg production of the thyroprotein-fed group has declined far less than the control group. (Turner and Kempster, 1947). The question has been raised as to the effect of continuous thyroprotein-feeding upon the body composition and gland and organ weight. Data was presented on the gland and organ weights of a limited number of Rhode Island Red hens fed thyroprotein for two consecutive years in comparison with normal hens (Turner et al. 1946). The object of the present study was to determine the progressive effect of feeding thyroprotein during a period of a year upon the glands and organs of White Leghorn hens similar to the hens on the longtime experiment. For comparison, the average weight of the glands and organs
Information on the selection of the fowls used in this experiment is presented in the preceding paper (Turner, 1948). A group of about 75 birds were selected at random from the control group and placed in a separate pen. They were fed the control ration to which thyroproteinf at the rate of 10 gm./lOO lbs. of feed was added. The sample of thyroprotein used in this study contained 2.7 percent thyroxine as determined by the method of Reineke et al. (1945). This sample of material has been used in the experiment upon the effect of continued feeding of thyroprotein to laying hens (Turner, et al. 1946). It had been bioassayed on growing chickens by Schultze and Turner (1945). The thyroprotein feeding was begun in August 1945. The first group of 10 birds was sacrificed in September after about 30 days of treatment. Each succeeding group was sacrificed following two months additional thyroprotein feeding until Sept. 1946. This latter group consisted of the 5 remaining birds. Each bird to be included in each bimonthly group was selected upon the
* Contribution from the Department of Dairy Husbandry, Missouri Agricultural Experiment Station, Journal Series No. 1060.
t The thyroprotein under the trade name of protamone was supplied by the Cerophyl Lab. Inc., Kansas City, Missouri.
EXPERIMENTAL METHODS
155
Downloaded from http://ps.oxfordjournals.org/ at Univ of Iowa-Law Library on June 8, 2015
D
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EXPERIMENTAL RESULTS
Since the individual birds selected to constitute each group of 10 hens were picked out of the larger groups of controls and thyroprotein-fed hens, the differences in body weight are only indicative of the success or failure of selecting birds of representative average weight (Table 1). The seasonal variation in the body weights of the same hens in the long time feeding experiment indicated that the feeding of thyroprotein had little effect on the average body weight in the Leghorn breed (Turner et al. 1945-46). It is not surprising, therefore, that the amount of body fat in the two groups with the advance of thyroprotein-feeding did not change significantly. Examination of the weights of the various body parts, endocrine glands, organs or digestive system from month to month with the advance of the time that the birds were fed upon thyroprotein indicate little cumulative effect of this mild degree of hyperthyroidism upon any part except the thyroid gland. This suggests that the amount of thyroprotein required to maintain higher spring and summer egg production in the White Leghorn breed does not place an excessive burden upon the body sufficient to cause enlargement of the heart, kidney, liver or upon the digestive system.
EFFECT OF THYROPROTEIN-FEEDING UPON THE THYROID GLAND
The continued feeding of thyroprotein causes a gradual but consistant decline in the average weight of the thyroid glands (Fig. 1). This would be expected when exogenous thyroid hormone is administered in excess of that normally secreted by the birds own thyroid. The reason for this becomes clear from an examination of the normal mechanism of control of thyroid hormone secretion rate by the pituitary as illustrated by the technique of measurement employed in the preceding paper (Turner, 1947). As an example let us consider a normal hen secreting 12 micrograms (7) of d, 1thyroxine equivalent each day. She has a thyroid gland weighing 140 mg. Her pituitary is secreting sufficient thyrotrophic hormone to maintain that sized thyroid gland. If less thyrotrophic hormone is secreted by the pituitary, then the bird's thyroid decreases in size and secretes less thyroxine. If more thyrotrophic hormone is secreted then the thyroid is enlarged and more thyroxine is secreted. It has been discovered that the rate of secretion of thyrotrophic hormone by the pituitary is regulated in part by the amount of thyroid hormone either secreted or administered (by injection or feeding) to the bird. Thus if the normal rate of thyroid secretion is reduced or completely stopped by feeding thiouracil, then the pituitary secretes more thyrotrophic hormone and the thyroid gland enlarges. On the other hand, if 6 micrograms of thyroxine were injected daily into the hen, there would then be 18 micrograms present. This would immediately cause the pituitary to decrease the secretion of thyrotrophic hormone about § and the thyroid in turn would soon secrete only § as much thyroxine or 6 micrograms. Thus in a few days following the administration of J the normal thyroxine secretion rate, the hen
Downloaded from http://ps.oxfordjournals.org/ at Univ of Iowa-Law Library on June 8, 2015
same basis of body weight as the birds selected in the previous experiment with representative numbers of each weight class in each group. The feed was removed about 24 hours before satrifice and the body weight included was the weight of bird after the fast at the time of sacrifice. The birds were decapitated. The blood volume was determined by the drain-out method. The glands and organs were dissected relatively free of fat and connective tissue and weighed on appropriate balances.
157
THYROPROTEIN-FEEDING TO LEGHORN H E N S
• o
200
O 150 i
0
Y ^
* ^ ^
" ^ \ ^
a.
> i tu
o
< a. u > <
50
O—O CONTROLS •
SEPT
•
THYROPROTEIN
I NOV
1
1 DEC
MAR
1 MAY
1 JULY
SEP
MONTHS FIG. 1. The effect of feeding thyroprotein to two-year-old White Leghorn hen for a period of a year upon the thyroid gland weight. It will be noted that there is a gradual decline in weight due to the fact that in the presence of an excess of thyroid hormone, the birds own thyroid ceases to function.
would be back- to the normal effective amount of thyroxine but her own glands would be furnishing \ and the injected thyroxine would be furnishing \. Thus it will be seen that the injection or feeding of thyroid material when less than or equal to the normal thyroxine secretion rate is without beneficial effect to the bird since that amount will simply depress the animals own thyroid secretion rate a corresponding amount. When, as in the present case, an amount of thyroprotein is fed which is in excess of the normal thyroxine secretion rate, then the birds own thyroids stop thyroxine secretion completely because, the excessive thyroxine in the blood causes the pituitary to cease entirely the secretion of the thyrotrophic hormone. Consequently, the thyroids steadily decrease in size due to the complete inactivity of the glands and the depletion in the glands of stored colloid in the lumen of the alveoli (Fig. 1).
DISCUSSION
The development of methods in this laboratory by which iodinated casein becomes highly thyroactive (Reineke and Turner, 1945) provides a cheap source of synthetic thyroprotein. The question arises whether such a product incorporated into the ration of domestic animals would (1) have favorable effects upon the growth rate, reproduction, egg production, milk production and other productive processes; and if so (2) would it unfavorably influence the continued ability of such animals to produce due to overstimulation of the vital organs thereby shortening the animal's life or reducing production after a limited period of "over stimulation." At the outset of our investigations it seemed desirable to determine if some degree of mild hyperthyroidism induced by the feeding of thyroprotein would favoraby influence the growth rate of fowls. In
Downloaded from http://ps.oxfordjournals.org/ at Univ of Iowa-Law Library on June 8, 2015
O 100
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C. W. TURNER
TABLE I.—Comparison of the gland and organ weights of control and thyroprotein-fed White Leghorn Hens
Normal feed
Difference**
Thyroprotein
304.9 4.9 -22.8 -14.7 0.9 9.5 7.8 1.7
2,138.0 899.4 90.5 228.5 51.2 63.6 16.9 46.7
—
— 5.4 137.9 16.9 177.5 1.3 41.8 4.4
8.4 7.0 33.5 37.2 13.9 1.4
-
Difference
2,043.0 980.0 195.2 286.2 57.7 53.7 8.8 44.9 57.8
2,025.0 994.9 129.2 284.3 57.2 59.9 9.8 50.1 67.7
-18.0 14.9 -66.0 - 1.9 - 0.5 6.2 1.0 5.2 9.9
6.3 155.7 19.2 120.1 2.4 23.3 4.6
7.6 115.9 18.3 158.4 2.3 22.0 4.2
1.3 -39.8 - 0.9 38.3 - 0.1 - 1.3 - 0.4
0.6 0.7 2.3 0.3 3.2 1.5
6.1 8.1 13.3 2.3 33.6 22.0
6.4 9.2 14.4 2.3 36.1 25.2
0.3 1.1 1.1 0 2.5 3.2
2.5 0.1 0.9 1.9 3.1 0.2
8.1 7.3 36.3 35.9 14.8 1.8
7.9 7.2 40.2 35.1 14.2 1.5
Difference
1,925.0 939.7 136.8 294.0 56.8 54.2 5.7 48.5 62.9
64.0 1.9 25.6 1.8 0.2 0.5 0.1 0.4 0.9
0.2 -65.0 - 2.5 -52.5 1.0 - 0.3 0
6.8 142.0 13.4 149.0 3.4 3.6 4.6
0.7 0.6 1.6 0.2 2.6 21.4
7.4 10.1 11.8 2.9 33.1 8.4
6.8 9.4 14.1 3.2 36.3 6.9
0.3 0.2 4.4 0.4 1.2 0
8.5 6.9 37.0 37.1 18.7 1.0
11.0 6.8 36.1 39.0 21.8 0.8
1.1 0.4 2.4 49.0 - 1.4 16.6 0.1 -
1,861.0 937.8 111.2 295.8 56.6 54.7 5.8 48.9 62.0
Thyroprotein
Thyroprotein
6.6 207.0* 15.9 201.5 2.4 3.9 4.6
-
6.7 8.7 13.9 2.5 32.1 51.7
Normal feed
-
-
-
Normal feed
-
0.2 0.1 3.9 0.8 0.6 0.3
TABLE I.—(continued)
Normal feed
Total Body Wt., gms. 2,007.0 N e t Carcass Wt., gms. 880.6 Body F a t , gms. 158.5 Skin & Feathers, gms. 280.4 Shank, gms. 49.2 Head, gms. 64.5 Comb, gms. 16.5 Head without Comb, gms. 48.0 Blood, drained out, cc. 72.6 Endocrine Glands Pituitary, m g . 7.9 Thyroid, mg. 150.3 Parathyroid, mg. 27.2 166.9 Adrenal, mg. Thymus, gm. 0.5 Ovary, g m . 53.1 Pancreas, gm. 3.8 Organs Heart, g m . 6.8 Lungs, gm. 8.2 Kidney, g m . 14.1 Spleen, g m . 1.6 Liver, gm. 40.2 55.7 Oviduct, gm. Digestive System Crop, g m . 8.5 Proventriculus, gm. 6.9 Edible Gizzard, gm. 36.4 36.7 E m p t y Small Intestines, gm. E m p t y Large Intestines, g m . 18.7 Bile, cc. 1.1
Thyroprotein
July, 1946
May, 1946
March, 1946 Glands a n d organs
Difference**
Normal feed
Thyroprotein
Difference
Normal feed
Thyroprotein
Difference
1,984.0 869.6 125.0 279.9 51.1 67.2 18.7 48.5 68.4
-23.0 -11.0 -33.5 - 0.5 1.9 2.7 2.2 0.5 - 4.2
2,043.0 874.5 110.4 260.8 51.4 71.8 22.5 49.3 72.2
2,052.0 872.8 75.9 243.6 53.2 74.9 27.7 47.2 72.1
9.0 - 1.7 -34.5 -17.2 1.8 3.1 5.2 - 2.1 - 0.1
1,725.0 784.5 57.4 230.5 55.4 64.2 18.7 45.5 67.9
1,634.0 762.9 69.5 239.6 51.3 67.1 21.2 45.9 57.5
-91.0 -21.6 12.1 9.1 - 4.1 2.9 2.5 0.4 -10.4
9.9 113.2 30.9 143.2 0.6 44.4 3.4
2.0 -37.1 '3.7 -23.7 0.1 - 8.7 - 0.4
9.3 150.4 33.5 158.7 0.7 62.7 4.3
9.1 92.0 33.7 170.9 1.1 51.9 4.6
- 0.2 -58.4 0.2 12.2 0.4 -10.8 0.3
9.6 122.5 54.5 144.6 0.8 37.6 3.8
9.7 69.7 37.7 137.9 1.1 15.6 3.1
0.1 -52.8 -16.8 - 6.7 0.3 -22.0 - 0.7
6.9 9.8 14.1 1.8 35.2 54.2
0.1 1.6 0 0.2 5.0 1.5
7.5 8.3 16.5 1.8 49.1 66.3
6.9 7.4 13.3 1.5 34.5 57.5
- 0.6 - 0.9 - 3.2 - 0.3 -14.6 - 8.8
6.7 8.1 13.6 2.4 40.4 44.8
6.1 8.1 11.9 1.9 34.2 22.6
- 0.6 0 - 1.7 - 0.5 - 6.2 -22.2
0.6 0.3 0.7 3.7 3.4 0.1
8.8 7.8 37.1 44.6 14.3 1.2
9.6 6.6 30.9 32.9 12.6 1.5
0.8 - 1.2 - 6.2 -11.7 - 1.9 0.3
6.5 7.6 34.2 39.1 21.1 1.3
7.1 7.0 32.2 35.5 15.3 1.3
-
7.9 7.2 35.7 33.0 15.3 1.0
-
* The average thyroid gknd weight appears too high. **Minus sign indicates that the thyroprotein-fed group were less in weight than the controls.
0.6 0.6 2.0 3.6 5.8 0
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T o t a l Body W t , gms. 1,833.1 894.5 N e t Carcass Wt., gms. 113.3 Body F a t , gms. 243.2 Skin & Feathers, gms. Shank, gms. 50.3 Head, gms. 54.1 Comb, gms. 9.1 45.0 H e a d without Comb, gms. Blood, drained out, cc. 58.1 Endocrine Glands 6.5 Pituitary, mg. 137.5 Thyroid, mg. 14.5 Parathyroid, mg. 128.5 Adrenal, m g . 2.7 T h y m u s , gm. 25.2 Ovary, gm. 4.3 Pancreas, g m . Organs 6.0 Heart, g m . 9.3 Lungs, g m . 12.3 Kidney, g m . 2.3 Spleen, g m . 29.5 Liver, g m . 30.3 Oviduct, gm. Digestive System 8.1 Crop, g m . 6.8 Proventriculus, gm. 37.9 Edible Gizzard, gm. 36.8 E m p t y Small Intestines, gm. 12.7 E m p t y Large Intestines, g m . 1.4 Bile, cc.
Jan., 1946
Nov., 1945
Sept:, 1945 Glands a n d organs
THYROPROTEIN-FEEDING TO LEGHORN H E N S
represents a decreased tolerance of thyroprotein with advancing age, it may represent a decreased normal thyroxine secretion rate as indicated in the preceding paper (Turner, 1948). The data presented in the present paper is interpreted as indicating that a degree of hyperthyroidism can be induced by the feeding of thyroprotein which will favorably influence productive processes such as egg production and which at the same time is so mild in character that the glands and organs (other than the thyroid gland) are unaffected and remain normal in weight. Thus the influence of mild hyperthyroidism having favorable physiological effects upon growth and reproduction should not be confused with the effects of marked hyperthyroidism induced in the past by the administration of high levels of thyroid or thyroxine which exceeded the normal thyroid secretion rate many fold. SUMMARY
A group of about 75 White Leghorn hens at the beginning of their second laying year were fed thyroprotein at the rate of 10 gm./lOO lbs. complete ration beginning in August 1945. Each two months for a period of a year a representative group of 10 birds were sacrificed and the various glands and organs were weighed and compared with the same glands and organs of a group of control birds. The thyroid glands of these birds gradually declined in weight in comparison with the controls. This decline in weight is interpreted as being due to the administered thyroprotein inhibiting the secretion of the pituitary thyrotrophic hormone and in turn the secretion of thyroxine. With no further thyroxine secretion, the glands gradually become depleted of stored colloid. Examination of the average weights of
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several studies where variable amounts of thyroprotein were fed it was observed that slightly greater growth was frequently obtained. (Parker, 1943; Irwin et al. 1943; Turner et al. 1944). The favorable influence of mild hyperthyroidism was especially apparent in the stimulation of feather growth. With the development of methods of synthesizing thyroprotein containing about 3 percent of thyroxine as determined by chemical methods, a number of practical trials have indicated stimulation of greater body and feather growth than observed in the controls by the feeding of about 0.04 percent (18 gm. /100 lbs. feed) of thyroprotein in the starter feed. As much as 0.1 percent (54 gm./lOO lbs. feed) has been fed to White Rocks without depressing growth significantly below the weight of the control group. With the development of methods of determining the thyroxine secretion rate of fowls (Schultze and Turner, 1945) it was discovered that the feeding of 0.009 percent of thyroprotein equaled the thyroid secretion rate of both White Rock and White Leghorn chickens. It thus appeared that the degree of hyperthyroidism induced by the feeding of slightly more than four times the amount of thyroprotein required by birds to equal their thyroid hormone secretion rate was most effective in stimulating growth. Further these birds could tolerate by feeding without detrimental effect upon growth about 30 times their normal thyroid hormone secretion. In the case of the laying hens, the addition of thyroprotein at the rate of 10 gm./lOO lbs. of complete feed was observed to be most effective in sustaining summer egg production. This is at a level only slightly more than twice the thyroxine secretion rate of growing birds. However, rather than consider that this
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160
C. W. TURNER
REFERENCES
Irwin, M. R., E. P. Reineke, and C. W. Turner, 1943. Effect of feeding thyroactive iodocasein on growth, feathering, and weights of glands of young chicks. Poultry Sci. 22:374-380. Parker, J. E., 1943. Influence of thyroactive iodocasein on the growth of chicks. Proc. Soc. Exp. Biol, and Med. 52:234-236. Reineke, E. P., and C. W. Turner, 1945. The effect of manganese compounds and certain other factors on the formation of thyroxine in iodinated casein. J. Biol. Chem. 161:613-619.
Reineke, E. P., C. W. Turner, G. O. Kohler, R. D. Hoover, and M. B. Beezley, 1945. The quantitative determination of thyroxine in iodinated casein having thyroidal activity. J. Biol. Chem. 161:599-611. Schultze, A. B., and C. W. Turner, 1945. The determination of the rate of thyroxine secretion by certain domestic animals. Mo. Agr. Exp. Sta. Res. Bui. 392. Turner, C. W., 1948. Effect of age and season on the thyroxine secretion rate of White Leghorn hens. Poultry Sci. 27:146-154. Turner, C. W., M. R. Irwin, and E. P. Reineke, 1944. Effect of feeding thyroactive iodocasein to Barred Rock cockerels. Poultry Sci. 23: 242-246. Turner, C. W., M. R. Irwin, and E. P. Reineke, 1945. Effect of the thyroid hormone on egg production of White Leghorn hens. Poultry Sci. 24: 171-180. Turner, C. W., and H. L. Kempster, 1947. Effect of mild hyperthyroidism on seasonal and yearly egg production of fowls with advancing age. Am. J. Physiol. 149:383-388. Turner, C. W., H. L. Kempster, and N. M. Hall, 1946. Effect of continued thyroprotein feeding on egg production. Poultry Sci. 25:562-569. Turner, C. W., H. L. Kempster, N. M. Hall, and E. P. Reineke, 1945. The effect of thyroprotein on egg production. Poultry Sci. 24:522-533.
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the various body parts, endocrine glands, organs or digestive systems from month to month indicated no cumulative hypertrophy or other changes which might be considered to be due to the continued feeding of thyroprotein. It was concluded that a degree of hyperthyroidism could be maintained by the continued feeding of thyroprotein at the rate of 10 gm./lOO lbs. of complete feed which would be effective in sustaining summer egg production yet was so mild in character that the glands and organs other than the thyroid would be unaffected.