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Basal Metabolism and Thyroid Size in Chickens Fed Thiouracil and a Thiouracil-Thyroprotein Combination
872
RESEARCH NOTES
The mutant red-breast factor described is interpreted as a low-grade melanin restrictor most readily expressed in the
lower range of the postero-anterad pigmentation gradient; it is augmented by the general restrictor influence of R, and overridden by estrogenic melanization in the female. It is proposed that the gene receive the symbolic accolade Rb (red breast). Information concerning availability of the Streaky-breasted Game or a bantam counterpart would be sincerely appreciated. REFERENCES Brown, E., 1929. Poultry Breeding and Production. 2 vols., Ernest Benn Ltd., London. Delacour, J., 1951. Pheasants of the World. Charles Scribner's Sons, New York. Kimball, E., 1953. Genetics of Buttercup plumage pattern in the fowl. Poultry Sci. 32:683-692. Kimball, E., 1954. Genetics of Birchen plumage pattern in the fowl. Poultry Sci. 33: 472-481. Silk, W. H., 1951. Bantams and Miniature Fowl. Poultry World, London. Waddington, C. H., 1953. Genetic assimilation of an acquired character. Evolution, 7: 118-127.
BASAL METABOLISM AND THYROID SIZE IN CHICKENS FED THIOURACIL AND A THIOURACILTHYROPROTEIN COMBINATION W. J. MELLEN 1 AND F. W. H I L L Department of Poultry Husbandry, Cornell University, Ithaca, New York (Received for publication May 20, 1954)
Singh and Shaffner (1950) have reported that a very small amount of thyroprotein (1 gram per 100 pounds of feed) completely overcame the depression of basal metabolic rate (BMR) due to 0.2 percent of thiouracil in the diet of twoweek-old chicks. Moreng and Shaffner (1949) reported that the same level of thyroprotein in combination with 0.2 percent thiouracil produced larger goiters in chicks than those produced by thiouracil alone. 1
Present address: Dept. of Animal & Poultry Industry, University of Delaware, Newark.
The level of thyroprotein used by these workers was one-fourth that which Schultze and Turner (1945) found would maintain normal thyroid size in growing chickens fed thiouracil, and therefore is presumably equivalent to one-fourth the normal thyroxine secretion. For this reason, plus the unexpected nature of the findings with respect to thyroid size, it was considered desirable to determine whether results similar to those of the Maryland workers could be obtained in another laboratory. Eighty-day-old
male
chicks
(BPR
Downloaded from http://ps.oxfordjournals.org/ at Monash University on June 20, 2015
both sexes, despite presence of B-black (dominant black) in the Birchen Game. Interpretation of e+ (wild type) pylezoning, due to action of the R component (Kimball, 1954), as a die-stamp effect is entirely too naive. Evidence will be submitted separately to show that (1) the R component of e+ has a single effect: eumelanin restriction, (2) the potential exists as a uniform quantum in all parts of the plumage, and (3) extraneous modifiers, particularly morphogenetic and physiological factors, including pigmentation gradients, determine a threshold of expression for the R-effect. Consonant with this view, e+ in its R component represents a single gene with a single effect, the complex phenotype (pyle-zoning) engendered depending upon extraneous modifiers of the R-effect.
873
RESEARCH NOTES TABLE 1.—Mean fasted body weights and basal oxygen consumption of BPRXRIR weeks of age.
Treatment
0 . 2 % thiouracil 0 . 2 % thiouracil plus 0.0022% thyroprotein
males 3 to 3i
Mean ean weight (grams)
Mean oxygen consumption (mlpejkg. perhr.)
Mean oxygen consumption consumptln (ml. pe? bird per hr.)
„ . . , „ t „ j *".,„„„ ' ^ n_ ^J° T / _ ! ™ fb i r -( J p e r hr.)*
139
1124
155
183
180
1194
216
189
* Coefficient of variation=9.7%.
adjusted for body size. The adjusted mean oxygen values are also presented in Table 1. Shortly after the metabolism determinations were completed, all chicks were sacrificed for a study of fresh thyroid weights. Since there had been no mortality, 40 chicks were available from each treatment. The data are presented in Table 2, and show that the small amount of thyroprotein added to the thiouracil diet exerted a pronounced positive effect upon both body weight and thyroid weight. Covariance analysis showed that the goitrogenic effect beyond that of thiouracil alone was significant, despite the large variability of the gland weights. With respect to basal oxygen consumption, the results of this experiment do not agree with the conclusions of Singh and Shaffner (1950). The present data show slightly greater oxygen consumption due to the addition of 0.0022 percent thyroTABLE 2.—Mean body weights and thyroid weights of BPRXRIR males 4 weeks of age
Treatment
0 . 2 % thiouracil 0.2% thiouracil plus 0.0022% thyroprotein
Mean body wt. (grams)
Mean thyroid wt. (mg.)
Mean adjusted thyroid wt. (mg.)
252
181
290
348
455
346*
Coefficient of variation=60% ' Significantly larger at 5 % level of probability.
Downloaded from http://ps.oxfordjournals.org/ at Monash University on June 20, 2015
XRIR) were randomly distributed to four brooder pens in two decks of a large battery. In each deck, one pen received a commercial starting mash to which had been added 0.2 percent of thiouracil, and the other pen received the same diet plus one gram of thyroprotein (Protamone) per 100 pounds of feed (0.0022 percent) . Measurements of basal oxygen consumption were made by the gravimetric method of Haldane (1892). A brief description of the method and its use in this laboratory has been given previously (Mellen and Hill, 1953). The determinations were made in 11 blocks of one-half day each, in a randomized complete blocks design, during the period from 3 to 3§ weeks of age. Replicate (deck) effects, if any, were confounded with block effects by the procedure of drawing birds for successive blocks alternately from the two replicate groups. Four birds at a time were run in all determinations. The minimum fasting time was 32 hours. Mean basal oxygen consumption values and the corresponding mean fasted body weights are shown in Table 1, where it can be seen that the chicks fed the combination of 0.2 percent thiouracil and 0.0022 percent thyroprotein were considerably larger than those fed thiouracil alone. Covariance analysis showed that the basal oxygen consumption of the two groups did not differ significantly when
874
N E W S AND NOTES
iodide may be liberated in the metabolism of diiodotyrosine, another component of thyroprotein. However, it seems doubtful that the small amount of iodide furnished by 0.0022 percent of thyroprotein could be influential. It is a pleasure to acknowledge the assistance of Miss Betty Fontaine and Dr. C. E. Howes in obtaining the thyroid weight data. REFERENCES Haldane, J., 1892. A new form of apparatus for measuring the respiratory exchange of animals. J. Physiol. 13: 419-430. Mellen, W. J., and F. W. Hill, 1953. Effects of thiouracil, thyroprotein, and estrogen upon the basal metabolism and thyroid size of growing chickens. Poultry Sci. 32: 994-1001. Moreng, R. E., and C. S. Shaffner, 1949. A thiouracil-thyroprotein treatment for fattening poultry. Poultry Sci. 28: 504-510. Schultze, A. B., and C. W. Turner, 1945. The determination of the rate of thyroxine secretion by certain domestic animals. Missouri Agr. Exp. Sta. Bull. 392. Singh, H., and C. S. Shaffner, 1950. Effect of thyroprotein and caloric level of diet on metabolic rate of chickens. Poultry Sci. 29: 575-758. Wheeler, R. S., and E. Hoffmann, 1950. The etiology of goiter in chicks from thyroprotein fed hens; negative role of inorganic iodide. Poultry Sci. 29: 306-307. Williams, R. H., A. R. Weinglass and G. A. Kay, 1944. Thiouracil storage in the thyroid as affected by thyrotropic hormone and potassium iodide. Amer. J. Med. Sci. 207: 701-705.
NEWS AND NOTES (Continued from page 870) given $1,000 to the University of California for use by the Poultry Department on research in egg quality. Kimber Farms, Niles, California have given an annual scholarship to a California State Polytechnic
College student at San Luis Obispo. It will be awarded to a poultry major selected from high school or junior college students applying for admission to the College.
Downloaded from http://ps.oxfordjournals.org/ at Monash University on June 20, 2015
protein to the thiouracil diet, after adjustment for difference in body size, but the increase was not statistically significant. When our oxygen values were expressed in ml. per kg. of body weight per hour (see Table 1), after the manner of the Maryland workers, an analysis of variance again indicated no significant difference between the two groups. A previous report from this laboratory (Mellen and Hill, 1953) showed that the BMR of thiouracil-treated chicks fasted at least 34 hours was not significantly different from the BMR of untreated controls, after adjustment of the data for differences in body weight. With respect to thyroid size, the results of this experiment confirm the report of Moreng and Shaffner (1949). The low level of thyroprotein used was apparently not sufficient to suppress the pituitary output of thyrotrophin, and thus to reduce the goitrogenic effect of thiouracil. It is not clear why the thyroprotein exerted an additional goitrogenic effect. According to Williams et al. (1944), iodide increases storage of thiouracil in the guinea pig thyroid and causes larger goiters, when administered with thiouracil, than thiouracil alone. There is 1.5 to 2.0 percent of inorganic iodide in thyroprotein, according to Wheeler and Hoffmann (1950), with the possibility that more
RESEARCH NOTES
The mutant red-breast factor described is interpreted as a low-grade melanin restrictor most readily expressed in the
lower range of the postero-anterad pigmentation gradient; it is augmented by the general restrictor influence of R, and overridden by estrogenic melanization in the female. It is proposed that the gene receive the symbolic accolade Rb (red breast). Information concerning availability of the Streaky-breasted Game or a bantam counterpart would be sincerely appreciated. REFERENCES Brown, E., 1929. Poultry Breeding and Production. 2 vols., Ernest Benn Ltd., London. Delacour, J., 1951. Pheasants of the World. Charles Scribner's Sons, New York. Kimball, E., 1953. Genetics of Buttercup plumage pattern in the fowl. Poultry Sci. 32:683-692. Kimball, E., 1954. Genetics of Birchen plumage pattern in the fowl. Poultry Sci. 33: 472-481. Silk, W. H., 1951. Bantams and Miniature Fowl. Poultry World, London. Waddington, C. H., 1953. Genetic assimilation of an acquired character. Evolution, 7: 118-127.
BASAL METABOLISM AND THYROID SIZE IN CHICKENS FED THIOURACIL AND A THIOURACILTHYROPROTEIN COMBINATION W. J. MELLEN 1 AND F. W. H I L L Department of Poultry Husbandry, Cornell University, Ithaca, New York (Received for publication May 20, 1954)
Singh and Shaffner (1950) have reported that a very small amount of thyroprotein (1 gram per 100 pounds of feed) completely overcame the depression of basal metabolic rate (BMR) due to 0.2 percent of thiouracil in the diet of twoweek-old chicks. Moreng and Shaffner (1949) reported that the same level of thyroprotein in combination with 0.2 percent thiouracil produced larger goiters in chicks than those produced by thiouracil alone. 1
Present address: Dept. of Animal & Poultry Industry, University of Delaware, Newark.
The level of thyroprotein used by these workers was one-fourth that which Schultze and Turner (1945) found would maintain normal thyroid size in growing chickens fed thiouracil, and therefore is presumably equivalent to one-fourth the normal thyroxine secretion. For this reason, plus the unexpected nature of the findings with respect to thyroid size, it was considered desirable to determine whether results similar to those of the Maryland workers could be obtained in another laboratory. Eighty-day-old
male
chicks
(BPR
Downloaded from http://ps.oxfordjournals.org/ at Monash University on June 20, 2015
both sexes, despite presence of B-black (dominant black) in the Birchen Game. Interpretation of e+ (wild type) pylezoning, due to action of the R component (Kimball, 1954), as a die-stamp effect is entirely too naive. Evidence will be submitted separately to show that (1) the R component of e+ has a single effect: eumelanin restriction, (2) the potential exists as a uniform quantum in all parts of the plumage, and (3) extraneous modifiers, particularly morphogenetic and physiological factors, including pigmentation gradients, determine a threshold of expression for the R-effect. Consonant with this view, e+ in its R component represents a single gene with a single effect, the complex phenotype (pyle-zoning) engendered depending upon extraneous modifiers of the R-effect.
873
RESEARCH NOTES TABLE 1.—Mean fasted body weights and basal oxygen consumption of BPRXRIR weeks of age.
Treatment
0 . 2 % thiouracil 0 . 2 % thiouracil plus 0.0022% thyroprotein
males 3 to 3i
Mean ean weight (grams)
Mean oxygen consumption (mlpejkg. perhr.)
Mean oxygen consumption consumptln (ml. pe? bird per hr.)
„ . . , „ t „ j *".,„„„ ' ^ n_ ^J° T / _ ! ™ fb i r -( J p e r hr.)*
139
1124
155
183
180
1194
216
189
* Coefficient of variation=9.7%.
adjusted for body size. The adjusted mean oxygen values are also presented in Table 1. Shortly after the metabolism determinations were completed, all chicks were sacrificed for a study of fresh thyroid weights. Since there had been no mortality, 40 chicks were available from each treatment. The data are presented in Table 2, and show that the small amount of thyroprotein added to the thiouracil diet exerted a pronounced positive effect upon both body weight and thyroid weight. Covariance analysis showed that the goitrogenic effect beyond that of thiouracil alone was significant, despite the large variability of the gland weights. With respect to basal oxygen consumption, the results of this experiment do not agree with the conclusions of Singh and Shaffner (1950). The present data show slightly greater oxygen consumption due to the addition of 0.0022 percent thyroTABLE 2.—Mean body weights and thyroid weights of BPRXRIR males 4 weeks of age
Treatment
0 . 2 % thiouracil 0.2% thiouracil plus 0.0022% thyroprotein
Mean body wt. (grams)
Mean thyroid wt. (mg.)
Mean adjusted thyroid wt. (mg.)
252
181
290
348
455
346*
Coefficient of variation=60% ' Significantly larger at 5 % level of probability.
Downloaded from http://ps.oxfordjournals.org/ at Monash University on June 20, 2015
XRIR) were randomly distributed to four brooder pens in two decks of a large battery. In each deck, one pen received a commercial starting mash to which had been added 0.2 percent of thiouracil, and the other pen received the same diet plus one gram of thyroprotein (Protamone) per 100 pounds of feed (0.0022 percent) . Measurements of basal oxygen consumption were made by the gravimetric method of Haldane (1892). A brief description of the method and its use in this laboratory has been given previously (Mellen and Hill, 1953). The determinations were made in 11 blocks of one-half day each, in a randomized complete blocks design, during the period from 3 to 3§ weeks of age. Replicate (deck) effects, if any, were confounded with block effects by the procedure of drawing birds for successive blocks alternately from the two replicate groups. Four birds at a time were run in all determinations. The minimum fasting time was 32 hours. Mean basal oxygen consumption values and the corresponding mean fasted body weights are shown in Table 1, where it can be seen that the chicks fed the combination of 0.2 percent thiouracil and 0.0022 percent thyroprotein were considerably larger than those fed thiouracil alone. Covariance analysis showed that the basal oxygen consumption of the two groups did not differ significantly when
874
N E W S AND NOTES
iodide may be liberated in the metabolism of diiodotyrosine, another component of thyroprotein. However, it seems doubtful that the small amount of iodide furnished by 0.0022 percent of thyroprotein could be influential. It is a pleasure to acknowledge the assistance of Miss Betty Fontaine and Dr. C. E. Howes in obtaining the thyroid weight data. REFERENCES Haldane, J., 1892. A new form of apparatus for measuring the respiratory exchange of animals. J. Physiol. 13: 419-430. Mellen, W. J., and F. W. Hill, 1953. Effects of thiouracil, thyroprotein, and estrogen upon the basal metabolism and thyroid size of growing chickens. Poultry Sci. 32: 994-1001. Moreng, R. E., and C. S. Shaffner, 1949. A thiouracil-thyroprotein treatment for fattening poultry. Poultry Sci. 28: 504-510. Schultze, A. B., and C. W. Turner, 1945. The determination of the rate of thyroxine secretion by certain domestic animals. Missouri Agr. Exp. Sta. Bull. 392. Singh, H., and C. S. Shaffner, 1950. Effect of thyroprotein and caloric level of diet on metabolic rate of chickens. Poultry Sci. 29: 575-758. Wheeler, R. S., and E. Hoffmann, 1950. The etiology of goiter in chicks from thyroprotein fed hens; negative role of inorganic iodide. Poultry Sci. 29: 306-307. Williams, R. H., A. R. Weinglass and G. A. Kay, 1944. Thiouracil storage in the thyroid as affected by thyrotropic hormone and potassium iodide. Amer. J. Med. Sci. 207: 701-705.
NEWS AND NOTES (Continued from page 870) given $1,000 to the University of California for use by the Poultry Department on research in egg quality. Kimber Farms, Niles, California have given an annual scholarship to a California State Polytechnic
College student at San Luis Obispo. It will be awarded to a poultry major selected from high school or junior college students applying for admission to the College.
Downloaded from http://ps.oxfordjournals.org/ at Monash University on June 20, 2015
protein to the thiouracil diet, after adjustment for difference in body size, but the increase was not statistically significant. When our oxygen values were expressed in ml. per kg. of body weight per hour (see Table 1), after the manner of the Maryland workers, an analysis of variance again indicated no significant difference between the two groups. A previous report from this laboratory (Mellen and Hill, 1953) showed that the BMR of thiouracil-treated chicks fasted at least 34 hours was not significantly different from the BMR of untreated controls, after adjustment of the data for differences in body weight. With respect to thyroid size, the results of this experiment confirm the report of Moreng and Shaffner (1949). The low level of thyroprotein used was apparently not sufficient to suppress the pituitary output of thyrotrophin, and thus to reduce the goitrogenic effect of thiouracil. It is not clear why the thyroprotein exerted an additional goitrogenic effect. According to Williams et al. (1944), iodide increases storage of thiouracil in the guinea pig thyroid and causes larger goiters, when administered with thiouracil, than thiouracil alone. There is 1.5 to 2.0 percent of inorganic iodide in thyroprotein, according to Wheeler and Hoffmann (1950), with the possibility that more