86
THYROIDAL ACTIVITY AND CÆCAL COCCIDIOSIS
[Vol. XXV, Part II,
bird) to obviate complications caused by larger doses of the parasite and to facilitate
counting of oocysts.
In lethal experimental infection, hyperthyroid chicks suffered more severe
caecal lesions (indicating the intensity of schizogonous cycles), listed appreciably
lower mortality (50 per cent) than the hypothyroid (76.4 per cent) and unmedicated
control (58.9 per cent) lots. Apparently the two observations, i.e. accelerated
endogenous cycle and lower mortality in hyperthyroid hosts, and vice versa in hypo-
thyroid ones, seem irreconcilable. But comparison of the growth rates of the three
lots during acute stage of infection provided the clue. Hypothyroid chicks lost
considerably (7.1 per cent) during the acute stage of disease (i.e. 5th to the 8th
day), whereas hyperthyroid lot even then showed an increase in live weight (1.8
per cent). This increase though slight is significant as it indicates that these birds
tolerated the infection better (as also shown by their brighter demeanour) than the
other two groups. Probably their continued feeding habit (influenced by thy-
roprotion, as both the other lots lost appetite during the crisis) kept up their vitality
and hence there was lowered mortality in them.
Thiouracil feeding, though resulted in increased fat deposition in chicks
adversely affected them and caused high mortality. The present investigation
has experimentally substantiated and confirmed conclusions deduced by Wheeler
et al., and Todd and his associates.
ACKNOWLEDGMENT
The author is indebted to Dr H. N. Ray (ex-Head of the Division of Parasi-
tology, Indian Veterinary Research Institute, Mukteswar-Kumaon) at present
Prof. of Protozoology, School of Tropical Medicine, Calcutta, for the valuable
guidance afforded in the conduct of experiments and for helpful criticism in proper
presentation of the data ; and also to the Indian Council of Agricultural Research
for the award of their Research Fellowship in Veterinary Parasitology (1952-54).
REFERENCES
Andrews F. N. and Bohren B.B. (1947). Influence of thiouracil and stilbestrol on growth, fattening
and feed efficiency of broilers. Poultry. Sci., 26 : 447
—And Schnetzler, E. E. (1946). Influence of thiouracil on growth and fattening in broilers. Ibid.
25 : 124
Ershoff, B. H. (1948). Conditioning factors in nutritional disease. Physiol. Rev. 28 : 107
Frick, L. P. and Ackert, J. E. (1948). Further studies on duodenal mucus as a factor in age resistance
of chicks to parasitism. J. Parasit. 34 : 206
Gargill, S. L. and Lesses, M. F. (1945). Toxic reaction to thiouracil. J. Amer. Med. Ass., 127 : 810
Glazner, E. W. and Jull, M. A. (1946). Effects of thiouracil dessicated thyroid, and stilbestrol
derivatives in various glands, body weight, and dressing appearance in the chicken. Poultry Sci.,
25 : 236
Grollman, A. (1947). Essentials of Endocrinology, J. B. Lippincott Co., Philadelphia
Irwin, M. R. Reineke, E. P. and Turner, C. W. (1943). Effect of thyroactive iodocasein on growth,
feathering, and weights of glands of young chicks. Poultry Sci., 22 : 347
Larsh, J. E. (1947). The effect of thyroid and thiouracil on the natural resistance of mice to infec-
tion with Hymenolepis. J. Parasit. 33 Dec. Suppl : 24
Leach F. B. and Spencer. T. (1951). Immunity and metabolic rate : the course of Notoedres Scabei
in rats with different metabolic rates. Parasitol., 41 : 224
Read, C. P. (1950). The vertebrate small intestine as an environment for parasitic helminths. Rice
Inst. Pamph., 37