Induced Hyperthyroidism and Growth of Parasitized Chicks

MIXNER and Upp (1947) found higher thyroxine secretion rates in “double-crossed” hybrid chicks than in “single-crossed” chicks. Their work implied that high thyroxine levels are associated with hybrid vigor. The above paper, as well as the literature relating growth and fattening of broilers with induced hypo- and hyper-thyroidism, suggested that such artificially induced physiological states in broilers might be employed in a study of the effects of these conditions upon the growth of parasitized chickens, and upon the growth of the parasites themselves. The data given here relate to the development of coccidial infections in New Hampshire broilers on a standard growing ration and on the same growing ration to which thyroprotein (Protamone * ) had been added. Data are also included on the amounts of growth made in 3 week test periods by the infected birds. These latter data complement in part the work of Wheeler et al. (1948) on the . . .