Avian thyroid isthmus.

An avian equivalent of the mammalian thyroid isthmus appeared in thiouracil-treated (.1% in feed from hatching to 6 and 8 weeks of age) chickens. In two experiments in which chickens were fed a diet containing thiouracil, thyroid tissue was found connecting the thyroid glands. Histological examination of the connecting tissue revealed that it was of the same cellular composition as the thyroid glands.

Performance of turkey poults when fed two levels of methionine with and without ipronidazole.

Two experiments were conducted to determine the effect of adding ipronidazole to the diet of turkey poults containing two different levels of methionine. A corn-soybean meal diet with 0 to .18% supplemental methionine was fed to Nicholas Large White poults from 1 to 21 days of age. The addition of .18% supplemental methionine significantly improved body weight and feed efficiency. The addition of ipronidazole to the diet with either level of methionine did not influence body weight, feed efficiency, or grams of sulfur amino acid required to produce a gram of weight.

Copper salts for growth stimulation and alleviation of aortic rupture losses in turkeys.

Approximately 4000 Large White, day-old turkey poults were used in a series of eight experiments to study the effects of dietary copper supplementation. The hens were grown to 15 or 16 weeks and toms to 24 weeks of age. Either copper as the oxide or sulfate (hydrate) at 120 ppm stimulated growth up to 10% with a concurrent reduction in feed requirement. Levels of 60 ppm were not adequate, whereas 240 ppm were not toxic. There was a greater response to copper in the presence of 4-nitrophenylarsonic acid (4-nitro) or with low protein diets. In two of the eight studies copper enhanced aortic elastin content. Incidence of aortic rupture was greater in the presence of 4-nitro and was reduced by one-half through copper supplementation. Liver copper was not altered by 60 or 120 ppm Cu; 240 ppm caused a significant increase.

The mutagenic action of nitroimidazoles. II. Tinidazole, ipronidazole, panidazole and ornidazole.

The 5-nitroimidazoles tinidazole (Fasigyn), ipronidazole (Ro-7-1554), panidazole and ornidazole (Tiberal, Ro-7-0207) in concentrations of 0.02--1 mM per liter increased the mutation frequency of Klebsiella pneumoniae. Escherichia coli K12 and Citrobacter freundii to streptomycin resistance, including streptomycin dependence, in Luria and Delbrück's fluctuation test. At low concentration (0.1 mM), the increase of the mutation frequency caused by each compound was nearly the same, i.e. 3--4 times the spontaneous mutation frequency. At higher concentrations, considerable differences between the mutagenic activities of the compounds occurred.