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INFLUENCE OF QUANTITATIVE THYROPROTEIN TREATMENT OF HENS ON LENGTH OF INCUBATION PERIOD AND THYROID SIZE OF CHICKS 1

1948; Oxford University Press; Volume: 43; Issue: 6 Linguagem: Inglês

10.1210/endo-43-6-430

1945-7170

Robert S. Wheeler, Edmund Hoffmann,

Animal Nutrition and Physiology

Previous work in this laboratory has shown that chicks hatched from eggs laid by thyroprotein-fed hens have greatly enlarged thyroids (Wheeler and Hoffman, 1948a). The presence of goiters suggested that the chicks might be hypothyroid and therefore, might exhibit reduced rate of embryonic development. A preliminary study of this aspect of the problem established that eggs of hens fed thyroprotein at a dietary level of 0.02% required 6 to 12 hours longer to hatch (Wheeler and Hoffman, 1948b). Both of these findings have recently been confirmed by the independent studies of McCartney and Shaffner (1948). The present study was designed to determine the interrelationships between degree of goiterogenicity, increase in length of incubation period, and level of thyroprotein fed with the view of attempting to explain the mechanisms involved. materials and methods To secure eggs for hatching, 60 year-old New Hampshire hens were divided at random into four groups of 15 birds. The hens were kept on littercovered floors in adjacent pens within the same house.