Thyroxine, Thiouracil and Embryonic Respiration in White Leghorns

Physiology of Turkey Embryos During Pipping and Hatching. III. Thyroid Function ,

“…Grossowicz (1946) injected thiourea into chick embryo yolk sacs between the 7th and 17th days of incubation and observed a delay of 10 days in pipping. Injections of eidier thiourea or thiouracil at various stages of incubation have corroborated these initial observations (Adams and Bull;1949;Adams and Buss, 1952;Romijn et al, 1952;Romanoff and Laufer, 1956;Sinha et al, 1959;Balaban and Hill, 1971). Balaban and Hill (1971) observed that thyroid function blocked by thiourea caused coincidental reduced loss of yolk sac material and delayed puncture of the chorioallantoic membrane, whereas exogenous injections of thyroxine (T 4 ) reinitiated both processes and led to successful hatching.…”

The Gaseous Environment of the Chick Embryo in Relation to Its Development and Hatchability

“…It is during this period that reciprocal activity appears between the pituitary and the thyroid (Willier, 1955;Thommes, 1958) and between the pituitary and the adrenal glands (Willier, 1955). The appearance of thyroid activity is reflected in embryonic 0 2 -uptake on the 10th day (Romijn and Lokhorst, 1951); also, this pattern of 0 2 -uptake by the embryo can be modified by exogenous thyroxin (Romijn et al, 1952). In the adult mammal, thyroxin administration augments and thyroidectomy protects against 0 2 toxicity (Bean, 1945(Bean, , 1964.…”

Rapeseed Meal in the Chicken Breeder Diet.

“…Despite the goitrogenicity of the rapeseed meal diets, production of thyroid hormone was apparently maintained by the male birds at an adequate level. Incubation time can be prolonged by injection of goitrogen into the egg after 8 days' incubation (Romyn et al, 1952). The thyroid glands of the newly hatched progeny of dams fed rapeseed meal showed hypertrophy, which was greater when the diet contained the higher level of rapeseed meal.…”