[Effect of hypophysectomy on survival, weight gain and food intake in chickens]

Hypophysectomy has been performed in 1, 20, 50, 90 and 110-day-old chickens. The effect of the pituitary ablation depended on both the age and the sex of the birds. Chicks hypophysectomized on the day of birth survived no more than 5 days. In the other experimental groups, the later the operation was done, the longer the chicks survived, with some rare exceptions. Survival was generally better in females. The weight gain was significantly slower in 50-day-old hypophysectomized chicks than in the controls. In the 90-day-old operated animals, slackening of weight gain was less pronounced; a catch-up weight gain began at 24 weeks and reached the control levels at about 45 weeks. These differences were still less marked in 110-day-old hypophysectomized chickens in which the catch-up weight gain was faster. In all the hypophysectomized chicks, food intake was less than in the controls, but its utilization was better than in the controls, especially the pair-fed controls.