Till M. Huston

Inhibitory effect of serotonin on ovulation in the domestic fowl, Gallus domesticus

Abstract Serotonin (5-HT) treatment (20 mg/kg) of White Leghorn layers 8 h before expected time of egg release from the ovary inhibited ovulation. This inhibitory effect was overcome by LH administration. Progesterone injection 14 h before anticipated ovulation caused premature ovulation. 5-HT injected 15 or 60 min before or after progesterone administration inhibited this ovulation. Non-significant inhibition (P

Influence of High Environmental Temperature on Fertility and Hatchability of Eggs of Domestic Fowl

C OMPARATIVELY little information has been published to indicate the effect of high environmental temperatures on fertility and hatchability in chickens. Upp and Thompson (1927), Funk (1935), and Hewang (1944) reported that fertility and hatchability decreased during the hot summer months. Wilson (1949) showed that fertility in the female was not seriously affected by high temperatures. It has been demonstrated by others, however, that the fertilizing capacity of the cock declines during hot weather (Parker and McSpadden, 1943; Huston and Wheeler, 1949). Ota, McNally, and Wilson (1955) found that fertility was reduced in a variable environment and that fertility and hatchability were improved by keeping the hens at a constant temperature of 65. F. The experiment reported here was designed to study the fertility and hatchability of eggs of fowl exposed continuously from time of hatch through the laying year to a controlled high environmental temperature.