Effect of gonadotrophin and sex steroid on the scoto-responses of day old chicks of Japanese quail, coturnix coturnix japonica

Abstract

Luteinizing hormone (LH) and testosterone propionate (TP) were tested for their effects on the development of scotorefractoriness in Japanese quail. Day old chicks of both the sexes were divided into four groups and treated with normal saline, LH (1 μg/100 g body weight) and two doses of TP (100 μg/100 g body weight- TP1 and 1 mg/100 gm body weight- TP2) over a periods of 14 weeks. In the male chicks, compared to control LH treatment advanced and low dose of TP suppressed the development of scotorefractoriness, while high dose of TP inhibited it completely and maintained the birds in scotosensitive state. On the other hand, in females, LH treatment increased the rate of sexual development resulting in the onset of egg laying earlier than that of control, but both the doses of steroid hormone suppressed ovarian development. It is suggested that, LH treatment not only induced a higher degree of reproductive development in short day quail but may also advance sexual maturity as under long daylength. Further, both the doses of male hormone had negative feedback effect on neuroendocrine axis and eliminated the attainment of scotorefractoriness i.e., reproductive development under short days.