TESTOSTERONE AND SEX RELATED PHYSICAL CHARACTERISTICS DURING THE MATURATION OF THE MALE JAPANESE QUAIL (COTURNIX-COTURNIX-JAPONICA)

A series of experiments was conducted to examine hormonal and physical aspects of reproduction in the maturing and adult male Japanese Quail. Testicular secretion of testosterone was demonstrated in the adult male by the elevated testosterone concentration in the testicular vein (12 ng/ml serum) as compared to the testosterone concentration in the left ventricle (4.5 ng/ml serum). Testosterone concentrations in the circulation were found to vary diurnally with high concentrations in the morning and evening and lowered concentrations in the midafternoon. In the maturing male, testosterone concentrations, testicular weight and cloacal gland area remained low until Day 21 and rose rapidly thereafter. Spermatozoa were first detected in the testes on Day 26. By 30 days of age, spermatozoa were found in the testes and in the vasa deferentia in small quantities and by Day 35 there were large concentrations at both sites. There was a significant positive temporal correlation of changes in cloacal gland area, testes weight and circulating concentrations of testosterone.