Variations of Gonadal Structures and Functions of Male Japanese Quail (Coturnix Japonica) in different Breeding Seasons of Punjab, Pakistan

Quail farming has attained much intention in our country to meet the increasing demand of meat and egg production. The reproductive status of birds is of prime importance for better production which is interrelated to hormonal profile and modulated by the seasonal variations. This study was conducted on the gonadal structures of 60 adult male Japanese quails (Coturnix japonica) over a year. The blood from each bird was subjected to extract serum and used for serum testosterone measurement by RIA technique. The macroscopic and microscopic dimensions of right and left gonads (testes) were measured. The results revealed a clear variation of testicular weight, volume, length, width, thickness, circumference and seminiferous tubule diameter and the thickness and composition of the germinal epithelium over the year. The testicular weight, volume, length, width, thickness, circumference and seminiferous tubule diameter were significantly (P<0.01) highest during peak breeding season (June –July). In contrast all gross parameters and seminiferous tubule diameter were significantly (P<0.01) decreased during low breeding (Sept.-Oct.) and non breeding season (Jan.-Feb). There was no significant (P>0.05) difference of all gross anatomical parameters observed between right and left testis of all season. There is a significantly high (P<0.01) concentration of serum testosterone recorded during peak breeding, decrease during low breeding and very low during non breeding season. In addition, testosterone has positive correlation with all morphological and histomorphometric parameters of gonads. There was a clear influence of different seasons on serum testosterone concentrations as the environmental parameters, such as temperature and rainfall were positively correlated with the in serum testosterone concentrations, but there was a negative correlation between the relative humidity and serum testosterone concentrations. It can be concluded from these findings that seasonal changes influenced the gonads (testis) along with serum testosterone level. Moreover, as a tropical avian species, maximum sexual activity of this bird under favorable environmental conditions coincided with the high gonadal steroid level, and vice versa.

Keywords: Japanese quail, Serum testosterone, Testes, Seminiferous tubule