The size and testis weight were evaluated and correlated in 25 adult male Japanese quail (Coturnix coturnix japonica), seeking information to enable the development of a predictive parameter of sperm production capacity. The birds were slaughtered and testes removed for measuring and weighing. The size and testis weight were compared between the left and right. The testicular parameters were correlated by determining the linear correlation coefficient. The gonadosomatic index was also determined, indicating the allocation of 3.68% of body weight in the testes, greater than described in literature. Despite the difference in shape between the left and right testis, weight was similar, suggesting that there is no difference in the capacity of sperm production amongst them. A statistical difference between the biometric values indicates that the left testicle is shorter and more rounded, while the right is longer and narrower. Body weight showed a low correlation with the testicular weight, 0.14 and 0.12 for the left and right testes, respectively. The parameters that best correlated with testicular weight were the width and thickness. Given the identification of a single parameter for comparison of males, the thickness of the left testis showed linear correlation coefficient of 0.89 with the sum of the weight of both testicles. From this information, noninvasive methods such as ultrasound could be used to estimate the reproductive potential and ease the comparison of male Japanese quail in elite selection nuclei, contributing to the genetic improvement of the species.
testicular dimensions; testicular weight; gonadosomatic index; Japanese quail
