Developmental study of fetus testis in Lori sheep

The aim of this study was to determine histomorphometric structure of sheep fetal testisduring early, mid and late gestation stage. Foeti were divided into 3 age groups according to measured crown-rump length (CRL). The observations showed that in the first group (20-50 mm CRL), sertoli cells and gonocytes were distinctly recognizable in the wall of the sex cords and leydig cells were found clearly in gonadal interstitium. In the second group (140-260 mm CRL), the tunica albuginea (TA) was developed into an outer fibrous and an inner vascular layer and the histological organization of rete testis was visible. In the third group (380-420 mm CRL), the testicular shape, size, and structure were more differentiated and the sex cords were obviously separated from each other. Micrometric findings showed that diameter of the TA and sexual diameter, and the number of leydig cells and sertoli cells increased with the growing significantly of age (P<0.05). The number of gonocytes and sex cords in each microscopic field increased comparing the first and second groups but decreased significantly in the third group (P<0.05). The biometric values between right and left testes were not statistically different (P>0.05).