Somatic and germ cell proliferation during post-natal development of the testis in the wild boar (Sus scrofa scrofa)

This study aimed to investigate the proliferation of cells in the seminiferous epithelium, the intrinsic rate of spermatogenesis and Sertoli cell index in wild boars, during the period from birth to 12 months of age. A total of 52 animals raised in captivity were assigned to 13 experimental groups. After unilateral orchidectomy, fragments of the testes were embedded in plastic resin and used to prepare slides for histometric analysis. Variables assessed in each age group included the characterization of cell populations in the seminiferous epithelium, the intrinsic rate of spermatogenesis, Sertoli cell index and the stages of testicular development in each animal. Gonocytes were in greater numbers in newborn animals, and by the fourth month were no longer identified. The population of spermatogonias increased from 3 to 9 months, after that showed a tendency to stabilization. Primary spermatocytes in pre-leptotene/leptotene were first seen in 8-month-old animals. Primary spermatocytes in pachytene, and round spermatids increase gradually in frequency in animals from 9 to 12 months of age. Undifferentiated support cells were very frequent at birth to 7 months and increased between 7 and 8 months, after that there was a tendency for no further increase in this cell type. We conclude that the Sertoli cell population stabilized in the pre-pubertal phase and germ cell population increased after puberty. The overall yield of spermatogenesis and Sertoli cell index were greater in animals around 12 months of age.