RESUMO
This study was designed to monitor the morphological development of the reproductive tract of the Nubian bucks in relation to puberty. Thirty-two Nubain male kids were used in the study. The animals were slaughtered at intervals of 2 weeks starting from 1 day old up to 24 weeks of age. Tissue samples were obtained from the testes and processed for ultrastructural studies. The boundary tissue of the newly forming seminiferous tubule adhered closely to the basal lamina. It consisted of a single continuous layer of myoid cells, the outer surface of which was covered by scattered fibroblasts. The ultrastructural study of the boundary of the seminiferous tubule revealed that it consisted of three layers; inner fibrous, middle and outer cellular. The seminiferous tubules at week one were lined by two layers of epithelia; spermatogonia and Sertoli cells in the basal layer, and primary spermatocytes in the second layer. A gradual increase in the diameter of the tubules and epithelial height continued to increase with age. Furthermore, spermatocytes number showed an increase with age. In conclusion, based on the appearance of spermatozoa in the lumina of the seminiferous tubules, puberty age was achieved between weeks 18 and 20.