Age Related Postnatal Micrometrical Changes of the Seminiferous Tubules, Sustentacular Cells and Various Spermatogenic Cells of the Testis in Assam Goats (Capra hircus L.) (Artiodactyla: Bovidae)

Post natal anatomical studies on the testis and its tubular system at various ages are important to better understand the sequence of their growth and development. Different measurements of various spermatogenic cells vary according to the length of cycles of the seminiferous epithelium and within different species of animals. Sixty six male Assam goats aged from day-old to ten mos were examined to determine the various micrometrical values of different spermatogenic and sustentacular cells at various ages of post natal life. These goats were distributed into six age groups as follows: group-I (day-old), group-II (2 mos), group-III (4 mos), group-IV (6 mos), group-V (8 mos) and group-VI (10 mos) consisting of eleven animals in each group. Different micrometrical measurements of the testes were recorded using Image Analyzer with ImagePro software (NIKON, Germany) and subsequently analyzed by using SPSS software version 11.5. The thickness of tunica albugenia, diameter of the tubules, height of the epithelium of the seminiferous tubules and their volume densities increased significantly with age. Similarly, the mean nuclear diameter and volume density of the spermatogonia, primary spermatocytes, secondary spermatocytes and round spermatids also increased with age. All the micrometrical parameters of the testes studied showed highly significant (P<0.01) values between different age groups, except with respect to the nuclear diameter of the spermatogonia and numbers of type A & B spermatogonia, as well as secondary spermatocytes per cross section of seminiferous tubule.