The seminiferous epithelial cycle and spermatogenesis in goats (Capra hircus)

Abstract

SUMMARYThe development of the acrosomic system and the spermatid nucleus were used to define 14 stages of the seminiferous epithelial cycle in goats; these stages provided a basis for the examination of the behaviour of different spermatogenic cells which gave an idea of the efficiency of spermatogenesis. Eighteen steps of acrosome development (spermiogenesis) were observed in testicular material stained with periodic acid-Schiff. The first 14 steps were used to classify SEC into 14 (I–XIV) stages which in turn were employed to study the pattern of differentiation of spermatogenic cells by counting them in each stage of the cycle. Three generations of type A (A1, A2, A3), one generation of type intermediate (In) and two generations of type B (B1, B2) spermatogonia could be distinguished. A1 spermatogonia divided primarily in stages IX–X to produce A2 spermatogonia which in turn divided in stages XII–XIII to produce A3 spermatogonia and A, spermatogonia. A3 spermatogonia divided in stage XIV to produce In spermatogonia whereas A1 spermatogonia did not divide till the next cycle but underwent 26·3 % degeneration. In spermatogonia divided to form B1 spermatogonia in stages III–V which further divided to produce B2 spermatogonia in stage VI. Types A3, In and B2 spermatogonia showed 15·0, 25·0 and 25·8% degeneration respectively. B2 spermatogonia divided in stages VII–VIII to produce double the number of primary spermatocytes which persisted without any degeneration till stage XIII of the following cycle and divided at the beginning of stage XIV to form double the number of secondary spermatocytes. These cells divided at the end of stage XIV to form less than double the number of young round spermatids, showing 10·4% degeneration. It is concluded that the development of the acrosomic system as well as the spermatid nucleus could be conveniently used to study the behaviour of spermatogenic cells and that the process of spermatogenesis was less efficient than thought previously.