Histological Insights into Testicular Apoptosis Associated with Spermatogenesis in Pre-Pubertal and Adult Meagre (Argyrosomus regius)

Abstract

Recombinant gonadotropins—synthetic versions of pituitary hormones—are increasingly utilised in aquaculture for broodstock management. In this study, we explored how recombinant follicle-stimulating hormone (rFsh) affects spermatogenesis in meagre (Argyrosomus regius), with the aim of enhancing our understanding of testicular apoptosis—a common form of programmed cell death involved in modulating germ cell development and sperm output. We assessed germ cell composition and testicular apoptosis in both pre-pubertal meagre treated with rFsh and adult fish in two spermatogenic phases (proliferative and meiotic). In pre-pubertal fish, rFsh treatment led to larger testes, wider seminiferous tubules, and increased sperm presence. There was a reduction in early spermatogonia (undifferentiated germ cells) but a rise in dividing germ cells, indicating progression toward meiosis. Notably, treated fish exhibited significantly lower spermatogonial apoptosis compared to controls, suggesting rFsh promotes germ cell survival by mitigating natural cell death. In adult fish, the density of spermatogonia decreased with the progression of spermatogenesis, whereas apoptosis increased and often involved entire clones of germ cells. Overall, the study demonstrates that rFsh effectively induces testicular maturation in pre-pubertal meagre by promoting progression toward meiosis and highlights how the role of apoptosis varies across reproductive stages.