Conservation of avian germplasm by interspecies spermatogonial transplantation: influence of recipient age on restoration of spermatogenesis by donor cells

Abstract

According to the latest assessment of the International Union for Conservation of Nature (IUCN), about 12.5% of the total 9,920 extant bird species in the world are threatened with extinction. This uncertain future facing wild birds emphasizes the importance of captive breeding programs for the conservation of a number of avian species. Assisted reproductive technologies such as sperm freezing and artificial insemination offer potential practical benefits for overcoming breeding difficulties encountered with wild birds. Nevertheless, despite the progress in freezing semen of domestic species, there is limited success with this technique in nondomestic species. An alternative approach to overcome this problem is to preserve germplasm through germ cell transplantation between different individuals or species. Recently, Pereira et al. [manuscript in preparation - Appendix I] confirmed that transfer of testicular germ cells between adult quail and chicken resulted in colonization of the seminiferous tublues by donor spermatogonia, but without complete restoration of the spermatogenesis. One fator possibly involved in the arrest of spermatogenesis is recipient age at transplantation, due to its influence in the accessibility to the testicular stem cell niche. Thus, this project aims to investigate the impact of recipient age on the success of spermatogonial xenotransplantation in the quail-chicken model. The results of this research will bring information that may elucidate some of the current obstacles to the use of interspecific transplantation for conservation of rare or endangered birds. (AU)