Testicular Germ Cell Depletion and Transplantation in Cattle and Sheep

Abstract

Germ cell transplantation has been shown to be a useful technique for studying spermatogenesis in rodents. In livestock species, the germ cell transplant technique could be used to produce transgenic animals and as a reproductive technology in extensive production systems. One of the contributing factors to poor success thus far has been poor recipient preparation, such as depletion of endogenous germ cells. This thesis investigated four depletion methods known to affect germ cells; heat, cold, chemotherapy (Busulfan) and irradiation. ... This thesis has found that testicular irradiation is the most successful method tested to deplete endogenous spermatogonia in the sheep testis. In addition, irradiated testes can support both endogenous and donor derived spermatogenesis. It seems that irradiation at high doses (15Gy) at the peri-pubertal to pubertal stage of testicular development can produce suitable recipients for germ cell transplantation and therefore is a potential methodology to increase the efficiency of germ cell transplants in livestock species.