ABSTRACT
Production of transgenic offsprings requires large numbers of one-cell embryos at the pronuclear stage, for gene injection. However, the procedure is expensive and leads to variable yields of embryos depending on the technique used, the individual response of the donor, semen quality and other factors. The efficiency of an in vitro capacitation system can be evaluated by the time required for sperm-egg penetration after gamete mixing. The incidence of polyspermy varies between IVF experiments, but is relatively high (10–20%) compared to natural conditions. Nowadays, sperm capacitation and fertilization in vitro are not limiting steps to generate one-cell sheep and goat zygotes. The in vitro production of viable zygotes with full developmental potential is mainly hampered by the quality of oocytes produced through IVM.
