Factors affecting porcine in vitro oocyte maturation, fertilization, and early embryo development

The thesis investigated the various factors influencing porcine in vitro maturation of an oocyte (IVM), fertilization (IVF), and early embryo culture (IVC). The study revealed that (1) the addition of cysteine during IVM was beneficial to early embryo development; (2) application of gradient Percoll and glutathione during sperm conditioning for IVF also improved the outcome of early embryo development; (3) when two common porcine embryo culture media, NCSU23 and BECM3 were tested for their ability to support porcine zygotes in vitro, the NCSU23 medium consistently showed an equal or better rate of embryo development; (4) the efficacy of two-step embryo culture using these two media was no better in supporting the development of embryos when compared to the single-step NCSU23 medium; (5) the developmental competence of the IVM-produced oocyte was maintained for at least 16h; (6) the oocyte activation by a combination treatment, calcium ionophore followed by 6-dimethylaminopurine, was the most effective among three common activation protocols evaluated; (7) the developmental competence of porcine oocytes was significantly affected by an interaction among the age of the donor animal, ovarian follicle size, and exogenous gonadotropic stimulation. In conclusion, this study provided a valuable assessment of the factors involved in porcine in vitro oocyte and embryo culture system.