抄録
This study introduces that newly developed serum-free media (IVD101 and IVMD101) can improve the yield and quality of bovine blastocysts from in vitro matured and fertilized oocytes. The media were particularly designed in the absence (IVD101) or presence (IVMD101) of bovine cumulus/granulosa cell (BCGC) coculture. The proportion of embryos developing to the blastocyst stage and the mean cell number per blastocyst in IVD101 and IVMD101 were greater than in serum-supplemented medium (TCM199+5% calf serum). Furthermore, the post-thaw survival rates of cryopreserved blastocysts derived in IVD101 and IVMD101 were superior to that of blastocysts derived in serum-supplemented medium. The serum-derived blastocysts showed abundant lipid droplets in cytoplasm under transmission electron microscopic observation and contained high levels of unsaturated fatty acids such as palmitoleic and oleic acids. The evidence may partly explain the sensitivity of serum-derived embryos after freezing and thawing. It is known that the embryo transfer of in vitro-derived embryos often results in the production of bovine calves with abnormalities such as heavier than normal birth weight and a high incidence of dystocia. In this study, high pregnancy rate of blastocysts cultured in IVD101 after embryo transfer was obtained and the birth weights of live calves derived in IVD101 were normal range of birth weights produced from in vivo-derived embryos. These new serum-free media are beneficial, not only for the study of the mechanisms of early embryogenesis, but also for mass production of good quality embryos for embryo transfer, cloning and transgenesis.
