Abstract
The objective of this study was to investigate the effect of selenium (Se) on in vitro development of bovine embryos. In CR1BSA, FBS-free medium, the bovine embryos could not proceed past the developmental block more efficiently to morula stage than in chemically undefined media. Addition of glutathione precursor, cysteine, with $\beta$-mercaptoethanol did not improve the development in chemically defined medium and neither did glutathione alone. Exogenous selenium improved the embryonic development to the morula and blastocyst stages at 6 days post-insemination (dpi) significantly (67.1% vs 57.5%, p<0.05), and blastocyst stage at 8 dpi (30.1% vs 20.5%, p>0.05). These improvements might be induced by elevated glutathione peroxidase activity due to addition of Se, and a possible mechanism of selenium to elevate the activity of glutathione peroxidase is discussed.