Development of bovine in vitro-matured follicular oocytes activated with ethanol

Bovine follicular oocytes cultured in vitro for 30 hours were activated by ethanol and then the developmental ability of the oocytes was assessed. When the activated oocytes were treated with cytochalasin B at concentrations of 0, 1.25, 2.5, 5 and 7.5 mug/ml, the percentages of oocytes having two pronuclei were 8, 18, 54, 66 and 60%, respectively. The percentage of the activated oocytes with two pronuclei also increased with increased exposure time to cytochalasin B. When the activated oocytes were treated with cytochalasin B (5mug/ml) for 10 hours, 20% of them cleaved after 36 hours and 5% of them developed to the eight-cell stage after 60 hours of culture. These results indicated that bovine in vitro matured oocytes can be activated by ethanol and develop to the eight-cell stage following treatment with cytochalasin B.