SYNERGISTIC EFFECT OF ETHANOL AND CYCLOHEXIMIDE ON ACTIVATION OF FRESHLY MATURED BOVINE OOCYTES

Bovine follicular oocytes were collected from ovarian antral follicles (2 to 7 mm in diameter) from slaughtered cattle. They were matured in vitro (IVM) for 23 to 24 h and then activated. In Experiment 1, 4 con centrations of ethanol were compared. The activation rates of oocytes were 4, 12, 36 and 27%, respectively, following exposure for 7 min to 0, 5, 7 and 10% ethanol. In Experiment 2, 7% ethanol was tested with e xposure times of 0, 5, 7.5 and 10 min, and 6, 32, 27 and 33% of the oo cytes were activated, respectively. In Experiment 3 the synergistic ef fect of ethanol and electric pulse was compared within 4 treatments: A ) 7% ethanol alone, B) electric pulse alone, C) ethanol first and then electric pulse treatment, and D) electric pulse first followed by eth anol exposure. Of the oocytes activated, 37, 31, 28 and 51%, respectiv ely, were from Treatments A through D. In Experiments 4 and 5 the poss ible synergistic effect of ethanol and a protein synthesis inhibitor, cycloheximide, was studied within 4 treatments: A) parthenogenetic con trol with no activation treatment, B) ethanol alone, C) cycloheximide alone, and D) ethanol treatment followed by cycloheximide. The oocyte activation rates in Experiment 4 in Treatments A through D, respective ly, were 9, 44, 43 and 84%. Corresponding values for development of oo cytes to the 2 to 8-cell stage after culture for 3 d (Experiment 5) we re 9, 20, 14 and 45%, respectively (P<0.05). exposure to 7% ethanol fo r 5 min followed by incubation with cycloheximide was the best activat ion treatment for bovine IVM oocytes.