USING RAPID I METHOD FOR VITRIFICATION OF BOVINE OOCYTES

BACKGROUND: Vitrification is commonly used for cryopreservation of gametes. OBJECTIVE: The study aimed at evaluating viability and developmental competence of bovine oocytes vitrified by Rapid-I method. MATERIALS AND METHODS: Oocytes after collection (group 1) and IVM (group 2) were vitrified using medium containing 18% Ficoll, 40% ethylene glycol, 0.3 M sucrose. To evaluate viability, oocytes after warming were stained with fluorescein diacetate and ethidium bromide. In experiment 2, oocytes after IVM and vitrification were activated by 0.5 mu M ionomycin in TCM 199 combined with 2 mM 6-DMAP in TCM 199 with 10% fetal bovine serum. RESULTS: Survival rate in group 1 was 58%, and 88% in the control. In group 2, 63% viable oocytes were found, compared to 82% in the control group. After parthenogenetic activation 27.2% morulas were observed. This percentage was lower than in the non-vitrified group (31%). CONCLUSION: Maturity stage of bovine oocytes has no effect on their survival after vitrification.