COCs were recovered by aspirating 2-6 mm diameter follicles, followed by three washes in modified TCM-199 (TCM-199 supplemented with 25 mmol/L Hepes, 25 mmol/L 〖NaHCO〗_3and 3% NBS) and three washes in maturation medium (TCM-199 suplemented with 10% ECS, 3% bovine follicular fluid, 100 µM cysteamine, 0.5 µg/mL FSH and 5 µg/mL LH).