One/Two Days Preservation of goat oocytes at refrigerator and their maturation in vitro

This study was conduct to evaluate the feasibility of one/two days preserving immature goat oocytes without freezing. Cumulus oocyte complexes (COCs) were obtained from ovaries of slaughtered goats. Selected COCs were kept in tissue culture medium (TCM-199) and 10% Fetal Calf Serum (FCS) and stored at 4°C for 1 or 2 days. After preservation, oocyte morphology and viability were evaluated. Post-warmed stored and Non-stored oocytes were cultured in TCM-199 and 10% FCS in CO₂ incubator for 30 h. Oocyte maturation was indicated by cumulus expansion after in vitro culture. Data analysis revealed a high percentage of morphologically normal and viable oocytes after preservation either for 1 or 2 days (70, 60 vs. 60, 50%, respectively) with low percentage of damaged oocytes. There was no significant difference in the maturation of stored oocytes for 1 or 2 days in comparison to fresh oocytes although the value of the fresh oocytes was higher (55, 50 vs. 65%, respectively). Thus, we have developed a simple method for preserving immature goat oocytes by refrigeration at 4°C for two days without evident damage of oocyte and keeping oocyte developmental competence.