EFFECT OF GRANULOSA AND CUMULUS CELLS ON IN VITRO DEVELOPMENT OF THE BOVINE FOLLICULAR OOCYTES

The effect of co-culture with cumulus cells and granulosa cells during maturation and development on in vitro developmental potency of follicular oocytes was examined. TCM-199 supplemented with 15% FCS and hormones was used as maturation medium. Sperm from frozen semen was capacitated in modified mTALP medium containing 0.3% BSA, $10{\mu}g/ml$ heparin and 5 mM/ml caffeine. The fertilized embryos were co-cultured on monolayer of cumulus cells or granulosa cells in TCM-199. The embryo co-cultured with cumulus cells showed higher percentage of embryo developed to morula and blastocyst (73.3%) than the embryo co-cultured without cumulus cells (30.8%). The percentage of oocytes developed to morula and blastocyst among cleaved oocytes was significantly (p < 0.05) higher in the oocytes co-cultured with cumulus cells during development (62.4%) than in the oocytes co-cultured with granulosa cells during maturation and with cumulus cells during development (52.3%), and in the oocytes co-cultured with granulose cells during development (52.8%). The results of this study indicate that co-culture of in vitro fertilized embryos with cumulus cells in the development medium increased the rate of embryos developed to morula and blastocyst among cleaved oocytes.