Effects of estradiol on in vitro maturation of buffalo and goat oocytes

Purpose The effects of estradiol on oocyte development seem to be varied among species. The present study investigated the effects of 17β-estradiol on in vitro maturation of buffalo and goat oocytes. Methods Cumulus oocyte complexes (COCs) were aspirated from large antral follicles of slaughtered buffalo and goat ovaries. COCs were cultured in TCM-199 medium supplemented with 0, 0.5, 1, and 1.5 µg/mL of 17β-estradiol for in vitro maturation. Then, oocytes were used for the examination of state of nuclear maturation and cumulus expansion. Results In both species, oocytes treated with 17β-estradiol showed higher cumulus expansion rate than control (0 µg/mL treated). In buffalo, the percentage of oocytes matured to the metaphase II (MII) stage increased in the concentration-dependent manner of 17β-estradiol. Similarly, estradiol positively influenced nuclear maturation of goat oocytes in vitro. Conclusions Estradiol has promoting effects on normalprogress of in vitro oocyte meiosis in buffalos and goats.