Fertilizability and subsequent developmental ability of bovine oocytes matured in medium containing epidermal growth factor (EGF).

We have previously shown that epidermal growth factor (EGF) is capable of promoting maturation of bovine cumulus-oocyte complexes in chemically defined serum-free medium. In this study, fertilizability and subsequent developmental capacity of bovine oocytes matured in EGF-containing medium were evaluated. Fetal bovine serum (FBS, 10%) and EGF at 10 ng/ml in Dulbecco's modified Eagles medium with Ham's nutrient mixture F-12 (DME/F12) significantly increased the rate of formation of two pronuclei compared with the rate obtained from DME-F12 alone (P<0.05). Early embryonic development was assessed during 48 h in culture. Data were evaluated in terms of cleavage and four- to eight-cell formation. Oocytes matured in 10 ng/ml EGF showed significantly higher rates of cleavage (P<0.01) and four- to eight-cell formation than did oocytes matured in control medium (P<0.05). Bovine oocytes matured in the presence of EGF can be normally fertilized and can cleave and develop in vitro up to the eight-cell stage.