Effect of epidermal growth factor (EGF) during oocyte maturation on in vitro production of bovine embryos

The aim of this experiment was to research the effect of Epidermal Growth Factor (EGF) during in vitro maturation (IVM) of bovine oocytes on the development of bovine embryos in vitro. The oocytes were recovered from ovaries of slaughtered cows. An IVM media containing serum was compared with chemically defined medias. As a result, 163 Cumulus oocyte complexed (COC's)were selected, with three or more layers of granulosa cells, and were incubated for 24 hours in one of the three maturation medias: 1) Modified OMM (T-1); 2) Modified OMM supplemented with 10 ng/ml of EGF (T-2); 3) Modified OMM supplemented with 10% of fetal bovine serum (T-3). Following IVM, COC's were inseminated with 2x10(6) spermatozoa / ml. After 18 hours of gamete coincubation, presumptive zygotes were denuded and placed in culture until the blastocyst stage. Cleavage rates were similar in T2 and T3, but significantly greater than in T-1 (P<0.05). Addition of EGF during in vitro maturation (TO did not yield more blastocyst compared to the other treatments. None the less, T3 (with serum) had a greater yield of blastocysts compared with T-1 (P<0.01). Results in this study show that the addition of EGF to chemically defined media produces similar cleavage rates and blastocyst yields to those obtained when using serum during IVM, representing an alternative for in vitro production of bovine embryos.