The Influence of Epidermal Growth Factor on Maturation and Fertilisation of Bovine Oocytes In Vitro*

The aim of the present study was to evaluate the efficiency of different doses of epidermal growth factor (EGF) on maturation and fertilisation of bovine oocytes in vitro. A total of 1209 high quality oocytes (follicles 2-8 mm in diameter, with unexpanded cumulus cells) were obtained by aspiration from ovaries collected at a slaughterhouse. The oocytes were then assigned into 6 groups: 1, 10, 100, and 1000 ng/ml EGF groups, as well as positive (EGF replaced with hCG) and negative (TCM 199 only, no supplement) control groups. Maturation and fertilisation rates were calculated at 39 °C in an atmosphere of 5% CO2 in air with maximum humidity for 24 and 20 h, respectively. Based on the cumulus expansion, no significant difference was found between the EGF groups. However, the highest dose of EGF (1000 ng/ml) had a lower percentage of 1 polar body extrusion than all other doses (P < 0.05). Considering monospermic fertilisation and non-fertilisation rates, a further significant difference (P < 0.05) was found between all the EGF groups. Moreover, there were also significant differences (P < 0.05) between the positive and negative control groups for all the parameters given. In conclusion, the data suggest that the EGF used as a media additive (more favourable at 100 ng/ml) on IVM can be useful for IVF of cattle oocytes.