Effect of Epidermal Growth Factor on In Vitro Maturation of Cat Oocytes Recovered from Ovaries at Follicular and Luteal Stages

This study aimed to determine the effect of different concentrations of Epidermal growth factor (EGF) on in vitro maturation (IVM) of cat oocytes collected from ovaries at follicular and luteal phases of reproductive cycle. A total of 612 cumulus oocytes complexes (COCs) were obtained from 42 queens at either follicular or luteal phases. Oocytes were cultured in: (1) TCM 199 (no EGF): (2) TCM 199 plus 10 ng/ml EGF; (3) TCM 199 plus 50 ng/ml EGF. in 5% CO2 aerobic condition for 48 hours According to the chromosomal analyses, each oocyte was placed into the following categories: germinal vesicle (GV), metaphase I (M I). metaphase II (M II) and degenerate. In the luteal phase. the number of oocytes that remained at the GV stage was higher in the EGF 50 group (41.7%; P < 0.05). In the follicular phase. the number of oocytes in M II stage was higher in EGF 10 group (37.9% P < 0.05). The percentage of matured oocytes that reached M II stage was higher in luteal phase (P < 0.05) than in follicular phase for all EGF treated groups. This concluded that. addition of low concentration of EGF (10 ng/ml) to maturation media has a positive effect on the oocytes in comparison with control group (0 ng/ml). In contrast, a high concentration of EGF (50 ng/ml) has a negative result on IVM of cat oocytes and oocytes collected from ovaries on luteal phase are more advisable than follicular phase.