DEVELOPMENTAL COMPETENCE OF IMMATURE PIG OOCYTES UNDER THE INFLUENCE OF EGF, IGF-I, FOLLICULAR-FLUID AND GONADOTROPINS DURING IVM-IVF PROCESSES

Epidermal growth factor (EGF) and insulin like growth factor-I (IGF-I) were evaluated for their effects on in vitro maturation and fertiliza tion in presence or absence of gonadotropin and porcine follicular flu id. Four groups were made with the addition of growth factors: none (c ontrol), EGF, IGF-I or EGF+IGF-I. Each group underwent four predefined treatments with gonadotropin (FSH and LH), follicular fluid, a combin ation of both, or none las control). Porcine cumulus-oocyte complexes (COCs) were matured in media containing the above-mentioned treatments for 42-44 h prior to fertilization with fresh sperm capacitated for 2 .5 h, At the end of the fertilization period, the presumable embryos w ere fixed, stained and examined as whole-mounts to ascertain their nuc lear status. The addition of EGF alone or in combination with IGF-I, s ignificantly increased the proportion of monospermic oocytes forming 2 normal pronuclei. Also, supplementation with both growth factors toge ther enhanced the percentages of pronucleus formation and total penetr ation. In addition, treatments with EGF+IGF-I significantly decreased (P<0.01) the incidence of degeneration in fertilized oocytes, However, no significant differences in the proportions of COCs undergoing poly spermy were observed among all treatments. These results suggest a sti mulatory effect of tested growth factors in maturation and fertilizati on of pig oocytes, Furthermore, gonadotropins and follicular fluid can be replaced by the addition of EGF and IGF-I to the maturation media with positive effects on fertilization rate.