Nuclear and Cytoplasmic Maturation of In Vitro Matured Denuded Oocytes in the Presence of Gonadotrophins, Oestradiol and Insulin in Nili Ravi Buffalo

The lower recovery of competent oocytes in buffalo species limits the commercialization of in vitro embryo production technology in field conditions. The present study aimed to improve the cytoplasmic and nuclear maturation of in vitro matured oocytes of Nili Ravi buffalo in the presence of hormones. The denuded oocytes (DOs) obtained by repeated pipetting were collected from 2-8mm follicles. A series of experiments were conducted to evaluate the effects of oestradiol (2 & mu;g/ml), recombinant human follicle stimulating hormone (0.05 IU/ml), human chorionic gonadotrophin (2 IU/ml) and insulin (0.12 IU/ml) alone or together in different combinations at intervals of 8, 16 and 24 h of incubation period during in vitro maturation on buffalo oocyte. The supplementation of TCM-199 with E2+rhFSH showed a highly significant increase in the diameter and maturation of oocytes (P<0.0001), as a greater number of the oocytes progressed to the metaphase II stage, and a lower proportion of the oocytes became degenerated (P<0.0001) after 24 h of incubation. The supplementation of medium with E2+rhFSH+hCG or E2+rhFSH+hCG+insulin also showed a significant increase in the meiotic maturation rate after 24 h (P<0.01 and P=0.04 respectively) and a significant decrease in the degeneration of the oocytes (P=0.001). The addition of insulin was not found to be effective for in vitro maturation. It is concluded that the addition of E2+rhFSH in culture media was found to be the best combination of hormones for in vitro maturation of denuded buffalo oocytes.