Influence of serum source on buffalo in vitro embryonic development with reference to heat inactivation

The present study was conducted to evaluate the effect of serum source either prepared or commercial, and the effect of serum heat inactivation on cleavage rate and subsequent embryo development in buffalo. Ovaries were collected from slaughtered buffaloes. The follicular contents were collected from 2 to 5 mm diameter ovarian follicles by aspiration. The recovered oocytes with at least two layers of compact cumulus cells and homogenous cytoplasm were selected. Oocytes were matured in vitro using TCM-199 supplemented with four types of 10% sera: heated commercial calf serum, unheated commercial calf serum, heated prepared buffalo calf serum and unheated prepared buffalo calf serum with antibiotics for 24–25 h at 38.5 °C in an atmosphere containing 5% CO₂ in air and 95% relative humidity. The in vitro matured oocytes were co-cultured with spermatozoa capacitated in Brackett and Oliphant medium containing caffeine and heparin for 4 h. Then they were cultured in TCM-199 with each of the four types of previous sera for embryo development. The rate of cleavage, morula and blastocyst was assessed after 3, 5 and 7 days of insemination. The results showed that there were no significant differences in cleavage, morula and blastocyst rates between the use of commercial calf serum and prepared buffalo calf serum either heated or unheated. It could be concluded that prepared buffalo calf serum can be used instead of imported calf serum to evolve the cost of protein supplement in buffalo IVF. Moreover, the serum inactivation by heat treatment seems to be unnecessary.