Assisted reproductive technologies (ARTs) can be applied to improve reproductive efficiencies in livestock species. In addition, ARTs have significant roles in the preservation of endangered species. 1 ARTs including artificial insemination (AI), cryopreservation, intra-cytoplasmic sperm injection (ICSI), multiple ovulation and embryo transfer (MOET), and in vitro embryo production (IVEP) have been used for improvement of domestic animals. In buffaloes, the response to superovulation treatment is poor, and ultimately, MOET is hardly applicable. However, oocytes recovered from slaughtered animals are used for IVEP. In vitro maturation (IVM) is the initial step of IVEP technology. IVM of oocytes involves collection of cumulus oocyte complexes (COCs) from antral follicles and culturing them until they reach to the metaphase II (MII) stage. 2