Effect of cysteamine during in vitro maturation on buffalo embryo development

The purpose of this study was to evaluate whether the addition of cysteamine during in vitro maturation (IVM) of buffalo oocytes enhances embryo development. Cumulus-oocyte complexes (COC) from slaughterhouse ovaries were matured in vitro in TCM 199 supplemented with 10% fetal calf serum (FCS), 0.5 mug mL(-1) FSH, 5 mug mL(-1) LH, I mug mL(-1) 17 beta estradiol and 0 (control), 50, 100 or 200 mu mol L-1 of cysteamine for 24 hours. The matured oocytes then were fertilized and cultured for 7 days. No beneficial effect on maturation and cleavage rate was related to the addition of cysteamine. However, the percentage of embryos that developed to compact morula and blastocyst stage was significantly higher (P less than or equal to0.01) for oocytes matured in medium containing 50 mu mol L-1 of cysteamine than it was for oocytes matured with 0, 100 and 200 mu mol L-1 cysteamine (22.6% vs 14.9%, 15.7% and 13% respectively); moreover, the addition of 50 mu mol L-1 of cysteamine during IVM significantly (P less than or equal to0.01) increased the proportion of transferable quality (Grades 1 and 2) embryos (19.3% vs 11.3%, 11.6% and 11.2% respectively). The present study showed that adding a thiol compound (such as cysteamine) to the IVM medium improves buffalo in vitro embryo production (IVEP) efficiency, which so far has been unsatisfactory. (C) 2000 by Elsevier Science Inc.