Evaluation of recovery, quality and in vitro nuclear maturation of oocytes obtained from buffalo and bovine ovaries

Ovaries of 86 buffaloes and 95 cows were collected from slaughterhouses and transported to the laboratory in saline solution at 36o C. The Cumulus-oocyte complexes (COCs) were recovered by follicular aspiration and only grades I and II COCs were selected and matured in TCM 199 supplemented with 10% fetal calf serum, sodium pyruvate, LH, FSH, estradiol, gentamicin and cysteamin, for 22-24 hours. A total of 714 and 1983 COCs were recovered from buffaloes and cows, respectively. In the buffaloes, the recovery rates of each COCs categories (grade I: 25.9%; grade II: 30.7%; grade III: 10.2%; denuded 18.6% and expanded: 14.6%) were lower than cows (31.8; 30.6; 15.4; 4.5; 17.7%, respectively) according to Mann-Whitney Test (p< 0.05). The percentage of bubaline oocytes that reached metaphase II (63.4% - 242/ 396) was lower than bovine oocytes (67.8% - 696/ 1234) under the same laboratory conditions. These differences observed in all analysis realized indicate that each species has peculiar phisiological characteristics.