Effect of Season and Ovarian Morphology of Egyptian Buffalo on Oocyte Quality and In Vitro Maturation Rate

Abstract

The aim of the current study was to investigate the effect of season, follicle size and corpus luteum (CL) on yield, quality and in vitro maturation of Egyptian buffalo oocytes. Ovaries were collected from abattoirs all over the year and cumulus oocytes complexes (COCs) were aspirated from visible small (≤3 mm), medium (3-6 mm) and large (>6 mm) follicles of normal ovaries. Ovaries were classified according to bearing mature CL3 into with and without CL. Oocytes quality were classified into good, fair, poor and denuded. Only good and fair quality oocytes were used for in vitro maturation in TCM-199 medium supplemented with 10% FCS, 10 µg/ml ovine FSH, 10 IU/ml hCG, 1 µg/ml Estradiol and 1% antibiotic antimycotic mix. Results revealed that a significant difference between the four seasons with significant increase of oocyte yield, quality and maturation for winter and spring than autumn and summer seasons. Oocytes aspirated from medium sized follicles (3-6 mm) were of higher in quality and maturation rate than large (> 6 mm) and small size follicles (≤ 3 mm). Recovery rate, quality and maturation rate of oocytes were higher for ovaries without CL than ovaries with CL. In conclusion, the winter season, medium sized follicles and ovaries without CL showed positive effects on recovery rate, quality and in vitro maturation of buffalo oocytes.