Meiotic maturation of Egyptian buffalo and cattle ovarian oocytes in vitro

ABSTRACT

This study was undertaken to determine the best culturing period needed to achieve a maximum proportion of in vitro maturation in both Egyptian buffalo and cattle oocytes. Cumulus-oocyte complexes [COC] were recovered from 2-6 mm follicles of buffalo and cattle abattoir ovaries and cultured in TCM 199 supplemented with 10% FBS, 1 mug/ml estradiol 17 beta and 5 mug/ml FSH at 39C in 5% CO2 in air for three different incubation periods [20, 24 and 30 hours]. At the end of the period, the oocytes groups were examined for cumulus expansion, then fixed, stained with orecine and examined under phase contrast optics for chromosomal analysis. Maturation rates of treatment 1 groups [20 hours] were 48% [12/25] and 60% [15/25] for buffalo and cattle oocytes, respectively. Treatment 2 groups [24 hours] maturation rates were 56% [14/25] and 80% [20/25], while maturation rates of treatment 3 groups [30 hours] were 32% [8/25] and 60% [15/25]. The cumulus cells expansion of buffalo oocytes was less than that of cattle oocytes generally, no differences were noticed among treatments. In conclusion, in spite of close results of the 20 hours period for buffalo oocytes, the 24 hours incubation period was found to be the most suitable maturation period for Egyptian cattle and buffalo oocytes. Further studies are needed to verify the maturation period effect on fertilizability and developmental capacity of buffalo oocytes in vitro