Buffalo Oocytes Maturation In Vitro as Affected by Vitrification of Whole Ovaries or Oocytes

Abstract

Aim of this paper is to find the possibility of in vitro maturation of buffalo oocytes recovered from vitrified whole ovaries. Ovaries from slaughtered buffaloes (n=400) were collected; out of these ovaries, 150 were fresh and 250 buffalo ovaries were vitrified and thawed. Number of all visible follicles was recorded on fresh ovaries and on each ovarian surface pre-and post vitrification, then oocytes recovery rate was calculated in fresh or vitrified ovaries. Oocytes were recovered by aspiration. From the recovered oocytes from fresh ovaries, COCs were vitrified by straw cryodevice. Post-thawing, morphologically normal oocytes from vitrified or fresh ovaries were vitrified. Results showed that numbers of total and normal follicles, and total and normal oocytes per ovary were significantly higher in fresh than in vitrified ovaries. Total number of abnormal follicles showed significantly (P<0.01) an opposite trend, while, the difference in number of abnormal oocytes/ovary was not significant. Oocytes recovered from fresh ovaries showed significantly higher recovery and normality rates than those recovered from vitrified ovaries. Percentage of compact and expanded oocytes was significantly higher, while percentage of denuded and partial denuded oocytes was significantly lower when oocytes were recovered from fresh than from vitrified ovaries. Maturation rate (MIIoocytes percent) was higher (P<0.05) when oocytes were recovered from fresh than from vitrified ovaries and those vitrified after recovery (62.50% vs. 35.90 and 27.50%, respectively). In conclusion, vitrification of the whole buffalo ovaries is a positive tool for genetic sources cryopreservation in term of beneficial effects on in vitro maturation of oocytes when compare with those directly vitrified after recovery from fresh ovaries.