Abstract

AKE-VILLANUEVA, Jesús Ricardo; AKE-LOPEZ, Jesús Ricardo; CENTURION-CASTRO, Fernando Gerardo  and  ORDONEZ-LEON, Érika Alina. Effect of cumulus cells on postwarming viability of vitrified bovine oocytes. Ecosistemas y recur. agropecuarios [online]. 2015, vol.2, n.5, pp.183-191. ISSN 2007-901X.

In order to evaluate the effect of the presence of cumulus cells on oocytes before vitrification, on their ability regarding maturation, fertilisation and embryo development in vitro after warming, 596 bovine oocytes were vitrified, 317 with cumulus cells (COC) and 279 without cumulus cells (DND). Vitrification was carried out using OPS straws and ethylene glycol+DMSO as cryoprotectants. After warming, the oocytes were matured in vitro (MIV), fertilised (FIV) and cultured for seven days. In order to evaluate MIV and FIV, around 20 % of mature oocytes and 20 % of fertilised oocytes were preserved and stained with Lacmoid. Cleavage rates were recorded 48 h after the culture started. The results were evaluated using a Ji square test. The post-warming oocyte recovery percentage was similar for both groups (p>0.05). The proportion of morphologically normal oocytes was slightly lower in the DND group (p<0.05). The proportion of mature oocytes was similar (p>0.05) for COC (47.5 %) and DND (47.8 %). The percentage of penetrated oocytes after FIV was low in both groups (COC=10.26 %; DND=15 %; p > 0.05). The percentage of divided oocytes after FIV was 2.9 % for COC (N=6) and 2.45 % for DND (N=4; p>0.05). No oocyte reached the morula or blastocyst stage. It is concluded that vitrification of oocytes with or without cumulus cells resulted in low percentages of fertilisation and cleavage and no embryonic development.

Keywords : Bovine oocytes; cumulus cells; IVF; IVM; vitrification.

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