Abstract

FERNANDEZ REYES, F; HERNANDEZ PICHARDO, J.E  and  CASTELLANOS GARCIA, Gabriela. VIABILITY OF in vitro IMMATURE AND MATURED PIG OOCYTES VITRIFIED WITH ETHYLEN GLYCOL AND TREHALOSE. Rev Salud Anim. [online]. 2012, vol.34, n.1, pp. 46-52. ISSN 0253-570X.

In order to assess the viability of immature oocytes (GV), matured in vitro (MII) after vitrification using glycol ethylene and trehalose, 503 ovaries were collected, from which 731 oocytes were obtained by aspiration of follicles from 3 to 5 mm. They were divided into 3 groups: Group 1) control (52 oocytes), Group 2) vitrification of oocytes under GV condition (326 oocytes) and maturing after heating and Group 3) vitrification of in vitro matured oocytes (353 oocytes). In group 1, after being cultured in vitro for 44 hours, maturation was assessed by staining with 1% orcein in 45% acetic acid. Groups 2 and 3 were vitrified using the two-step protocol (equilibrated and vitrification), viability was assessed at heating time (devitrification), by staining with thiazolyl blue (MTT). The results of maturation in group 1, was with the presence of GV 44%, in state of MI (condensed chromatin or metaphase I), 23% and 33% MII. Viability in group 2 was 100% fresh, at heating time 76% and at 44 h of culture in vitro after heating 13%. Group 3 oocytes before vitrification had a viability of 94.8% and 50% after heating. It is concluded that although viability is higher at heating time in immature oocytes than in those mature, the latter may have a major advantage for further development in assisted reproduction, since in those immature, viability is much more reduced when cultured 44 hours for in vitro maturation.

Keywords : pig; oocyte; vitrification; in vitro maturation; in vitro fertilization.

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