In vitro maturation of oocytes from non-stimulated common wombats.

Abstract

Assisted reproductive techniques, such as in vitro oocyte maturation in conjunction with in vitro fertilisation, may be used as a tool to manipulate reproduction. Using the common wombat as a model for the critically endangered northern hairy-nosed wombat, the present study examined whether oocyte maturation could be achieved under field conditions. At the time of collection, no oocytes were at the metaphase II (MII) stage (0/42). After 60 h culture using the submarine incubation system, 34% of oocytes (24/70) matured to telophase/MII, as indicated by the presence of a polar body. The proportion of oocytes that reached MII was higher for oocytes collected from follicles >2 mm in diameter compared with follicles <2 mm (40% v. 22%, respectively). The presence of cumulus cells alone did not influence the maturation potential. Oocytes without cumulus cells collected from follicles >2 mm in diameter had the highest maturation rate (58%). Maturation was not affected by the reproductive status of the common wombat or a delay of up to 5 h before oocyte collection. In conclusion, the present study demonstrated that oocytes collected from non-stimulated common wombats can mature to MII in culture.