Vitrification of in vitro matured goat oocytes and the effect on in vitro fertilization

To study the impact of vitrification of in vitro matured caprine oocytes on in vitro fertilization (IVF), ovaries were collected from a local abattoir and goat oocytes aspirated. The oocytes were subjected to in vitro maturation (IVM) for 27 h. Twenty-seven hours post IVM oocytes were cryopreserved in a vitrification solution (VS) consisting of propylene glycol (40%, w/v) and trehalose (0.25 mol l−1) in PBS with 4% (w/v) BSA. Some oocytes were exposed to propylene glycol without cryopreservation to check the degree of damage induced by propylene glycol. In the vitrified group, 94.3% of the oocytes were viable for IVF. 16.1% of the oocytes were damaged after thawing. From the vitrified group, 75.8% of the oocytes were subjected to IVF, while for 18 h. Cytological studies following fixing of the IVF oocytes revealed 17.37% of the oocytes showing a pronucleus in the control group, compared to 8.08 and 7.86% in the vitrified and cryoprotectants exposed groups, respectively. This study revealed that goat oocytes can be successfully cryopreserved using a simple vitrification method. However, the fertilizing ability of oocytes was severely affected by both vitrification and exposure to cryoprotectants.