Effect of "ice blockers" in solutions for vitrification of in vitro matured ovine oocytes.

Polymers have been used as a substitute for serum in vitrification solutions for embryos and oocytes. This study was designed to replace serum with defined commercial macromolecules in vitrification solution for in vitro matured ovine oocytes. Oocytes were cryopreserved in two vitrification solutions (16.5 percent ethylene glycol + 16.5 percent dimethyl sulphoxide) supplemented with 1 percent of SuperCool X-1000 and 1 percent SuperCool Z-1000 (Ice Blockers) or 20 percent foetal calf serum (FCS). After warming, oocytes viability and developmental potential after processing for in vitro embryo production were assessed. The number of viable oocytes (87.4 percent and 85.9 percent), cleaveage rates (21.4 percent and 19.6 percent) and blastocyst development rates (4.8 percent and 4.5 percent) were similar for Ice Blockers and FCS, respectively. On the basis of these findings, it may be concluded that combined use of Ice Blockers (SuperCool X-1000 and SuperCool Z-1000) as supplementation in vitrification solution offers similar results to serum for vitrification of in vitro matured ovine oocytes.