Developmental potential of vitrified goat oocytes following somatic cell nuclear transfer and parthenogenetic activation

Oocyte cryopreservation is an alternative tool in assisted reproductive technology. The objective of this study was to determine the developmental potential of vitrified goat oocytes after somatic cell nuclear transfer (SCNT). In vitro matured goat oocytes were vitrified by Cryotop method. The survival rate of vitrified oocytes at 1 h after thawing determined by fluorescein diacetate staining was 92.1% which was significantly lower than that of fresh oocytes (99.3%). Live oocytes from both vitrified and fresh groups were used as recipient cytoplasts for SCNT. No significant difference in fusion rate was found between vitrified (97.6%) and fresh (93.2%) oocytes. The cleavage rates of vitrified oocytes in the SCNT and parthenogenetic activation (PA) embryos (29.6% and 27.9%) were significantly lower than those from fresh SCNT and PA oocytes (80.9% and 91.1%). The developmental rates to 8-cell stage of SCNT and PA embryos from vitrified oocytes were also lower than that of fresh oocytes. There was no significant difference among the groups in the development to morula stage (11-27%). However, the blastocyst rate of PA embryos derived from fresh oocytes (12.5%) was significantly higher than the other groups (1.2-3.3%). Although high survival rate of vitrified oocytes was obtained, the cleavage, 8-cell, and blastocyst formation rates of SCNT and PA embryos from vitrified oocytes were still lower than those of fresh oocytes.