Abstracto

Development before and after cryopreservation of porcine parthenogenetic embryos derived from early-delipated oocytes

Yubo Qing, Wenmin Cheng, Yingchao Liua, Xiaobing Lia, Weirong Pana, Honghui Lia, Si Lia, Baoyu Jiaa, Hongye Zhao*, Hongjiang Wei*

The present study investigated the effect of delipation (lipid droplet removal) on the developmental competence of porcine oocytes. Delipated (+/−) and/or vitrified (+/−) oocytes were subjected to parthenogenetic activation, the viability of the early parthenogenetic embryos was recorded, and the embryos were then transferred to recipients for further development. The results showed that the cleavage and blastocyst rates of the parthenogenetic embryos from the early delipated oocytes were significantly lower than those of embryos from a control group (undelipated oocytes) (P<0.05). After transfer to recipient pigs, these embryos were able to further develop and to produce parthenogenetic fetuses. Using the minimum volume cooling (MVC) method, the parthenogenetic embryos from early delipated oocytes could be cryopreserved by vitrification at 1-cell to early blastocyst stages. After thawing, the early blastocyst stage was found to be optimal for vitrification. Also embryos vitrified at 2-4 cells derived from early delipated oocytes were transferred into two recipient pigs, and resulted in limb-bud stage fetuses. In conclusion, the results demonstrated that parthenogenetic fetuses can be produced from porcine embryos before or after vitrification by a strategic combination of in vitro-matured (IVM) oocyte delipation with vitrification at any early embryonic developmental stage. This approach may have application to cryopreservation of cloned and intracytoplasmic sperm injection (ICSI) embryos derived from delipated oocytes.