Birth of Piglets After Transfer of Embryos Cryopreserved by Cytoskeletal

Pig embryos suffer severe sensitivity to hypothermic condi-tions, which limits their ability to withstand conventional cryo-preservation. Research has focused on high lipid content of pig embryos and its role in hypothermic sensitivity, while little re-search has been conducted on structural damage. Documenting cytoskeletal disruption provides information on embryonic sen-sitivity and cellular response to cryopreservation. The objectives of this study were to document microfilament (MF) alterations during swine embryo vitrification, to utilize an MF inhibitor dur-ing cryopreservation to stabilize MF, and to determine the de-velopmental competence of cytoskeletal-stabilized and vitrified pig embryos. Vitrified morulae/early blastocysts displayed MF disruptions and lacked developmental competence after cryo-preservation; hatched blastocysts displayed variable MF disrup-tion and developmental competence. Cytochalasin-b did not im-prove morula/early blastocyst viability after vitrification; how-ever, it significantly (P, 0.05) improved survival and develop-ment of expanded and hatched blastocysts. After embryo transfer, we achieved pregnancy rates of almost 60%, and litter sizes improved from 5 to 7.25 piglets per litter. This study shows that the pig embryo cytoskeleton can be affected by vitrification and that MF depolymerization prior to vitrification improves blastocyst developmental competence after cryopreservation. After transfer, vitrified embryos can produce live, healthy piglets that grow normally and when mature are of excellent fecundity