Utilization of porcine invitro-produced parthenogenetic embryos for co-transfer with vitrified and warmed embryos.

Abstract

The present study was conducted to evaluate the possibility of using invitro-produced parthenogenetic (PA) embryos for co-transfer with morulae that had been collected invivo and cryopreserved. The proportion of PA blastocysts (20.5%) was higher than that of their invitro fertilization (IVF) counterparts (16.6%). Although there were no differences in morphology or diameter between the two groups, the number of cells in early PA blastocysts after invitro culture for 6days was lower than for IVF blastocysts (25.7 and 30.4 cells, respectively), and the number in recovered PA blastocysts was also smaller than that in recovered IVF blastocysts (37.4 and 50.2 cells, respectively). When 10 morulae warmed after vitrification were co-transferred with 10 PA blastocysts (total 20 embryos) to the uterus of five recipients, the rates of pregnancy and farrowing did not differ, but the average period until spontaneous abortion tended to be longer relative to the control (when 20 morulae were transferred). These data suggest that invitro-produced PA embryos offer the possibility of assisted pregnancy for cryopreserved embryos; further experiments will be needed to confirm the beneficial effect of this approach on piglet production.