In this study, we investigated the effect of donor cell passage number, lineage, and sex on the efficiency of cloned embryo transfer in the endangered Vietnamese Ỉ pig. Cloned Ỉ pig embryos were generated using somatic cell nuclear transfer technology. In Experiment 1, Ỉ pig fibroblasts (ID:6004) at the 5^th and 6^th passages resulted in significantly higher pregnancy, farrowing, and piglet production rates compared with those at the 4^th and 7^th passages. In Experiment 2, pregnancy, farrowing, and piglet production rates did not differ significantly between donor cell groups of male and female origin (P > 0.05). Among cloned Ỉ piglets that died within the first week postpartum, the number of female piglets was marginally higher (1/4 vs 0/4, P > 0.05). In Experiment 3, statistical analyses revealed no significant differences in pregnancy rates, farrowing outcomes, or one-week survival of live cloned piglets across the three donor cell lines (IDs: 6004, 9154, and 9157) (P > 0.05). These findings demonstrate that donor cell passage number is a critical factor influencing the efficiency of cloned Ỉ pig embryo transfer, whereas donor cell sex and cell line identity exert no significant effect.

In this study, we investigated the effects of donor cell on the efficiency of producing cloned Ỉ pigs, an endangered Vietnamese breed. Cloned Ỉ pig embryos were generated using somatic cell nuclear transfer technology (SCNT). The results demonstrated that pregnancy, farrowing, and piglet production rates of Ỉ pig fibroblasts (ID:6004) at the 5th and 6th passages were significantly higher compared with those observed at the 4th and 7th passages. Under the conditions of this study, no significant effect of donor cell sex or cell lines on the efficiency of cloned Ỉ pig embryo transfer was observed. The pregnancy, farrowing, and piglet production rates did not differ significantly between donor cell groups of male and female origin (p > 0.05). Similarly, no significant differences were observed in pregnancy rates, farrowing outcomes, or one-week survival of live cloned piglets among the three donor cell lines (IDs: 6004, 9154, and 9157) (p > 0.05). These findings contribute to improving the efficiency of the somatic cell nuclear transfer (SCNT) technique in efforts to conserve the critically endangered Vietnamese Ỉ pig.