Optimizing of Activation Protocols and Production of Transgenic Pigs Expressing Human Lysozyme by Somatic Cell Nuclear Transfer

In order to improve the cloning efficiency and obtain human lysozyme(hLY) gene transgenic pigs,the present study was carried out to investigate the effects of different electric activation parameters and chemicals on in vitro development of embryos derived from parthenogenesis(PA) and somatic cell nuclear transfer(SCNT).The results showed that the electric strength could influence the fusion rate and developmental ability of SCNT embryos(P 0.05),and number of electric pulses had no significant effect on SCNT embryos development(P 0.05),yet different variation tendency was found in developmental ability between PA and SCNT embryos under same activation parameters.The blastocyst rate of SCNT embryos was improved when treated with CHX+CB for 4 h after electric activation(P 0.05),whereas 6-DMAP did not(P 0.05).On the contrary,either CHX+CB or 6-DMAP treatment after electric pulses could improve the blastocyst rate of PA embryos,indicating that the best activation method for PA was not necessarily the best for SCNT.The best activation protocol of SCNT embryos in our study is two pulses of 100 μs,direct current of 1.6 kV/cm electric strength with 100 μs interval,and followed by CHX+CB treatment for 4 h.With the activation protocol,the mammary gland expressed hLY transgenic pigs were generated.It could help for improving piglets survival rate in transgenic breeding.