Table 2.

Comparison of cloning efficiency resulted from using wild-type and PB vectors-transfected transgenic fetal fibroblast as donor cells for SCNT.

Donor fetal fibroblast genotype	Transgenic	Wild-type
No. of transferred cloned embryos	1542	5128
No. of recipients	7	23
No. of embryos/recipient	≈220	≈226
No. of pregnant recipients (pregnancy rate) #	4 (57.14%=4/7)	11 (47.83%=11/23)
No. of farrowed recipients (farrowing rate)	4 (57.14%=4/7)	9 (39.13%=9/23)
No. of delivered cloned piglets (birth rate)	20* (1.30%=20/1542)	31◎ (0.60%=31/5128)
No. of delivered live normal cloned piglets (birth rate)	18 (1.17%=18/1542)	24 (0.47%=24/5128)

^#Pregnancy of recipients was examined at one month after embryo transfer.

^*All these 20 piglets were born alive and 2 of them showed abnormalities.

^◎Three of these 31 piglets were stillborn, and 4 of the remaining live piglets showed abnormalities.