Abstracto

Evaluation of cloning efficiency based on the production of cloned Diannan miniature pigs

Weirong Pan, Guozhong Zhang, Yubo Qing, Honghui Li, Wenmin Cheng, Xin Wang, Xiaobing Li, Yingchao Liu, Yuanyuan Qi, Jia Wang, Liangxue Lai, Hong-Ye Zhao*, Hong-Jiang Wei

The cloning efficiency currently observedis low and can be calculated using different methods. Therefore, a reasonable evaluation method for calculating cloning efficiency in pigs is important to promote the application of genetically modified miniature pigs in biomedical fields. In this study, we proposed a method for scientific evaluation of cloning efficiency in pigs based on the production of cloned Diannan miniature pigs. Of 9 recipient sows that were transferred with cloned embryos, 8 (88.9%) sows became pregnant, and 7 (87.5%) of these gave birth to 37 piglets, 22 (59.5%) of which were alive and 17 survived to adulthood (more than 1 year of age). Among the 15 stillborn piglets, 11 piglets experienced intrapartum death due to dystocia, and the other 4 died due to blastocolysis in the late stage of pregnancy. The highest number of littermates was 11 piglets. All 3 piglets delivered by Caesarean section were alive and healthy. The procedure used to clone pigs is a costly process in terms of time and money; specifically, it requires 677.7 to 1265.4 minutes and 715.8 to 764.5 dollars to transfer 50 to 400 cloned embryos to one recipient. The cloning efficiency defined as the total number of cloned piglets (including dead piglets and mother piglets) divided by the total number of transferred embryos was 0.93%, while the cloning efficiency obtained based on the total number of live piglets divided by the total number of recipients was 2.44 piglets. The value is higher than those previously obtained using 19 different types of donor cells. These findings suggest that donor cells derived from Diannan miniature pigs are a valuable source of cells for somatic cell nuclear transfer and defining cloning efficiency in pigs as "the total number of live cloned piglets divided by the total number of recipient sows transferred" may be a reasonable scientific strategy.