On March 31, 2022, an ordinary "surrogate" sow gave birth to 7 cloned purebred Landrace pigs after a gestation period of 110 days. These are cloned animals as a result of automated operations for the entire cloning process. The scientific research team of Nankai University realized the "breeding" of cloned pigs through whole-process robot automation, a groundbreaking achievement in the world. 

With the support of the Key Technologies R&D Program of China, the scientific research team led by Prof. Zhao Xin of Nankai University, in concert with the Institute of Animal Husbandry and Veterinary Medicine of Tianjin Academy of Agricultural Sciences, studied the automated operation-based cloning technology in response to the problems of artificial cloning technology, and made a breakthrough. The team becomes the only team in the world to implement the whole process of robot operation and automated operation-based cloning.

Automated operation-based cloning technology harnesses microscopic vision to establish a holistic field of view with a resolution that extends from centimeter level to sub-micron level. It improves the operation efficiency and realizes the batch cloning operations. The automatic cloning operation based on the minimum force is achieved through cell force analysis. Through the intracellular strain evaluation, we can reduce the damage to oocytes during cloning operation, improve embryonic development after cloning operation, and ensure more accurate cloning operation.

Thanks to automated operation-based cloning technology, the blastocyst rate, symbolic of the success of cloning, rose from 10 percent under manual operation to 27.5 percent under automated operation, an increase of 2.75 times. The results of the team’s work show that the litter size of a single surrogate sow has increased from an average of less than 5 pigs under artificial cloning to three litters in two batches under roboticized and automated cloning, totaling 24 pigs, 8 pigs per litter on average, up by more than 60 percent. In addition, the team’s first cloned pigs bred by automatic operations have been used for breeding and production. Nine of the 13 healthy cloned pigs are used as stock animals, with an animal stock rate of 69 percent, which doubles the 35 percent for ordinary breeding pigs. 

Automated operation-based cloning technology offers a way for large-scale increase of ancestral original breeding pigs, and for the wide application of cloning technology for pig breeding and practical production. This provides a solution for China to rapidly "reproduce" excellent animal varieties on a large scale.

(Edited and translated by Nankai News Team)