Chinese doctors have successfully transplanted part of liver from a genetically altered pig to a monkey, a hospital announced on Wednesday in Xi'an, Shaanxi province.

The 10-hour operation was performed on Tuesday by a team of doctors at Xijing Hospital of the Fourth Military Medical University. The recipient was a Tibetan macaque, a species found only in China.

Dou Kefeng, the team leader and a professor at the hospital, said the operation, the result of a four-year research project, was the first of its kind successfully performed in Asia.

The pig was genetically altered to suppress rejection of the liver by removing its antigen gene. The monkey selected had biochemical, immunological and anatomical characteristics very close to human physiology, Dou said.

Its vital signs were stable after the transplant surgery.

On June 27, 2012, South Korean media reported that South Korean scientists had transplanted a heart and kidney from a cloned pig to two monkeys, which survived for 24 and 25 days after the operation. Similar experiments have been conducted in several countries, including the United States, Germany, Australia and Japan.

Dou said that the organs from genetically altered pigs are preferred alternatives to human organs and the success of this surgery laid a theoretical and experimental basis for the clinical application of such transplants, which could provide a solution to the shortage of human organs for transplants.

The hospital, which began performing liver transplants in 1997, is a leader in the field in China and has performed more than 300 successful organ transplants, Dou said.