By Lisa Richwine
WASHINGTON (Reuters) - U.S. scientists said on Sunday they had genetically engineered pigs that make beneficial fatty acids and may one day serve as a healthier source of pork chops or bacon.
The pigs produced omega-3 fatty acids, compounds that have been shown to improve cardiac function and reduce the risk of heart disease in people.
The only way now for humans to get omega-3s is through taking dietary supplement pills or by eating certain fish. Some fish, however, may have high levels of toxic mercury.
Seeking another source of omega-3s, researchers transferred a worm gene called fat-1 into pig cells in a laboratory. They used cloning technology to create embryonic cells that were implanted into the womb of a normal pig.
The gene produced an enzyme that converted the less desirable omega-6 fatty acids that the pigs naturally produced into omega-3s, the researchers wrote in the journal Nature Biotechnology.
Tissue from the piglets that were born at the University of Missouri-Columbia had high levels of omega-3s and less omega-6, the researchers said. The total amount of fat was the same as in normal pigs.
The omega-3 pigs "could represent an alternative source as well as be an ideal model for studying cardiovascular disease and autoimmune disorders" that also may be impacted by boosting the healthy fat, said Dr. Yifan Dai, a University of Pittsburgh scientist who transferred the worm gene into the pig cells.
Too much omega-6 is considered a chief contributor to high rates of obesity and heart disease, the leading killer of Americans. Experts encourage higher consumption of omega-3.
Pregnant women are told omega-3s are important for fetal development but are warned to limit consumption of fish that may be high in mercury, which can harm a fetus.
"In this case, we think our pigs will help a lot," Dai said.
Whether meat from the omega-3 pigs or other genetically altered animals will ever reach Americans' dinner plates is uncertain. Regulators have been debating for years if milk or meat from cloned animals is safe to consume, and some industry experts wonder if consumers would embrace it.
Dai said the genetically altered pigs appeared healthy and looked the same as normal pigs. Researchers will further study the impact of the extra omega-3.
The pig researchers used the same technology that one member of the team, Dr. Jing Kang of Massachusetts General Hospital, had previously used to produce mice that make omega-3s. Other scientists are trying to make fish, chickens and cows rich in omega-3s.