Pittsburg Tribune-Review, PA
03-27-06
Cloned pigs to be used in omega-3 study
By Jennifer Bails
TRIBUNE-REVIEW
Health-conscious consumers might one day have the option of getting their fish
fats from the other white meat.
Scientists have announced they have cloned pigs carrying a gene necessary to
produce omega-3 fatty acids, which are believed to protect against disease and
regulate growth and development.
Researchers will use the designer pigs to further investigate how omega-3 fatty
acids work in the body. The pigs also could provide an alternative dietary source
of these essential compounds, said study leader Dr. Yifan Dai, a surgery
professor at the University of Pittsburgh.
"We always should be looking for ways to improve the product for consumers,
and this is clearly one avenue we can take to achieve that," said animal science
expert Steven Lonergan of Iowa State University, who wasn't involved in the
research.
Omega-3 fatty acids are a form of polyunsaturated fats found in fatty fish and fish
oils that might help prevent heart disease, cancer, diabetes, arthritis and even
depression. More popular foods such as grains, plant-based oils and poultry
have less beneficial omega-6 fatty acids.
The federal government has no guidelines for intake of omega-3 fatty acids, but
nutritionists encourage some people to eat fatty fish such as salmon and herring
at least twice a week to balance the typical omega-6 rich American diet.
Fatty fish, however, can contain dangerously high levels of toxic mercury.
Overfishing threatens scarce marine resources, and rising prices make fish and
fish products too expensive for many consumers and farmers.
"Health recommendations advise increased consumption of oily fish and fish
oils," wrote epidemiologist Eric Brunner of University College London in last
week's issue of the British Medical Journal. "We probably do not have a
sustainable supply of long chain omega-3 fats."
Pork -- or other meat and poultry -- juiced up with fish fats might help resolve
that.
To achieve the biotech feat, Dai first inserted into pig cells an adapted version of
a worm gene aptly named fat-1. The gene produces an enzyme to convert
omega-6 fatty acids to omega-3 fatty acids. Dai then shipped his genetically
modified pig cells to reproductive technology expert Randall Prather at University
of Missouri-Columbia, who cloned the pigs.
Results of the study were released Sunday in an online edition of the journal
Nature Biotechnology and will be detailed in its April 8 publication.In the study,
researchers implanted more than 1,600 embryos into 14 immature female pigs.
Twelve of the pigs became pregnant, leading to the birth of six cloned piglets that
carried the fat-1 gene. Muscle cells from one of these pigs, which died of heart
failure, were used to reclone eight healthy piglets that also had the gene. Five
still survive, Prather said.The concentration of omega-3 fatty acids in the cloned
piglets was three times higher than in normal piglets but about 10 percent to 15
percent of the amount found in salmon, Dai said. The pigs also had a significantly
lower ratio of abundant omega-6 fatty acids to beneficial omega-3 fatty acids.The
scientists plan to breed more of these pigs for research purposes, because the
benefits of omega-3 fatty acids are still under debate. But don't expect to buy
omega-3-rich ham or bacon any time soon. The federal Food and Drug
Administration does not allow cloned livestock to enter the food chain. The
omega-3-rich pigs would need additional FDA clearance because they are
genetically modified, and that is a long and expensive process, Prather said.Also,
the pork industry will be reluctant to pursue the technology because of divided
public opinion on genetically modified foods, said Iowa State University
agriculture professor Max Rothschild, national pig genome coordinator for the
U.S. Department of Agriculture."As a science issue, it's fantastic," he said. "As a
consumer issue, the jury is still out and not likely to be positive."
In the study, researchers implanted more than 1,600 embryos into 14 immature
female pigs. Twelve of the pigs became pregnant, leading to the birth of six
cloned piglets that carried the fat-1 gene. Muscle cells from one of these pigs,
which died of heart failure, were used to reclone eight healthy piglets that also
had the gene. Five still survive, Prather said.
The concentration of omega-3 fatty acids in the cloned piglets was three times
higher than in normal piglets but about 10 percent to 15 percent of the amount
found in salmon, Dai said. The pigs also had a significantly lower ratio of
abundant omega-6 fatty acids to beneficial omega-3 fatty acids.
The scientists plan to breed more of these pigs for research purposes, because
the benefits of omega-3 fatty acids are still under debate.
But don't expect to buy omega-3-rich ham or bacon any time soon. The federal
Food and Drug Administration does not allow cloned livestock to enter the food
chain. The omega-3-rich pigs would need additional FDA clearance because
they are genetically modified, and that is a long and expensive process, Prather
said.
Also, the pork industry will be reluctant to pursue the technology because of
divided public opinion on genetically modified foods, said Iowa State University
agriculture professor Max Rothschild, national pig genome coordinator for the
U.S. Department of Agriculture.
"As a science issue, it's fantastic," he said. "As a consumer issue, the jury is still
out and not likely to be positive."
Jennifer Bails can be reached at jbails@tribweb.com or (412) 320-7991.