[tt] I'll Have My Burger Petri-Dish Bred, With Extra Omega-3

[Eugen Leitl]

http://discovermagazine.com/2008/oct/22-i.ll-have-my-burger-petri-dish-bred/article_print

I'll Have My Burger Petri-Dish Bred, With Extra Omega-3

09.22.2008 How researchers can make meat that's better for you—and better for
animals.

by Susan Kruglinski & Karen Wright

Image courtesy of Paul Kosnik and Robert Dennis

How do you prefer your beef? Certified Angus, grass fed, or culled from a
petri dish? That last option may be coming your way soon, courtesy of Jason
Matheny*, a biologist at Johns Hopkins University. He is the founder of New
Harvest, a loosely knit consortium of international scientists who are
investigating an innovative new way of satisfying the world’s craving for
meat. They plan to grow it in a lab—no animals required.

Lab-grown meat won’t make many top-10 lists as a natural food, but the New
Harvest Web site calls it “less unnatural than raising farm animals in
intensive confinement systems, injecting them with synthetic hormones, and
feeding them artificial diets made up of anti­biotics and animal wastes.”
Known as in vitro or cultured meat, the end product, grown from stem cells,
could alleviate environmental and health concerns associated with most animal
protein (not to mention moral qualms about eating animals), making it the cut
of choice.

To a certain extent, in vitro meat has already been produced hundreds of
times in labs around the world, as stem cell researchers crank out bits of
artificial muscle and connective tissue, hoping to mend weak hearts or
reverse muscular dystrophy. But only a brave few have engineered tissues
expressly for the purpose of making hamburger. In 2000 NASA engineered a bit
of goldfish meat as a possible food for astronauts on marathon journeys, and
in 2003 a group of Australian artists with a background in tissue engineering
served tiny portions of petri-dish muscle (drowning in sauce to avoid the
flavor question) to an invitation-only dinner party.

Currently, most research into lab-grown meat comes from biologists in the
Netherlands. The Dutch government is funding the work, perhaps a natural fit
for the first country on the planet to have a Party for the Animals in its
legislature. Henk Haagsman, one of the lead scientists on the Dutch project
and a member of the New Harvest advisory board, says the key to making in
vitro meat is to get stem cells to divide repeatedly, ultimately spawning
billions of offspring; those daughter cells would then fuse and mature into a
uniform, solid block. So far, Haagsman has created a small layer of fused
meat cells—something akin to the world’s thinnest slice of bologna—grown from
a single pig-muscle cell.

For cells to mature, they must soak in a nutrient-rich soup. The current
soup—costly “fetal bovine serum,” or calf’s blood—may soon be replaced by an
inexpensive, plant-based substitute that offers a major advantage: It avoids
using any animal-based products, satisfying the ethical concerns of some
vegetarians. As the cells mature, they must also be stimulated to move as
they would be by bone growth and body movement in a living animal. This is
done by giving electric jolts or by manually stretching the polymer
scaffolding that anchors the cells. In the course of stimulation, the cells
convert from what scientists describe as “meat-flavored Jell-O” to the
striated, textured fibers we associate with steak.

Until researchers get stem cells to regenerate uniformly, however, test-tube
meat at the deli could remain just a dream. If edible beef is the goal, you
don’t want any hoof or fur mixed in with it, but as of now, scientists cannot
consistently control what type of cells are produced.

Growing meat from single cells could reduce the opportunity for disease and
contaminants to enter the food supply and eliminate the environmental impact
(such as clearing Amazon rain forest to create grazing land) of raising
livestock. Moreover, Methany contends, the meat would be healthier and could
be nutritionally enhanced. “You could have a hamburger with the fatty acid
profile of salmon,” he says. “It could prevent heart attacks rather than
cause them.”

The scientists working on cultured meat believe its flavor should eventually
compare favorably to that of natural meat, but Methany says so far he doesn’t
know of any scientist who has taken a taste. “At least they haven’t fessed up
to it, but at the end of an experiment, you’ve got tissue, so why not bread
it and fry it up?”

* Correction: The article originally misspelled Matheny's last name. Return
to the corrected sentence.

Giving Food the Omega Factor

Long before lab-grown beef reaches your local diner, you may find yourself
chowing on a different kind of technologically enhanced meat: the omega
burger, fortified with that fatty acid known as omega-3.

Health-conscious consumers already seek out canola, flaxseed, walnuts, and
soy products rich in beneficial alpha-linolenic acid (ALA), an omega-3 fatty
acid. Even more dramatic effects on human health have been documented with
eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the longer-chain
lipids found in fish oil. These substances have shown promise for the
treatment and prevention of diseases from type 2 diabetes and rheumatoid
arthritis to asthma, cancer, dementia, and, most conclusively, heart disease.
“We could probably eliminate 40 percent of cardiovascular disease in the
United States if we could engineer the food supply to have at least two grams
a day of EPA and DHA,” says biochemist Joseph Hibbeln of the National
Institute on Alcohol Abuse and Alcoholism in Bethesda, Maryland.

Unfortunately, those fatty acids may be running low in the global larder. The
best dietary source of long-chain omega-3s are oily, cold-water fish such as
salmon, tuna, herring, and mackerel. Yet many of these fish populations have
experienced massive declines since the 1970s. Other foods can be infused with
EPA and DHA, but only up to a point. Chickens that are fed fish extracts and
algae oils produce eggs and flesh with enhanced concentrations of long-chain
fatty acids, and omega-3 eggs are already a supermarket staple. But getting
the good lipids into other livestock is more difficult. Fish oils and algae
extracts are too expensive to feed to larger animals. There is also a problem
with the multi­chambered stomachs of cattle and sheep: They convert healthy,
poly­unsaturated omega-3s into very unhealthy saturated fats.  +++

To solve this last issue, animal re-­searcher Scott Kron­berg at the USDA
Agricultural Research Service (ARS) lab in Mandan, North Dakota, is feeding
sheep flaxseed that has been treated to prevent conversion of ALA into
saturated fat. Those sheep were found to have 25 percent more omega-3s in
their muscle than did grain-fed animals. Grass-fed cattle also benefited by
eating the treated flaxseed; their beef contained almost half a gram of
omega-3s per eight-ounce serving. But most of those omega-3s were in the form
of the less-useful ALA. “If we could come up with a cheaper source of EPA and
DHA for feed, it would be worth looking at too,” Kron­berg says.

Other researchers are doing just that. Bioprocess engineer Rafael Garcia of
ARS and biochemical engineer Zhiyou Wen of the Virginia Polytechnic Institute
and State University in Blacksburg are designing a study to grow EPA- and
DHA-producing microbes using low-cost by-products of other processes, such as
glycerol from biodiesel production and rendered animal protein from
slaughterhouses. The microbes could then be used to make an inexpensive
livestock feed supplement.

And then there is the EPA-enhanced pig genetically engineered by Randall
Prather, a livestock reproductive biologist at the University of
Missouri–Columbia National Swine Resource and Research Center. Prather cloned
pigs that carried an enzyme for converting less-beneficial fatty acids into
EPAs. Not only do the clones carry up to 15 times more EPA than do normal
pigs, but they also appear leaner and more active. Prather’s pigs won’t be
going to market anytime soon, however; no transgenic animal has yet been
approved for human consumption in the United States. Although Prather has no
plans for testing the enzyme on cattle, other researchers do. Can the omega-3
burger be far behind?

See DISCOVER's recent news story on the FDA's plan to regulate food from
genetically engineered animals.