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Public Radio's Environmental News Magazine (follow us on Google News)


Air Date: Week of

The newer, cleaner pigs. (Photo: Dr. Cecil Forsberg)

Animal manure on industrial farms can wreak environmental havoc. Manure contains phosphorous that leeches into waterways, causing algae blooms that can kill off marine life. At the University of Guelph in Ontario, microbiologist Cecil Forsberg has found a solution to the problem. He genetically modified pigs to produce low-phosphorous manure. The DNA Files producer Brian Mann reports.


Well, closer to home pigs are a problem. Seems when pigs pig-out, they produce polluting phosphorus, which is why one Canadian scientist has been working for years to market “Enviropigs”—animals genetically engineered to be kinder to the environment.

Brian Mann has our story, which originally aired on “The DNA Files”.

MANN: A mile outside of Guelph, Ontario, the tree lined streets give way to fields and stretches of wood. Microbiologist Cecil Forsberg points me down a gravel drive towards what looks like a modern industrial farm.

FORSBERG: You make a left turn. I’d stay away from the front door where your vehicle can pick up the smell.

MANN: It’s a rental. So I don’t mind the smell.


MANN: We park a safe distance away. Despite the wind, there is an odor—cows and mowed grass, but overwhelming it all, the sickly sweet stench of pig manure. Forsberg opens the door to a sprawling barn operated by the University of Guelph. The building is part pigsty, part high tech laboratory. Massive fans churn constantly, maintaining the temperature and easing the odor. Pigs are famous for eating a lot, and it turns out they’re not very efficient at digesting the kind of corn and soybeans that make the cheapest livestock feed. As a consequence, their poop is thick with undigested waste products, including phosphorous. For 11 years, this has been Cecil Forsberg’s obsession.

FORSBERG: We thought this would be an ideal project to undertake, because of the extensive phosphorous pollution one finds within areas where there’s very intensive livestock production.

MANN: The phosphorous problem is a conundrum of modern agriculture. As the human population grows, we require more and more food. That means more cows and pigs, which industrial farmers have supplied pretty handily. But the side effects of those huge factory farms can be devastating.

WATZIN: Oh, we have a crème de la crème spot. We’re right on the waterfront in Burlington.

MANN: Mary Watzin is director of the Rubinstein Ecosystems Science Laboratory on Lake Champlain. The lake is beautiful, a huge craggy waterway that cuts between Vermont, New York State, and Canada. But phosphorous run-off from large pig and dairy farms has trigged disgusting algae blooms.

WATZIN: You wouldn’t miss it, if you saw it. The water looks like there’s green stuff in scums on the surface.

MANN: Algae can create conditions that gobble up a lake’s oxygen. Watzin says, suffocating fish, and throwing the natural ecology into a tailspin. In recent years, toxic concentrations have risen, and several animals exposed to the algae have died.

WATZIN: There are two toxins, actually, produced in Lake Champlain. One is a neurotoxin or brain toxin, and that’s been responsible for most of the dog deaths.

MANN: Half a dozen dogs have died, Watzin says. The other toxin found during autopsies destroys liver tissue. No humans have been affected so far, because the algae looks so gross that people won’t go near it. But a lot of towns along the shore still draw their drinking water from the lake and as industrial agriculture spreads around the world, producing more and more phosphorous, Watzin says precious water sources are gumming up with this algae soup, which brings us back to Cecil Forsberg’s “Enviropig.”


MANN: Forsberg wades into a pigpen, waist deep in what looked like everyday Yorkshires, pale skinned, rubbery nosed pigs. The unique thing about these animals isn’t their voracious appetites, but a genetic modification with their salivary glands. Remember how pigs aren’t very good at digesting the phosphorous in corn and soybeans? Well, it happens that some bacteria are great at it. They naturally produce an enzyme that dissolves the phosphorous.

The newer, cleaner pigs. (Photo: Dr. Cecil Forsberg)

Forsberg’s team managed to introduce this clever enzyme from a bacterium into these animals. They even managed to arrange the DNA so that the gene is expressed in the pig’s salivary glands. So when an “Enviropig” munches corn, the enzyme in its saliva digests the phosphorous. As a result, Forsberg says, the “Enviropig” produces 60 percent less phosphorous than a normal pig. That’s twice the reduction that farmers achieve even when they use better and more expensive grains, and when they feed their pigs’ costly dietary supplements. Even better, Forsberg says, these pigs seem normal in every other way.

FORSBERG: Although we haven’t eaten any of the pork—in fact, it’s illegal until there’s regulatory approval—I am 99.9 percent confident that the flavor of the pork from these pigs will be equivalent to that from conventional pigs.

MANN: But there’s a wrinkle. Pig farmers in Ontario helped to fund the first round of “Enviropig” research, but the project still faces years of testing and regulatory hurdles, and the big grants from an industry group called Ontario Pork have dried up.

FORSBERG: I’m embarrassed to admit it, but we have no genuine commercial interest in these pigs.

MANN: Could I have a ham and swiss? Actually I’d rather have a BLT, please.


MANN: After touring the farm, he takes me to a Tim Horton’s restaurant. The fast food chain is everywhere in Canada, one more link in our industrial food economy. Forsberg looks around at the crowd grabbing a quick lunch. As the world’s population grows, so will our hunger for those BLT and ham sandwiches, which means more pigs, more polluted waterways, and more toxic algae blooms.

FORSBERG: I don’t view this scientific advancement as being one to increase the quantity of food. I view it as a trait within an animal that reduces its environmental impact. Sustainability, I think, is the key issue, which I would raise.

MANN: I’m Brian Mann.

GELLERMAN: Our story on the Enviropig comes to us courtesy of SoundVision Productions in Berkeley, CA.



Guelph Transgenic Pig Research Program

The DNA Files – “Designing the Garden: Food in the Age of Biotechnology”


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