Meet the Enviro pig

In a ground-breaking development, Ontario researchers have developed a pig that excretes 50 per cent less phosphorus
BY ROBERT IRWIN
Picture a pig that may excrete slightly less manure but as much as 50 per cent less phosphorus, the component targeted most in pork-industry related environmental problems.

Now imagine that you actually spend less money feeding this special pig because its nutritional needs are met with a ration containing a reduced amount of costly supplemental phosphorus.

Meet Wayne, the so-called Enviropig, a transgenic porker that is so new and unexpected his owners weren't sure how to spell his name. If you are an Ontario pork producer, you already have a piece of this easier-on-the-environment pig thanks to the 20 cents per hog deducted by Ontario Pork from settlement cheques.

"Why am I so excited?" asks Harry Stam, chairman of Ontario Pork's research committee. "In the last two years, anything that has come out environmentally has been negative towards pork. This is a real positive." Neither Stam nor anyone else involved with the discovery can say how much Enviropig means financially to Ontario pork producers. Nor does anyone know how much money will be needed to make the pig a commercial success. Enviropig - a Yorkshire boar - was farrowed mid-April at the University of Guelph by a sow from the Arkell research station. The dam had been implanted with specially injected embryos originally fertilized by a Yorkshire boar from the Ontario Swine Improvement stud.

Except for a gene implanted when it was an embryo, Enviropig is identical to every other pig. That so-called phytase gene allows the pig to generate large amounts of phytase in its parotid gland, one of the salivary glands. Phytase allows the pig to utilize phosphorus found in feedstuffs like corn and soybeans. Ruminants can do this naturally, but phosphorus, tied up in plants in the form of phytic acid, simply passes through monogastrics like pigs, chickens and even people, adding significantly to waste output.

Producers can supplement rations with phytase derived from a fungus, but most seem to believe it's not cost effective. (See Will pig be cash cow?) Enviropig's special gene was created from a common E. coli bacterium found at levels of around one per cent of the bacteria in a normal human or animal gut. Further testing is expected to confirm that the gene is confined to the salivary gland and is not present in the meat or manure produced.

Key Ontario Pork officials and University of Guelph staff have been quietly contemplating their shared research breakthrough made by Dr. Cecil Forsberg, Dr. John Phillips and doctoral student Serguei Golovan. Their strategy was to lie low until U.S. patent attorneys could protect the technology worldwide. Made wary by earlier public reactions to biotechnology, they also wanted time to consider the best way to announce their complex biotechnology breakthrough.

University of Guelph spokesman Alex Wooley says Farm & Country's dogged pursuit of the story over the years allowed it to glean details of early results of the research. It could take at least five more years and many more research dollars before Enviropig's descendants reach a commercial pig farm. Still, Stam suggests one day environmentally conscious consumers "may even pay a premium for environmentally friendly pork."

In return for investing some $250,000 of producers' money in the research over the past four years, the pork board, which has an $800,000 annual research budget funded by producer check-offs, becomes the exclusive world licensee. The discovery is expected to attract pig breeding companies from around the world. Ironically, demand could eventually be greater in European countries and parts of the United States, where the land base won't support the swine population, than in Ontario, which has a relatively small number of pigs. Enviropig could even be useful in Third World countries that lack a source of non-organic phosphorus and therefore can't raise pigs efficiently.

Forsberg is prepared for some backlash against the fact that the animal is a genetically modified organism (GMO) or transgenic. However, he says, "There's such a positive aspect to it that they can't walk all over you and say it's all bad. It's one of the few transgenic stories that has a good side to it."

Forsberg also notes it's unprecedented for farmers to control GMO technology, customarily the domain of large corporations. He likens the discovery process to "playing the 6-49," and says the project is a tribute to the "courage and the vision of Ontario pork producers." Beginning late last year Forsberg's team conducted the first few implantations of the phytase gene together with a regulator from a mouse gene. The latter allows the trait to be expressed, serving as a switch that turns on the gene and increases production of phytase in the parotid gland.

Sows in the research project farrow fewer piglets, typically between five and six instead of the litters of 10 or more seen on commercial farms. The f irst sow farrowed just three piglets from 30 micro-injected embryos. Tails are docked on the research pigs as they are on any farm. By examining cells from the clipped tails researchers determine the presence of the phytase gene.

Forsberg insists no one was discouraged when it didn't turn up in the first three piglets. "When you're playing the lottery you play it on the long term," he says.

He knew if his genetic construct was correct the gene would appear with a frequency of just one-tenth of a per cent. The second sow delivered one stillborn and four born alive. She later lay on one of the piglets, crushing it.

When Golovan discovered the gene's presence in cells from one of those four tails, there was no celebrating until he verified it wasn't from the stillborn animal or the piglet that had been crushed.

Ontario Pork has since financed the replacement of 14 farrowing crates at the university with a model "that is more piglet-friendly," Forsberg relates. Mid-June, 30 more piglets had been farrowed. None had the gene.

Plans are to farrow approximately five sows a week until December. The goal is to get enough animals with the gene to allow Enviropig to be reproduced naturally at far lower cost.

When the first Enviropig weighed 15 kg, he had enough phytase in a single millilitre of his saliva to hydrolyze between five and six kilograms of feed. That's equivalent to having the standard rate of about 1,500 units per kg of supplemental fungal-derived phytase added to a swine ration.

But as Forsberg points out, a 15-kg pig can't eat that much feed, and growing pigs secrete about 200 millilitres of saliva during a feeding. "It seems to produce enough enzyme to really satisfy its own needs," he observes.

Technical questions remain about how Enviropig's phytase will perform during practical trials. Growth rate could be affected by the transgenic process; that must be evaluated before pronouncing Enviropig an unqualified success. Before weaning, the pig was growing as fast as his non-transgenic sisters.

Later, he appeared to be gaining more slowly. "That could be chance or it could be diet," Forsberg speculates.

There's been no effort to examine the pigs physically. "We're going to have to have offspring before we touch the pig," Forsberg explains. As with any 45-day-old boar, no one knows whether Enviropig will breed normally. If he does, there's no guarantee he will pass on his phytase gene to offspring.

However, other work at Guelph on transgenic pigs for the Novartis xenotransplant program has shown they can naturally reproduce their special qualities. Forsberg's team immediately notified Health Canada, the Canadian Food Inspection Agency and Environment Canada of their discovery. There are no specific guidelines for transgenic animals, but Enviropig will be subject to requirements of the Novel Foods Act before it can be sold commercially.

Funds and assistance for this research came from Ontario Pork, OMAFRA, Ontario Swine Improvement, the National Sciences and Engineering Research Council of Canada and the University of Guelph.

© copyright 1999 Agricultural Publishing Company Limited.



back





Will pig be cash cow?

Will the world beat a path to the door of the University of Guelph, where scientists recently bio-engineered an environmentally friendly pig?

"I don't want to make any judgment because I don't know the numbers," explains Dr. John Gibson, a University of Guelph geneticist and consultant to Ontario Swine Improvement, as well as several pig breeding organizations.

While noting "the research has been kept pretty much under wraps," Gibson predicts eventual acceptance will depend on the economic benefits the pig offers and the advantages of any competing technologies.

At present the only way producers can reduce manure output and their dependence on purchased inorganic phosphorus is by supplementing feed with phytase, an enzyme derived from fungi. It is marketed in Canada by BASF.

Phytase increases availability of natural phosphorus found in feedstuffs like corn and soybeans.

"We have wondered why producers and feed companies haven't picked up on it more," confides Janice Murphy, OMAFRA swine nutritionist. Murphy is also a member of the Ontario Pork research committee, which recently found that only about five per cent of Ontario producers are using phytase. In Quebec, where land for pig farms is scarce and manure use is more closely regulated, Murphy discovered that 30 per cent of producers use phytase. Next year, phytase supplementation will be mandatory in the state of Maryland, and it is used by many pork producers in certain parts of Europe. "Cost-benefit comes out either even or slightly positive to the bottom line," Murphy concludes.

Since natural phosphorus is tied up by phytic acid, also referred to as phytate, U.S. government and seed company researchers have been working on ways to produce low phytate (LP) corn and soybeans. Pioneer Hi-Bred and partner Optimum Quality Grains have been developing a corn hybrid that is currently being tested on farms in the environmentally sensitive Delmarva poultry-producing area of the U.S.

University of Minnesota scientists report yield reductions in their experimental LP hybrids of between five and nine per cent. However, they predict selective breeding may eliminate the yield lag.

The LP trait may even be stacked with other desirable traits such as higher oil or protein. But higher seed and distribution costs are also likely. "If the corn turned out to be at the same cost level as the phytase pig, I think one would always go the corn route," Gibson predicts. He says that's because it would be easier to get the corn into the marketplace than to distribute the pig gene to the worldwide swine population. - Robert Irwin

© copyright 1999 Agricultural Publishing Company Limited.



back









ID: 1273