Short-sighted solution to the wrong problem

Phosphorus It’s fertilizer, not a pollutant, so why not manage pigs in a way we can use it?

Reading Time: 3 minutes

“It would be giving the animal a gene, which nature made a mistake by not giving them.”

If there is one sentence that captures why the world’s first GMO pig never made it to market, it would be this comment from one of the lead researchers on the University of Guelph project back in 2001.

The notion that nature screwed up by not making pigs the way humans like to raise them was not only misplaced, it was dangerously short sighted, as demonstrated by the dead end this project now faces.

Researchers had a “eureka” moment in the late 1990s, at the height of scientists’ enthusiasm over their newly emerging abilities to transfer genes between species.

If copious quantities of phosphorus-rich liquid manure was a problem for the rapidly expanding pork industry in North America, why not genetically design a pig that excretes less phosphorus in its manure? Up to 75 per cent of the phosphorus in modern hog rations is in the form of phytate, which hogs can’t digest. So it passes through the digestive tract and is excreted in the manure, which then contains unnaturally high concentrations of phosphorus relative to nitrogen. To partially address the issue, producers add phytase to the feed, which increases the phosphorus absorption and reduces the amount of P in the poo.

Scientists successfully spliced an E. coli gene that makes phytase with a mouse gene that controls a protein excreted through the salivary glands, and inserted it into Yorkshire pigs, creating what became known as the Enviropig.

Their hypothesis was correct. The Enviropigs didn’t require the added expense of phytase supplements and excreted up to 60 per cent less phosphorus in their manure. They were promoted as an economic and environmental solution.

But 10 years later, the pigs never made it to market, the research funds have dried up and the 16 pigs remaining in the program face euthanasia with their genetic material being put into cold storage.

What happened?

For starters, a low-P pig didn’t come close to solving the economic and environmental sustainability issues facing the sector. Even with manure that contained a better balance of phosphorus to nitrogen, concentration in the industry has still resulted in nutrient overloads on soils located close to large hog barns.

With many soils seen as phosphorus deficient, the problem isn’t too much phosphorus, which is a finite resource. The problem is that when it is contained in liquid manure, it can’t be cost effectively moved to the areas that need it.

If a technological fix was in order, it would seem more productive to invest in technologies that extract the P from the manure, or in production systems that used composting or other means to make it more manageable.

Secondly, genetically modified anything has proven to be a tough sell with consumers, which partly explains why there wasn’t a long list of investors waiting in line to commercialize the Enviropig. The fact that it provided no tangible benefits to consumers, such as better-tasting meat, didn’t help.

And perhaps the problem wasn’t a poorly designed pig but rather the system being used to raise it. Pigs were never made to live on grains alone. Their digestive systems, which aren’t that much different from humans, were designed to extract nutrients from highly varied sources, including the sun, which enhances our own ability to absorb nutrients.

The notion that pigs should be allowed to forage rather than spend their days in biosecure darkness is considered heresy in modern efficient hog production. But if you think about it, it addresses most of the manure and odour issues. It goes a long way towards silencing the animal welfare critics too.

Of course, that’s not going to happen. But neither, it seems, is the Enviropig. It was a short-sighted solution to the wrong problem. May it rest in peace.

About the author

Vice-President of Content

Laura Rance

Laura Rance is vice-president of content for Glacier FarmMedia. She can be reached at [email protected]



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