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Biotech critters may gain greater public acceptance

Published on December 3, 2010 3:01AM

Last changed on December 31, 2010 10:40AM

Excessive docility may upset people, professor says


Capital Press

As production of genetically engineered livestock edges closer to becoming a mainstream reality, biotech developers are bracing for an even more vociferous debate than that over transgenic crops.

However, such animals are expected to alleviate serious environmental and disease problems, which experts say may affect public acceptance of the technology.

"As that pressure increases, I think people will change their perspective," said Cecil Forsberg, a professor emeritus at the University of Guelph in Ontario, Canada, who helped develop a genetically engineered pig.

Though some transgenic animals are bound to cause controversies, vehement opposition to the technology is not a foregone conclusion in every case, said Paul Thompson, a professor at Michigan State University who has studied the ethics of genetic engineering in livestock.

"There are some particularly touchy areas," he said.

The welfare of the animal itself will likely be a key issue, Thompson said.

Alterations that cause the appearance of suffering are most likely to be attacked, he said. People may also be uncomfortable with animals that diverge from the norm in behavior or temperament.

"Dominance and aggression are very plausible targets for advanced technologies," but the public may be uneasy about animals that are so docile they can't fend for themselves, Thompson said.

If biotechnology can correct or mitigate harmful genetic conditions in animals, on the other hand, those alterations probably won't cause much of a stir, he said.

Outrage over genetic engineering is highly visible in some cases, such as the ongoing fight over recombinant bovine somatotrophin, or rBST, a hormone introduced in the 1990s that increases milk production in dairy cattle.

What's often overlooked is that another substance derived from transgenic microorganisms was introduced at roughly the same time but has never been widely debated, said Thompson.

An enzyme needed for making cheese, known as chymosin or rennin, was traditionally obtained from slaughtered calves, he said. Now, the enzyme is typically produced by transgenic bacteria and fungi.

"Nobody raised a stink about it at all," Thompson said.

Forsberg hopes the University of Guelph's "enviropig" will gain public acceptance due to its potential to reduce pollution.

Up to 80 percent of the phosphorous consumed in feed by pigs is not digestible, since it's locked up inside phytate molecules, he said. That excess phosphorous, expelled though feces, has been blamed for contaminating water.

Researchers at the university have developed a pig with a gene from E. coli bacteria that allows the animal to produce an enzyme known as phytase, which can release phosphorous from that molecule. A partial gene from the mouse directs that enzyme to the pig's salivary glands.

In young pigs, the amount of phosphorous in feces is reduced by 60 to 65 percent. As the animals mature, the rate of reduction falls to about 30 to 35 percent. The decrease occurs because young pigs use more phosphorous to grow bones, whereas older ones don't need as much, Thompson said.

Aside from boosting the pig's speed of growth by 10 percent under some circumstances -- which would help farmers -- the alteration doesn't seem to have any effect on the animals, he said.

"They seem to be as healthy as conventional pigs," Thompson said.

The BioDak company in Kimball, S.D., has similarly found no adverse health effects in cattle resistant to bovine spongiform encephalopathy, or mad cow disease, said Edward Hamilton, the firm's owner.

The gene responsible for generating prions -- a type of protein that can transmit the disease -- has simply been turned off in the animals, he said. "Essentially, there is no prion production, which is why they're resistant to BSE."

The cattle were initially developed by the Hematech company, which used them to create antibodies for fighting disease in humans.

For the antibodies to be safe for people, the cattle had to pose no risk of BSE infection, Hamilton said. However, Hematech's intent was to commercialize the antibodies, not the cattle.

Hamilton bought the technology from Hematech in 2008 with the goal of gaining regulatory approval from the U.S. Food and Drug Administration to sell the cattle.

At this point, BioDak's focus is more on the cattle's use for medical and industrial applications, rather than for beef or dairy production, he said. If the cattle industry faces disruptions similar to past BSE outbreaks, that may become a stronger possibility.

"That's farther down the road," Hamilton said. "That's not the situation today."


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