Antibody Omelets Improve Growth in Poultry and Livestock

May 1, 1997

Some small farms in Wisconsin may soon become antibody factories, raising laying hens that produce growth-stimulating antibodies in their egg yolks. When fed to farm animals, the customized yolks increase growth rates, and the animals become more efficient at converting feed to meat.

Egg-yolk antibodies work by changing the environment in an animal's gut, explains Mark Cook, a poultry scientist at UW-Madison's College of Agricultural and Life Sciences. Gut peptides control feed intake and gastrointestinal function in animals. Cook knew that the immune system stimulates the release of gut peptides that decrease feed intake. Food-animal producers sometimes feed antibiotics, which reduce the immune stimulus by knocking out some gut bacteria. "We wanted another strategy to reduce the level of peptides that impair gut function," Cook says. "We wanted to use an antibody to bind these peptides so they can't disrupt gut function."

The chicken egg yolk provides an inexpensive source of antibodies. "We can trick the hen into making antibodies to gut peptides. She puts them in the egg yolk, then all we have to do is feed the yolk." Cook developed the hen-tricking method, which is patented and licensed through the Wisconsin Alumni Research Foundation.

The egg-yolk antibodies have proven as effective as antibiotics in increasing growth and feed efficiency in chickens and swine, according to Cook. Some studies have shown that low-level feeding of antibiotics to livestock can produce drug-resistant bacteria; by feeding antibodies instead of antibiotics, producers can avoid this problem.

A joint venture between DuPont and ConAgra is now scaling egg-yolk antibodies into mass production. More than a dozen companies are involved, ranging from private research labs to poultry farms to equipment manufacturers. The primary company is DCV Biologics of Wilmington, Del.

Egg-yolk antibody farms will provide opportunities for some Wisconsin and Midwest farmers. The antibodies will be produced by contract on small farms of 5,000 to 15,000 laying hens, thus providing an alternative form of agriculture for some small family farms, according to Cook.

The producing farms must be small for reasons of quality control. "We can't put all our eggs in one basket," he explains. "If you got a disease on a million-chicken farm, you could lose all the product."

A 5,000- to 15,000-hen farm produces enough antibodies to supply one integrated broiler operation that processes one million birds a week. "Right now, to be competitive in the commodity shell-egg industry, you need a very large operation, so this is truly an alternative for the small family farm," Cook says.

Using the same technology, Cook is also developing medicinal products for humans.

CONTACT: Mark Cook, (608) 262-7747