How do we keep food animals healthy when bacteria and other pathogens are so good at outsmarting drugs intended to work against them?

In an innovation that holds great promise, CALS animal sciences professor Mark Cook and scientist Jordan Sand have developed an antibiotic-free method to protect animals raised for food against common infections.

The innovation comes as growing public concern about antibiotic resistance has induced McDonald’s, Tyson Foods and other industry giants to announce major cuts in antibiotic use in meat production. About 80 percent of antibiotics in the United States are used by farmers because they both protect against disease and accelerate weight gain in many farm animals.

The overuse of antibiotics in agriculture and human medicine has created a public health crisis of drug-resistant infections, such as multidrug-resistant Staphylococcus aureus (MRSA) and “flesh-eating bacteria.”

“You really can’t control the bugs forever; they will always evolve a way to defeat your drugs,” says Cook.

Cook and Sand’s current work focuses on a fundamental immune “off-switch” called Interleukin 10 or IL-10, manipulated by bacteria and many other pathogens to defeat the immune system during infection. He and Sand have learned to disable this off-switch inside the intestine, the site of major farm animal infections such as the diarrheal disease coccidiosis.

“People have manipulated the immune system for decades, but we are doing it in the lumen of the gastrointestinal system. Nobody has done that before,” Cook says.

Cook vaccinates laying hens to create antibodies to IL-10. The hens transfer the antibody to their eggs, which are then blended, pasteurized and sprayed on the feed of the animals he wants to protect. The antibody neutralizes the IL-10 off-switch in those animals, allowing their immune systems to better fight disease.

In experiments with more than 300,000 chickens, those that ate the antibody-bearing material were fully protected against coccidiosis and other gastrointestinal diseases that commonly affect poultry.

Smaller tests with larger animals also show promise. In one example, animal sciences professor Dan Schaefer and his graduate research assistant, Mitch Schaefer, halved the rate of bovine respiratory disease in beef steers by feeding them the IL-10 antibody for 14 days.

Cook and Sand, who have been working on the IL-10 system since 2011, are forming Ab E Discovery LLC to commercialize their research. One of the four patents they have filed through the Wisconsin Alumni Research Foundation has just been granted, and WARF has awarded a $100,000 Accelerator Program grant to the inventors to pursue the antibiotic-replacement technology. The Discovery to Product partnership between UW and WARF played a key role in helping Cook and Sand prepare it for commercialization.

Cook has already turned his research and some 40 patented technologies into start-up companies including Aova Technologies, which improves animal growth and feed efficiency, and Isomark LLC, which is developing a technology for early detection of infection in human breath.