The poultry industry loses up to $6 billion annually due to necrotic enteritis, a preventable intestinal disease in poultry, including broiler chickens.

An Arkansas Agricultural Experiment Station poultry science researcher is evaluating a new possible solution using a novel vaccine combined with a bile acid regimen.

Xiaolun "Jack" Sun, a researcher and associate professor for the experiment station, the research arm of the U of A System Division of Agriculture, was awarded a four-year, $650,000 grant by the U.S. Department of Agriculture's National Institute of Food and Agriculture to advance the research. Sun is developing a vaccine and exploring the use of bile acids to fight this serious and costly disease that's impacting producers' productivity and profits.

"We want to develop a new measure to prevent this disease," Sun said. "We want to develop something effective and affordable to bring the desired results to the industry."

Necrotic enteritis has been controlled by coccidiostats and antibiotics. Coccidiostats are a type of medication used in poultry and livestock production to prevent and control coccidiosis, a parasitic disease.

Sun said concerns of antimicrobial resistance by consumers, the poultry industry and regulatory agents have prompted restrictions on the use of antimicrobials in the U.S. poultry industry. These restrictions likely contributed to an increase in necrotic enteritis.

The disease that generally affects young broiler chickens is caused by an overgrowth of the bacteria Clostridium perfringens and a parasite called Eimeria maxima in the small intestine. The bacteria and the parasite damage the animal's intestinal wall, impeding nutrient absorption. In chickens, symptoms include poor growth, diarrhea, depression, deformed feathers and, in some cases, death.

Sun aims to develop a "multiepitope fusion antigen" vaccine, or MEFA vaccine, to target C. perfringens growth and infection in the gut.

A multiepitope fusion antigen is a type of recombinant protein, which is a protein produced by genetically engineered cells. What makes MEFA vaccines unique is the combination of multiple "antibody-generating sites," called epitopes, into one protein. Epitopes are the parts of the protein that trigger an immune response.

By having multiple epitopes in one molecule, MEFA vaccines can simultaneously target several features of the disease-causing pathogen, known as virulence points. Sun said this theoretically makes the vaccine more effective by triggering a stronger and broader immune response.

In simple terms, a MEFA vaccine is like a multi-tool that can target different weaknesses in a pathogen, providing better protection against infections.

Sun will also explore how bile acids can inhibit the pathogen's growth and chicken necrotic enteritis. Bile acids, which are synthesized in the liver and stored in the gallbladder, aid in fat emulsification and nutrient absorption in the intestine. Sun says there's increasing evidence that bile acids are effective against bacterial pathogens.

C. perfringens vaccines in the field already exist with limited protection, but Sun says his vaccine will be the first MEFA vaccine developed specifically against C. perfringens multiple virulence sites and necrotic enteritis.

Sun's team includes Ph.D. student Bilal Alrubaye and master's student Janashrit Shrestha. They are focusing on different aspects of the MEFA vaccine development and bile acid research.

"I have seen firsthand the impacts of antimicrobial resistance of necrotic enteritis and its possible impact on human health," Shrestha said. "So, it's a privilege to work on this research with Dr. Sun. I'm learning a lot."

Minimizing the effects of necrotic enteritis

The central hypothesis of this research is built upon the researchers' preliminary findings that a C. perfringens sporulation vaccine and dietary deoxycholic acid significantly reduced necrotic enteritis in chickens.

The team will construct and evaluate MEFA vaccines in the lab and with live chickens, including through oral delivery. The research will also investigate the efficacy of administering bile acids.

Sun is hopeful his research will result in the development of an effective and low-cost MEFA vaccine and bile acid treatment that can significantly reduce necrotic enteritis.

"We are honored and very happy to receive this grant to continue this work, but we also know it comes with a lot of responsibility," Sun said. "We aim to get effective results that are worth the funding, providing poultry producers with new tools to prevent necrotic enteritis, ultimately improving poultry health, enhancing producer profitability and ensuring a safer and more sustainable food supply."