ATHENS, Ga. — Poultry and feed industry researchers are identifying potential new guards against salmonellosis, one of the most common foodborne illnesses in the United States.
Vaccines exist that protect chickens from Salmonella enteritidis (SE) serotypes, the most common cause of foodborne salmonellosis, but those vaccines do not inhibit non-SE serotypes. Researchers at the U.S. National Poultry Research Center are laying the foundation for new vaccines that will counteract more salmonella types.
But that is a daunting task. Researchers must analyze more than 4,000 salmonella proteins, trying to find those that might be combined in a vaccine. The challenge does not end after that, for those proteins must then be put into a form where multiple proteins might be combined into a vaccine.
Advanced DNA technology helped the researchers hone in on 30 specific proteins. “A battery of these subunit proteins was produced using the recombinant technology,” explained Hung-Yueh Yeh, a scientist with the USDA’s Agricultural Research Service.
Yeh and colleagues worked specifically with proteins found in the flagella and fimbriae, structures which protrude from some salmonella cells. Their research found promising protein combinations.
“The main goal of our research is to find protein antigens that are able to induce (the) chicken to generate antibody production,” said Yeh. Those antibodies prevent salmonella colonization in the chicken, reducing the possibility of salmonella prevalence in chicken.
Due to advances in recombinant DNA technologies, “the researchers can apply these technologies to identify the common immune signature in a precise way, and produce the well-defined protective subunit (a part of a molecule) proteins for vaccination in chickens,” Yeh said.
The next steps that will build on this research involve testing the promising combination as a vaccine in larger groups of poultry: broilers, layers and turkeys.
“We anticipate that these proteins be tested in all three systems, as well as in other food-producing animals in the near future, and hope to reduce salmonella contamination and provide safe poultry and meat products for human consumption,” Yeh said.
And the research could have even broader impact. “Because salmonella is an important human bacterial pathogen, we hope that we will be able to collaborate with others to test” possible human immune responses to the key proteins, according to Yeh, in a statement emailed to Farm World.
More than 1 million patients were treated for salmonellosis in 2013, with 19,336 patients hospitalized, according to the USDA. That resulted in more than $3.7 billion in health care and other costs.
This research was funded by USPOULTRY Foundation through an endowing Foundation gift from Cal-Maine foods.
Sources of salmonella can occur throughout the poultry production environment. Another research project, funded by the livestock, poultry and feed industries, will determine if feed mills and manufacturers are possible sources of salmonella contamination.
The University of Arkansas will in the coming year test feed samples invited from 250 feed mills, according to the American Feed Industry Assoc. (AFIA). If any salmonella strains are present, further testing will determine the specific type.
The project hypothesizes that no harmful samples will be found.
"As an industry, we have long believed that salmonella is not a threat in food for animals as it is for people, due to the types of grains and ingredients used and the stringent regulatory procedures and processes in place to avoid contamination," said Preston Buff, AFIA director for regulatory affairs.
The project is funded through a $50,000 grant, headed by the Institute for Feed Education & Research (IFEEDER), in partnership with the AFIA, National Pork Board, National Renderers Assoc., Poultry Protein and Fat Council, U.S. Poultry and Egg Assoc. and U.S. Soybean Board.