Effect of dietary ß-glucan on intestinal microbiota diversity and Salmonella vaccine immunogenicity and efficacy in pigs

Authors: Loving, Crystal; Bearson, Shawn; Bearson, Bradley - Brad; Kerr, Brian; KIROS, TADELE - Phileo Lesaffre Animal Care; Shippy, Daniel; Trachsel, Julian

Submitted to: Veterinary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/27/2022
Publication Date: 12/28/2022
Citation: Loving, C.L., Bearson, S.M., Bearson, B.L., Kerr, B.J., Kiros, T.G., Shippy, D.C., Trachsel, J.M. 2022. Effect of dietary ß-glucan on intestinal microbiota diversity and Salmonella vaccine immunogenicity and efficacy in pigs. Veterinary Microbiology. 278. Article 109648. https://doi.org/10.1016/j.vetmic.2022.109648.
DOI: https://doi.org/10.1016/j.vetmic.2022.109648

Interpretive Summary: Alternatives to antibiotics can improve pig growth, limit the negative impact of infectious disease, and/or reduce colonization with foodborne pathogens. Soluble fibers, including beta-glucans, can be added to piglet diets, which is also a common time for vaccine administration. While beta-glucans are knows to modulate immune responses, a study was completed to determine the impact of a dietary beta-glucan product on intestinal bacteria and the immune response to a Salmonella vaccine. Overall, the beta-glucan product altered microbial diversity in the intestinal tract, but did not alter the immune response to the vaccine. Pigs given the Salmonella vaccine had reduced shedding of Salmonella in feces, and less Salmonella in the tissue, with or without the product in the diet. Overall, Salmonella vaccination can reduce Salmonella in pigs, and vaccine can be administered while on the beta-glucan product.

Technical Abstract: Alternatives to antibiotics to improve animal performance, limit the negative impact of infectious disease, and/or reduce colonization with foodborne pathogens is a major focus of animal agricultural research. beta-glucans, a generally-recognized-as-safe (GRAS) product derived from various sources, are used in swine and can serve as both a prebiotic and/or stimulant of the immune system given the expression of beta-glucan receptors on immune cells. When supplied in the diet of nursery pigs, it is unclear how dietary additives, particularly those known to modulate immune status, impact immunogenicity and efficacy of mucosal-delivered vaccines. Salmonellosis is one of the most common bacterial foodborne infections in the United States, and consumption of contaminated pork is a major source of human infection. Reduction of foodborne Salmonella in pigs via vaccination is one strategy to reduce contamination risk and subsequently reduce human disease. We examined the ability of dietary beta-glucan to modulate fecal microbial diversity, and immunogenicity and efficacy of a mucosally-delivered, live-attenuated Salmonella vaccine during the nursery period. While dietary beta-glucan did modulate fecal alpha diversity, it did not alter the induction of peripheral Salmonella-specific IFN-gamma secreting T-cells or Salmonella-specific IgA in oral fluids. In addition, vaccination did reduce Salmonella enterica serovar Typhimurium fecal shedding and tissue colonization. Overall, addition of beta-glucan to the nursery diet of pigs may have beneficial effects that do not alter mucosal vaccine immunogenicity and efficacy.