Effects of ß-glucan on Salmonella enterica serovar Typhimurium swine colonization and microbiota alterations

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

Submitted to: BMC Porcine Health Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/16/2023
Publication Date: 2/14/2023
Citation: Bearson, S.M., Trachsel, J.M., Bearson, B.L., Loving, C.L., Kerr, B.J., Shippy, D.C., Kiros, T.G. 2023. Effects of ß-glucan on Salmonella enterica serovar Typhimurium swine colonization and microbiota alterations. BMC Porcine Health Management. 9(7). Article 003024. https://doi.org/10.1186/s40813-023-00302-4.
DOI: https://doi.org/10.1186/s40813-023-00302-4

Interpretive Summary: Salmonella is a human foodborne pathogen, and pigs are asymptomatic carriers of Salmonella. In swine production systems, Salmonella can be found in the housing environment, feed, water sources, and lairage. The environmentally ubiquitous nature of Salmonella combined with its carrier-status in pigs creates a need for control strategies to limit Salmonella in swine. We evaluated a soluble fiber, reported to have beneficial properties on gut health, porcine immunity and growth performance, for its effect on the porcine gut microbiome as well as Salmonella colonization of the intestinal tract of pigs. In-feed supplementation with the ß-glucan product resulted in less Salmonella in the cecal contents of pigs receiving ß-glucan, although no difference in Salmonella fecal shedding was observed between the pigs receiving ß-glucan compared to the pigs consuming a non-amended control diet. Favorable changes in fecal microbial communities were noted in the ß-glucan-fed pigs, suggesting a modest beneficial influence of the ß-glucan product on the swine gut.

Technical Abstract: Background The 2017 Veterinary Feed Directive eliminated the use of medically important antibiotics for growth promotion of food animals; thus, alternative growth promoters are highly desirable by food animal producers to enhance animal health and reduce pathogen colonization, including the human foodborne pathogen Salmonella. ß(1-3)(1-6)-D-glucan (ß-glucan) is a soluble fiber with prebiotic characteristics; it has been shown to modulate immune and intestinal functions that strengthen swine resistance to health challenges such as bacterial infections when supplemented in the diets of growing pigs. The current study evaluated the effects of a ß-glucan product on gut microbial community structure as well as Salmonella shedding and intestinal colonization. Results Five-week-old pigs were fed a ß-glucan amended diet at 500g/ton (n=13) or a non-amended control diet (n=14) for three weeks, followed by inoculation of the 27 pigs with 1 × 109 colony forming units of Salmonella enterica serovar Typhimurium strain UK1. While remaining on the respective diets, fecal samples collected at 2, 4, 7, and 16 days post-inoculation (dpi) were similar for Salmonella shedding counts between the two diets. At 16 dpi, Salmonella counts were significantly lower in the cecal contents of the ß-glucan-fed pigs (P=0.0339) and a trend towards a significant reduction was observed in the Peyer’s patches region of the ileum (P=0.0790) compared to the control pigs. Pigs fed ß-glucan for three weeks exhibited an increase in members of the Clostridia class in their fecal microbial communities, and after inoculation with Salmonella, several potentially beneficial microorganisms were enriched in the microbiota of ß-glucan-fed pigs (Lactobacillus, Ruminococcaceae, Prevotellaceae, Veillonellaceae, Bifidobacterium and Olsenella). Conclusion Administration of ß-glucan modestly altered the swine gut microbiome with limited reduction of Salmonella colonization in the intestinal tract.