Effects of dietary supplementation of galactooligosaccharides and seaweed-derived polysaccharides on an experimental Salmonella Typhimurium challenge in pigs

Pork and pork products are recognized as vehicles of Salmonella Typhimurium (S. Typhimurium) infection in humans. Galacto-oligosaccharides (GOS) and seaweed-derived polysaccharides (seaweed extract [SWE]) have been shown to exhibit antimicrobial and prebiotic activity. The aim of the present study was to assess the ability of GOS and SWE supplementation to reduce S. Typhimurium infection in vivo. Grower-finisher pigs (n = 10/treatment) were randomly assigned to 3 dietary treatments: 1) basal, 2) basal + 2.5 g GOS/kg feed, and 3) basal + SWE (containing 180 mg laminarin/kg feed and 340 mg fucoidan/kg feed). Following an 11-d dietary adaptation period, pigs were orally challenged with 108 cfu/mL S. Typhimurium. Pigs remained on the diets for a further 17 d and were then sacrificed for sample collection. The SWE supplementation reduced (P < 0.05) S. Typhimurium numbers in fecal samples collected 7 d after challenge. In addition, SWE reduced (P < 0.05) S. Typhimurium numbers in digesta from the cecum and colon. Expression levels of IL-10 and MUC2 in ileal tissue were increased (P < 0.05) for the GOS treatment group. The SWE treatment group had reduced (P < 0.05) expression levels of IL-22 in colonic tissue. The IL-6 and TNF-alpha expression levels in the colon were reduced (P < 0.05) for both GOS and SWE treatments. In conclusion, addition of SWE reduced fecal and intestinal S. Typhimurium numbers after S. Typhimurium challenge compared with the basal diet. The proinflammatory response after S. Typhimurium was reduced in grower-finisher pigs through supplementation of GOS and SWE.