Effects of dietary supplementation with Laminaria hyperborea, Laminaria digitata, and Saccharomyces cerevisiae on the IL-17 pathway in the porcine colon.

An unregulated T(h)17 inflammatory response has been highlighted as a major contributor to the underlying pathology of inflammatory bowel diseases (IBD) whereas regulatory T (T(REG)) cells) have been highlighted as pivotal in suppressing autoimmune and inflammatory responses in the gut. Following dietary supplementation, β-glucans have been shown to reduce the T(h)17 signature molecule IL-17a in the porcine colon. To expand this observation we examined the effects of supplementing feeds with β-glucans derived from seaweeds Laminaria hyperborea and Laminaria digitata and the yeast Saccharomyces cerevisiae on gene expression of a range of cytokines, receptors, and signal transducing molecules relevant to the T(h)17 and T(REG) pathways in the porcine colon. All sources of β-glucans significantly decreased the expression of T(h)17-related cytokines (IL-17a, IL-17F, and IL-22), receptor IL23R, and IL-6. There was no alteration to the T(REG)-related target, Foxp3, or to TGF-β, although a significant reduction in IL-10 was observed in the L. digitata supplementation group.