The influence of dietary locust bean gum and live yeast on some digestive immunological parameters of piglets experimentally challenged with Escherichia coli

Gums and yeast cells are natural mannose-rich products that can be used as subtracts for adhesion of gram-negative bacteria. The aim of the study was to investigate the role of dietary locust bean gum (LBG; Salmosan, ITPSA, Spain) or live yeast (Saccharomyces cerevisiae Sc47; Actisaf, Lesaffre, France) as immunological enhancers of the intestinal function of piglets. Treatments included a noninfected group fed with a control diet and 4 other groups orally challenged with 1x10(8) cfu of Escherichia coli K88. The challenged groups were fed the control or the control diet supplemented with colistin, LBG, or yeast. Twenty-five Landrace x Duroc piglets weaned at 4 wk were used. The animals were group housed, challenged on day 14, and euthanized 2 d later. Blood, bile, ileum, and mesenteric lymph node (MLN) samples were obtained for analysis of C-reactive protein (CRP), secretory immunoglobulin A (sIgA), and Toll-like receptors 2 (TLR2) and 4 (TLR4). Challenge increased the level of CRP of piglets fed the control diet, but this did not happen in the piglets fed the supplemented diets (P < 0.001). Challenge upregulated TLR2 in MLN and TLR4 in ileum and MLN (P < 0.05). This was prevented by yeast supplementation for the TLR2 in MLN and TLR4 in ileum. Pigs fed colistin and LBG diets showed intermediate but nonsignificant responses. In conclusion, the results suggest that colistin, live yeast, and LBG reduce the levels of CRP in blood of piglets challenged with E. coli, and yeast reduces the expression of Toll-like receptors in the intestine.