In vitro test on the ability of a yeast cell wall based product to inhibit the Escherichia coli F4ac adhesion on the brush border of porcine intestinal villi

The ability of a yeast cell wall (YCW)-based product (SENTIGUARD C; Nutriad) to inhibit the enterotoxigenic Escherichia coli F4ac (ETEC) adhesion on the brush border of porcine intestinal villi was tested. The ETEC suspensions were preincubated with 2 batches of the product (A and B) at different concentrations (10, 5, and 0.5%, wt/vol) or with their filtrates (AF and BF) and then with intestinal villi susceptible to ETEC adhesion. In all the trials, ETEC suspensions were also preincubated with egg yolk (E) immunized against ETEC to assess the maximum inhibition of the adhesiveness or directly with the villi [control group (Con)] to verify the maximum adhesiveness of the pathogen. For each treatment, 20 different villi were observed, brush border measured, and the adherent pathogens counted. A scanning electron microscope analysis was used to confirm the ability of ETEC to adhere on the YCW. The E treatment significantly reduced the pathogen adhesion on the villi compared with the C group in all the trials (P < 0.001). Both batches of SENTIGUARD C significantly reduced the pathogen adhesion on the villi compared with the C group at the concentration of 10 and 5% (P < 0.001) but not at the concentration of 0.5%. The BF did not significantly reduce the ETEC adhesion whereas the AF significantly increased bacterial adhesion (P = 0.015). The microscopy results confirm the ability of ETEC to adhere on YCW. Taken together, our results indicate the ability of the SENTIGUARD C to contain the intestinal infection from ETEC in young pigs with the affinity of ETEC to YCW.