BACKGROUND:For many years,yeast cell walls (YCW) and mannan oligosaccharides (MOS) have been used as alteatives to antibiotics and health feed additives to enhance the growth performance and health of food animals.In the present study,the inhibitory effects of YCW and MOS on the adhesion of enteropathogenic bacteria to intestinal epithelial cells were tested.METHODS:YCW and MOS were extracted from Saccharomyces cerevisiae (XM 0315),and the morphology of YCW and MOS bound to pathogenic bacteria was observed by scanning electron microscopy (SEM).Real-time fluorescent quantitative PCR was used to quantitatively analyze the effects of YCW and MOS on the adhesion of Escherichia coli (CVCC3367) and Salmonella pullorum (CVCC520) to Caco-2 cells.RESULTS:The results showed that YCW inhibited E.coli and S.pullorum binding to Caco-2 cells by 95％ and 74％,respectively,whereas MOS prevented E.coli and S.pullorum binding by 67％ and 50％,respectively.CONCLUSIONS:These data suggest that YCW has a stronger ability than MOS to inhibit pathogenic bacteria from adhering to Caco-2 cells in vitro.