Saccharomyces cerevisiae strains retain their viability and aflatoxin B1 binding ability under gastrointestinal conditions and improve ruminal fermentation.

The aim was to evaluate both the ability of yeast strains to survive and bind AFB(1) under ruminant gastrointestinal conditions and the effect of these yeast strains on ruminal fermentation. Yeast viability was studied under simulated gastrointestinal conditions. AFB(1) binding ability was evaluated at different pH values as present in the ruminant gastrointestinal tract. The effect of yeast strains on cellulose digestion and volatile fatty acids production by ruminal bacteria was also evaluated. All yeast strains were able to survive under gastrointestinal conditions and to adsorb AFB(1) at the different pH assayed. The strain RC016 showed the highest binding percentage at the three tested pH. The number of cellulolytic bacteria in ruminal fluid increased in the presence of RC008 and RC016 yeast strains. The concentration of acetate and propionate after ruminal fermentation increased with the addition of RC008 and RC016 strains; this effect was less significant with RC009 strain. Strains RC008 and RC016 are potential probiotic to be included in animal feed: they help to increase fibber digestibility and could reduce AFB(1 )bioavailability in the gastrointestinal tract. Viable S. cerevisiae RC008 and RC016 strains with both probiotic and mycotoxins adsorption properties could be used as feed additives in ruminant feedstuff.