In non ruminant species, a large range of mode of action can explain the positive effect of
yeast supplementation. It is, however, difficult to find a hierarchy between all these mechanisms
of action. If it is clear that some benefits obtained with Saccharomyces cerevisiae are due to
some components present in the yeast cell walls, it seems to be fundamental, however, that the
yeast remains alive in the digestive tract, in order to benefit of the largest range of benefits.