In Saccharomyces cerevisiae, the two major polysaccharides, constituting up to 90% of the cell wall dry weight, are α-D-mannan and β-D-glucan, which have remarkable properties to interact with the immune system of the host. Modulation of mucosal immunity by the binding of these two
polysaccharides to the specific receptors of immune cells provides beneficial effects on animal health and resistance to diseases.