Yeast prebiotic, which is a high-quality combination of mannanoligosaccharides (MOS) and β-(1,3 and 1,6)-poly-D-glucans, extracted from the cell walls of yeast of a specially selected strain of Saccharomyces cerevisiae. It is intended for the prevention of intestinal colonization by pathogenic microorganisms, especially Colibacteria and Salmonella, normalization of the microflora of the gastrointestinal tract, improvement of productivity and preservation of animals, poultry and aquaculture.