Abstract: This invention relates to a composition for additives which can be employed in animal feeds, or as growth promoters, or as nutraceuticals, or as prebiotics, or as additives for the control and prophylaxis of pathogenic bacteria in the intestinal tract of animals or farmed animals. An immunomodulatory and promoter composition for controlling the population of undesirable bacteria of the intestinal microbiota, comprising the components indicated below: (a) Fructooligosaccharides (FOS); (b) Galacto-oligosaccharides (GOS); (c) Mannan-oligosaccharides (MOS); (d) 1,3 and 1,6 Beta-glucans.