There are various ways to maintain a stable and predictable microbes composition in the gastrointestinal tract of poultry. With the nutrition correction the dynamics of the microbiome population is possible, and, consequently, the moderation of productivity, broiler chickens in particular. The purpose of the research was to study the balance of the gastrointestinal tract microbiota and metabolic processes in the broiler chickens body in the prevention of mycotoxicoses by introducing “Belasorb” mycotoxins adsorbent into the diet. Based on the conducted studies we found that the mycotoxin adsorbent contributes to an increase in the level of lactobacilli in the gastrointestinal tract of broilers – by 0.3x10 – 1,2x10 CFU/g, bifidobacteria – by 0.1x10 – 2,4x10 CFU/g and a decrease in the level of enterobacteria – by 0.2x10 – 0.3x10 CFU/g, Escherichia coli bacteria – by 1,4x10 – 1,6x10 CFU/g, and also yeast and mold fungi – by 0.5x102 – 0.7x102 CFU/g. There was a significant improvement of metabolic processes in the broiler chickens body which contributed to the optimization of protein and mineral metabolism, nitrogen- and nitrogen-free substances as well as an increase in the natural resistance of poultry body, and consequently, resistance to diseases of non-infectious etiology.