The development of biological products synthesizing metabiotics-amino acids, vitamins and other biologically active substances in the gastrointestinal tract of animals is considered as the most promising approach to the formation of microbiocenosis of intestinal microflora. The use of metabolic products of probiotic microorganisms (metabiotics) is an actual direction in the study of the metabolism of probiotic microorganisms and a reasonable alternative to the use of feed antibiotics in animal diets. Moreover, the creation of biologically active feed additives based on them is relevant for the correction of intestinal microbiocenosis and stimulation of non-specific immunity. The aim of the research is the scientific and practical justification of fermentation of molasses by probiotic microorganisms and the possibility of creating a biologically active feed additive. The research objectives included the study of the efficiency of cultivation of Clostridium thermocellulociticus, Ruminococcus olbus, Clostridium lochheadii on a nutrient medium from beet molasses; obtaining culture fluid with metabiotics of probiotic microorganisms; explanation of research results to create a dietary supplement for animals. The studies found that during cultivation, the maximum number of probiotic microorganisms that make up the enzymatic probiotic Cellobacterin is 9,9х10 6 CFU / cm 3 in 15% nutrient medium. According to the test results, the variability of the mass fraction of the amount of fermentable sugars in the range of 53.70%-33.79%, the hydrogen index from 6.70 to 3.87 in the experimental samples of cultivated microorganisms was established. A significant excess of Arginin was found to be 2.8 times, Tyrosine 57.7-66.1 times, Leucine + isoleucine 3.90-6.65 times, and other non-replaceable and conditionally replaceable amino acids. The metabiotics of cultivated probiotic agents from the vitamin group are represented mainly by group "B". The content of oxalic acid in the test samples is slightly lower with respect to the control within 3.8%-33.2%. The content of acetic acid is lower than the control by 27.4%. The increase in amber acid in all experimental samples is 49-41 times higher in relation to the control. Thus, the composition of metabiotics provides the basis for further research in the development of biologically active additives for animals.