Analysis of the influence of enzyme preparations produced using technological microorganisms on the microbiome and cellular immunity of rats

Abstract

The observed increase in the production of enzyme preparations (EP) using mutant and genetically modified microorganisms makes it necessary to assess their risks to consumer health. However, at present, their possible influence on the microbiome, immune status of the macroorganism has not been sufficiently studied. The purpose of the research was to assess the effect of two EP - the complex of hydrolases with proteolytic and nuclease activity from the Aspergillus oryzae RCAM 01134 mutant strain (EP1) and the neutral protease - bacillolysin and serine protease from the Bacillus subtilis-96 (VKM B-3499D) mutant strain (FP2) on the intestine microbiome and cellular immunity indices of the experimental animals. Material and methods. The experiment on the subacute toxicity of EP1 and EP2 was carried out for 30 days using Wistar rats (7 groups of 10 males each). EP was administered to animals intragastrically in doses 0 (control - saline solution); 1, 10 and 100 mg/kg body weight per day. The composition of the cecum microbiocenosis was studied by inoculating tenfold dilutions of the cecum contents on the differential diagnostic media. The quantitative content of short-chain fatty acids (SCFA - acetic, propionic, isobutyric, butyric, isovaleric, valerianic acids) in the colon contents was determined by highperformance gas chromatography. The expression of T- and B-lymphocyte and NK-cell receptors (CD45RА+, CD3+, CD161+, CD3+CD4+, CD3+CD8+) in rat peripheral blood was determined using an FC-500 flow cytometer. Results. The data obtained as a result of the microbiocenosis studies of the cecum contents indicate that EP1 and EP2 administration had a reliable effect on the quantitative and qualitative composition of aerobic microorganisms, including opportunistic microorganisms, as well as it lead to a weak increase in the number of bifidobacteria and lactobacilli. The development of an inflammatory process in animals of all experimental groups have been caused by the changes in the qualitative and quantitative composition of various groups of microorganisms in the cecum contents, SCFA level in the faeces and indicators of cellular immunity under intragastric administration of FP1 and FP2 for 30 days. Conclusion. The revealed difference in the composition of the cecum microbiocenosis, SCFAs produced by the intestinal microflora, and the cellular immunity indices of the experimental animals under EP1 and EP2 administration, in our opinion, is due to the spectrum of metabolites produced by the intestinal microflora, as well as strains of Aspergillus oryzae RCAM 01134 and Bacillus subtilis-96 (VKM B-3499D). The features of the relationship between the spectrum of SCFAs produced by the intestinal microflora, their quantity and the percentage of T- and B-lymphocytes in the blood of rats indicate different mechanisms of the influence of EP1 and EP2 on the microbiome and immune status of the macroorganism.