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The requirements for the safety of food products obtained by microbial synthesis are including as obligation for to conduct toxicological studies - the study of various biochemical and immunological markers of toxic effects. The necessity of these studies is explained by a possible change in the structure of food ingredients produced by a microbial cell and, consequently, a change in their biological properties, as well as the possible presence of living forms and/or DNA of producer strains or of their toxic metabolites in these ingredients. At the same time, it is well known that the nutrient composition of foods has a significant impact on the composition and properties of microorganisms that make up the gut microbiome, which, in turn, determines the immune status. The purpose of the research was to justify the analyses of gut microbiocenosis composition for inclusion in the protocol of safety investigation of foods obtained by microbial synthesis [on the example of an enzyme preparation (EP) - a complex of glucoamylase and xylanase from a genetically modified strain of Aspergillus awamori Xyl T-15].

The introduction of methods for food production using microbial synthesis, including those obtained with the help of genetically modified (GM) microorganisms, at the present stage, allows to increase production volumes and reduce the cost of food. At the same time, such products in accordance with TR CU 021/2011 "On food safety" are classified as a "novel food"» and can be placed on the market only after its risk estimation for health. The emergence of new data and research methods in the last years has made it necessary to improve the risk assessment system for this category of food.

Influence of probiotic fermented milk product on the intestinal microbiota, hematological parameters and immune status of the experiment in vivo at Wistar rats was studied. It was shown, that entering of probiotic strains of Bifidobacterium bifidum 791, Bifidobacterium longum B-379M and Lactobacillus acidophilus NK1 u Streptococcus thermophilus in composition fermented milk products in the total quantity of 2,1 x 10(7) CFU/ sm3 in digestive tract within three weeks has a positive influence on the resident of colon microbiota. Significant increasing of population levels of Bifidobacterium, Enterobacteriaceae with normal biochemical properties, registered a strong tendency to increase the content of Lactobacteria, which led to a decreasing the number of potential pathogenic transient flora with pathogenic factors. Monitoring of body mass in experimental animals has shown that including of fermented milk product with probiotic strains in diet has a positive influence on the feed uptake. Probiotic properties of the product also have stimulated effect on the immune status of the rat: improvements in cell immunity (increasing the relative amount of T-helper cells, immuneregulatory index) and hematological parameters (increase

Influence of probiotic fermented milk products on the intestinal flora, hematological parameters and immune status of the experiment in vivo at rats is studied. Entering in digestive tract of probiotic strains of Lactobacillus acidophilus NK-1 and Bifidobacterium bifidum 791 at the level of hundreds of millions CFU in a day (from 1,7 x 10(8) to 9 x 10(8) CFU) in composition fermented milk products renders on the whole positive, but not significant statistically influence on the indexes of colon microflora and immune status of rats, and it must be extended for the achievement of reliable effect.

Intestinal microbiocenosis condition, cytokine IL-6, IL-10 and TNF-alpha levels and allergic sensitivity in experimental systemic anaphylaxis test were studied in rats that received intragastrically nanoparticles of titanium dioxide. The results obtained were discussed from the standpoint of possible health risks related to nanodimensional titanium dioxide exposure.

In experiments in rats it is set, that peroral introduction with the feed of mould spores in a doze 10(3) CFU/g results in a disbalance of microbiocenosis of intestine. It shows up violation of localization of bifido- and enterobacteria and their increased growth in a small intestine. Thus, also antagonistic activity of an aerobic component of microflora is reduced and frequency of detection of potential-pathogenic types of enterobacteriaceae is increased. Entering of fungi spores at a dose 10(6) CFU level is accompanied by more expressed infringements of aerobic populations of intestinal microflora in rats.

An influence was studied in experiment of intragastrically administrated milk cream contaminated with mould fungi spores on systemic anaphylactic reaction gravity in Wistar albino rats sensitized with egg albumin (EA). During 28 days sensitized rats intragastrically received cream containing 10(3) or 10(6) colony forming units of 5 fungal species in one cm3. After being challenged rats developed mild anaphylactic shock followed by elevation of small intestinal permeability for macromolecular tracer polyethylene glycol 4000. An increase of small intestinal permeability was also noticed in unsensitized rats that were fed with cream contaminated with 10(6) spores per cm3. Unexpectedly these effects were not additive: the intestinal permeability in sensitized rats decreased at maximal level of contamination. This may be explained by strengthening of gastrointestinal motility in these animals. Significant elevation of antibody production against EA was revealed in sensitized rats that received cream contaminated by spores at high level. The data obtained signify that milk products fungal contamination that could not be revealed by sense may nevertheless have negative impact on intestinal barrier function and sensitization.

In experiences on rats is shown, that 22 daily upkeeping of animals on a diet including eritrit in a dose 1 g/weight of a body, do not cause any changes from the party intestinal microflora and morphological structure of internal bodies. However, the specified doze eritrit causes statistically authentic increase of levels conditionally-pathogenic anaerobius of the representatives microflora, first of all staphylococcus and citratessimilation enterobacteria.

In tests on rats subject to study were the effects of native tetracycline, thermally treated and used in doses of 100 mg/kg, of tetracycline in a dose of 20 mg/kg and of penicillin on the secretion of bile and generation of free and conjugated bile acids and cholesterol, as well as upon the cholesterol content in the blood and liver tissues with complete and protein-deficient rations. With complete ration tetracycline in its native and thermally treated forms provoked a fall in the cholesterol content in the bile and hepatic tissue, a rise in percentage of free bile acids and a decline of the tauroconjugates percentage. With a protein-low ration tetracycline called for an increased concentration of the bile cholesterol with simultaneously increasing concentration of cholic acid.