This research was performed to study the effect of iron nanoparticles with variable size, its oxides and alloys onliving systems. Analysis of the results showed manifestation of acute toxicity over a wide concentration range forFeCo alloy nanoparticles and low toxic characteristics for iron nanoparticles and its oxides. To develop acutetoxicity high concentrations of iron nanoparticles and iron oxide nanoparticles were required. Calculation oftoxicity index allowed to rank studied nanoparticles samples in descending order of toxic action: FeCo →Feа →Fe3O4а →Feb = Fe3O4b.Correlation was direct between particle size and the intensity of the impacton living systems. According toobtained data,the smaller the particle size the greater its biological activity. The presence of cobalt in the alloyFeCo nanoparticles contributed to the increase of biological activityand as a consequence increase toxic effects.These studies revealed biological activity of iron nanoparticle and its oxides without development of toxic effectat doses of 0.25 - 0.000718 M which characterizes them as biotic.

The paperis aimed at studying the increasing efficiency in the poultry meat production when using iron and copper nanoparticles in nutrition. A maximum increase in the gain in live weight of chickens by 9-12 % in comparison with the control group in the first week after the injection of nanoparticles is observed. An increase in values of a number of blood parameters (hemoglobin, total protein, white blood cells) is noted. Copper nanoparticles increase the body’s immune response on the first dayof experiment by several orders in comparison with both control and iron nanoparticles. The analysis of mineral exchange data showed a decrease in a number of toxic (As, Pb, Al, Cd) elements and an increase in the level of a number of essential (Mg, Co, Fe, Cu, Na, F) elements in broiler tissues after exposure to copper nanoforms and iron nanoforms. The analysis shows more effective influence on the metabolic processes of chickens and require further detailed study of the processes of their transformation in the broiler body. The obtained result shows the possibility of using these forms in the industrial production of animal feed.

In the experiment, the biological activity of copper and zinc alloy nanoparticles prepared by gas phase synthesis in an argon atmosphere was assessed. Nanoparticle preparations differed in phase composition and specific surface for CuZnNPs1 - 36 m2/g, CuZnNPs2 - 22 and CuZnNPs3 NP - 15 m2/g. As the test cultures, E.coli K12 TG1 pF1, E.coli K12 MG1655 katG::lux, E.coli MG1655 pRecA-lux, E.coli K12 MG1655 psoxS::lux were used. As the results showed, phase composition and specific surface area of nanoparticles were their toxicity factors. CuZnNPs3 is the most toxic among the studied samples, the percentage of zinc phase in it, in comparison with other tested powders, is the largest (52.3%), and the percentage of metallic copper is the smallest (7.9%). Within further works is to carry out controlled synthesis that will allow changing the toxicity of the nanoparticles under study by phase composition and specific surface.

Background and Aim: The existing data demonstrate that gut microbiota is involved in regulating mineral metabolism in cattle, although the data are quite contradictory. The study aimed to evaluate Saccharomyces cerevisiae-based probiotic’s effects on gut microbiota, systemic metabolism, and dairy cows’ essential trace element and mineral body burden. Materials and Methods: Fifteen cows received a daily supplement of a 50 g S. cerevisiae-based probiotic, fortified with methionine, choline, eugenol, cinnamaldehyde, and Capsicum oleoresin, for a month. 16S metagenomic sequencing was used to evaluate the taxonomic features of fecal microbiota. Serum trace elements and minerals levels were determined through inductively coupled plasma mass spectrometry. Results: Supplementation with S. cerevisiae-based probiotic complex significantly increased alpha and beta diversity, as well as the abundance of Mediterranea and Clostridium IV within the Bacillota phylum, whereas that of Bacteroidota and specifically unclassified Bacteroidales and unclassified Oscillospiraceae decreased. Following probiotic supplementation with the S. cerevisiae-based complex, gut microbiota modulation led to a significant boost in circulating levels of calcium, copper, selenium, and zinc. Creatinine levels decreased while total cholesterol levels increased within normal limits in the serum analysis. Conclusion: The observed improvement in trace elements and minerals in dairy cows might be due to changes in intestinal microflora caused by supplementation. Therefore, probiotic supplementation in cattle may be considered a potential tool for improvement of mineral nutrition in cattle. However, the influence of probiotic treatment and modulation of mineral metabolism on milk productivity and overall performance in cattle is yet to be estimated. Keywords: gut microbiota, minerals, probiotic, Saccharomyces cerevisiae, trace elements.