Abstract. For the prevention and treatment of oxidative stress, adaptogenic and anti-stress drugs are used, aimed at removing or neutralizing the pathogenic factor. Of particular interest is the study of omega-3 and omega-6 long-chain polyunsaturated fatty acids and their transformation into bioactive lipid mediators. Polyunsaturated fatty acids are structural components of biological membranes, substrates of lipid peroxidation and precursors of eicosanoids, the composition of which changes during oxidative stress. According to the gas chromatographic analysis of the blood plasma fatty acid composition, it was established that in birds receiving standard compound feed, an increase in the saturation of serum lipids was observed due to an increase in the content of palmitic (p<0.01) and myristic (p<0.001) fatty acids, and the sum of unsaturated fatty acids was probably reduced (p<0.001) due to the reduced content of essential fatty acids. By adding bionano-selenium to the diet, the relative content of saturated fatty acids decreases in the fatty acid composition of quails’ blood plasma phospholipids compared to intact quails. A decrease in the content of monounsaturated fatty acids of the ω-9 family was also recorded. Since phospholipids are the basis of lipoproteins, their fatty acid composition listed above may indicate an improvement in the transport function of blood plasma. At the same time, the amount of cholesterol esterified with fatty acids decreased in the blood plasma of the experimental birds, which in the complex allows us to conclude about the positive effect of the complex drug on the fatty acid formula of blood serum lipids.