The article presents the results of a study of the amino acid and fatty acid composition of the liver of Arbor Acres broilers, which were fed with ultrafine particles of silicon dioxide at a dose of 100, 200, 300 and 400 mg per kilogram of mixed feed. It was found that the use of UFP SiO2 in the cultivation of broilers contributes to an increase in the liver of poultry I-IV experimental groups of arginine content by 0.45-0.70%, histidine by 0.75-1.60%. The content of leucine, isoleucine, valine, threonine, and phenylalanine increased in the liver of broilers of the III-IV experimental groups by 0.11-0.96%, 0.1-0.6%, 0.10-0.13%, 0.13-0.47%, 0.23-0.53% compared to the control group. The content of linoleic acid in the liver samples of broilers of the I-IV experimental groups increased by 1.80-36.4%, the content of linolenic acid in the liver of experimental chickens of the III-IV experimental groups increased by 0.1-0.2%, and oleic acid – by 0.6-3.3%, respectively. A sharp increase in the content of AST and ALT in the blood of broiler chickens of the experimental groups was not observed, although there is a dose-dependent increase in the activity of these enzymes, which indicates an increase in liver function against the background of the action of ultrafine silicon dioxide.