For 24 weeks, rabbits were fed feed containing non-oxidised or oxidised rapeseed oil. At the beginning of the experiment and every six weeks the rabbits were weighed and blood was taken. After the experiment was completed, their liver was dissected for biochemical and histological examinations. The activity of alanine aminotransferase, aspartate aminotrasferase, glutamate dehydrogenase, sorbitol dehydrogenase, and aldolase in blood plasma and liver were determined. Enzymes of the protein and liver metabolic pathways were determined using kinetic and spectrophotometric methods. The content of fatty acids was determined by means of fatty acid methyl ester concentration measurement using gas chromatography. It was found that the applied diet with oxidised rapeseed oil caused the development of slight liver steatosis and disturbances in the activity of enzymes involved in the liver pathways, despite the fact that it was a balanced diet, and differed only in the ratio of saturated to unsaturated fatty acids. The obtained results indicate that more profound oil oxidation and its increased supply in diet may result in the development of liver steatosis.