In order to determine some of the mechanisms of action that explain the anti-steatosis effect of Ulva prolifera, the authors analysed liver gene expression of diacylglycerol O-acyltransferase 1 (Dgat1) and diacylglycerol O-acyltransferase 2 (Dgat2), two enzymes involved in triglyceride assembly, and in line with the results concerning liver triglycerides, the increase induced by the high-fat diet in these parameters was prevented by both doses of the seaweed. This evidence concerns the gene DGAT1 and steatosis.