Abstract: Objective To investigate the influence of whey proteins （WP） on serum lipid metabolism and hepatic fatty infiltration changes in rats with nonalcoholic fatty liver disease（NAFLD）. Methods 35 SD rats were randomly divided into control （n=12）,model （n=11） and the therapeutic groups （n=12）. The control group were fed with normal diet,and the other two groups were fed with high-fat diet.Meanwhile,the therapeutic group were treated with WP（100mg/ml,0.5ml/d）. All rats were sacrificed at the end of six weeks.The pathological changes in livers in all rats were pathologically evaluated with HE stain,and the serum biochemistry index was also measured. Results Compared with the control group,the degree of fatty and inflammation were more serious in the model group,while oral administration of WP reduced the final body and liver weights of rats;the alanine transaminase was 34.8±5.6U/l,and serum triglyceride level was 0.2±0.1mmol/l in WP group,obviously reduced as compared to those in model group;liver histology showed an improvement of fatty infiltration in therapeutic group;the NAFLD activity score was significantly improved from 6.2±0.9 to 2.9±1.4（P<0.01） in WP group. Conclusions The obtained Results indicate that WP play a possible role in the regulation of liver biochemistries in the rat with NAFLD.The regulatory effect of WP is accompanied by an improvement in fatty infiltration and hepatic inflammation.

Key words: NAFLD, Whey proteins, NAFLD activity score, Rats