Because of the modulator action of probiotics on the intestinal microflora and consequent influence on the gut-liver axis, the aim of the study was to investigate the effects of a dietary supplementation with a probiotic, the Primalac 454, on the nonalcoholic fatty liver disease induced by dietary protein restriction in broilers. The dietary 0.05% Primalac 454 supplementation was performed in 3 week old Ross-308 broiler chickens fed with a control (20% crude protein) basal diet or with a low protein (14% crude protein) diet for 4 weeks. Body weights, weight gains, food intake and food efficiency were weekly recorded in each group containing 30 chicks and at the end of the experiment, the conventional liver histopathological analysis was coupled to the determination of the carcass yield, the relative visceral organ weights, the serum protein, albumin, triglyceride and cholesterol concentrations and the AST (aspartate amino-transferase) and ALT (alanine amino-transferase) activities in 25 birds from each group. The final body weights, the weight gains, the food efficiency, the carcass yield as well as the serum protein, albumin and cholesterol concentrations and the serum AST activity were significantly depressed in birds fed with the low protein diet supplemented or not with the probiotic compared to the controls whereas the relative liver and abdominal fat weights and the serum triglyceride concentrations were significantly increased. In parallel, a steatohepatitis was evidenced in liver from the protein restricted broilers. However, when the probiotic supplementation was performed, the histological grade, the steatosis and cell ballooning scores significantly diminished although the serum biochemical parameters except the serum protein concentrations (which were slightly but significantly increased) were not modified compared to the not supplemented birds. These results demonstrate that the probiotic supplementation limits the intensity of the liver fatty disease induced with dietary protein restriction in broilers.