The purpose of this study was to investigate the protective effect of Bacillus subtilis fermented silkworm powder (BFSP) and Aspergillus kawachii fermented silkworms powder (AFSP) on alcohol-induced hepatotoxicity in Sprague-Dawley rats. Alcohol-feeding rats were fed with diets containing silkworm powder (SP) or both BFSP and AFSP at the 5% (w/w) levels for 4 weeks. Alcohol administration resulted in a significant increase in the activities of liver marker enzymes, aspartate aminotransferase (AST), γ-glutamyl transpeptidase (γ-GTP) and lactate dehydrogenase (LDH). Administration of BFSP markedly prevented alcohol-induced elevation of serum AST, γ-GTP and LDH activities, and the levels of blood alcohol and acetaldehyde. Interestingly, in comparison with both SP and AFSP, BFSP administration drastically increased both hepatic alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH) activities, suggesting that BFSP was more effective in the reduction of blood alcohol and acetaldehyde. BFSP administration showed the highest induction of hepatic ADH expression in alcohol-feeding rats. Also, alcohol treatment resulted in increasing lipid peroxidative index (thiobarbituric acid-reactive substances) and decreasing antioxidant status (reduced glutathione) in the liver. Thus, these results suggest that BFSP treatment improved the antioxidant status of alcoholic rats by decreasing the levels of lipid peroxidative index and by increasing the levels of antioxidant status in the liver and serum. Specially, the concentrations of serum total cholesterol, free fatty acid and hepatic triglyceride were increased, but these parameters were significantly influenced by the BFSP in the alcohol treatment. Unlike the action of alcohol treatment on fatty liver, BFSP administration attenuated lipid droplet accumulation in hepatocytes. A high level of ADH was also observed in AFSP administered rats; on the other hand, a significant change in ALDH was not observed. Therefore, the SP can be a promising candidate in the prevention alcohol-induced hepatotoxicity and oxidative stress.
