EFFECT OF MILK WHEY AND ITS FERMENTATION PRODUCTS BY LACTIC-ACID BACTERIA ON MITOCHONDRIAL LIPID PEROXIDE AND HEPATIC-INJURY IN BILE DUCT-LIGATED RATS

The study was carried out to assess whether bovine milk whey and its p roducts fermented by lactic acid bacteria could ameliorate the lipid p eroxidation of hepatic mitochondria associated with cholestatic liver injury due to bile duct ligation. Rats were maintained on one of five diets for 3 weeks before being operated upon and killed 3 weeks after bile duct ligation. The diets included one deficient in vitamin E (con trol diet) and others supplemented with either 5% milk whey or 5% milk whey fermented with Bifidobacterium longum (B. longum), Lactobacillus acidophilus (L. acidophilus), and Streptococcus salivarius subsp, the rmophillus (S. thermophillus). Bile duct-ligated rats, compared with s ham-operated rats, had higher organ weights (liver and spleen), higher serum alkaline phosphatase activity, higher serum bilirubin concentra tion, and higher content of hepatic mitochondrial lipid hydroperoxide. The rats fed on diets containing milk whey fermented with B. longum a meliorated the elevation of organ weights, enzyme activity, bilirubin concentration, and content of mitochondrial lipid hydroperoxide. Milk whey and milk whey fermented with L. acidophilus and S. thermophillus also suppressed the elevation of mitochondrial lipid hydroperoxide, bu t had no ameliorating effects on organ weights, enzyme activity, and b ilirubin concentration. The elevation of serum lipid hydroperoxide was ameliorated in rats fed on diets containing milk whey and milk whey f ermented with B. longum and S. thermophillus. The reduction in plasma alpha-tocopherol due to bile duct ligation was ameliorated in those ra ts fed on diets containing milk whey fermented with B. longum as well as by S. thermophillus. These results suggest that a milk whey ferment ed with lactic acid bacteria exerts a beneficial effect on free radica l-mediated hepatic injury.