EFFECTS OF A MEAL OF FISH-OIL OR CORN-OIL ON BILE-FLOW AND COMPOSITION IN RATS PREVIOUSLY ADAPTED TO DIETS CONTAINING FISH-OIL OR CORN-OIL

Chronic feeding of diets rich in n-3 or n-6 fatty acids influences the fatty acid profile of biliary phospholipids. We have examined whether the fatty acid composition of a single meal affects the fatty acid co mposition of biliary phospholipids, bile flow and lipid composition. A dult male Sprague-Dawley rats were fed diets containing either corn oi l or fish oil (MaxEPA) for a period of 2 weeks. At the end of the feed ing period, rats were fitted with exteriorized cannulas in the duodenu m and bile duct. They were then given intraduodenally a bolus of an em ulsion of fish or corn oil plus sodium taurocholate. Bile was collecte d hourly for 6 hours. Both previous diet and the infused fat affected the fatty acid composition of bile. Bile secretion was higher in MaxEP A infused rats. Neither diet nor oil infused alone had an effect on th e concentrations of biliary cholesterol or phospholipid but a signific ant interaction was observed between diet and oil infused. Both factor s independently affected bile acid concentration. There was a decrease over time in the levels of cholesterol, phospholipid, and bile acids as well as the proportions of 18:1(n-9), 18:2(n-6), 20:4(n-6), 20:5(n- 3) and 22:6(n-3) for all groups. An increase in 18:0 was observed over the 6 hour collection period, regardless of previous diet or oil infu sed. The results indicate that 1) 18:1(n-9), 20:5(n-3), and 22:6(n-3) in bile phospholipids are influenced by the previous diet and the fat infused, 2) the type of fat in the diet or a meal can alter bile flow and, 3) Combined, diet and infused fat had a significant effect on the concentrations of biliary cholesterol and phospholipids but independe ntly affected bile acid secretion.