Effect of non-digestible oligosaccharides on gut microecosystem in rats

Effect of commercial or new-developed preparations of non-digestible oligosaccharides: fructo-oligosaccharides, lactulose, corn dextrins and corn resistant starch, on microecology of Wistar rats was investigated, A control group was fed a casein diet with 10% cellulose. The experimental groups were administered diets in which cellulose was replaced by the examined preparations. After 4-week feeding experiments, a high increase in live bifidobacteria number by 1.2 and 1.4 log cfu/g of faeces was found in groups fed resistant starch and lactulose. An increase in coliform number by 0.6-0.8 log cfu/g was found in all the groups. No or only negligible changes in numbers of the total mesophilic aerobic and facultatively anaerobic bacteria count, and the spores of anaerobic and aerobic bacteria, were observed. Fructo-oligosaccharides and lactulose lowered pH and gave the best trophic effect in caecum (significantly increased weights of: caecum with contents, cecal walls and cecal contents as well as dry weight of contents), whereas resistant starch increased markers of unhealthy cecal changes (N-NH3 content and beta-glucuronidase activity). The activity of bacterial saccharolytic enzymes changed in a substrate-specific manner in relation to the examined non-digestible oligosaccharide preparations. (C) 2002 Elsevier Science Ltd. All rights reserved.