Effects of dietary grape seed tannins on rat cecal fermentation and colonic bacterial enzymes
1996
Tebib, Katia | Besançon, Pierre | Rouanet, Jean-Max
In rats, the effects of a 12-wk supplementation of a purified diet with 71 mg/kg monomeric or polymeric grape seed tannins were explored on cecal fermentation and colonic bacterial enzymes. Weight gain was affected by addition of polymers to the diet. There was a significant increment of volatile fatty acids (VFA) pool and a pH decrease in the cecal contents of rats fed polymeric tannins, compared to controls. When expressed per gram of nitrogen content, the concentrations of all colonic fecal bacterial enzyme activities tested (β-glucosidase, β-glucuronidase, mucinase and nitroreductase) were decreased, due to a dilution effect. In these experimental conditions, monomeric tannins exhibited neither beneficial nor detrimental effect. On the other hand, these results show that although at a low dietary level equivalent of a daily amount of 0.5 L red wine, polymeric grape seed tannins exert a beneficial cecal metabolic and colonic protective effect.
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