Abstract
The suppressive effect of ingesting a viscous exudate of mekabu on the rate of cecal fermentation in rats was evaluated from the lactic acid concentration in the cecum. Powdered feed including 7.5% fructooligosaccharides and 10% freeze-dried viscous exudate of mekabu were mixed with twice the amount of water to form a paste, and this was fed to male Wistar rats for four days. Feeding was limited 3 h after the start of the dark period. On the final day, the rats were sacrificed either 3 or 6 h after feeding, and the tissue weight of the gastrointestinal segments, the weight of the gastro-intestinal lumen contents, the viscosity of the cecal contents and the cecal organic acid concentration were measured. The retention time of the contents in various segments of the gastro-intestinal tract was estimated from the weight of the gastro-intestinal lumen contents. The retention time in the stomach and small intestine was prolonged after the ingestion of the viscous exudate of mekabu. This effect is thought to have been dependent on the viscosity of the contents. The lactic acid concentration in the cecal contents of the rats that had consumed a diet containing a viscous exudate of mekabu was lower than that in rats that had consumed a diet without the additive. This indicates that consumption of the viscous exudate suppressed the rate of fermentation by the cecal bacteria. Ingestion of the viscous exudate of mekabu increased the viscosity of the gastro-intestinal lumen contents and decreased the rate at which the substrate flowed into the cecum. At the same time, the metabolism of the intestinal bacteria was inhibited by the flow into the cecum of the low-fermentability viscous substances themselves.
