Abstract
In vivo and in vitro effects of arabinogalactan (AG), non-digestible polysaccharide from larch, on the intestinal bacteria of rat and human were investigated. Fecal pH was significantly decreased and fecal moisture was increased by feeding AG to rats. However, no marked changes of the fecal short-chain fatty acids (SCFA) were observed. During the cultivation of rat fecal bacteria in AG-containing media, total sugar decreased and SCFA accumulated. These findings suggest that the intestinal bacteria of rats utilize AG. Twelve species of human and rat intestinal bacteria were cultivated in AG-containing media. After 24 hours cultivation, the cell number of Bifidobacterium longum especially increased to 70-fold, pH of the media significantly decreased, SCFA accumulated and total sugar decreased. These observations indicate that AG is remarkably utilized as carbon-source by B. longum. In addition, Clostridium sordellii among other bacteria utilized AG.
