We examined the simulated digestive juice tolerance and effect on cecal organic acids of mice of Lactobacillus paracasei NFRI 7415, evaluating it with in vitro and in vivo assay systems and using Lactobacillus casei for comparison. In in vitro assays, the cholesterol adsorption rate of L.casei and L.paracasei were 39. 4% and 50. 9%, respectively, and bile acid adsorption rates 33. 8% and 40. 9%. Cholesterol adsorption was higher in L.paracasei than in L.casei, and it was revealed that the

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... al rate of L.paracasei in the stomach was high. In addition, L.paracasei showed gastric juice resistance and bile tolerance. As a result of testing for harmful intestinal bacteria of L.paracasei and L.casei, the growth of Escherichia coli was inhibited in the mixed-cultured with L.casei. But, L.paracasei was not obser ved the effect of inhibiting the growth of the harmful intestinal bacteria. In order to investigate organic acid in appendix contents, male ICR mice were divided into two feeding groups for 4 weeks: a control (CO) group and a lactic acid bacterium (LB) group. Among organic acids in appendix contents, acetic acid showed the highest value in both groups. In the LB group, lactic acid and iso-butyric acid were also detected, but they were not detected in the CO group. These organic acids are a metabolism product produced in intestinal bacteria, and therefore indicate that L.paracasei had an influence on the intestinal microflora of the LB group. (₁₁)₁₃₁ 1 .緒 言 ヒトの腸管内には,₁, ₀₀₀種類以上,₁₀₀兆個,重量で 約 ₁ kg の腸内細菌が存在している ₁ ) 。腸内環境は健康 に深く関連しており,腸内細菌叢のバランスを整えるこ とが疾病の予防や改善に有効であると考えられている ₂ ) 。 乳酸菌は,古来よりヨーグルトやチーズなどの乳製品を はじめ,清酒,ワイン,漬物と幅広い発酵食品に利用さ