青年人肠道菌群分布及关键益生菌群落结构分析

Distribution of Youth Intestinal Flora and Analysis of Key Probiotics Community

以 30例 2 0～ 2 5岁中国青年人的肠道菌群为研究对象 ,采用纯培养方法和 16SrDNA测序等分子生物学技术并结合代谢产物 β_半乳糖苷酶和短链脂肪酸的测定 ,分析了此年龄段健康人群肠道菌群分布和益生菌群落结构。实验表明 ,高厌氧菌水平和高B E值 (175 6 6 )反映出此年龄段人群良好的肠道环境 ;肠道关键益生菌群落结构分析表明 ,双歧杆菌由 1～ 4种菌种组成 ,青春双歧杆菌 (检出率 93 3% ,占总双歧杆菌数量百分比 >85 % )、长双歧杆菌 (检出率 86 7% ,占总双歧杆菌数量百分比 10 % )为肠道优势双歧杆菌 ,其余菌种在不同人肠道中的差异数量只占不到 5 % ,此年龄段青年人肠道具有呈现稳定的双歧杆菌群落结构 ,肠道双歧杆菌群落结构与膳食结构、生活环境等因素相关性不大 ,主要与人的生理年龄紧密相关 ;卷曲乳杆菌和唾液乳杆菌为青年人肠道优势乳杆菌 (检出率分别为 86 7%和 93 3% ,两者之和占总乳杆菌的数量百分比为 6 0 %～ 75 % ) ,但其余乳杆菌在不同人肠道中的之间的差异数量达到 2 0 %～ 30 % ,肠道乳杆菌群落结构与饮食结构、生活环境等因素紧密相关 ,不同个体具有各自独特的乳杆菌群落组成。

Study on intestinal flora of 30 Chinese youth (age 20～25) was conducted, including bacterium separating, counting, analysis and 16S rDNA sequencing and identification of Bifidobacterium and Lactobacillus, simultaneously with detection of β-galactosidase and short-chain fatty acids. The results showed that large quantity of anaerobe and B/E values(175.66)indicate the healthy intestinal condition of youth. Study on key probiotics community revealed that Bifidobacterium community usually composed of 1～4 strains and B.adolescentis (Detection rate 93.3%,amount pecentage >85%)and B.longum (Detection rate86.7%,amount pecentage 10%) were dominant strains in youth intestine; amount of other Bifidobacterium occupy less than 5%. It showed that Bifidobacterium community was relative stable and seems to have very close relation to the people's age but have less relation to diets and living environment. Comparatively, Lactobacillus had a more complex community, L.crispatus and L.salivarius (Detection rate 86.7% and 93.3% respectively, amount percentage 60%～75%) were dominant strains, other Lactobacillus strains were various among subjects and whose amount percentage difference reaches 20%～30%. It showed that Lactobacillus community may more depend on diets and individuals. Study on Chinese youth intestinal flora, especially on strain-level of probiotics, together with detection of (β-galactosidase) and short-chain fatty acids in the feces will be very helpful for deep understanding of intestinal microecology, developing effective probiotics products and building an evaluation system to reflect intestinal environment.