乳酸菌与β-葡聚糖共微胶囊化处理对两者胃肠道生物利用度影响的机理研究

Recent studies in journals such as Nature and Science showed that the gastrointestinal bioavailability of probiotics and nutrients has got highly attention. Probiotics are sensitive to external conditions and often need microencapsulation to improve their bioavailability. Recent studies have found that co-microencapsulation of probiotics and prebiotics can further improve the survival rate of probiotics in the gastrointestinal tract. However, few in-depth studies have been conducted on the systematic effects of co-microencapsulation on both gastrointestinal bioavailability. In our group, Lactobacillus zeae LB1 microencapsulation method has already been established, and it has been found that beta-glucan (polysaccharide prebiotic) can promote the growth of Lactobacillus. However, it is unclear whether co-encapsulation of Lactobacillus and beta-glucan has any effect on their gastrointestinal bioavailability. Therefore, based on these pre-researches, we are going to use biochemistry, metabolomics and genetic engineering methods to further study the mechanism of co-microencapsulation to the bioavailabilities of Lactobacillus and beta-glucan. The results from this research will give effective models for studying the effect of co-microencapsulation to the bioavailability of probiotic and prebiotic.

Nature、Science等期刊最新研究表明，基于益生菌和营养物质胃肠道生物利用度的研究已成为国内外关注热点。益生菌对外界条件很敏感，常需微胶囊化方式提高其生物利用度，最新研究发现将益生菌与益生元共微胶囊化能更进一步提高益生菌在胃肠道中的存活率。然而，针对益生菌与益生元共微胶囊化对两者胃肠道生物利用度有何系统影响，目前尚无深入研究。本课题组前期已建立乳酸菌L. zeae LB1微胶囊化方法，同时发现β-葡聚糖（多糖类益生元）能促进该乳酸菌生长，但不清楚将该乳酸菌与β-葡聚糖共微胶囊化对两者胃肠道生物利用度有何影响及其作用机制是什么？因此，本课题拟在前期基础上，交叉使用生物化学、代谢组学、基因工程等技术手段，体内外深入研究乳酸菌与β-葡聚糖共微胶囊化对两者胃肠道生物利用度的影响机制这一科学问题，其研究结果可为益生菌与益生元共微胶囊化及其胃肠道生物利用度提供研究模型。

基于益生菌和营养物质胃肠道生物利用度的研究已成为国内外关注热点。益生菌对外界条件很敏感，常需微胶囊化方式提高其生物利用度，最新研究发现将益生菌与益生元共微胶囊化能更进一步提高益生菌在胃肠道中的存活率。然而，针对益生菌与益生元共微胶囊化对两者 胃肠道生物利用度有何系统影响，目前尚无深入研究。本研究使用青稞β-葡聚糖为模式益生元，Lactobacillus plantarum 550为模式益生菌，使用喷雾干燥法对两者进行微胶囊化，体外研究发现两者共微胶囊化后，益生菌在体外模拟消化6 h后，益生菌活菌浓度仅下降1.95 Log CFU/g，在4°C存储8周后，益生菌的活力基本保持不变。动物实验研究发现，在小鼠胃、十二指肠、空肠、回肠、盲肠、结肠内容物中，含青稞β-葡聚糖的益生菌微胶囊组活菌浓度显著高于其他组别，灌胃后32h后，仍能在盲肠和结肠内容物中检出活菌，表明青稞β-葡聚糖能显著增加微胶囊化益生菌在肠道的保留时间，具有促进益生菌在盲结肠定植的潜力。高通量测序结果表明，与对照相比，青稞β-葡聚糖显著增加乳杆菌属和双歧杆菌属的丰度；含青稞β-葡聚糖的益生菌微胶囊显著上调乳杆菌属、双歧杆菌属、阿克曼菌属、拟杆菌属、梭菌属等丰度，促进有益菌群增殖，改善肠道微生态。此外，通过测定粪便中有机酸含量，发现青稞β-葡聚糖可被肠道菌群降解，促进短链脂肪酸的产生，尤其是丙酸和丁酸；益生菌则促进乙酸和丁酸的产生；两者共微胶囊化对于乙酸、丙酸、丁酸等短链脂肪酸的产生具有协同增效的潜力。本研究结果可为益生菌与其他多糖类益生元共微胶囊化处理对两者胃肠道生物利用度的深入研究提供理论依据和研究模型。