基于菌株特异性的三株乳杆菌对仔猪益生机制的比较研究

Lactobacillus species as probiotics are one of antibiotics alternatives with the most potentiality. However, the effectiveness of Lactobacilli in application is unstable and the mechanisms are far unknown. Especially, the principle of Lactobacillus isolates selection is unclarified. Most probiotics are selected based on their in vitro activities; the colonization, metabolism and regulation on the intestine are largely unexplored. In this project, the in vivo mechanisms of three different Lactobacillus strains in the piglets' intestine will be compared based on the three isolates with in vitro strain-specific activities. The effect of modulating intestinal microbiota will be compared through PCR-DGGE, and the differences of small intestinal proteomes exerted by the three Lactobacilli will be studied by 2-DE and MS. The mutual probiotics mechanisms of three isolates will be screened. Moreover, the specific difference among the Lactobacilli with strain-related activities will be compared. The comparative study trys to explain the mechanism of the beneficial bacteria in regulating the health of intestine in the weaning piglets, which provides the theoretical basis on the selection of probiotics and direct application in feed science.

乳杆菌作为在畜牧生产中最具抗生素替代潜力的益生菌之一，日渐被市场接受和认可，但是效果不稳定，具体的作用机制不明，尤其是菌株选育上具有一定的不确定性，大多基于菌株体外的生物活性，其在体内的增殖、代谢及对肠道的调控机理尚无定论。本项目以三株乳杆菌菌株特异性的体外活性为基础，比较不同菌株在仔猪胃肠道的作用机制。本项目采用PCR-DGGE的方法比较研究三株乳杆菌对肠道菌群调节能力，并通过2-DE及MS采用比较蛋白质组学的研究方法比较乳杆菌对仔猪小肠粘膜蛋白质表达差异性；从中找出三株乳杆菌"益生"机制的共性机理，并能基于菌株的特异性探讨不同菌株间的个体差异。本项目将系统揭示乳杆菌对断奶仔猪肠道调控的机制，并能为益生乳杆菌的选育和应用提供直接的理论指导。

本项目以三株乳杆菌菌株特异性的体外活性为基础，比较不同菌株在仔猪胃肠道的作用机制。本项目采用PCR-DGGE的方法比较研究三株乳杆菌对肠道菌群调节能力，并通过2-DE及MS采用比较蛋白质组学的研究方法比较乳杆菌对仔猪小肠粘膜蛋白质表达差异性；从中找出三株乳杆菌"益生"机制的共性机理，并能基于菌株的特异性探讨不同菌株间的个体差异。采用单因素试验和正交设计获得了三株乳杆菌的最佳发酵培养基质；采用PB试验、最陡爬坡试验及中心组合设计获得了乳杆菌最适的保护剂配方，最大限度保持乳杆菌制备冻干粉过程中存在的存活率下降的问题；优化了乳杆菌内源乳化微胶囊化的条件，达到了乳杆菌94%左右的包封率，制备出的微囊化乳杆菌浓度达到1011CFU/g以上。以此为基础将乳杆菌配制到仔猪日粮中，研究乳杆菌对断奶仔猪生长性能、粪便菌群及肠黏膜蛋白质组表达差异的影响，结果表明，三株乳杆菌实验组与抗生素组类无显著性差异；而不同乳杆菌组，对仔猪生长的影响有差异，L. reuteri G8-5的效果最差，这与前期在大鼠试验中的结果一致。粪便样品以及肠道粘膜样品正在处理分析当中。