副干酪乳杆菌L9对小鼠肠道短链脂肪酸含量的影响

目的:评价副干酪乳杆菌L9对健康小鼠肠道内短链脂肪酸(short chain fatty acids,SCFAs)含量的影响。方法:选取3周龄BALB/c雄性小鼠50只,随机分为副干酪乳杆菌L9高、中、低剂量组、阳性对照组(商业菌株Lactobacillus casei strain Shirota)、阴性对照(生理盐水)组共5组,以0.2 m L/d的剂量连续灌胃小鼠21 d并收集第0、21天小鼠粪便。第21天处死小鼠后搜集收集盲肠内容物,利用气相色谱仪观察内容物中SCFAs的变化,并且利用实时定量聚合酶链式反应(real-time polymerase chain reaction,RT-PCR)分析肠道菌群数量的变化。结果:与第0天相比,第21天小鼠粪便中SCFAs中乙酸、丙酸含量极显著上升(P0.01),Bifidobaceterium spp.、Lactobacillus属数量和丁酰辅酶A转移酶(butyryl-Co A:acetate Co A-transferase,CoAT)基因的表达量显著升高(P0.05);盲肠内容物中,低剂量组和高剂量组中的Bifidobaceterium spp.数量和CoAT基因表达量分别与第0天和阴性对照组相比有显著差异(P0.05)。实验结果表明:副干酪乳杆菌L9可以调节肠道菌群,促进健康小鼠肠道中SCFAs的产生,并且与商业菌株Lactobacillus casei strain Shirota相比,副干酪乳杆菌L9对肠道内丙酸、丁酸的含量和肠道中Bifidobaceterium spp.的数量有更好的促进作用。

Effect of Lactobacillus paracasei L9 on the Content of Intestinal Short Chain Fatty Acids in Healthy Mice

Objective: To evaluate the effect of Lactobacillus paracasei L9 on the content of intestinal short chain fatty acids (SCFAs) in healthy mice. Methods: Fifty three-week-old BALB/c male mice were randomly divided into 5 groups: high dose, medium dose, low dose, positive control and negative control groups. After continuous administration at a dose of 0.2 mL/day per mouse for 21 days, mouse feces were collected, and the cecal contents were also examined after sacrificing the mice on day 21. The changes in SCFAs concentrations of samples were analyzed by gas chromatography, and RTPCR was used to analyze the changes in the intestinal flora. Results: The concentration of short-chain fatty acids including acetic acid, propionic acid and butyric acid increased significantly (P < 0.05), when compared with those observed before administration. The counts of Bifidobaceterium spp. and Lactobacillus and the expression level of butyryl-CoA:acetate CoA-transferase gene (CoAT) were increased significantly (P < 0.05) in feces of mice on day 21. For the cecal contents, Bifidobaceterium spp. count and the expression level of CoAT in low-dose and high-dose groups showed a significant difference (P < 0.05) those in normal saline group. Conclusion: Lactobacillus paracasei L9 can adjust the intestinal flora and promote the production of short chain fatty acids in the intestine of healthy mice. Compared with commercial strain Lactobacillus casei strain Shirota, L9 has a better effect on promoting the yield of propionic acid and butyric acid and hte growth of Bifidobaceterium spp. in the intestine.