| A total of 61 Lactobacillus strains isolated from traditionally fermented dairy products(mainly isolated from home-made koumiss) in Mongolia and Xingjiang of China were assessed for potential probiotic properties. After their tolerance of bile salt and survival rates in artificial gastrointestinal juice at pH3.0 and ability to remove cholesterol from culture had been evaluated, 13 stains of Lactobacilli were further identified by 16S rDNA sequences homology analysis for their good probiotic properties. Potential Bile Salt Hydrolase activity were examined by high-performance liquid chromatography (HPLC) analysis. Based on these data,9 strains of Lactobacilli were selected for a feeding trial on account of their various assimilation of cholesterol abilities and binding of cholesterol abilities and BSH activity. The effects of nine strains on serum lipids and liver and fecal cholesterol and fecal total bile acids were estimated in rats fed a high lipid alone or supplemented with different Lactobacillus strains for 4 weeks.The results provides the basic data for systematically understanding possible mechanisms of cholesterol removal in-vitro and in-vivo by Lactobacillus, and gives useful information for further exploitation and utilization of lactic acid bacteria in traditional fermented milk products.Twelve strains of Lactobacilli were selected for potential probiotic properties on account of their strong bile-salt resistance and low pH tolerance and hydrophobicity properties. Our findings indicated that cholesterol removal and growth are closely related. Cholesterol assimilation in the presence of 0.3% bile showed good relationship with bile tolerance of the strains.Three strains showed stronger binding of cholesterol ability than others.Thirteen strains of Lactobacilli that had been identified by standard conventional identification methods were further identified by16S rDNA sequences homology analysis. The results showed ten strains had the same as results with traditional classification. Three strains which showed different results by conventional identification methods and 16S rDNA sequences homology analysis were further analyzed. The last results showed 16S rDNA sequences homology analysis can be deemed credible.Four strains of Lactobacilli were selected for their Bile Salt Hydrolase activity by HPLC analysis. Cholesterol concentration in the washing buffers showed greatly relationship with bile salt hydrolase activity of the strains.In order to evaluate the correlation of Lactobacillus strains cholesterol-lowering effects and possible mechanisms of cholesterol removal between in vitro and in vivo, 9 strains of Lactobacilli were selected for a feeding trial on account of their various assimilation of cholesterol abilities and binding of cholesterol abilities and BSH activity. The results showed that all of Lactobacillus strains were effective in reducing serum total cholesterol , triglyceride and low- density lipoprotein cholesterol, and liver cholesterol, while increasing the fecal excretion of total cholesterol, compared with the model group. Those strains which had strong assimilation and blinding of cholesterol abilities in vitro would excreted more cholesterol in fecal than the others. Those strains which had BSH activity would excreted more bile acid in fecal than the model group, and the amount of total bile acid in fecal was consistent with the activity of BSH in vitro. The hepatic tissue slice and the aortal tissue slice in rat fed a different diet were observed. The results showed fed LIP-1 can greatly alleviate pathological changes of the hepatic tissue and the aortal tissue. Our findings indicated those strains which had strong assimilation and blinding of cholesterol abilities in vitro would greatly reduce serum cholesterol in vivo.
|
PDF Full Text Request