Authors : Xiao-hong Zhu, Zhen-quan Yang, Rui-xia Gu, Yun Sun, Mao-lin Lu, Yi-Feng Zhang and Hui-jing Wang
Abstract: The objectives of this study were to screen Lactic Acid Bacteria (LAB) isolates with potential probiotic property of assimilating cholesterol and to confirm whether consumption of selected strains would significantly prevent an increase of serum cholesterol in mice fed a high cholesterol diet. Six hundred and seventeen LAB strains isolated from variety of traditional dairy products in Xinjiang, China, were examined in vitro for their acid and bile tolerance and 14 LAB isolates including three S. thermophilus, two E. faecium, three L. lactis subsp. lactis, one L. casei, L. plantarum and L. delbrueckii. subsp. bulgaricuss and three L. rhamnosus were found to remain at the levels of <104 CFU mLG1 after 3 h of incubation at pH 2.5 or 0.3% (w/v) oxgall, which indicated that these strains may survive upper gastrointestinal tract conditions. These 14 acid and bile tolerant strains exhibited variable cholesterol lowering abilities in vitro and the cholesterol reducing rate ranged from 5.46-50.35% per 109 CFU, in which strains S. thermophilus X1, E. faecium X5, E. faecium Y5 and L. rhamnosus g x 10 showed significantly higher (p<0.05) ability to remove cholesterol in media than that of the other strains examined. The effect of fermented milk with L. rhamnosus g x 10 or S. thermophilus X1 or E. faecium X5 and E. faecium Y5 on serum total cholesterol, high-density lipoprotein, low-density lipoprotein and triglycerides were determined in rats fed on a cholesterol enriched diet. The results indicated that L. rhamnosus g x 10 fermented milk significantly decreased serum total cholesterol level of rats in experimental group compared with that of model group (p<0.05). The serum triglycerides level in the rats fed the LAB isolates fermented milk was also tended to decrease but the decrease was not significant. The liver tissue sections were carried out to evaluate effects of probiotic strain in vivo. it was observed that histopathological changes in livers from those rats given cholesterol enriched diet supplemented with yoghurt enriched S. thermophilus X1 (Exp.1 group), S. thermophilus X5 (Exp. 2 group), E. faecium Y5 (Exp. 3 group) and L. rhamnosus g x 10 (Exp. 4 group) was less extensive than those of mice receiving cholesterol enriched diet alone in model group, furthermore, L. rhamnosus g x 10 group was found to be almost the same as the rats fed cholesterol-free diet from blank group in liver tissues. The present study demonstrated some lactic acid bacteria isolates from Chinese traditional dairy products were effective in decrease serum total cholesterol and had potential of treating hypercholesterolemia.
Xiao-hong Zhu, Zhen-quan Yang, Rui-xia Gu, Yun Sun, Mao-lin Lu, Yi-Feng Zhang and Hui-jing Wang, 2009. Screening Lactic Acid Bacteria Isolates with Potential Probiotic Properties of Cholesterol lowing from Chinese Traditional Fermented Dairy Products. Research Journal of Dairy Sciences, 3: 25-31.