Antioxidant and cholesterol assimilation activities of selected lactobacilli and lactococci cultures.

In present study, three strains of lactic acid bacteria (LAB) viz. Lactobacillus casei, Lactobacillus acidophilus and Lactococcus lactis and milk fermented with these strains have been studied for antioxidant and cholesterol assimilation activities in-vitro and in-vivo, in addition to the effect on total lactobacilli, lactococci and coliform counts into the gut of mice fed with diets supplemented by fermented milk. All three selected strains exhibited potent 2,2-diphenyl-1-picrylhydrazyl, malonaldialdehyde and hydrogen peroxide radical scavenging abilities as well as inhibition of linoleic acid peroxidation activity. These activities were highest in Lb. casei as followed by Lb. acidophilus and Lc. lactis. In addition, these bacterial cultures also exhibited good in-vitro cholesterol assimilation potential. Oral administration to mice of milk fermented with selected LAB strains, slightly decreased blood cholesterol, increased colonization of total lactobacilli and lactococci, and decreased coliforms in the intestinal tissues as well as faecal samples. These results indicate that, selected LAB strains have good antioxidant, hypocholesterolemic and coliform removal activities. It may suggest that, a novel functional food can be obtained by supplementation of selected LAB in milk, which may have various health beneficial properties such as antioxidant and hypocholesterolemic activities.

Modulation of cytokine gene expression in spleen and Peyer's patches by feeding dahi containing probiotic Lactobacillus casei in mice.

OBJECTIVE: In present study, feeding effect of probiotic dahi containing Lactobacillus casei on immune system in terms of cytokine gene expression in the spleen and Peyer's patches of mice was evaluated. METHODS: Animals were divided into three groups and fed with; synthetic diet [control group (CD)], dahi containing mixed dahi culture [control dahi-fed group (CDF)]; and probiotic dahi fed group (PDF) for 28 days. The mRNA levels of IL-2, IL-4, IL-6 and IFN-gamma were examined after 14 and 28 days. Total lactobacilli and lactococci counts were determined in the feces. RESULTS: The mRNA levels of IFN-gamma in both spleen and Peyer's patches was found to be significantly increased in PDF animals after 14 and 28 days (P < 0.05) compared with CD and CDF groups. The abundance of IL-2 mRNA also increased significantly in the Peyer's patches of PDF-fed animals. No significant changes were observed in mRNA levels of IL-4 and IL-6 in both spleen and Peyer's patches during whole experimental period. Further, total fecal lactobacilli and lactococci counts in the PDF group were significantly increased during first 10 days, then remained higher up to day 28 compared to other two groups. CONCLUSION: It is concluded that feeding probiotic dahi enhanced the expression of Th1 type cytokines (IFN-gamma and IL-2), especially in the mucosal immune organ (Peyer's patches) rather than in systemic organs (the spleen). This indicates that feeding with probiotic dahi may strengthen the host immune system and protect against the progression of various immune-mediated diseases.

Oral administration of dahi containing probiotic Lactobacillus acidophilus and Lactobacillus casei delayed the progression of streptozotocin-induced diabetes in rats.

In this study, the effect of dahi containing probiotic Lactobacillus acidophilus NCDC14 and Lactobacillus casei NCDC19 (73 x 10(8) cfu/g) on progression of streptozotocin (STZ)-induced diabetes in rats (15 g/day/rat) for 28 days was investigated. Feeding of probiotic dahi significantly suppressed the incremental peaks and area under the curve and delayed reduction of insulin secretion during oral glucose tolerance test more than skim milk or control dahi. The feeding of milk products reduced the total cholesterol, triglycerides, LDL and VLDL-cholesterol and increased HDL-cholesterol levels (P<0.05). Moreover, probiotic dahi significantly suppressed STZ-induced oxidative damage in pancreatic tissues by inhibiting the lipid peroxidation and formation of nitric oxide, and preserving antioxidant pool such as glutathione content and activities of superoxide dismutase, catalase and glutathione peroxidase. The results suggest that the supplementation of probiotic Lb. acidophilus and Lb. casei with dahi cultures increased the efficacy of dahi to suppress STZ-induced diabetes in rats by inhibiting depletion of insulin as well as preserving diabetic dyslipidemia, and inhibiting lipid peroxidation and nitrite formation. This may empower antioxidant system of beta-cells and may slow down the reduction of insulin and elevation of blood glucose levels.

Formation of oligosaccharides in skim milk fermented with mixed dahi cultures, Lactococcus lactis ssp diacetylactis and probiotic strains of lactobacilli.

Milk fermented with mixed dahi cultures NCDC167, Lactococcus lactis ssp diacetylactis NCDC60 and two probiotic strains; Lactobacillus acidophilus NCDC14 and Lb. casei NCDC19 were evaluated after fermentation (14 h) and during 8 d storage at 7 degrees C. The beta-galactosidase activity was found to increase after fermentation leading to the hydrolysis of lactose and production of glucose, galactose and oligosaccharides; that subsequently decreased during storage. The viable counts of lactococci and lactobacilli decreased during storage yet remained >106 cfu/ml after storage. The results of present study indicate that all the selected cultures have ability to produce oligosaccharides (prebiotics) due to transgalactosidal and lactose hydrolysis activities of beta-galactosidase. The cultures developed an active synbiotic formula by maintaining sufficient probiotic viable counts to exert health benefits to the consumers.