In the present study, effect of dahi containing probiotic Lactobacillus casei (probiotic dahi) was evaluated to modulate immune response against Salmonella enteritidis infection in mice. Animals were fed with milk products along with standard diet for 2 and 7 days prior to the S. enteritidis challenge and continued on the respective dairy food-supplemented diets during the postchallenge period. Translocation of S. enteritidis in spleen and liver, beta-galactosidase and beta-glucuronidase enzymatic activities and secretory IgA (sIgA) in intestinal fluid, lymphocyte proliferation, and cytokine (interleukin [IL]-2, IL-4, IL-6, and interferon-gamma [IFN-gamma]) production in cultured splenocytes were assessed on day 2, 5, and 8 of the postchallenge period. Colonization of S. enteritidis in liver and spleen was remarkably low in probiotic dahi-fed mice than mice fed milk and control dahi. The beta-galactosidase and beta-glucuronidase activities in intestinal fluid collected from mice prefed for 7 days with probiotic dahi were significantly lower at day 5 and 8 postchallenge than in mice fed milk and control dahi. Levels of sIgA and lymphocyte proliferation rate were also significantly increased in probiotic dahi-fed mice compared with the other groups. Production of IL-2, IL-6, and IFN-gamma increased, whereas IL-4 decreased in splenic lymphocytes collected from probiotic dahi-fed mice. Data showed that dahi prefed for 7 days before S. enteritidis challenge was more effective than when mice were prefed for 2 days with dahi. Moreover, probiotic dahi was more efficacious in protecting against S. enteritidis infection by enhancing innate and adaptive immunity than fermented milk and normal dahi. Results of the present study suggest that prefeeding of probiotic dahi may strengthen the consumer's immune system and may protect infectious agents like S. enteritidis.
Dahi containing probiotic Lactobacillus acidophilus and Lactobacillus casei has a protective effect against Salmonella enteritidis infection in mice.
Salmonella enteritidis infection has received attention during recent years owing to its high prevalence worldwide. In the present study, the protective effect of probiotic dahi (curd) supplemented with Lactobacillus acidophilus and L. casei against Salmonella enteritidis infection in mice is investigated. Seven days pre-feeding with probiotic dahi significantly increased anti-S. enteritidis sIgA (secretary IgA) antibodies and lymphocyte proliferation in S. enteritidis infected mice. IL-2, IL-6 and IFN-gamma production were significantly increased in supernatant of cultured splenocytes collected from mice pre-fed with probiotic dahi, while IL-4 levels were not changed significantly. Moreover, activities of beta-galactosidase and beta-glucuronidase, and counts of S. enteritidis in intestine, liver and spleen were decreased, whereas total lactobacilli in faeces were increased in mice pre-fed with probiotic dahi. Pre-feeding of probiotic dahi for 7 days was more effective than 2 days pre-feeding. Thus, the results indicate that, pre-feeding with probiotic dahi ameliorated S. enteritidis infection by stimulating specific and non-specific immune response. Above all, it lowered colonization of gastrointestinal tract as well as translocation of S. enteritidis.
Antimicrobial effect of lactic acid producing bacteria culture condensate mixture (LCCM) against Salmonella enteritidis.
Park JH, Seok SH, Cho SA, Baek MW, Lee HY, Kim DJ, Chung MJ, Kim SD, Hong UP, Park JH.
Department of Laboratory Animal Medicine, College of Veterinary Medicine and School of Agricultural Biotechnology, Seoul National University, San 56-1, Shillim-Dong, Kwanak-Gu, Seoul 151-742, Korea.
The antimicrobial effects of a lactic acid producing bacteria culture condensate mixture (LCCM) were assessed against Salmonella enteritidis. In the presence of LCCM, bacterial growth was assessed in vitro by the measurement of optical density (OD) and viable bacterial counting. At concentrations of 1.25 and 2.5% LCCM, OD values were significantly lower than that of the control broth, and at concentrations of 5 and 10% LCCM, OD values did not increase for the entire period of experiment. At 8 h after incubation, the viable bacterial numbers in 5% and 10% LCCM-containing broths were remarkably lower than that in the control broth. This antimicrobial ability of the LCCM was fundamentally attributed to causing cell death rather than inhibiting growth. Even when the pH of LCCM-containing broth was adjusted to 7.2, the number of viable bacteria was significantly lower in the broths containing LCCM over 2.5% than that in control broth at 8 h after incubation. However, the OD value of each culture in the presence of each concentration of the LCCM increased over 1.0 at the completion of the experiment. The in vivo antimicrobial effects of the LCCM against S. enteritidis were also assessed. In S. enteritidis-infected mice, the LCCM decreased both the viable bacteria found in the feces and the mortality rate of the mice. These findings showed that the LCCM might have an antimicrobial ability against S. enteritidis.
Suggested topic: Protective effects of Moringa oleifera root extract on lipopolysaccharide/D-galactosamine induced acute liver injury in rats. Studies have shown that Moringa oleifera extracts have hepatoprotective effects in rats against drug-induced acute liver damage as evidenced by reduced serum markers (ALT, AST levels) of liver damage. The mechanism of action is on the enhancement of antioxidant activity and maintenance of antioxidant levels. From the literature (see below), they used extracts obtained from leaves. Maybe we can investigate or compare the effects of MO extracts obtained from other parts of the plant (e.g. roots) with MO extracts from leaves or if extracts from roots have protective effects against drug or substance-induced liver injury. In order to fit the study in a given time-frame (which is limited), we will focus on MO’s effects on acute liver damage. MO is also readily available in the local setting, popular to the community and not difficult to acquire. Lipopolysaccharide/D- galactosamine as agent for inducing acute liver damage was suggested since no studies used this yet. Also, outcomes for this study only require blood samples in order to assess the effect on liver function.