Zdzisława Libudzisz

Probiotic Lactobacillus strains: in vitro and in vivo studies

Three Lactobacillus strains (LOCK 0900, LOCK 0908, LOCK 0919) out of twenty-four isolates were selected according to their antagonistic activity against pathogenic bacteria, resistance to low pH and milieu of bile salts. Intragastric administration of a mixture of these strains to Balb/c mice affected cytokine TH1-TH2 balance toward nonallergic TH1 response. Spleen cells, isolated from lactobacilli-treated mice and re-stimulated in vitro with the mixture of heat-inactivated tested strains, produced significantly higher amounts of anti-allergic tumor necrosis factor- and interferon-γ than control animals whereas the level of pro-allergic interleukin-5 was significantly lower. Lactobacillus cells did not translocate through the intestinal barrier into blood, liver and spleen; a few Lactobacillus cells found in mesenteric lymph nodes could create antigenic reservoir activating the immune system. The mixture of Lactobacillus LOCK 0900, LOCK 0908 and LOCK 0919 strains represents a probiotic bacterial preparation with possible use in prophylaxis and/or therapy of allergic diseases.

Impact of heat-inactivated Lactobacillus casei and Lactobacillus paracasei strains on cytokine responses in whole blood cell cultures of children with atopic dermatitis

Heat-inactivated Lactobacillus casei LOCK 0900, L. casei LOCK 0908 and Lactobacillus paracasei LOCK 0919 strains, applied to blood cell cultures obtained from children with atopic dermatitis induced production of anti-allergic TH1 cytokines (interleukin-12, interleukin-18, interferon-γ, tumor necrosis factor-α) and regulatory transforming growth factor-β1), but did not stimulate pro-allergic interleukin-5. The lactobacilli-mixture remarkably enhanced the TH1 response compared to single strains. This synergistic effect was not observed for transforming growth factor-β1. In contrast, the amount of interleukin-10 was found to be considerably lower when cells were stimulated with lactobacilli-mixture compared to single strains. The mixture of Lactobacillus strains represents a probiotic bacterial preparation modulating in vitro cytokine profile of allergic children towards anti-allergic TH1 response.

Detoxification of mycotoxins by probiotic preparation for broiler chickens.

Biological decontamination of mycotoxins using microorganisms is one of the well known strategies for the management of mycotoxins in foods and feeds. Among the different potential decontaminating microorganisms,Saccharomyces cerevisiae and lactic acid bacteria represent unique groups, which are widely used in food fermentation and preservation. The aim of this study was to determine the influence of spontaneous fermentation with the use of probiotic bacteria and yeast (Lactobacillus paracasei/casei ŁOCK 0920,L. brevis ŁOCK 0944,L. plantarum ŁOCK 0945,Saccharomyces cerevisiae ŁOCK 0142), on reduction of sum of aflatoxines (B1, B2, G1, G2) and ochratoxin A concentration during fermentation and the microflora pattern during fermentaton. The probiotic bacteria and yeast applied creates a starter culture for flour fermentation that has a stable feature of detoxication of aflatoxines and especially ochratoxin A.

Probiotic lactic acid bacteria detoxify N-nitrosodimethylamine

Humans can be exposed to N-nitroso compounds (NOCs) due to many environmental sources, as well as endogenous formation. The main nitrosamine found in food products and also synthesised in vivo by intestinal microbiota is N-nitrosodimethylamine (NDMA). It can cause cancer of the stomach, kidney and colon. The effect of four probiotic Lactobacillus strains on NDMA was studied under different culture conditions (24 h in MRS, 168 h in modified MRS N, and 168 h in phosphate buffer). HPLC and GC-TEA methods were used for NDMA determination in supernatants. The influence of lactic acid bacteria on NDMA genotoxicity was investigated by means of the comet assay. Additionally, the effect of NDMA (2–100 µg ml–1) on the growth and survival of the probiotic strains was studied. The results indicate that the bacteria decreased NDMA concentration by up to 50%, depending on the culture conditions, time of incubation, NDMA concentration, pH and bacterial strain. Lb. brevis 0945 lowered the concentration and genotoxicity of NDMA most effectively by up to 50%. This could be due to either adsorption or metabolism. The growth and survival of the bacteria was not affected by any of the tested NDMA concentrations.

Probiotic preparation reduces the faecal water genotoxicity in chickens fed with aflatoxin B1 contaminated fodder

The aim of the study was to evaluate the influence of a probiotic preparation on the genotoxicity of faecal water of broiler chickens fed with a fodder contaminated with aflatoxin B(1) (AFB(1)) at 1 or 5mg per kg. Human blood lymphocytes were exposed to chickens faecal water samples and DNA damage was measured using the comet assay. Genotoxicity of faecal water did not depend on the AFB(1) concentration in the fodder. The mean DNA damage, measured as the percentage of DNA in the tail of the comets, for chickens fed with fodder with AFB(1) at 1 mg/kg was 16.80±0.66, at 5 mg/kg - 16.73±1.51 and in the controls - 12.79±0.66. The supplementation of fodder with the probiotic preparation decreased the extent of DNA damage to 10.02±0.39 for 1 mg/kg AFB(1) and to 11.89±0.72 for 5 mg/kg.

Ability of intestinal lactic bacteria to bind or/and metabolise phenol and p-cresol

Intestinal microflora can contribute to colon cancer by the production of substances playing a role in carcinogenesis. Metabolites of protein fermentation in the colon, such as ammonia, H2S, indole, phenol, skatole are toxic. Lactic bacteria existing in the colon may exert an anti-carcinogenic action, but the mechanism is poorly understood. In the present study the ability of intestin|al lactobacilli to bind or metabolise phenol and p-cresolin vitro was determined.Lactobacillus strains were cultivated in MRS and in a modified MRS broth with reduced concentrations of carbon source. Phenol and p-cresol content in the media were from 2 to 10 μg/ml. In MRS medium lactobacilli could decrease the concentration of phenol and p-cresol and it was 0.2-5.8 μg/ml for phenol and 0.2-1.4 μg/ml for p-cresol. After cultivation in a modified MRS broth, the decrease was 0.5-2.0 μg/ml for phenol and 0.5-2.4 μg/ml for p-cresol. The binding capacity of bacterial cells was rather low. After incubation of non-growing bacteria the decrease of phenol concentration was 0.1-0.5 μg/ml and p-cresol 0.1-2.8 μg/ml. But the ability of growing lactobacilli to metabolise the compounds cannot be excluded. After interaction of lactobacilli with 10 μg/ml of phenol they displayed a lower genotoxicity, as evaluated by the alkaline comet assay. The phenomenon not always depended on the decrease of phenol concentration, but on the medium, the strain of bacteria and for phenol it ranged from 32 to 48%.Lactobacillus strains tested did not lower the genotoxicity of p-cresol.

Feeds with Probiotics in Animals’ Nutrition

The discovery of penicillin by Alexander Fleming in 1928 was a turning point which fundamentally revolutionized human and veterinary medicine. Antibiotics in veterinary medicine have been used to prevent and control bacterial infections and as growth promoters. Prevention and control of bacterial infections have been achieved by a therapeutic, metaphylactic or prophylactic application of antibiotics. Therefore, the substances, predominantly of the same class as in human medicine, have been used in veterinary medicine. Antibiotics regularly administered to animals in order to improve their growth, to better the use of feed and to reduce the number of falls have been defined as antibiotic growth promoters. The use of AGP in the European Union was approved by the Council Directive of 23 November 1970 concerning feed additives (70/524/EEC).

Dietary resistant dextrins positively modulate fecal and cecal microbiota composition in young rats.

The objective of the present study was to demonstrate the effect of dietary resistant dextrins, as potential prebiotics, on the intestinal microflora of young rats. Enzyme-resistant dextrin, prepared by heating of potato starch in the presence of hydrochloric (0.1% dsb) and tartaric (40% dsb) acid at 130ºC for 2 h (CA-dextrin). The experiment was performed on 24 Wistar male rats at 3-wk of age, divided by analogues in three experimental groups (control, starch and dextrin). Analyses determined the overall bacterial counts and the counts of Lactobacillus, Bifidobacterium, Bacteroides and Clostridium strains within the feces and cecal contents of rats using fluorescence in situ hybridization method. CA-dextrin had no effect on primary growth indicators (body weight, body weight gain, dietary consumption) or the mass of the small intestine and the cecum, but dextrins caused a reduction in pH and the concentration of ammonia within the cecal contents. That supplementation of diet with resistant dextrins had a positive effect on composition of intestinal microflora in rats. It increased the counts of Bifidobacterium and Lactobacillus strains both in the feces and in the cecum. Moreover, it reduced the counts of Clostridium and Bacteroides strains. These results may suggest that resistant dextrins exerted a prebiotic-like effect in the large intestine.