Adriana Nowak

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.

Protective effect of lactofermented red beetroot juice against aberrant crypt foci formation, genotoxicity of fecal water and oxidative stress induced by 2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine in rats model.

The aim of the study was to investigate the effects of beetroot juice fermented by Lactobacillus brevis 0944 and Lactobacillus paracasei 0920 (FBJ) on carcinogen induction of aberrant crypt foci (ACF) in rat colon. 2-Amino-1-methyl-6-phenylimidazo[4,5-b] pyridine (PhIP) was used as carcinogen, which was administrated intragastrically at a dose of 10 μg/day, every day of the experiment. Additionally, we investigated the cytotoxicity and genotoxicity of fecal water from experimental animals in the Caco-2 cell line, evaluated by MTT test and the comet assay, respectively, as well as by the count of bacteria adhered to colon epithelium assessed by fluorescence in situ hybridization. Oxidative stress in rats was expressed by measuring serum antioxidant status and the level of malondialdehyde in the kidneys and liver. The experimental rats were divided into four groups based on diet type: basal diet, basal diet supplemented with FBJ, basal diet and PhIP treatment, and basal diet supplemented with FBJ and PhIP treatment. FBJ significantly reduced the number of ACF in PhIP-treated rats (from 59 ± 18 to 26 ± 4). Moreover, the number of extensive aberrations (more than 4 crypts in a focus) decreased from 52 ± 18 to 18 ± 4. Fecal water obtained from rats fed with a PhIP-containing diet induced pronounced cytotoxic and genotoxic effects in Caco-2 cells, but FBJ supplementation of the diet abolished these effects. In groups fed dietary PhP and FBJ the latter was found to increase the antioxidant status of serum from 40% to 66% depending on the fraction. Reduced concentration of malondialdehyde was found only in the kidneys of rats fed with PhIP and FBJ. FBJ present in the diet of rats causes a reduction of MDA in the kidneys from 118.7 nmol/g tissue to 100 nmol/g tissue. The presence of FBJ in the diet of rats significantly increased the count of bacteria, including Lactobacillus/Enterococcus and Bacteroides-Prevotella group adhered to colonic epithelium. In conclusion, supplementation of the diet with lactofermented beetroot juice may provide protection against precancerous aberrant crypt formation and reduce the cytotoxic and genotoxic effects of fecal water and improve the oxidative status of the organism.

Protective effect of lactofermented beetroot juice against aberrant crypt foci formation and genotoxicity of fecal water in rats.

The aim of the study was to investigate the effects of beetroot juice fermented by Lactobacillus brevis 0944 and Lactobacillus paracasei 0920 (FBJ) on carcinogen induction of aberrant crypt foci (ACF) in rat colon. N-Nitroso-N-methylurea (MNU) was used as carcinogen, which was administrated intragastrically at a dose of 50 mg/kg on the 23rd and 26th day of the experiment. Additionally, we investigated the cytotoxicity and genotoxicity of fecal water from experimental animals in the Caco 2 cell line, evaluated by MTT/NRU tests and the comet assay, respectively, as well as by the count of bacteria adhered to colon epithelium assessed by fluorescence in situ hybridization and DAPI staining. The experimental rats were divided into four groups based on diet type: basal diet, basal diet supplemented with FBJ, basal diet and MNU treatment, and basal diet supplemented with FBJ and MNU treatment. FBJ significantly reduced the number of ACF in MNU-treated rats (from 55±18 to 21±6). Moreover, the number of extensive aberrations (more than 4 crypts in a focus) decreased from 45±21 to 7±4. Fecal water obtained from rats fed with an MNU-containing diet induced pronounced cytotoxic and genotoxic effects in Caco 2 cells, but FBJ supplementation of the diet abolished these effects. The presence of FBJ in the diet significantly increased the count of bacteria, including Lactobacillus/Enterococcus, adhered to colonic epithelium. In conclusion, supplementation of the diet with lactofermented beetroot juice may provide protection against precancerous aberrant crypt formation and reduce the cytotoxic and genotoxic effects of fecal water.

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.