The aim of our study was to evaluate the effects of the different probiotic strains, Lactobacillus plantarum LS/07 and Lactobacillus plantarum Biocenol LP96, on lipid metabolism and body weight in rats fed a high fat diet. Compared with the high fat diet group, the results showed that Lactobacillus plantarum LS/07 reduced serum cholesterol and LDL cholesterol, but Lactobacillus plantarum Biocenol LP96 decreased triglycerides and VLDL, while there was no change in the serum HDL level and liver lipids. Both probiotic strains lowered total bile acids in serum. Our strains have no significant change in body weight, gain weight, and body fat. These findings indicate that the effect of lactobacilli on lipid metabolism may differ among strains and that the Lactobacillus plantarum LS/07 and Lactobacillus plantarum Biocenol LP96 can be used to improve lipid profile and can contribute to a healthier bowel microbial balance.

Natural bioactive supplements have been extensively studied as preventive agents. The aim of this study was to investigate the efficacy of inulin enriched with oligofructose and Hyppocastani extractum siccum as preventive agents of experimentally induced colon carcinogenesis in rats. Colon carcinogenesis was induced by N,N dimethylhydrazine (DMH) in a dose of 21mg/kg body weight s.c., five times at weekly intervals. Sprague Dawley rats (n = 45) were divided into a control group without DMH; control group with injected DMH; group receiving inulin and injected DMH; group receiving Hyppocastani extractum siccum and injected DMH; group receiving inulin and Hyppocastani extractum siccum and injected DMH. The beneficial effects of natural compounds were determined by analysis of caecal parameters such as pH, composition of microflora, activity of bacterial glycolytic enzymes and production of short-chain fatty acids (SCFA). The counts of coliforms were decreased in the groups receiving inulin enriched with oligofructose (P < 0.01), Hyppocastani extractum siccum (P < 0.001) and the combination of these supplements (P < 0.001). The counts of lactobacilli were significantly increased in all experimental groups receiving natural compounds (P < 0.01; P < 0.001). Experimental groups receiving natural compound alone and in combination resulted in a significant decrease in the activity of β-glucuronidase (P < 0.01; P < 0.001). Administration of inulin and Hyppocastani extractum siccum separately significantly increased the concentration of SCFA compared to the control group with DMH. The achieved results indicate the beneficial effect of prebiotics and plant extracts on metabolic processes in the colon and suggest that they could exert a preventive effect on colon carcinogenesis induced by DMH.Keywords: carcinogenesis; prebiotics; plant extract; prevention List of abbreviations DMH = N, N dimethylhydrazine; SCFA = short chain fatty acid; CRC = colorectal cancer; α-GAL = α-galactosidase;