Abstract
The aim of our study was to monitor the effects of dietary synbiotics on experimentally infected mice. Sixty mice were divided into the following three groups: negative control group C1, positive control group C2 (mice infected with enterotoxigenic Escherichia coli O149:F4NAL), and experimental group LF (Lactobacillus reuteri CCM 8617RIF + 10% flaxseed + E. coli O149:F4NAL). Supplements were administered for 42 days. Microbiological, hematological, and biochemical analyses, electrophoretic analysis of lactate dehydrogenase (LDH) isoenzymes, and analysis of fatty acids using gas chromatography and isotachophoresis were performed. We recorded higher numbers of jejunal and ileal lactic acid bacteria, lower Enterobacteriaceae counts in the feces of the animals, and an increased production of organic acids in the synbiotic-fed group. The supplements applied favored n-3 polyunsaturated fatty acid (PUFA) metabolism and inhibited n-6 PUFA metabolism; thus, they influenced the n-6 to n-3 and eicosapentaenoic to arachidonic acid ratios. Additionally, the incorporation of n-3 PUFAs to the cell membrane decreased the activity of LDH, transaminases, and alkaline phosphatase. Results obtained in our study indicate the positive effect of continuous supplementation of combination of probiotic cheese enriched with L. reuteri CCM 8617RIF and crushed flaxseed on composition of intestinal microflora and alleviation of the course of infection induced by pathogenic bacterium E. coli O149:F4NAL.
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Key Points
The aim of this study was to observe whether the synergic effects of Lactobacillus reuteri CCM 8617RIF and flaxseed fed to mice experimentally infected with Escherichia coli O149:F4NAL could (a) affect the counts of Enterobacteriaceae in the jejunum, ileum, and faeces and E. coli O149:F4NAL in the feces could (b) affect the counts of lactic acid bacteria and L. reuteri CCM 8617RIF in the jejunum, ileum, and feces, production of SCFAs in the cecum and feces, as well as the fatty acid composition of the intestine cell membranes through the modulation of PUFA metabolism, and whether these changes in fatty acid composition could be associated with glucose levels and cell integrity. Based on these hypotheses and previous findings in piglets, this study analyzed the level of glucose in the blood, the activity of hepatic enzymes, and LDH in various tissue types.
The study confirmed a synergistic effect of feed supplementation of the combination of flaxseed as a source of alpha-linolenic acid and fibers (prebiotic function) and L. reuteri CCM 8617RIF in the form of cheese on the selected intestinal microbiota of mice from group LF infected with E. coli O149:F4NAL, manifested by a significant increase in LAB associated with a significant decrease in Enterobacteriaceae counts in the jejunum and ileum sections. Stimulation of population of LAB is of specific importance not only for their potential influence on the function and health of the intestine but also due to their potential antagonistic activities toward pathogenic bacteria. The positive effect of the supplemented additives on the intestinal metabolism was substantiated by higher cecal production of acetoacetic, lactic, succinic, acetic, and butyric acids and higher level of all SCFAs in the feces of mice, which, together with the predominantly synthesized n−3 PUFAs in the body, contribute to the better integrity of cell membranes.
Results of this study indicate the positive effect of continuous supplementation of combination of the probiotic cheese enriched with L. reuteri CCM 8617RIF and flaxseed on composition of intestinal microflora and alleviation of the course of infection induced by pathogenic bacterium E. coli O149:F4NAL.