Prebiotic activity of isomalto-oligosaccharides

  • Author / Creator
    Ketabi, Ali
  • Isomalto-oligosaccharides (IMO) with α(1→6) and α(1→4) glucosidic linkages are produced by enzymatic conversion of starch. Isomalto-oligosaccharides are partially digested in the intestine but little information is available regarding their metabolim in vivo. It was the aim of this study to investigate IMO metabolism by lactobacilli and bifidobacteria and to determine the effect of IMO diet on intestinal microbiota in a rodent model, and a rodent model for inflammatory bowel disease (IBD). Different strains of bifidobacteria and lactobacilli were grown in de Man Rogosa Sharpe media with IMO as sources of carbohydrates. Substrates and metabolites of carbohydrates metabolism were analyzed. Lactobacilli metabolized isomaltose whereas isomalto-triose and higher degree of polymerisation (DP) oligosaccharides were metabolized by bifidobacteria first. To determine the modulating effects of IMO in the intestine, a group of six F344 rats were fed IMO diet for six weeks and compared to rats fed control diet. Assessment of intestinal microbiota and their metabolites was performed by PCR- denaturing gradient gel electrophoresis (PCR-DGGE), quantitative PCR (qPCR) and quantification of short chain fatty acids (SCFA). The Lactobacillus group was one of the dominant bacterial taxa in the fecal samples of rats. Isomalto-oligosaccharides selectively stimulated lactobacilli and increased their diversity in rats compared to those on control or inulin diet. The potential health benefit of IMO was evaluated in a rodent model for IBD. Three groups of HLA-B27 rats were fed IMO, fructo-oligosaccharides (FOS) or control diet for 12 weeks. The Lactobacillus group and bifidobacteria numbers were increased significantly in the fecal samples of rats fed IMO or FOS diet respectively. Numbers of Enterobacteriaceae family were significantly increased in the rats fed IMO or FOS diet compared to the control group. Clostridium coccoides group, Clostridium leptum group, Clostridium cluster XI and total number of bacteria were significantly decreased in the rats fed FOS diet compared to the rats fed control diet. Moreover, IMO and FOS diets showed a unique effect on intestinal microbiota compared to the control diet. Cecum histology scores showed a significant decrease of inflammation in the rats fed IMO or FOS diet compared to the rats fed control diet.

  • Subjects / Keywords
  • Graduation date
  • Type of Item
  • Degree
    Doctor of Philosophy
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
  • Language
  • Institution
    University of Alberta
  • Degree level
  • Department
    • Department of Agricultural, Food, and Nutritional Science
  • Supervisor / co-supervisor and their department(s)
    • Gänzle, Michael (Agricultural, Food and Nutritional Science)
  • Examining committee members and their departments
    • Bressler, David (Agricultural, Food and Nutritional Science)
    • Hutkins, Robert (Food Science and Technology, University of Nebraska)
    • Dieleman, Levinus (Medicine, Center of Excellence for Gastrointestinal Inflammation and Immunity Research)
    • Vasanthan, Thava (Agricultural, Food and Nutritional Science)