Abstract Bachelor Project FBT 2018-2019: Evaluation of the effect of oat fibers in the Simulator of the Human Intestinal Microbial Ecosystem (SHIME®)
It is known that metabolites produced by gut bacteria have an effect on host’s health. For example, short chain fatty acids provide energy to the epithelial cells in the gut and have been linked with several health-promoting properties. Butyrate, in particular, has immunomodulatory potential and has been associated with cancer prevention. Several studies have therefore explored the potential improvement of health by modulating the gut microbiota, with the main focus on pre- and probiotics. In this thesis, the effect of a low concentration of a test product containing oat fibers on the gut microbiota of three different donors was evaluated. The evaluation was performed in the Simulator of the Human Intestinal Microbial Ecosystem (SHIME®). Each SHIME unit consisted of a succession of reactor vessels which represent the stomach, small intestine, proximal and distal colon. The proximal and distal colon were inoculated with a fecal inoculum obtained from a single donor. For two weeks, control samples were taken to obtain baseline values in terms of microbial activity. During the next six weeks, the SHIME units were treated repeatedly with the test product. Three times per week samples from the proximal and distal SHIME vessels were taken for short chain fatty acid (SCFA), lactate and ammonium analysis. Supplementation of the test product resulted in an increase of SCFA, lactate and ammonium concentrations compared to the control period for all donors tested. The increase in SCFA and lactate concentrations suggested that the test product has a prebiotic potential, while the increase in ammonium levels suggested enhancement of proteolytic fermentation. Indeed, because a low amount of test product was administered, this probably caused a fast depletion of carbohydrates in the product, leading to microbial fermentation of the additional proteins in the product. In the future, a higher concentration of test product could be tested, in order to determine if this could limit ammonium increase and to prove consistency of prebiotic potential.