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Abstract

BackgroundA study was designed to elucidate effects of selected carbohydrates on composition and activity of the intestinal microbiota. Five groups of eight rats were fed a western type diet containing cornstarch (reference group), sucrose, potato starch, inulin (a long- chained fructan) or oligofructose (a short-chained fructan). Fructans are, opposite sucrose and starches, not digestible by mammalian gut enzymes, but are known to be fermentable by specific bacteria in the large intestine.ResultsAnimals fed with diets containing potato starch, or either of the fructans had a significantly (p < 0.05) higher caecal weight and lower caecal pH when compared to the reference group, indicating increased fermentation. Selective cultivation from faeces revealed a higher amount of lactic acid bacteria cultivable on Rogosa agar in these animals. Additionally, the fructan groups had a lower amount of coliform bacteria in faeces. In the inulin and oligofructose groups, higher levels of butyrate and propionate, respectively, were measured.Principal Component Analysis of profiles of the faecal microbiota obtained by Denaturing Gradient Gel Electrophoresis (DGGE) of PCR amplified bacterial 16S rRNA genes as well as of Reverse Transcriptase-PCR amplified bacterial 16S rRNA resulted in different phylogenetic profiles for each of the five animal groups as revealed by Principal Component Analysis (PCA) of band patterns.ConclusionEven though sucrose and cornstarch are both easily digestible and are not expected to reach the large intestine, the DGGE band patterns obtained indicated that these carbohydrates indeed affected the composition of bacteria in the large gut. Also the two fructans resulted in completely different molecular fingerprints of the faecal microbiota, indicating that even though they are chemically similar, different intestinal bacteria ferment them. Comparison of DNA-based and RNA-based profiles suggested that two species within the phylum Bacteroidetes were not abundant in numbers but had a particularly high ribosome content in the animals fed with inulin.

Re‐evaluation of alginic acid and its sodium, potassium, ammonium and calcium salts (E 400–E 404) as food additives

“…The Panel noted that an increased caecum weight in animals fed high amounts of carbohydrates is considered a physiological response to an increased fermentation. Increased caecum weight has been observed in rats fed carbohydrates other than alginic acid and its salts (Leegwater et al, 1974;Licht et al, 2006). Animals fed diets containing potato starch, inulin or oligofructose had significantly higher caecum weights and lower pH values than the reference animal group (Licht et al, 2006).…”

“…Increased caecum weight has been observed in rats fed carbohydrates other than alginic acid and its salts (Leegwater et al, 1974;Licht et al, 2006). Animals fed diets containing potato starch, inulin or oligofructose had significantly higher caecum weights and lower pH values than the reference animal group (Licht et al, 2006). Different groups of animals fed modified diets containing increased concentrations of potato starch, hydroxypropyl starch and hydroxypropyl distarch glycerol showed increases in the relative caecal weights, filled and emptied, with increasing concentrations of the various hydroxypropyl starches.…”

Effect of dietary fat to starch content on fecal microbiota composition and activity in dogs1

“…However, high-fat diets are generally low in complex carbohydrates, including starch, contributing to the effects caused by these diets (Graf et al, 2015). It is acknowledged that part of starch may escape digestion and induce changes in the gut microbiota (Licht et al, 2006). To our knowledge, the effect of high-fat diets on canine gut microbiota remains uncertain.…”

The Murine Lung Microbiome Changes During Lung Inflammation and Intranasal Vancomycin Treatment

“…DNA was extracted from BAL and from caecum samples. The DGGE method is extensively used to compare gut bacterial profiles without preexisting knowledge of their composition using universal primers based on 16s RNA gene sequences [ 11 - 13 ].…”