Fermentation to Short-Chain Fatty Acids and Lactate in Human Faecal Batch Cultures Intra- and Inter-Individual Variations versus Variations Caused by Changes in Fermented Saccharides

Abstract

The fermentation to short-chain fatty acids, lactate, and ammonia from several non-starch polysaccharides, glucose, and albumin was investigated in 16.6% faecal homogenates. Increasing concentrations (0-30 mg/ml) of glucose, wheat bran, pectin, ispaghula, cellulose, or albumin incubated for 24 h in homogenates pooled from three individuals increased short-chain fatty acid production linearly. Amounts and ratios of short-chain fatty acids formed were highly dependent on the type of substrate fermented. Fermentable saccharides increased ammonia assimilation, in contrast to the metabolic inert cellulose. Nine faecal homogenates sampled from three individuals at three occasions were incubated for 6 and 24 h. The production of total short-chain fatty acids, acetate, propionate, and butyrate and the accumulation of D- and L-lactate changed considerably in relation to the type of substrate added (cellulose, ispaghula, wheat bran, pectin, gum arabic, and glucose; p less than 10(-4)-10(-7). In contrast, there were no significant (p greater than 0.05) differences in organic acid formation between the nine homogenates, and the intra- and inter-individual variations were of the same magnitude. Variations in fermentation, when measured as organic acid formation, were therefore related to the type of substrate fermented rather than the individual tested.

Application of the Colon-Simulation Technique for Studying the Effects of <i>Saccharomyces boulardii</i> on Basic Parameters of Porcine Cecal Microbial Metabolism Disturbed by Clindamycin

“…In addition it could be confirmed by microbial studies of the incubation fluid that the numbers of total viable counts, lactobacilli, enterobacteria, streptococci and clostridia were in same range as respective numbers present in the cecal fluid of the donor animals [22]. In comparison with fecal batch cultures as described by Mortenson et al [23], it is a further advantage of COSITEC that the accumulation of end-products cannot occur due to its semicontinuous character and that the microbial population is obtained from those parts of the hindgut which are physiologically relevant. It also has to be taken into account that the composition and the ratio between living and autoclaved microbes of the fecal flora are different from the respective cecal and colonic flora.…”

The regulatory and scientific approach to defining gum arabic (Acacia senegal and Acacia seyal) as a dietary fibre

“…SCFA production: Several investigations have shown that higher proportions of propionate and butyrate are produced by fermentation in vitro and in vivo from gum arabic than from other hydrocolloids such as pectin (May et al, 1994;Michel et al, 1998;Mortensen, Hove, Clausen, & Holtug, 1991;Titgemeyer, Bourquin, Fahey, & Garleb, 1991;Topping, Mock, Trimble, Storer, & Illman, 1988). Table 2 shows a comparison of several investigations, giving also the source of the bacteria used.…”

Metabolism of Maillard reaction products by the human gut microbiota – implications for health

“…Certain oligosaccharides such as fructooligosaccharides and galactooligosaccharides and the polysaccharide inulin, may be fermented preferentially by bifidobacteria, which has given rise to the concept of prebiotics, nondigestible food components that selectively stimulate one or a limited number of beneficial bacteria within the gut [15,21]. Non-starch polysaccharides include pectin, arabinogalactan, inulin, guar gum and hemicellulose, which are readily fermented by the colonic microbiota, and lignin and cellulose, which are much less fermentable [22,23]. Endogenous carbohydrates, chiefly from mucin and condroitin sulfate, contribute about 2 -3 g/day of fermentable sub-strate [8].…”