Effect of oligosaccharides and fibre substitutes on short-chain fatty acidproduction by human faecal microflora

The microbial fermentation of dietary fibre and oligosaccharides has been s hown to be involved in several physiological mechanisms that promote coloni c health. One of these beneficial mechanisms is the production of short-cha in fatty acid (SCFA) as the main by-products of dietary fibre and oligosacc haride microbial fermentation. Major SCFAs produced are acetate, propionate and butyrate. Each of these acids appear also to be involved in selective physiological events that lead to improving health. This study evaluated th e fermentation of several oligosaccharides and commercial fibre substitutes using fresh faecal inocula. Typical SCFA production after 24 h was 42.4+/- 5.5 mg/ml. Results indicated that hydrolyzed guar gum after 24 h significan tly (P = 0.0001) produced the highest levels of total SCFA (54.6+/-0.7 mg/m l) and was involved as well in high production of propionate and butyrate ( 19.8+/-0.3 and 15.5+/-0.03 mg/ml, respectively). Cellulose and psyllium hus k were also involved in high production of propionate (21.0+/-0.5) and buty rate (16.8+/-0.5 mg/ml), respectively. The results of this study indicated several differences in the production of SCFAs by colonic microflora in the presence of oligosaccharides and fibre substitutes. The important physiolo gical implications of these findings are discussed. (C) 2000 Academic Press .