Intra-caecal short chain fatty acids are altered by dietary pectin in the rat.

When Dark Agouti rats were changed from a conventional pellet diet containing 3.3% crude fibre and 4% fat to the experimental diet containing 5% pectin and 17% fat, the levels of n-butyrate in the caecum rapidly decreased more than fivefold. Such a change could be important as n-butyrate is known to be a major energy source for colonocytes, and to affect colon tumour cell development in vitro. Striking decreases in the caecal concentrations of the short chain fatty acids isobutyrate, n-valerate and isovalerate occurred when Wistar rats were fed an experimental diet containing 5% pectin as the only dietary fibre, compared to rats fed the experimental diet containing no dietary fibre. These large changes in the short chain fatty acid profile, caused by pectin supplementation, have important implications for the metabolism and health of the colon.