The velocity of pellet propulsion in guinea pig distal colon is differentially modified by short‐chain fatty acids (1110.8)

Abstract

INTRODUCTION: Short‐chain fatty acids (SCFAs) are produced by commensurate bacteria in the colon. The type and concentration of SCFAs depend on dietary intake of carbohydrate and fiber. While most fermentation occurs in proximal colon, unabsorbed SCFAs entering the distal colon are likely to modify propulsion initiated by fecal pellet‐induced distension. AIM: To determine the effect of SCFAs on pellet propulsion in distal colon. METHODS: The distal colon was removed from guinea pig and placed in an organ bath containing Kreb’s buffer. Following equilibration, video tracking software was used to measure the velocity of propulsion of a clay pellet placed in the orad end of a segment. Pellets propulsion was repeated during intraluminal perfusion of Kreb’s buffer containing individual SCFAs at 30 mM caudad to the pellet at 0.1 ml/min. RESULTS: The mean velocity of pellet propulsion in the absence of SCFAs was 1.5 ± 0.2 mm/sec. Luminal perfusion with 30 mM sodium butyrate increased the velocity of pellet propulsion by 30 ± 4% (p<0.05) whereas luminal perfusion with 30 mM sodium propionate decreased velocity of pellet propulsion by 75 ± 8%. Conclusion: Propionate had opposing effects to butyrate on the velocity of propulsion of artificial clay fecal pellets in the guinea pig distal colon. These studies suggest that the movement of feces in the colon depends not only on distension but also on the chemical (i.e. dietary) composition of the feces and the microbiota.Grant Funding Source: Supported by DK34153