Butyrate and propionate production from D-mannitol in the large intestine of pig and rat

Fermentation of D-mannitol and the bacteria responsible for it were analyzed by 13C-NMR spectroscopy and amplified ribosomal restriction analyses (ARDRA) on intestinal bacteria in pig cecal digesta and in a rat in vivo feeding trial. [1-13C]-Mannitol was fermented by pig cecal digesta mainly to [2-13C]-propionate, [3-13C]-propionate, [2-13C]-butyrate, and [4-13C]-butyrate. Dietary D-mannitol at a 5% level induced significantly higher cecal butyrate concentration in the rat model. The evolution of rat fecal bacteria due to feeding with D-mannitol suggested the involvement of a lactate-utilizing butyrate producer, Clostridium indolis, in the stimulation of butyrate production. Rat intestinal microbiota is often difficult to extrapolate to that of humans, but the stimulation of the lactate-utilizing butyrate producers and propionate producers was suggested by the 13C-NMR spectroscopy of the end products of pig cecal fermentation and ARDRA on rat fecal bacteria. These results suggest the potential of D-mannitol as a prebiotic, which modifies large intestinal fermentation to produce more butyrate and propionate.