EFFECT OF DIETARY CHITOSAN ON FECAL MICROBIOTA AND FECAL METABOLITES OF HUMANS

The effects of chitosan (CS) intake on faecal microbiota and faecal metabolites were studied in eight healthy volunteers who consumed a mixed free choice diet (control diet) for 2 wks before and after CS intake (CN-1 and CN-2 period, respectively), and the same diet with an additional 3 g CS/day for 1 wk (CS-1 period) and 6 g CS/day for 1 wk (CS-2 period). During CS intake, there was no detectable change in the concentrations of the microorganisms examined throughout the experimental periods. However, the frequency of occurrence of lecithinase-negative clostridia decreased significantly (P<0.05). Faecal concentrations of ammonia, phenol, p-cresol and indole were significantly reduced (P<0.05). The values of total volatile fatty acid showed a significant increase (P<0.01) from 14.3 +/- 3.2 mg/g to 20.3 +/- 2.4 mg/g on day 14 of the intake, with a significant increase of acetic (P<0.05) and propionic (P<0.01) acids, and a decrease of iso-valeric acid (P<0.05) during the intake. The moisture and weight of the faeces were slightly increased during the intake, while the pH values were slightly decreased.