In consistence with the observed increase in the Clostridum cluster XIva, as well as with another previous report [25], our study revealed a significantly

higher amount of butyrate in the animals fed diet containing either 3.3% or 7% pectin (Table 1 and Table 2). Butyrate ITF2357 is considered to be particularly beneficial to the gut mucosa because it induces apoptosis in cancer cell lines and functions as fuel for the enterocytes [26, 27]. Our results strongly suggest that the observed changes in the microbiota of the apple-fed rats should be attributed mainly to the pectin present in the apples. This is not surprising, since pectin is probably the component of the whole apple most likely to escape digestion and reach the cecal

environment. However, it should be noted that the content of pectin in the apples corresponds to only approximately 0.15% in the diet, and we find it likely that also other components present in the apples contribute in concert to the observed effect on the microbiota. click here In support of this, it has been reported that apple pectin and a polyphenol-rich apple concentrate had more effect on cecal fermentations and lipid metabolism in rats when fed together than when fed separately [25]. In the present study, we found a significant increase in GUS enzyme activity in cecum of the 7% pectin-fed rats. This is surprising, since it contradicts a number of other reports showing that dietary pectin reduces GUS activity in the intestinal environment [28–32]. However, in consistence with our observations, Thiamet G Rowland and coworkers [33] reported a significant increase of GUS activity in rats after consumption of a diet containing 5% pectin, and Bauer and coworkers [34] reported a pectin-induced

10-fold increase in fecal GUS activity in pectin-fed rats. Additionally, Dabek et al. [35] reported that GUS activity is preferentially found in members of the Firmicutes phylum, whose populations were increased in the 7% pectin fed rats. GUS is generally considered as a biomarker for colon cancer development, since it has the potential to activate liver glucuronated toxins and mutagens [36]. However, GUS may in this way also activate beneficial compounds, such as liver glucuronated plant polyphenols [37]. Thus, the interaction between dietary pectin, GUS activity and colon carcinogenesis remains to be clarified. Conclusions The reduction of pH, potentially caused by the increased SCFA production, and the increased cecal weight observed in the pectin-fed rats (7% in the diet) indicate increased cecal fermentation, which is considered beneficial for gut health.