To evaluate whey functional ingredients (WFI) as source of non-digestible nutrients for fecal bacteria from donors with intestinal bowel disease (IBD) in vitro.
The WFI whey protein isolate (WPI), glycomacropeptide (GMP) and a galacto-oligosaccharide rich whey protein concentrate (GOS-W), and peptone (control) were subjected to in vitro digestion (IVD) and freeze dried to be used in fecal culture medium. Fecal de-identified samples from 10 healthy and 9 mild-moderate IBD subjects were subjected to in vitro fecal fermentation for 24 h. Fecal bacteria and culture supernatants were analyzed using standard analytical procedures to quantify bacteria relative abundance, and metabolites in culture supernatants. Short chain fatty acids were quantified in fecal supernatants by HPLC analysis. HT29-MTX intestinal cells were treated with sterile-filtered fecal culture supernatants (2.5% v/v) to assess production of reactive oxygen species (ROS) using 10 μM of 2′7′ dichlorodihydrofluorescein diacetate (H2DCFDA) reagent.
Among the WFI tested, WPI tended to modulate the relative abundance of bacteria that have been reported to decrease during IBD conditions such as R. hominis, R. intestinalis and R. torques. Metabolites in fecal culture supernatants showed that propionic acid concentrations in IBD controls were higher than healthy controls and WFI fermentations decreased those levels making them similar to the healthy controls. In contrast, the concentration of lactic acid tended to be higher in the GOS-W fecal culture supernatant, but only reached significance (P > 0.05) when compared to GMP-supplemented medium. No differences in acetic acid and butyric acid concentrations were found between IBD controls and WFI treatments. Results also showed that WPI, GOS-W and GMP fecal culture supernatants prevented ROS production in HT29-MTX cells when compared to their respective IBD-controls.
WPI favorably modulated the relative abundance of bacteria relevant in IBD while all WFI metabolites produced after in vitro fecal fermentation mitigated oxidative stress. These findings suggest the potential of WFI to moderate adverse conditions associated with IBD.
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