3.3. Change in SCFAs from Baseline to Endpoint
SCFAs are a group of fatty acids that have a relatively small number of carbon atoms in their molecular structure. They are produced by the fermentation of dietary fibers by gut bacteria in the colon. SCFAs play important roles in gut health and overall metabolism, as they can provide energy to colon cells, influence immune function, and affect various physiological processes. Three SCFAs typically produced in larger quantities by gut microbiome are acetate, propionate, and butyrate and in smaller quantities are isobutyrate, isovalerate, valerate, and hexanoic acid [The concentration of SCFAs is graphically presented in Meanwhile, isobutyrate decreased in all three groups, whereas isovalerate decreased in the PS and the Control groups (−0.86 ± 0.63 and −0.80 ± 0.61 μmol/g, respectively) but increased in the WE group (0.79 ± 0.63 μmol/g), compared to baseline. Additionally, valerate increased in the WE group (0.19 ± 0.45 μmol/g) and the PS group (0.35 ± 0.45 μmol/g), but not the Control group, as it was decreased. Finally, total SCFA concentrations remained stable in the WE group, while they increased in the PS and Control groups. The PS group showed better attainment of a higher total SCFAs concentration compared to the WE and Control groups. However, we observed that concentrations of hexanoic acid, phenol, and p-cresol increased in the WE group but decreased in the PS group, compared to baseline. These specific phenol and p-cresol compounds derive from the metabolism of aromatic amino acids, such as tyrosine, phenylalanine, and tryptophan, originating from dietary proteins. In summary, the supplementation of whole eggs demonstrated the potential to preserve the constancy of gut microbiota metabolite levels yet concurrently appeared to heighten the precursors of potentially adverse metabolites, including phenol and p-cresol, also recognized as uremic toxins.