Comparative analysis of non-fermented and Saccharomyces boulardii-fermented whey: Peptidomic profiling, in silico bioactive peptide analysis, and in vivo evaluation of serum proteins and immune response

Fermentation of whey with Saccharomyces boulardii enhances the release of bioactive peptides with functional properties. This study assessed the antioxidant and anti-inflammatory potential of peptides from fermented whey using in silico and in vivo methodologies. Fermented whey underwent in vitro digestion, followed by peptidomic analysis. Bioinformatics tools identified 292 peptides in digested non-fermented whey and 715 peptides in digested fermented whey, with a greater proportion predicted as anti-inflammatory (40% vs. 50%). In the in vivo experiment, 15 cats were supplemented with either fermented or non-fermented whey for 20 days. The treated group showed a significant increase in IgA (8.71–15.3 mg dL⁻¹, p < 0.05), stable leukocyte levels, higher monocyte counts (0.65–0.90 × 10³ μL), and maintained ferritin concentrations, whereas the control group exhibited greater leukocyte variation and a ferritin decrease (17.0–12.8 μg L⁻¹). These results indicate that fermentation enhances whey's bioactivity, reinforcing its potential as a functional ingredient for immune and inflammatory regulation.