Whey protein hydrolysate maintains the homeostasis of muscle metabolism in exercise mice and releases potential anti-fatigue peptides after gastrointestinal digestion.

Whey protein hydrolysate (WPH) has been proven to possess anti-fatigue effects, but its regulatory mechanism on muscle metabolism in exercise mice is unclear. In the present study, the effects of WPH on muscle metabolites in mice before and after exercise were explored using metabolomics techniques. Results showed that 34 muscle metabolites were significantly altered by exercise in the WPH group, which was less than 71 in the WP group and 101 in the control group. Specifically, supplementation of WPH significantly increased the levels of amino acid and carbohydrate metabolites (i.e., 1-methylhistamine, guanidoacetic acid, melibiose, and xylulose 5-phosphate) pre-exercise, thereby delaying energy depletion and maintaining metabolic homeostasis during exercise. Furthermore, simulated gastrointestinal digestion (SGID), peptidomics and bioinformatics tools were employed to screen potential peptides in WPH. A total of 37 peptides with 2–5 residues in WPH were resistant to SGID (peak intensity > 10⁵). Among them, YGLF showed favorable potentials in physicochemical property, bioavailability, bioactivity, SwissTargetPrediction, and molecular docking. In addition, the anti-fatigue activity of YGLF was evaluated in vivo. YGLF (100 mg/kg) significantly increased the contents of glucose, glycogens, and amino acids and decreased the levels of lactate and urea nitrogen in mice after exercise. These findings may serve as a reference for the screening of anti-fatigue peptides. [Display omitted] [ABSTRACT FROM AUTHOR]