Responses to β-alanine and carnosine supplementation of mussel Mytilus coruscus as revealed by UPLC–MS/MS based untargeted metabolomics

Abstract Histidine-containing dipeptides (HCDs) have been demonstrated with important physiological functions in vertebrates. This study was executed to investigate the contents and metabolic profiles of HCDs in an invertebrate, the mussel Mytilus coruscus was selected. The carnosine/anserine analysis indicated that M. coruscus contain anserine with a higher concentration than that of carnosine, and the increases in HCDs concentrations due to β-alanine injection and carnosine injection were observed, confirming that Mytilus belongs to a species with the ability of HCDs synthesis. Further metabolomics analysis was performed based on ultra-performance liquid chromatography-tandem mass spectrometry technology to explore the effects of β-alanine injection and carnosine injection, respectively, on the whole mussel tissue. A total of 1,868 significantly differential metabolites (SDMs) were detected between the β-alanine injected, carnosine injected, and the control M. coruscus groups. The SDMs induced by β-alanine injection were enriched mainly in energy metabolism, lipid metabolism, and amino acid metabolism of mussel, while carnosine injection mainly disrupted arachidonic acid metabolism, steroid hormone biosynthesis, and retinol metabolism in the mussel. The activities of antioxidant enzymes from the whole mussel tissue extracts before and after β-alanine/carnosine injection were measured, and both treatments showed significant elevation of enzymatic activities of superoxide dismutase and catalase. Considering the positive effects of β-alanine injection on mussel metabolism, this study provided a clue for the potential application of β-alanine supplementation in mussel farming.