Crayfish shell peptide mediated Nrf2-PPARγ pathway to improve Cu-induced oxidative stress and lipid metabolism disorders in zebrafish

Bioactive peptides have rich nutritional value and multiple biological functions, which plays a crucial role in health of aquatic animals. In this study, we screened crayfish shell bioactive peptides based on molecular simulation, and analyzed their effects on oxidative stress and lipid metabolism disorders induced by excessive copper (Cu) diet in zebrafish. The protein hydrolysates were prepared by enzymatic hydrolysis of crayfish shell protein using trypsin, and the peptide sequences were determined by LC-MS/MS. The peptide LPLWPY (LY-6, the molecular weight is 787.94 Da) identified using peptide database PeptideRanker prediction and molecular docking showed strong antioxidant potential. In vivo experiments of zebrafish showed that dietary supplementation of LY-6 peptide significantly improved the adverse effects of oxidative stress and abnormal lipid metabolism caused by excessive Cu diet. The results of zebrafish primary hepatocytes revealed that LY-6 peptide promoted the antioxidant capacity and lipid metabolism normalization of cells by regulating nrf2 and pparγ signaling pathways, thereby reducing oxidative stress and lipid accumulation. The findings of this study revealed that antioxidant peptide LPLWPY with strong from crayfish shell protein hydrolysates could alleviate oxidative stress and lipid metabolism abnormalities caused by excessive Cu diet in zebrafish, thus could be recommended as a potential functional feed ingredient for fish nutrition. It provides theoretical basis and reference for aquatic animal nutrition regulation and development of novel feed additives. • Successfully screened the crayfish shell peptide LY-6 with strong antioxidant activities. • LY-6 peptide could alleviate oxidative stress and lipid metabolism abnormalities caused by excessive copper diet in zebrafish. • LY-6 peptide promotes antioxidant capacity and lipid metabolism normalization in primary hepatocytes of zebrafish by regulating nrf2 - ppar γ pathway.