DPP4 and metabolic dysfunction-associated steatotic liver disease: Plasma acetoacetyl-CoA synthetase, dipeptidyl-peptidase 4, glutamine synthetase, and glutathione S-transferase concentrations are well-established biomarkers for NAFLD, which were selected from the plasma of the NAFLD model of laying hens and reported to be related to liver fibrosis and liver injury [15].