A recent investigation was performed to identify the potential biomarkers for NAFLD in laying hens, which indicates that the concentrations of plasma acetoacetyl-CoA synthetase (AACS), dipeptidyl-peptidase 4 (DPP4), glutamine synthetase (GLUL), and glutathione S-transferase (GST) can serve as biomarkers for NAFLD. The gene discussed is GLUL; the disease is metabolic dysfunction-associated steatotic liver disease.