GPT and fatty liver disease: A series of biological assessments were conducted, including systemic metabolic evaluations (body weight, serum alanine aminotransferase (ALT)/aspartate aminotransferase (AST), and lipid/glucose levels), hepatic steatosis (hematoxylin and eosin (H&E) staining), intestinal microbiome characterization (16S rRNA gene genomic analysis), and comprehensive metabolite profiling of cecal contents (non-targeted metabolomics).