Data Sheet 1_Multi-omics profiling identifies intestinal microbial shifts and tissue-specific immunometabolic changes associated with experimental Nocardia seriolae challenge in hybrid sturgeon (Acipenser baerii♀ × Acipenser schrenckii♂).docx

ITS profiling also showed differences in fungal diversity and community composition among groups, although no fungal genus remained significant after false discovery rate (FDR) correction. RNA-seq revealed tissue-specific transcriptional responses, with the liver showing a larger number of differentially expressed genes than the spiral valve intestine. Hepatic pathways were mainly related to immune recognition, complement and coagulation cascades, antigen processing, and stress-related responses, whereas intestinal transcriptional changes involved phagosome, cell adhesion, and mucosal immune-related pathways.

Metabolomic analysis showed tissue- and stage-related metabolic changes, with clearer pathway-level evidence in the spiral valve intestine at 14 dpi, particularly involving amino acid metabolism and protein digestion and absorption. Representative metabolites related to lipid and bile acid metabolism, carnitine-associated lipid utilization, energy metabolism, and purine/nicotinamide metabolism also showed sampling-stage-related variation.

Genus–metabolite association analysis further identified candidate relationships between intestinal bacterial genera and representative metabolites.</p>Discussion<p>These findings provide a multi-omics view of intestinal microbial and tissue-specific immunometabolic changes associated with experimental N. seriolae challenge in hybrid sturgeon. The candidate genus–metabolite relationships provide a basis for future targeted validation of microbial and metabolic features associated with nocardial infection.</p>