GABA and feeding: A pathway to alleviate LPS-induced anorexia in northern snakehead (Channa argus)

Fish aquaculture profitability largely hinges on growth performance, which is governed by voluntary feed intake. Multiple biotic and abiotic stressors in rearing environments trigger inflammatory responses and suppress appetite, resulting in reduced feeding and growth loss in farmed fish. Lipopolysaccharide (LPS), a cell-wall component of Gram-negative bacteria, can induce anorexia via neuro-intestinal inflammation. γ-aminobutyric acid (GABA) acts as a key neurotransmitter modulating appetite and stress tolerance, yet its mechanistic actions against LPS-induced anorexia remain poorly characterized in Channa argus (northern snakehead). This study aimed to clarify whether dietary GABA relieves LPS-induced feeding suppression and to decipher the underlying molecular mechanisms through combined in vitro cell assays and in vivo feeding challenge trials. For the in vitro component, primary mixed hypothalamic neural cells (containing neural stem cells, astrocyte like cells and mature neurons) isolated from northern snakehead were subjected to LPS, GABA and combined GABA + LPS treatments. LPS exposure activated inflammatory signalling, up regulated pro-inflammatory mediators (tnf-α, il-1β) and anorexigenic genes (pomc, leptin), and down regulated orexigenic transcripts (npy, agrp). GABA co-treatment counteracted these molecular perturbations, restoring appetite related gene expression and reversing LPS-induced neuronal metabolic dysregulation. Untargeted metabolomics further showed that neuroactive ligand-receptor interaction, taste transduction and amino-acid metabolic pathways were majorly modified by LPS and GABA interventions. In the in vivo feeding trial, juvenile northern snakehead were fed graded dietary GABA (0–150 mg/kg) for 8 weeks, followed by intra anal LPS administration to establish an in vivo anorexia model. Quadratic regression indicated that the optimal dietary GABA dosage for maximum growth was 110.01–120 mg/kg. Pre-supplementation with GABA ameliorated LPS-triggered growth retardation. GABA normalized hypothalamic GABA-synthase (GAD, DAO) activities, restored intestinal endocrine balance by elevating ghrelin and decreasing cholecystokinin (CCK), IL-1β and TNF-α. Transcriptional profiling of hypothalamic and intestinal tissues confirmed that GABA remodelled the expression of feeding‑ and inflammation‑associated genes in both central and peripheral tissues. Collectively, dietary GABA mitigates LPS‑induced neuro‑intestinal inflammatory disturbance and re‑balances central‑peripheral appetite signalling in northern snakehead. This work provides molecular evidence supporting GABA as an eco-friendly feed additive to improve feed intake and growth of farmed northern snakehead exposed to inflammatory stress.