Bacillus amyloliquefaciens Alleviates Clothianidin-Induced Liver Oxidative Stress and Growth Suppression in Goslings.

Clothianidin (CLO), a widely used neonicotinoid insecticide, may pose a health risk to waterfowl through contaminated feed ingredients and agricultural residues. This study investigated whether dietary Bacillus amyloliquefaciens (BA) could alleviate CLO-induced growth suppression and liver oxidative injury in goslings. Fourteen-day-old Holdobagy goslings were assigned to five treatments for 21 days: control, 2.5 mg/kg CLO, 2.5 mg/kg CLO plus 60 ppm BA, 10 mg/kg CLO, and 10 mg/kg CLO plus 60 ppm BA. CLO exposure reduced final body weight and average daily gain, increased liver index, elevated serum alkaline phosphatase (AKP), aspartate aminotransferase (AST), and malondialdehyde (MDA) levels, and decreased liver total antioxidant capacity (T-AOC) and superoxide dismutase (SOD) activities (p < 0.05). Histological analysis further showed hepatocyte disorganization, vacuolar degeneration, congestion, and inflammatory infiltration, which were partially alleviated by BA supplementation. Serum untargeted metabolomics showed clear separation among treatment groups. CLO exposure altered 130 and 215 differential metabolites at the low and high doses, respectively, whereas BA supplementation regulated 115 and 170 differential metabolites under the corresponding CLO backgrounds (p < 0.05). These metabolites were mainly enriched in amino acid metabolism, ATP-binding cassette (ABC) transporters, purine metabolism, riboflavin metabolism, glutathione metabolism, glycerophospholipid metabolism, and fatty acid biosynthesis/degradation pathways. Liver transcriptomic analysis identified 761 and 1283 differentially expressed genes after low- and high-dose CLO exposure, respectively, while BA supplementation altered 338 and 440 genes (p < 0.05). Enriched pathways included peroxisome proliferator-activated receptor (PPAR) signaling, fatty acid metabolism, pyruvate metabolism, glycolysis/gluconeogenesis, pentose phosphate pathway, glutathione metabolism, cell adhesion molecules, and adipocytokine signaling. This study adds new evidence on the protective role of BA against CLO-induced toxicity in goslings by combining physiological, histological, metabolomic, and transcriptomic observations. Overall, BA partially mitigated CLO-induced growth inhibition and liver oxidative injury, potentially through coordinated regulation of redox homeostasis, lipid and energy metabolism, and liver metabolic remodeling.