Dietary paeonol addition relieves the detrimental effect of waterborne cadmium on fish growth and liver health in largemouth bass (Micropterus salmoides).

This study aimed to explore the effect of paeonol (PAE) on growth performance and liver health in largemouth bass (Micropterus salmoides) exposed to cadmium (Cd). Five experimental groups were designed: one control group reared in clean water and fed a basal diet (CONT), alongside four cadmium-exposed groups maintained in 2.75 mg/kg Cd-containing water and fed the basal diet supplemented with 0 mg/kg (Cd), 100 mg/kg (PAE100-Cd), 200 mg/kg (PAE200-Cd), and 400 mg/kg PAE (PAE400-Cd), respectively. The experiment lasted for 56 days. The results showed that Cd exposure significantly inhibited the growth performance of largemouth bass, caused liver dysfunction and pathological tissue damage, led to oxidative stress, inflammatory response, and apoptosis, and induced the expression of the epidermal growth factor receptor (ErbB1)-extracellular signal-regulated kinase (ERK) pathway genes. However, PAE supplementation (200-400 mg/kg) significantly improved the growth performance of largemouth bass. In addition, 200-400 mg/kg PAE reduced the serum levels of hepatic injury biomarkers (AKP, ALT, LDH, and AST) and alleviated histopathological lesions. Furthermore, PAE200-Cd increased the activities of superoxide dismutase (SOD) and catalase (CAT) and reduced malondialdehyde (MDA) levels in the liver. Moreover, PAE200-Cd and PAE400-Cd down-regulated the expression of interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), nuclear factor kappa-B p65 (NF-κB p65), ErbB1, and cellular FBJ osteosarcoma oncogene (C-fos) in the liver. PAE200-Cd significantly increased the expression of cytochrome P450 family 1 subfamily A (CYP1A1) and downregulated the expression of metallothionein (MT) and cysteine-aspartic proteases-9 (Caspase-9). The optimal PAE dose for counteracting waterborne Cd-induced growth impairment and hepatic oxidative stress was 173.37-173.90 mg/kg for largemouth bass.