Toxicological effects of sulfamethoxazole (SMX) and tire micro-particles (TMPs), alone or in combination, on the hepatopancreas of Litopenaeus vannamei

As the metabolic center of crustacean invertebrates, hepatopancreas plays a crucial role in metabolic detoxification and nutrient storage. Although sulfamethoxazole (SMX) and tire micro-particles (TMPs) are emerging marine pollutants, their combined hepatotoxic effects on lipid metabolism in crustaceans remain poorly understood. In this study, Litopenaeus vannamei were exposed to SMX and TMPs for 14 days. Hepatopancreatic lesions, lipid metabolism parameters, SMX bioaccumulation, and transcriptomic analysis were evaluated. Results revealed that SMX and TMPs co-exposure induced: (1) significant histological damage to hepatopancreas, accompanied by elevated levels of hepatopancreatic lesion markers; (2) a marked increase in lipid accumulation and altered fatty acid composition in hepatopancreas; (3) enhanced activities of lipid synthesis enzymes, increased triglyceride and total cholesterol levels, and reduced lipase activity; (4) dysregulation of metabolic pathways, characterized by upregulation of fatty acid synthesis-related pathways and downregulation of fatty acid decomposition-related pathways, alongside disruption of oxidative stress and detoxification pathways. Comparative analysis illustrated that SMX and TMPs co-exposure exhibited more toxicity than individual treatments. These findings demonstrated that SMX and TMPs synergistically impair hepatopancreatic function via lipid metabolism disruption and bioaccumulation, posing a potential threat to crustacean health and significant ecological risks in marine environments.