Toxicity of chronic copper exposure on Chinese mitten crab (Eriocheir sinensis) and mitigation of its adverse impact by myo-inositol

Copper (Cu) is a widespread pollutant in water and has posed a significant threat to aquatic animals' health. It is essential to find a strategy to reduce the adverse effects of copper on aquatic organisms. This study investigated the role of myo-inositol (MI) in the reducing chronic toxicity induced by copper in Chinese mitten crab (Eriocheir sinensis). Two diets, including 0 mg/kg and 1600 mg/kg MI were fed to crabs exposed to 0 μg/L and 40 μg/L Cu²⁺ for 7 weeks. Dietary MI could improve the decreased weight gain and specific growth rate induced by copper exposure. Copper exposure increased the copper levels in the whole body and hepatopancreas, increased the malondialdehyde content, and suppressed the antioxidant enzymes system of the crabs. Simultaneously, copper exposure induced DNA fragmentation, decreased the gene expression/activities of immune-related genes/enzymes and the expression of the anti-apoptotic genes, and increased the gene expression of heat shock protein 70 and pro-apoptotic genes. The mitochondrial dysfunction, increased the gene expression of inflammation-related genes and caused the higher activity of damage-related enzymes in the crabs under Cu exposure. The administration of dietary MI markedly ameliorated the copper-induced oxidative stress, immune and hepatopancreas damage, mitochondrial dysfunction, apoptosis and inflammatory responses. This study indicates that dietary MI supplementation can effectively alleviate the negative effect of chronic copper exposure on E. sinensis.