Cadmium-induced oxidative stress, histopathology, and transcriptomic changes in the hepatopancreas of Fenneropenaeus merguiensis

Cadmium (Cd) is a threatening heavy metal pollutant to aquatic organisms. The hepatopancreas plays a crucial role in combating environmental stress and enhancing the immune defense of aquatic species. The exact mechanism behind the damage induced by Cadmium in the hepatopancreas of Fenneropenaeus merguiensis is unclear. Thus, this study aimed to elucidate the potential mechanisms of Cadmium's impact on the hepatopancreas of F. merguiensis through physiological, histological, and transcriptomic analyses. After 72 h of F. merguiensis exposure to the 0.5 mg/L concentration of cadmium results in the reduction of superoxide dismutase and catalase activities, coupled with an increase in hydrogen peroxide and malondialdehyde levels, which leads to damage in both the gills and hepatopancreas. This causes severe histological changes in the gills and hepatopancreas of F. merguiensis, characterized by irregularities in the gill filaments and ruptures in the basal membrane of the hepatopancreas. Comparative transcriptomic analysis of F. merguiensis revealed the upregulation of several genes associated with pathways related to metabolism (ko01100), antigen processing and presentation (ko04612), and cell apoptosis (ko04215), indicating adaptive response mechanisms to Cadmium exposure. Transcriptomic analysis also showed that Cadmium exposure induced the expression of genes related to detoxification and apoptosis, such as heat shock proteins, metallothionein, and Caspase-3, suggesting adverse effects on the normal physiological functions of F. merguiensis. Our study provides comprehensive insights into the toxicological mechanisms and impacts of Cadmium on F. merguiensis.