Effects of Ammonia Stress on the Antioxidant, Ferroptosis, and Immune Response in the Liver of Golden Pompano .

Ammonia is the main harmful environmental substance affecting fish culture. The liver is the immune and metabolic organ of fish, and its physiological homeostasis will affect the health of the organism. In this study, healthy golden pompano juveniles were exposed to 5 mg/L (A5) and 10 mg/L (A10) ammonia-N stress for 7 days and then the variation characteristics of the physiological homeostasis of the liver were analyzed at multiple biological levels. After ammonia stress, the liver showed obvious morphological changes and stress responses. Specifically, the oxidative stress indexes, such as the activities of the anti-superoxide anion generation capacity (ASC) and superoxide dismutase (SOD), were elevated in the A5 and A10 groups, while the glutathione peroxidase (GPx) activity and glutathione (GSH) content were disturbed; the relative expression levels of the and genes were increased in the A10 group, while the expressions of the and were decreased in the A5 and A10 groups. Ferroptosis related genes, such as the relative expressions of , , and were increased in the A5 and A10 groups, and were decreased in the A5 group but elevated in the A10 group, and , , , and were only increased in the A10 group. Inflammation related genes, such as , , and relative expression levels, were increased in the A10 group, was increased in the A5 and A10 groups, while was decreased in the A5 group but increased in the A10 group. Immune related genes, such as the expression levels of and , were increased in the A5 group but decreased in the A10 group. The integrated biomarker responses revealed that the hepatotoxicity of ammonia was concentration-dependent, and there was a high correlation between oxidative stress, ferroptosis, inflammation, and immune function changes. These results reveal the hepatotoxicity of ammonia stress on .