Response of juvenile crucian carp (Carassius auratus) to long-term ammonia exposure: feeding, growth, and antioxidant defenses

We investigated the effect of long-term ammonia exposure on feeding, growth, and some antioxidant parameters of liver, gill, and blood of juvenile crucian carp (Carassius auratus). In chronic exposure experiments, juvenile crucian carp were exposed to different concentrations of NH(3)-N (0.107, 0.214, 0.321, 0.428 mg L(-1)) for 45 days. Ammonia in the external environment significantly impaired the feeding and growth of juvenile crucian carp; additionally, enzymatic (superoxide dismutase (SOD) and catalase (CAT)) and non-enzymatic (glutathione (GSH) and malondialdehyde (MDA)) antioxidants in fish liver showed their protective functions significantly when oxidative stress occurred, but specific results were variable depending on time, ammonia concentration, and the tissue.