Acute toxicity of manganese in goldfish Carassius auratus is associated with oxidative stress and organ specific antioxidant responses

Manganese is a relatively common, yet poorly studied element in freshwater ecosystems, where it can be significantly bioconcentrated. The knowledge about the mechanisms of Mn toxicity on fish health is still limited. The aim of the present study was to assess the potential induction of oxidative stress and the antioxidant response after a 96 h waterborne Mn-exposure (at 0.1 and 1 mM) in gill, kidney, liver and brain of goldfish (Carassius auratus). Mn 1 mM induced an increase of lipid hydroperoxides, superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities in all tissues with the exception of SOD inhibition in the brain. Particular response of catalase (CAT) was indicated—its inhibition in the liver and kidney, but activation in the gill. Exposure to Mn 0.1 mM provoked most prominent changes in the liver and did not change the indexes in brain. These results strongly suggest that Mn exposure caused a generalized oxidative stress in the fish and revealed an organ specific antioxidant response involving a differential modulation of the SOD, CAT and GPx activities.

▶ Oxidative stress is involved in Mn toxicity in fish. ▶ Mn induced an organ specific antioxidant response in liver, kidney, gill and brain. ▶ A pattern of compensation between the CAT and GPx activities was observed. ▶ The antioxidant potential of brain was weak compared to that of other organs.