Aluminum Toxicity in the Flag Tetra Hyphessobrycon heterorhabdus (Teleostei:Characidae) at Environmentally Relevant Concentrations in the Amazon Region

Aluminum (Al) is a metal that occurs naturally in the Amazon region in high concentrations, which may increase due to the effects of mining. As it is a pro-oxidant and generates oxidative stress, we investigated biochemical biomarkers in the gills, liver and muscle of the native fish Hyphessobrycon heterorhabdus after exposure to different concentrations of Al (0.5 mg/L, 1 mg/L and 10 mg/L) in an acidic medium (pH = 5) for 96 hours. Biomarkers such as total antioxidant capacity and glutathione S-transferase activity showed no significant differences in the organs studied. The liver showed a uniform response, with no change in lipid peroxidation levels (LPO). In the gills, fish exposed to 1 mg/L showed a decrease in LPO and a subsequent increase at 10 mg/L, indicating metal toxicity at the highest concentration and an induction of antioxidant defenses at 1 mg/L. In muscle, exposure to 1 mg/L induced an increase in LPO. However, in the group exposed to 10 mg/L, the fish stabilized the damage level. We conclude that H. heterorhabdus is tolerant to acidity and the environmental concentration (0.5 mg/L) and suffers oxidative stress at higher concentrations, but with different responses for each tissue analyzed.