An integrated biomarker assessment of biochemical responses in a freshwater fish species after vanadium pentoxide (V₂O₅) exposure

Vanadium (V) is a toxicant becoming increasingly concentrated in freshwater with the potential to affect aquatic organisms. Vanadium pentoxide (V₂O₅), accumulated in fish, can act as an oxidizing agent and cause oxidative damage. To determine the effects of V₂O₅ on exposed adult Oreochromis mossambicus, acute exposure experiments were conducted. Bioaccumulation and biomarker analyses were performed on various excised tissues of the exposed fish. As expected, accumulated V concentrations in the gills increased as the exposure concentration increased. Gill tissue accumulated more vanadium than muscle tissue. Metallothionein content increased in the highest concentrations compared to the lower concentrations, therefore showing that metallothionein proteins were attempting to sequester V₂O₅ in the tissues. Superoxide dismutase (SOD) showed an excitation at lower concentrations and inhibition as the exposure concentrations increased, possibly due to ROS detoxification. Catalase activity decreased from the first exposure concentration to the last concentration; this could have been due to SOD compensation. Protein carbonyl concentration decreased as the concentrations of V₂O₅ increased, indicating an inhibition of protein oxidation. The IBRv2 comparison revealed the biochemical responses caused by V₂O₅ more effectively than traditional statistical analysis.