Multivariate analysis of biochemical responses using non-invasive methods to evaluate the health status of the endangered blackfin goodeid (Girardinichthys viviparus)

The study of endangered fish species is quite a complex process that involves, in the worst case, the sacrifice of specimens. To solve this ethical problem, some laboratory studies have been conducted in the skin mucus layer (SML) on fish species with valuable results. However, to date research evaluating a panel of biomarkers in the SML of wild fish does not exist. In the current study we assessed the effects of pollutants (E₁, E₂, E₃, EE₂, BPA, NP, OP, Cu, Fe, Mn, Pb, Zn, C₁₀H₈, C₁₆H₁₀, C₁₈H₁₂, B[a]P C₂₀H₁₂, B[k]F C₂₀H₁₂, C₂₂H₁₂) upon a panel of biomarkers [O₂, H₂O₂, lipid peroxidation (as TBARS), carbonyl proteins (RC=O), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), vitellogenin (VTG) and metallothionein (MT)] evaluated in the SML of the wild endangered Girardinichthys viviparus inhabiting two polluted lakes in Mexico Valley. Possible relationships were analyzed by principal components analysis (PCA) and redundancy analysis (RDA). The main finding was a clear induction of pro-oxidant forces (ROS) in the SML, probably related to biotransformation of estrogenic and phenolic compounds, in addtion to a redox process of Cu and Fe. As a consequence, oxidative tissue damage (TBARS and RC=O) and increases in antioxidant defenses were observed. In male fish, VTG was associated with bisphenol A (BPA) apparently potentiated by Cu and Fe water concentrations; meanwhile, in female fish VTG was linked to estrogens. By PCA, MT was correlated with Fe and Cu; however, it was not linked with diminution of oxidative stress. For the first time have demonstrated the useful of the SML using a panel of biomarkers for monitoring the health of wild fish.