Used of fish immune parameters in environmental risk assessment
Résumé
Currently, for environmental risk assessment, multi-biomarker approach based on complementary parameters in term of substances, measured effect and biological integration levels were developed with some biochemical biomarkers, such as ethoxyresorufine-o-deethylase (EROD), glutathione-S-transferase (GST), glutathione peroxidase (GPx), lipid peroxidation (TBARS) and acetylcholinesterase (AChE). This approach allows integration of each environmental factor by restitution of qualitative and quantitative exposure variation. Nevertheless, use of these biochemical parameters was not enough to obtain clear information about fish and ecosystem health. Now, components of the fish immune system are considered as an attractive non-specific marker for environmental biomonitoring which integrate measure of exposure over time and may reflect the combined results of simultaneous contamination to several chemicals. Moreover, immune parameters were attractive due to their ecological importance by direct implications in individual fitness and population growth. In this way, the present work proposed the use of fish immunomarkers (i.e. apoptosis, necrosis and respiratory burst activity) together with more current biochemical biomarkers (i.e. EROD, GST, GPx, TBARS and AChE) to better evaluate fish health. The determination of a relationship between fish immune capacities and Fish Based Index (FBI), a useful indicator of ecosystem health by monitoring fish population, were also search. This work demonstrated that selected immune and biochemical biomarkers were able to discriminate sites in function of contaminant effect since sampling conditions were optimized to reduce biomarker variability and increase parameters robustness. In the multiple discriminant analysis, the sites were highly correlated with apoptosis, respiratory burst, GST and EROD activity. Moreover, the use together of biochemical and immune markers increase the percentage of fish correctly classed in each site (from 45 % with only biochemical data to 68 % with immune/biochemical values) and enhanced site separation (increase of dotted line from 5.51 to 11.71 after agglomerative hierarchical clustering). The relationship between immune capacities and FBI must further be demonstrated. So, this study argues for attractive utilization of immunomarkers for determination of environmental risk assessment in addition with a set of biochemical biomarkers currently used.