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(275) Sub-cellular to individual organisation levels: the first step indicating ecological relevance of biomarkers. Castro, Bruno1,2, Sobral, Olímpia1,2, Ribeiro, Rui2, Guilhermino, Lúcia 1,3, 1 2 3 ABSTRACT- Biochemical biomarkers are commonly recognised as highly sensitive indicators of early exposure to contaminants. However, many authors discuss the ecological relevance of contaminant-induced alterations at the sub-individual or sub-cellular level. The aim of this study was to validate, in an actual field situation, the use of biomarkers as ecologically relevant sublethal parameters, by comparing their responses with those of individually based endpoints (lethality and feeding inhibition). For such a purpose, an in situ bioassay with guppy (Poecilia reticulata) was performed in an acid mine drainage impacted reservoir. Three contaminated sites were chosen along the contamination gradient, and an upstream lagoon was chosen as a reference site. Lethality, biomarker response (acetylcholinesterase, lactate dehydrogenase and glutathione S-transferase) and post-exposure feeding were analysed at the end of the assay (96 h). Feeding experiments were performed after the 96-h in situ exposure period, and consisted of a behavioural assay and a feeding trial. Significant alterations were observed in AChE and LDH in the most contaminated sites, and fish exposed in those sites also exhibited inhibition of feeding. This study has shown that biomarker responses can be related to behavioural changes and inhibition of feeding, thus being significant at higher organisation levels. Research must continue, broadened to other contamination sources as well as to other species, so that biomarkers can be more frequently implemented in risk assessment studies, where rapid and relevant responses are required. Key words: Poecilia reticulata, biomarkers, feeding inhibition, ecological relevance |
