| Summary: | International audience Since glass eels (Anguilla anguilla) are continuously exposed to contamination throughout their migratory journey through the estuaries, to a certain extent the fall in the population of this endangered species may be due to this exposure, which is especially acute in estuaries under high urban pressure. Metabolomics was used in this study to assess the effects of the previously selected contaminants, diazepam, and irbesartan, on glass eels. An exposure experiment to diazepam, irbesartan, and their mixture was carried out over 7 days followed by 7 days of depuration phase. After exposure, glass eels were individually killed using a lethal bath of anaesthesia, and then an unbiased sample extraction method was used to extract separately the polar metabolome and the lipidome. The polar metabolome was submitted to targeted and non-targeted analysis, whereas for the lipidome only the nontargeted analysis was carried out. A combined strategy using partial least squares discriminant analysis and statistical analysis (ANOVA, t-test, and fold-change analysis) was used to identify the metabolites altered in the exposed groups with respect to the control group. The results of the polar metabolome analysis revealed that glass eels exposed to diazepam-irbesartan mixture were the most impacted ones, with altered levels for 11 metabolites, some of them belonging to the energetic metabolism, which was confirmed to be sensitive to these contaminants. Additionally, seven lipids were also found ysregulated after exposure to the mixture. In the same vein, the same metabolomics approach was also used to find the differences in the metabolic profile of the two behavioural phenotypes of glass eels (migrants and nonmigrants). Nonmigrant glass eels showed lower overall metabolic values than migrant glass eels, and the lipidome analysis also showed alterations in the levels of eight cholesterol esters. These two findings offer new research perspectives to explain this facultative migration of glass eels and ...
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