title: Evidence of trophic transfer of microcystins from the gastropod Lymnaea stagnalis to the fish Gasterosteus aculeatus.
abstract: According to our previous results the gastropod Lymnaea stagnalis exposed to MC-producing cyanobacteria accumulates microcystins (MCs) both as free and covalently bound forms in its tissues, therefore representing a potential risk of MC transfer through the food web. This study demonstrates in a laboratory experiment the transfer of free and bound MCs from L. stagnalis intoxicated by MC-producing Planktothrix agardhii ingestion to the fish Gasterosteus aculeatus. Fish were fed during five days with digestive glands of L. stagnalis containing various concentrations of free and bound MCs, then with toxin-free digestive glands during a 5-day depuration period. MC accumulation was measured in gastropod digestive gland and in various fish organs (liver, muscle, kidney, and gills). The impact on fish was evaluated through detoxification enzyme (glutathion-S-transferase, glutathion peroxydase and superoxyde dismutase) activities, hepatic histopathology, and modifications in gill ventilation, feeding and locomotion. G. aculeatus ingestion rate was similar with intoxicated and toxin-free diet. Fish accumulated MCs (up to 3.96±0.14μgg-1DW) in all organs and in decreasing order in liver, muscle, kidney and gills. Hepatic histopathology was moderate. Glutathion peroxydase was activated in gills during intoxication suggesting a slight reactive oxygen species production, but without any impact on gill ventilation. Intoxication via ingestion of MC-intoxicated snails impacted fish locomotion. Intoxicated fish remained significantly less mobile than controls during the intoxication period possibly due to a lower health condition, whereas they showed a greater mobility during the depuration period that might be related to an acute foraging for food. During depuration, MC elimination was total in gills and kidney, but partial in liver and muscle. Our results assess the MC transfer from gastropods to fish and the potential risk induced by bound MCs in the food web.
authors.affiliation: Unité de Recherche Interactions Animal-Environnement, EA 4689, Bat 18, Campus du Moulin de la Housse, BP 1039, 51687 REIMS Cedex 2, France. Electronic address: emilie.lance@univ-reims.fr.
authors.forename: Emilie
authors.initials: E
authors.lastname: Lance
authors.affiliation: UMR CNRS 6553, University of Rennes 1, 263 Avenue du Général Leclerc, CS 74205, 35042 Rennes Cedex, France.
authors.forename: Anais
authors.initials: A
authors.lastname: Petit
authors.affiliation: National Institute for Industrial Environnement and Risks, Verneuil sur Halatte, France.
authors.forename: Wilfried
authors.initials: W
authors.lastname: Sanchez
authors.affiliation: UMR INRA Bio3P, Université de Rennes 1, 263 Avenue du Général Leclerc, CS 74205, 35042 Rennes Cedex, France.
authors.forename: Christelle
authors.initials: C
authors.lastname: Paty
authors.affiliation: UMR CNRS 6553, University of Rennes 1, 263 Avenue du Général Leclerc, CS 74205, 35042 Rennes Cedex, France.
authors.forename: Claudia
authors.initials: C
authors.lastname: Gérard
authors.affiliation: UMR CNRS 6553, University of Rennes 1, 263 Avenue du Général Leclerc, CS 74205, 35042 Rennes Cedex, France.
authors.forename: Myriam
authors.initials: M
authors.lastname: Bormans
keywords: Accumulation; Cyanotoxin; Fish; Food web; Free and bound microcystins; Gastropod; Transfer