Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5751152 | Science of The Total Environment | 2017 | 8 Pages |
â¢MeHg exposure decreased K and BB-ratio, but increased HSIâ¢Muscle GST was induced by warming and MeHg, but not by their combinationâ¢Brain CAT was induced by warming and MeHg, but not by their combinationâ¢Liver GST and CAT were induced by MeHg, regardless of temperature exposureâ¢MeHg exposure did not enhance HSP70/HSC70 induction caused by warmingâ¢Increased temperature did not enhance AChE inhibition due to MeHg exposure
The ecotoxicological effects of methylmercury (MeHg) exposure have been intensively described in literature. Yet, it is still unclear how marine biota will respond to the presence of MeHg under climate change, namely ocean warming. The present study aimed to investigate, for the first time, fish condition [Fulton's K index (K), hepatosomatic index (HIS) and brain-to-body mass ratio (BB-ratio)] and several stress-related responses in an ecologically and commercially important fish species (Dicentrachus labrax) exposed for 28 days to dietary MeHg (8.0 mg kg-1 dw) and temperature increase (+ 4 °C). Results showed significant impairments on fish condition, i.e. up to 34% decrease on K, > 100% increase on HIS and 44% decrease on BB-ratio, compared to control conditions. Significant changes on tissue biochemical responses were observed in fish exposed to both stressors, acting alone or combined, evidencing the relevance of assessing possible interactions between different environmental stressors in ecotoxicological studies. For instance, muscle showed to be the least affected tissue, only revealing significant alterations in GST activity of MeHg-enriched fish. On the other hand, liver exhibited a significant induction of GST (> 100%) and CAT (up to 74%) in MeHg-enriched fish, regardless of temperature exposure, as well as decreased SOD activity (19%) and increased HSP70/HSC70 content (87%) in fish exposed to warming alone. Brain showed to be affected by temperature (69% of GST inhibition and > 100% of increased CAT activity), MeHg (> 100% of increased CAT activity, 47% of SOD inhibition and 55% of AChE inhibition), as well as by the combination of both (GST, SOD and AChE inhibition, 17%, 48% and 53%, respectively). Hence, our data provides evidences that the toxicological aspects of MeHg ca be potentiated by warmer temperatures, thus, evidencing the need for further research combining contaminants exposure and climate change effects, to better forecast ecological impacts in the ocean of tomorrow.
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