Effects of increased salinity on oxidative stress status in the freshwater mussel Unio ravoisieri

ABSTRACT

Freshwater salinisation is an environmental challenge that threatens freshwater species survival. We investigated the influence of increased water salinity on the oxidative status in the bivalve Unio ravoisieri. Under laboratory conditions, 3 sodium chloride (NaCl) concentrations (2.5, 5 and 7.5) were tested for 7 days compared to a control salinity concentration (0.7), mimicking sampling site condition. Biomarkers of oxidative stress including superoxide dismutase (SOD) and catalase (CAT) activities and glutathione (GSH) and malondialdehyde (MDA) were assessed in gills and digestive gland. Furthermore, acetylcholinesterase (AChE) activity was assessed, as a marker of neurotoxicity. Findings showed that the highest concentration of salinity has significantly disturbed oxidative metabolism in both gills and digestive gland by modulating the activity of CAT and the levels of GSH and MDA compared to the control condition (all p < 0.05). Moreover, significant enhance of AChE activity has been found in both gills and digestive gland with the three concentrations (all p < 0.05), except for 2.5 in gills (p > 0.05) compared to control condition. Overall, our study has shown that water salinity constitutes a serious challenge for Unio ravoisieri, and that CAT activity could be used as a sensitive marker for the evaluation of the effect of freshwater salinisation on freshwater.

KEYWORDS:

• Climate change
• salinity
• oxidative stress
• freshwater mussels
• Unio ravoisieri
• biomarkers

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Amal Lassoued

Amal Lassoued is a PhD student doing a thesis dealing with the effects of abiotic factors on freshwater mussels.

Noureddine Khalloufi

Noureddine Khalloufi is a hydrobiologist specialized in freshwater mollusks including gastropods, stygobite gastropods and mussels. The research works focus on taxonomy, Ecotoxicology, Biogeography and conservation, in particular, for North African aquatic ecosystems.

Wiem Saidani

Wiem Saidani is a biologist and environmentalist whose work is focused on aquatic toxicology and the biological effects of xenobiotics in marine and freshwater species. Her recent research and writing are a case study with phosphate base compounds.

Abdelhafidh Khazri

Abdelhafidh Khazri does researcher in Environmental Ecotoxicology at the University of Carthage Tunisia. He has more than 17 years experience in environmental biomonitoring and chemical analysis research. His research focuses on ecology and ecotoxicology, with an emphasis on extreme, polluted or marine and freshwater ecosystems.

Neziha Ghanem-Boughanmi

Néziha Ghanem-Boughanmi is a Professor in Plant Sciences whose research theme is salinity and the induced secondary oxidative stress at cellular level.

Jaouad Bouayed

Jaouad Bouayed is an associate Professor at the Université de Lorraine, and he is a neuroscientist by training. His scientific focus rests on investigating the effects of nutrients, phytochemicals and dietary contaminants on brain.

Mossadok Ben-Attia

Mossadok Ben-Attia is a Professor in Biostatistic with expertise also in activity concept and ecological risk of emerging substances.