Rainbow trout (Oncorhynchus mykiss) chemosensory detection of and reactions to copper nanoparticles and copper ions. (May 2020)

• Record Type: Journal Article
• Authors: Razmara, Parastoo; Sharpe, Justin; Pyle, Gregory G.
• Is Part Of: Environmental pollution. Volume 260(2020)
• Publication Date: 2020-05
• Subjects: Copper nanoparticles -- Chemosensory detection -- Behavioral avoidance -- Rainbow trout; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2020.113925
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Copper is known to interfere with fish olfaction. Although the chemosensory detection and olfactory toxicity of copper ions (Cu 2+ ) has been heavily studied in fish, the olfactory-driven detection of copper nanoparticles (CuNPs)—a rapidly emerging contaminant to aquatic systems—remains largely unknown. This study aimed to investigate the olfactory response of rainbow trout to equitoxic concentrations of CuNPs or Cu 2+ using electro-olfactography (EOG, a neurophysiological technique) and olfactory-mediated behavioural assay. In the first experiment, the concentration of contaminants known to impair olfaction by 20% over 24 h (EOG-based 24-h IC20s of 220 and 3.5 μg/L for CuNPs and Cu 2+, respectively) were tested as olfactory stimuli using both neurophysiological and behavioural assays. In the second experiment, to determine whether the presence of CuNPs or Cu 2+ can affect the ability of fish to perceive a social cue (taurocholic acid (TCA)), fish were acutely exposed to one form of Cu-contaminants (approximately 15 min). Following exposure, olfactory sensitivity was measured by EOG and olfactory-mediated behaviour within a choice maze was recorded in the presence of TCA. Results of neurophysiological and behavioural experiments demonstrate that rainbow trout can detect and avoid the IC20 of CuNPs. The IC20 of Cu 2+ was below the olfactory detection threshold of rainbow trout, as such, fish did not avoid Cu 2+ . The high sensitivity of behavioural endpoints revealed a lack of aversion response to TCA in CuNP-exposed fish, despite this change not being present utilizing EOG. The reduced response to TCA during the brief exposure to CuNPs may be a result of either olfactory fatigue or blockage of olfactory sensory neurons (OSNs) by CuNPs. The observed behavioural interference caused by CuNP exposure may indicate that CuNPs have the ability to interfere with other behaviours potentially affecting fitness and survival. Our findings also revealed the differential response of OSNs to CuNPs and Cu 2+ . Graphical abstract: Image 1 Highlights: Fish olfactory sensory neurons respond to nano (CuNPs) and soluble Cu differently. Rainbow trout can avoid the 20% olfactory inhibitory concentration (IC20) of CuNPs. The Cu 2+ IC20 was below the olfactory detection threshold of rainbow trout. A 15 min exposure to CuNPs impaired the perception of a social cue, taurocholic acid. Abstract : Olfactory sensory neurons have a differential response to Cu nanoparticles and Cu 2+ . Copper nanoparticles can serve as an olfactory stimulus leading to an aversion behaviour in fish.