Chronic exposure to low concentrations of waterborne cadmium during embryonic and larval development results in the long‐term hindrance of antipredator behavior in zebrafish

Abstract

Abstract-Cadmium has been recognized for some time as a potent environmental pollutant with the capability of disrupting olfactory-mediated behaviors. Failing to respond to chemical cues in the environment could adversely affect foraging, reproduction and predator avoidance. Recognizing this impaired perception as a serious ecological problem has been undermined by the fact that the damage is often reversible; short depuration periods of 5 d may allow for the re-establishment of responses to chemical cues. In this experiment, early life stage zebrafish were continuously exposed for 50 d at 0, 0.2, 2.0, and 20 g Cd/L. The subjects were depurated for 14 d and then subjected to behavioral testing where antipredator responses to chemical alarm cues were observed. Our data show that continuous exposure during rearing to a concentration as low as 20 g Cd/L is sufficient at eliminating antipredator behavior in zebrafish (Danio rerio) even after the source of the cadmium had been removed for 14 d. Furthermore, subjects raised under a 10-fold lower concentration also showed alteration in their behavioral responses, taking significantly longer to respond to the predation threat. Exposure to low levels of cadmium throughout development may alter neurogenesis, subsequently resulting in long-term impairment of chemical cue perception.

Role of Nrf2 antioxidant defense in mitigating cadmium-induced oxidative stress in the olfactory system of zebrafish

“…Other investigators have shown that a brief Cd exposure (3 h) at 80 hpf leads to long-term behavioral deficits in the juvenile zebrafish as measured by decreased alarm responses (Blechinger et al, 2007). Similarly, embryonic zebrafish exposed to 20 μg·L −1 Cd for 50 days did not respond to alarm cues even after a 2 week depuration, suggesting a disruption of olfactory neurogenesis (Kusch et al, 2008). In the present study, olfactory cell death and disruption of the olfactory sensory epithelium were observed under short-term exposure to 25 μM Cd (2810 μg·L −1 Cd) in larvae, supporting the hypothesis that cell death and the disruption of olfactory sensory cells are mechanisms of Cd-induced olfactory impairment .…”

Zebrafish as potential model for developmental neurotoxicity testing

“…Exposing fish to a toxicant before exposure to an alarm cue can lead to information about the olfactory-mediated behavioural effects of this substance. It was shown for example that chronic exposure to low concentrations of cadmium during development results in long-term impairment of alarm responses in zebrafish (Kusch et al, 2008;Matz and Krone, 2007).…”

Heavy Metal Pollutants and Chemical Ecology: Exploring New Frontiers

“…Heavy metal pollutants for which these effects have been shown include Cu (Carreau and Pyle 2005;Pyle and Mirza 2007), Cd (Honda et al 2008;Kusch et al 2008), and Hg (Smith and Weiss 1997). Some studies have taken these investigations into the field to show that fish in metal-contaminated lakes respond differently from fish in uncontaminated lakes.…”