Effects of aluminium and cadmium on hatching and swimming ability in developing zebrafish

Abstract Aluminium and cadmium are biologically non-essential metals with a role in neurodegenerative and neuromuscular diseases. As an attractive model for neurobehavioural studies, zebrafish at 6 h post fertilization were exposed to 9, 18, 36 and 72 μM CdCl 2 and 50, 100 and 200 μM AlCl 3 , respectively, for 72 h, and motility such as distance moved, mean velocity, cumulative movement, meander and heading were measured by DanioVision equipment. The hatching time was also analysed. A delay in the exit from the chorion was observed in all treated larvae with respect to the controls. CdCl 2 acted on the exit from the chorion of larvae with a dose-dependent delay. By contrast, the delay caused by AlCl 3 was greater at low concentrations. A dose-dependent reduction in swimming performance was observed in the larvae exposed to CdCl 2 . Instead, for those exposed to AlCl 3 , swimming performance improved at higher concentrations although values were in general lower than those of control. All the parameters had a similar trend except the meander parameter which showed a dose-dependent reduction. These data show that cadmium and aluminium can delay hatching and alter swimming ability in the early developmental stages of zebrafish, albeit with different effects, suggesting that exposure to sublethal concentrations of both metals can change behavioural parameters.