Chronic exposure of 2,2',4,4'-tetrabromodiphenyl ether (PBDE-47) alters locomotion behavior in juvenile zebrafish (Danio rerio)

In the present study, we used zebrafish (Danio rerio) as a model to address possible effects of chronic exposure of polybrominated diphenyl ether (PBDE) flame retardants on locomotion behavior, body size, and gonad development in fish. Zebrafish were fed food dosed with PBDE-47 (control, solvent control, low, medium, and high dose groups) from 21 days post hatch (dph) to 90 dph. Fish locomotion parameters, including maximum swimming speed, total distance moved, and percent time active, were assessed using a video-based animal movement analysis system. At the end of the exposure, all fish were euthanized for length and weight measurement, and then subjected to either whole fish histological analysis or tissue PBDE-47 measurement. Survival, body size, and gonad histology were similar between the five groups. However, both total swimming distance and percent time active were negatively correlated with tissue PBDE-47 concentration and were significantly lower in the high dose group. Tissue levels of PBDE-47 in the exposed fish were comparable to that reported in previous field studies. In summary, this study showed that developmental exposure of PBDE-47 at an ecologically relevant level altered locomotion behavior without affecting body size or gonad development of zebrafish.