Effects of three different embryonic exposure modes of 2, 2', 4, 4'-tetrabromodiphenyl ether on the path angle and social activity of zebrafish larvae.

The toxicological research of polybrominated diphenyl ethers (PBDEs) has focused on its neurotoxicity; however, many questions still remain. For example, behavioral effects other than basic locomotion are seldom reported. To further evaluate the neurobehavioral toxicity of 2, 2', 4, 4'-tetrabromodiphenyl ether (BDE-47), a typical PBDE congener in animal tissues, we employed three different exposure modes, namely, continuous, early pulse, and interval exposure, to investigate the path angle and social activity changes of zebrafish larvae exposed to BDE-47 using automated equipment (Zebrabox). The results showed that different exposure modes might have different effects on the larval path angle and social activity. BDE-47 treatments caused more responsive turns in all exposure modes in the path angle test and more contacts in most of the two-fish social tests, indicating that the neurobehavior of larvae was disturbed by BDE-47. The light condition was also a key impact factor in the effects of BDE-47. The effects of BDE-47 were different during the dark and light conditions. Our study shows a useful neurobehavioral test method for environmental pollutant monitoring and further supports the utility of zebrafish to study neurobehavior, indicating that the path angle has the potential to be a practicable behavioral indicator.