Exposure to diclofop-methyl induces immunotoxicity and behavioral abnormalities in zebrafish embryos

Diclofop-methyl (DM) is widely used in agriculture and may lead to serious toxicity. However, a limited number of studies have been performed to evaluate the toxicity of DM in the immune and nervous systems of animals. Here, we utilized a good vertebrate model, zebrafish, to evaluate the toxicity of DM during the developmental process. Exposure of zebrafish embryos to 0.1, 0.3 and 0.5 mg/l DM from 6 h post fertilization (hpf) to 72 hpf induced developmental abnormalities, such as shorter body lengths and yolk sac edemas. The number of immune cells in zebrafish larvae was significantly reduced, but the inflammatory response was not influenced by DM treatment. The expression of immune-related genes were downregulated and the levels of oxidative stress were upregulated by DM exposure. Moreover, locomotor behaviors were inhibited by DM exposure. Therefore, our results suggest that DM has the potential to induce immunotoxicity and cause behavioral changes in zebrafish larvae. This study provides new evidence of the influence of DM exposure on aquatic ecosystems.