Disruption of zebrafish (Danio rerio) sexual development after full life-cycle exposure to environmental levels of triadimefon

• Zebrafish were exposed to environmental levels of triadimefon from 24 h post fertilization to 120 days post fertilization.
• The impact of triadimefon on reproductive function in zebrafish was evaluated.
• Histological examination showed that the sex ratio of fish skewed to male exposed to 0.5 μg/mL triadimefon.
• Triadimefon had the potential to adversely affect the sexual development and breeding success.

In this study, zebrafish was exposed to environmental levels of triadimefon (0.125, 0.25, 0.5 μg/mL) from 24 h post fertilization to 120 days post fertilization. Several endpoints that related to reproductive function were evaluated. It was found that the body length, body weight and vitellogenin transcription were significantly reduced for fish exposed to triadimefon. Histological examination showed that the sex ratio of fish skewed to male and female exposed to 0.5 μg/mL triadimefon had immature ovary. The breeding success, as determined from data on egg production and spawning, was reduced in fish exposed to 0.25 μg/mL triadimefon. In the offspring, the reduced egg fertility, hatching rate and survival were observed in eggs exposed to 0.5 μg/mL triadimefon. These findings indicated that triadimefon had the potential to adversely affect the sexual development and breeding success through the multiple endocrine actions.