Abstract: Objective To study the reproductive toxicity effects of dibutyl phthalate (DBP) on F₀ (parent) and F₁ (parent) zebrafish. Methods Fourty-eight pairs of adult zebrafish were randomly divided into 4 groups: blank control group, 0.01% acetone solvent control group, 625 µg/L DBP low-dose group, and 1250 µg/L DBP high-dose group. After 30-day exposure, F₀ zebrafish in each group were mated and the number of eggs, fertilization rate and 72-hours hatchability were recorded. After being kept for 180 days in clean water, F₀ and F₁ zebrafish in each group were again mated, and the replacement mating test were conducted. The Vetellogenin (VTG) mRNA of F₀ and F₁ zebrafish was measured by RT-PCT, and gonad histopathology was performed. Results The fertilization of F₀ and F₁ zebrafish in 1250 µg/L DBP group was significantly lower than that in blank control or in 625 µg/L DBP group; histological examination showed that DBP slightly inhibited ovarian development of the F₀ and F₁ zebrafish and slightly increased the cortical vesicular stage oocyte (Coc) and perinucleolar stage oocyte (Poc). In F₀ male zebrafish of 1250 µg/L DBP group, the sperm count in the testes was reduced, and the spermatocyte (sc) and Leydig cells were slightly increased. In F₁ male zebrafish of 1250 µg/L DBP group, the development of testes was inhibited significantly, manifested as the co-existence of abnormal seminiferous tubules, reduced sperm count and Leydig cell hyperplasia. Exposure to DBP could not induce the expression of VTG mRNA in either F₀ or F₁ male zebrafish, indicating that DBP has no estrogen-like effects on zebrafish. Conclusion Exposure to 1250 µg/L DBP can induce reproductive toxicity in F₀ and F₁ zebrafish. The number of eggs and egg hatchability were reduced. Abnormal seminiferous tubules, reduced sperm count as well as Leydig cell hyperplasia were found.

Key words: Zebrafish, Dibutyl phthalate(DBP), Reproductive toxicity, F₀, F₁