Parental exposure to azoxystrobin causes developmental effects and disrupts gene expression in F1 embryonic zebrafish (Danio rerio)

Abstract

The fungicide azoxystrobin induces reproductive toxicity in adult zebrafish. However, data are lacking regarding the impact of azoxystrobin in the F1 generation after parental exposure. To address this knowledge gap, parental zebrafish (F0) were exposed to 2, 20 and 200 μg/L azoxystrobin for 21 days. Following this, fertilized F1 embryos from the exposed parents were either exposed to the same concentration as their corresponding exposed parents (F0+/F1+) or were reared in clean water (F0+/F1-) for 96 h ("+", exposed; "-" unexposed). Likewise, F1 embryos from the non-exposed parents were either reared in clean water (F0-/F0-) as the control group or were exposed to 2, 20 and 200 μg/L azoxystrobin (F0-/F1+) for 96 h. Mortality, deformities, hatching rate, body length, and the expression of transcripts related to the endocrine system, oxidative stress, and apoptosis were measured. Increased mortality, higher malformation rate, decreased hatching rate, and a shorter total body length, as well as up-regulated cyp19b, vtg1, vtg2, p53, casp3, and casp9 mRNA and down-regulated sod1 and sod2 mRNA were detected in F1 embryos from the F0 and F1 exposure group at 20 and 200 μg/L azoxystrobin (F0+/F1+) when compared with the group from the F0 exposure alone (F0+/F1-). Interestingly, F1 exposure alone (F0-/F1+) did not induce mortality, developmental impairments, nor morphological deformations compared to the control group, but it did increase expression level of sod1, sod2, cat, p53, and casp9 at 200 μg/L azoxystrobin. Taken together, these data suggest that azoxystrobin affects survivability, development, and genes involved in the endocrine system, oxidative stress, and apoptosis in F1 embryos if their parents are initially exposed to this fungicide compared to embryos from non-exposed parents. Moreover, the effects are more severe if the offspring are continuously exposed to azoxystrobin similar to their parents.

Keywords: Azoxystrobin; F1 embryos; Parental exposure; Zebrafish.