Glyphosate-based Herbicide (GBH) Causes Damage in Embryo-larval Stages of Zebrafish (Danio Rerio)

<title>Abstract</title> Glyphosate-Based Herbicides (GBH) show risks to the environment and also to aquatic organisms, such as fish. The present work aimed to evaluate the effects of GBH exposure on <italic>Danio rerio</italic> embryos at drinking water concentrations. Zebrafish embryos were exposed to 250, 500, and 1000 µg/L of Roundup Original DI® for 96 hours. Glyphosate concentration in water, parameters physicochemical water, mortality, hatching rate, heart rate, malformations, behavior, and biomarkers were evaluated. Our results showed that at 6 hours post-fertilization (hpf), the animals exposed to GBH 500 increased mortality as compared to the control. The hatching rate increased in all groups exposed at 48 hpf as compared to the control group. The embryos exposed did not present changes in the spontaneous movement and touch response. Exposed groups demonstrated a higher number of malformations in fish embryos as compared to the control. Most malformations were: pericardial edema, yolk sac edema, body malformations, and curvature of the spine. In heart rate, we can see that bradycardia occurred in groups exposed, as predicted due to cardiac abnormalities. We recorded a significant decrease in GST (GBH 250 and GBH 500) and AChE (GBH 250) activity. No differences were found between the groups in the concentration of protein, ACAP, TBARS, ROS, NPSH, and catalase. The damage in all evaluated stages of development was aggravated by the mortality and malformations. The large-scale use of GBHs, coupled with the permissiveness of its presence could be the cause damage to the aquatic environment affecting the embryonic development of non-target organisms.