Toxicidade do herbicida Roundup WG durante o desenvolvimento embrionário e larval do peixe-zebra Danio rerio.

Journal or Publishing Institution: issertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas, Programa de Pós-Graduação em Biologia Celular e do Desenvolvimento, Florianópolis

Study: https://repositorio.ufsc.br/handle/123456789/216216

Author(s): Durante, L.D.S.

Article Type: Study

Abstract:

Abstract: Glyphosate-based herbicides have been increasingly used worldwide in order to inhibit the growth of weeds in agriculture and thus, to the increase production. However, due to the high solubility of these herbicides in water, when applied in the crops, penetrate toward to the soil, being able to reach aquatic environments and affect non-target organisms. Thus, the aim of the present study was to characterize the toxicity of the glyphosate-based herbicide, Roundup WG ® (RWG ® ), during embryonic and larval development, using Danio rerio as a study model. Embryos and larvae were exposed to environmentally relevant concentrations of 0.065 mg/L (maximum limit established by CONAMA for drinking water for human consumption) and 6.5 mg/L (simulates peak contamination events in the environment). Thus, analyses of (i) survival of embryos and larvae, (ii) hatching and spontaneous movements of embryos, (iii) heartbeat of embryos and larvae, (iv) internal and external morphologies (vitellinic edema, pericardial edema, aspect of the chorion, asymmetry of the eyes, body and flow curvature, asymmetry of the fins, body pigmentation, and expansion of the swimming bladder), (v) morphometry of the eye area, pericardial area, yolk area of the midgut, swimming bladder area, total length of the larvae, (vi) cell proliferation and apoptosis and (vii) exploratory and phototropism behavior of the larvae were performed. The results showed a significant increase in the mortality of embryos and larvae exposed to the concentration of 0.065 mg/L RWG ® (p < 0,0001; p < 0,05), as well as a reduction in spontaneous movements of the embryos, when compared to control (p < 0.05). The hatching rate, assessed at 2 and 3 days post-fertilization (dpf), did not differ significantly among groups. The heartbeat of embryos exposed to concentrations of 0.065 and 6.5 mg/L RWG ® differed significantly only in the 2 dpf, when compared to control (p < 0.001); at 3 dpf the heartbeat of the larvae exposed to the concentration of 0.065 mg/L RWG ® and to the concentration of 6,5 mg/L RWG ® did not differ from the control; at 4 dpf the heartbeat of the larvae exposed to the concentration of 0.065 mg/L RWG ® decreased significantly when compared to the larvae exposed to concentration of 6.5 mg/L RWG ® , which did not differ from the control (p < 0.05); at 5 dpf, the heartbeat of larvae exposed to concentration of 6.5 mg/L RWG ® increased significantly when compared to the control (p < 0.05); at 6 dpf, the larvae exposed to concentrations of 0.065 mg/L RWG ® and 6.5 mg/L RWG ® showed a significantly higher heart rate, when compared to control (p < 0.05). The morphological analysis and the body morphometry of the larvae did not differ significantly between the groups, as well as the exploratory and phototropism behavior of the larvae. Cell proliferation decreased significantly in the eye region of larvae with 3 dpf exposed to concentrations of 0.065 mg/L RWG ® and 6.5 mg/L RWG ® , when compared to control (p < 0.001). Apoptosis increased significantly in the eyes and gills in larvae with 3 dpf exposed to concentration of 6.5 mg/L RWG ® compared to larvae exposed to the concentration of 0.065 mg/L RWG ® and the control (p < 0.001; p < 0.05). Larvae with 6 dpf exposed to the concentration of 0.065 mg/L RWG ® showed a significantly reduction in cell proliferation only in the head region when compared to control (p < 0.05). These results demonstrated the toxic effect of low concentrations of glyphosate-based herbicide mg/L RWG ® , considered environmentally relevant, on the development of D. rerio embryos and larvae.

Keywords: Roundup, glyphosate, Danio rerio

Citation:

Durante, L.D.S., 2020. Toxicidade do herbicida Roundup WG durante o desenvolvimento embrionário e larval do peixe-zebra Danio rerio.

Record ID: 2697