Evidence of cytogenetic and histological damage in specimens of Astyanax lacustris (Pisces, Characidae) exposed to the hydrogen cyanide-based herbicide Dormex®

Abstract

The herbicide Dormex®, a solution of hydrogen cyanamide, is a growth regulator capable of breaking the dormancy of fruit plants, and is commonly applied in agriculture. However, the biological effects of this product on non-target organisms are unknown. The present study investigated the biological response of Astyanax lacustris (Lütken, 1875) specimens exposed to Dormex® using a chromosome aberration test, the mitotic index, and the histological analysis of the gills. Forty specimens of Astyanax lacustris were obtained from a local breeding facility and divided into 10 groups (nine experimental and one control) with four fish in each aquarium (group). The control group was maintained for 24 hours in dechlorinated water while the experimental groups were allocated to one of nine different treatments, with three concentrations of Dormex®, 0.05, 0.1 and 0.5 mL L-1, and exposure for 24, 48 and 72 hours. The fish exposed to Dormex® presented chromosomal aberrations of a number of types, including chromosomal breaks, acentric fragments, decondensation, and gaps at the three Dormex® concentrations, at all exposure times. The mitotic index decreased significantly in comparison with the control group. The histological preparations of the gills revealed alterations such as hyperplasia, and lamellar fusion and edema, whereas in the control group the structure of the gills was preserved. The cytogenetic analysis revealed the genotoxic potential of the herbicide Dormex® and the morphological alterations of the gills demonstrated the sensitivity of the fish, which responded rapidly to the stressor. These findings reinforce the need for special care and restrictions on the use of these herbicides in agricultural areas located near aquatic environments.

Contrasting tourism regimes due to the COVID-19 lockdown reveal varied genomic toxicity in a tropical beach in the Southern Atlantic

“…Among these are heavy metals (aluminum, zinc, lead, selenium, chromium, nickel and cadmium etc. ), nicotine, ethyl phenol, ammonia, formaldehyde, butane, acrylonitrile, toluene, benzene, alkaloid, cyanide, and asbestos most of which have a genotoxic effect (Al-Saleh et al, 2020 ; Gökalp et al, 2020 ; Laio et al, 2019 ; Salem et al, 2018 ; Thirunavukkarasu et al, 2020 ; Yamin et al, 2020 ; Zafra-Lemos et al, 2021 ; Zhang et al, 2020 ). The origin of the majority of these chemical compounds in cigarettes come from pesticides, insecticides, herbicides, and fungicides used in tobacco culture (Lee, 2012 ), which also present genotoxic potential (Amaeze et al, 2020 ; Oliveira et al, 2020 ).…”

Metabolic responses in the gills of Yellowtail Lambari Astyanax lacustris under low‐ and high‐temperature thermal stress

“…Yellowtail Lambari are small fish (10-15 cm in length) that inhabit small lakes, streams, and rivers and have an omnivorous feeding habit (Bennemann et al 2005;Viana et al 2013). This species is an important natural resource and a good model in environmental studies, since changes in environmental quality affect its metabolic conditions (Stevanato and Ostrensky 2018;Gnocchi et al 2020;Macêdo et al 2020;Warren and Burr 2020;Zafra-Lemos et al 2021).…”