Toxicity and genotoxicity in Astyanax bimaculatus (Characidae) induced by microcystins from a bloom of Microcystis spp

Abstract

Studies of genotoxicity in fish caused by cyanobacterial microcystins can be useful both in determining the sensitivity of native species, as well as comparing exposure routes. The genotoxicity caused by the microcystins LR and LA from a bloom collected in a eutrophic lake, was revealed in the fish Astyanaxbimaculatus, a native species from South America. LC50 (72 h) was determined as 242.81 μg L -1 and LD50 (72 h) as 49.19 μg kg -1 bw. There was a significant increase of DNA damage in peripheral erythrocytes, following intraperitoneal injection (ip) with tested concentrations of 24.58 μg kg -1 bw and 36.88 μg kg -1 bw, as well as through body exposure to a concentration of 103.72 μg L -1 . Micronucleus (MN) induction was observed after ip injections of 24.58 μg kg -1 bw and 36.88 μg kg -1 bw for 72 h, as well as following body exposure for 72 at 103.72 μg L -1 . Thus, both exposure routes resulted in MN induction and DNA damage. Apoptosis-necrosis testing was carried out only by ip injection with concentrations of 24.58 μg kg -1 bw and 36.88 μg kg- 1 bw. Exposure to microcystins at lower concentrations induced more apoptosis than necrosis in peripheral erythrocytes, whereas exposure at higher concentrations gave rise to both conditions. Thus, Astyanax bimaculatus can be considered as a species sensitive to the genotoxic effects caused by microcystins.

Experimental immunology Assessment of the potential genotoxic and proapoptotic impact of selected cyanotoxins on fish leukocytes

“…There are only a few studies on the potential genotoxicity of cyanobacterial products on these organisms. Available data indicate that cyanotoxins may induce changes in nuclei of kidney cells, erythrocytes or embryos of different fish species [18][19][20]. Moreover, disruption of some vital functions of immune cells of fish was reported [21].…”

Análise de parâmetros de qualidade da água e teste de genotoxicidade em peixes da bacia hidrográfica do rio Pirapozinho – SP, Brasil

“…Foram analisados micronúcleos em peixes lambari (Astyanaxbimaculatus), tilápia (Oreochromis spp) e piapara (Megaleporinusobtusidens). Estas duas primeiras espécies têm sido avaliadas e consideradas sensíveis à ação genotóxica causada pela exposição a xenobióticos (Silva et al, 2010;Rocha et al 2011;Bogoni et al, 2014;Coppo et al, 2018). Entretanto, os estudos com Megaleporinus são escassos e relacionados a análises do conteúdo de DNA de sequências satélites (Crepaldi & Parise-Maltempi, 2020).…”

Lack of genotoxicity in Astyanax bimaculatus and Oreochromis niloticus of 17α-methyltestosterone used in fish hatcheries to produce male monosex populations

“…The species, besides playing a central role in riverine food webs, is sensitive to environmental degradation. These characteristics make it an excellent bioindicator, commonly present in Brazilian ponds and rivers, where it is a nontarget potential of this androgen (da Silva et al, 2010). In our previous study, A. bimaculatus and O. niloticus were exposed for 28 days through food containing MT (60 mg/L), as normally occurs in fish hatcheries.…”