Effects of the 2,4-D herbicide on gills epithelia and liver of the fish Poecilia vivipara

Abstract

Pesq. Vet. Bras. 34(6):523-528, junho 2014 523 RESUMO.-[Efeitos do herbicida 2,4-D no epitélio das brânquias e no fígado do peixe Poecilia vivípara.] A toxicidade aguda do herbicida 2,4-D foi investigada através dos efeitos no peixe Poecilia vivípara (Bloch et Schneider, 1801). Grupos de peixes foram expostos ao herbicida nas concentrações de 10, 20 e 40ml por litro de água, durante 24 horas. As brânquias e o fígado foram estudados. A concentração letal média (CL50) do herbicida para a espécie em questão foi de 34,64ml/l. Foram realizadas colorações histoquímicas e coloração de Feulgen para identificar glicoconjugados e DNA, respectivamente, nos tecidos acima citados. Os métodos histoquímicos revelaram os tipos de glicoconjugados presentes nas células mucosas e nos grâ-nulos. Os quatro tipos de células mucosas apresentaram glicoconjugados neutros, ácidos, ou ambos em um mesmo tipo celular. Observou-se a presença crescente de sialomucinas do grupo controle até o grupo exposto a maior concentração de 2,4-D, sugerindo aumento da viscosidade do muco e, consequentemente, formação de placas que impedem as trocas gasosas e a osmorregulação. A fusão lamelar observada no grupo exposto a 40ml de 2,4-D sugere ser um mecanismo de defesa. Os hepatócitos apresentaram processo de vacuolização nos grupos 10 e 20ml/l. No grupo de 40ml/l, observou-se a presença de células de Ito, micronú-cleos e hepatócitos normais e outros com edema nuclear. Este estudo indica a importância da avaliação de riscos se- The 2,4-dichlorophenoxyacetic acid, usually named 2,4-D is one of the most widely used herbicides in the world. Acute toxicity of 2,4-D herbicide was investigated through its effects on guppies (Poecilia vivipara Bloch et Schneider 1801). Fish were exposed to the herbicide at concentrations of 10, 20 and 40μl per liter of water for 24 hours to determine its effects on gills and liver epithelia. The estimated LC50 was 34.64μl of 2,4-D per liter of water. Histochemical analyses and Feulgen's reaction were conducted to detect glycoconjugates and DNA, respectively, in gills and liver epithelia. Histochemistry revealed qualitative variations of glycoconjugates present on mucous cells and granules. The four types of mucous cells contained neutral granules, acids, or both. Increasing amounts of syalomucins were observed from the control group to the group exposed to the highest concentration of 2,4-D, suggesting increased mucous viscosity and the formation of plaques that could inhibit gas exchange and osmoregulation. Lamellar fusion observed in the group exposed to 40μl of 2,4-D suggests a defense mechanism. Hepatocytes showed vacuolization in the 10 and 20μl/L groups. The 40 μl/L group showed normal hepatocytes as well as changed ones, many Ito cells, micronuclei, and nuclear swelling. These effects may be associated with toxicity or adaptative processes to cellular stress. The data from this study indicates the importance of assessing similar risks to aquatic species and suggests that Poecilia vivipara is an adequate biological mo...

Histological Alterations in Common Carp (Cyprinus carpio Linnaeus, 1758) Gills as Potential Biomarkers for Fungicide Contamination

“…Changes in the circulatory system such as vasodilation and aneurysms indicate increased blood vessels pressure. Such histological alterations in fish gills have also been reported in other studies such as Campagna et al (2007); Peebua et al (2008); Ramírez-Duarte et al (2008); Vigário and Sabóia-Morais (2014) under the influence of different pesticides. The present study found aneurysms, which actually were not observed in the common carp gills when it was exposed to thiamethoxam.…”

Effects of low, subchronic exposure of 2,4‐Dichlorophenoxyacetic acid (2,4‐D) and commercial 2,4‐D formulations on early life stages of fathead minnows (Pimephales promelas)

“…The results suggest that exposure to the active ingredient in these formulations, 2,4‐D, is responsible for the negative survival impacts. In contrast, the literature has shown that pure 2,4‐D compounds had no effect on survival at low, ecologically relevant concentrations on older juvenile and adult fathead minnows (US Environmental Protection Agency ; Coady et al ; Vigário and Sabóia ). To our knowledge, no published studies have tested the impacts of environmentally relevant doses (0.00–2.00 ppm) of pure 2,4‐D exposure on survival from fertilization to 14 dph in any fish species.…”

Spatial and temporal trends and flow dynamics of glyphosate and other pesticides within an agricultural watershed in Argentina

“…There is a lack of information about the occurrence of 2,4‐D in aquatic ecosystems, but the present study indicates that 2,4‐D is a frequent pollutant in surface water of agricultural areas, and it should be included in monitoring programs. Also, it is relevant to study the presence of 2,4‐D in surface water because it can induce adverse effects on aquatic biota, as reported by Vigário and Sabóia‐Morais in the South American fish Poecilia vivipara .…”