Subchronic exposure to diflubenzuron causes health disorders in neotropical freshwater fish, Prochilodus lineatus

Abstract

The action of diflubenzuron (DFB) was evaluated in a freshwater fish, Prochilodus lineatus, after exposure to 0.06, 0.12, 0.25, or 0.50 mg L(-1) DFB for 14 days. Erythrocyte nuclear abnormalities (ENA), the gill activity of Na(+)/K(+)-ATPase, H(+)-ATPase and carbonic anhydrase (CA), and lipid peroxidation (LPO) and histopathological changes in the gills and liver were determined. The number of micronuclei increased in fish exposed to 0.25 and 0.50 mg L(-1) DFB. Plasma Cl(-) and the CA activity decreased, while the activity of Na(+)/K(+)-ATPase and of H(+)-ATPase increased in fish exposed to 0.25 and 0.50 mg L(-1) DFB. LPO did not change in the gills but increased in the liver of fish exposed to 0.25 and 0.50 mg L(-1) DFB. In the gills, histopathological changes indicated disperse lesions and slight to moderate damage in fish exposed to 0.50 mg L(-1) DFB, whereas in the liver, these changes were significantly greater in fish exposed to 0.25 and 0.50 mg L(-1) DFB, indicating moderate to severe damage. Continuous exposure to DFB is potentially toxic to P. lineatus, causing heath disorders when the fish is exposed to the two highest DFB concentrations, which are applied to control parasites in aquaculture and to control mosquito populations in the environment.

Histological and Histometric Evaluation of the Liver in Astyanax Bimaculatus (Teleostei: Characidae), Exposed to Different Concentrations of an Organochlorine Insecticide

“…In this work, the action of Thiodan ® at sublethal concentrations was found not to affect the liver as a whole, but did manifest itself in the form of the occurrence of specific lesions in the liver parenchyma in the different treatments. DTC in the livers of lambaris were not severe, as they showed no necrosis and exhibited only Stage I and II morphological changes (these stages being classified as repairable) as reported in other studies (Langiano Vdo and Martinez, ; Simonato et al, ; Benze et al, ; Wolf et al, ). Moreover, an increased frequency of histological alterations can indicate dysfunctions induced by toxic agents, since metabolically active areas of the liver are reduced, leading to a possible reduction in the overall functions performed by this organ (Oliveira Ribeiro et al, ; Pacheco and Santos, ; Benze et al, ).…”

“…This change would demonstrate a pathophysiological condition caused by lack of biliary excretion and metabolism (Pacheco and Santos, ) through the lack of release of the bile into the digestive tract (Simonato et al, ; Benze et al, ). This type of change can be found in fish exposed to toxins (Pacheco and Santos, ; Benze et al, ) and also in fish that have some nutritional problem when kept in captivity (Langiano Vdo and Martinez, ). The present study found that the different concentrations of Thiodan ® in the different 96‐hr treatments were insufficient to develop histopathological evidence of bile stagnation.…”

“…Change in the diameters of the nuclei of hepatocytes can be considered a response to a stressor, and is indicative of activation of liver function as a result of increased metabolic activity against adverse conditions (Langiano Vdo and Martinez, ; Sarma et al, ; Benze et al, ). On the other hand, a decrease in the size of the nuclei can be related to the possible multiplication of hepatocytes during the replacement of damaged cells (Braunbeck et al, ; Gul et al, ).…”

“…Histopathologically, this type of change is observed in the cytoplasm of hepatocytes by the presence of yellowish-brown granules where bile would be synthesized. This change would demonstrate a pathophysiological condition caused by lack of biliary excretion and metabolism (Pacheco and Santos, 2002) through the lack of release of the bile into the digestive tract (Simonato et al, 2008;Benze et al, 2014). This type of change can be found in fish exposed to toxins (Pacheco and Santos, 2002;Benze et al, 2014) and also in fish that have some nutritional problem when kept in captivity (Langiano Vdo and Martinez, 2008).…”

“…Morphological changes in the liver may include the appearance of vacuolization of hepatocytes, glycogen depletion, alteration of capillary sinusoids, change in size of hepatocytes, and necrosis (Cengiz et al, 2001;Glover et al, 2007) which, according to some authors, may influence the synthesis of vitellogenin in the liver and the formation of vitellogenic follicles (Al-Ghais, 2013;Barni et al, 2014;Marcon et al, 2014Marcon et al, , 2015. Furthermore, hepatic physiology can be compromised differently depending on the period of exposure to pesticides, the concentration of the contaminant, and dietary habits (Ribeiro et al, 2006;Al-Ghais, 2013;Barni et al, 2014;Benze et al, 2014).…”