Pathological and histometric analysis of the gills of female Hyphessobrycon eques (Teleostei:Characidae) exposed to different concentrations of the insecticide Dimilin registered

• Published in: Ecotoxicology and environmental safety 2016-09, Vol.131, p.135-142
• Main Authors: Marcon, Lucas, Lopes, Diego Senra, Mounteer, Ann Honor, Goulart, Amara Manarino Andrade, Leandro, Mila Vasques, dos Anjos Benjamin, Laercio
• Format: Article
• Language: English
• Subjects: Hyphessobrycon
• ISSN: 0147-6513
• DOI: 10.1016/j.ecoenv.2016.05.016

Female individuals of Hyphessobrycon eques were exposed to Diflubenzuron (Dimilin registered ) in order to determine whether exposure to sublethal levels of this insecticide causes changes in gill morphology. Fish were exposed to 0.01, 0.1 and 1.0mgL-1 for 96h and 17 days and then submitted to pathological and histometric evaluation. Pathological lesions, such as hyperplasia, lamellar fusion, vascular congestion, secondary lamellar disarray, vasodilatation, hemorrhage and increased lamellar epithelium, were significantly more common in the gills of fish exposed to Dimilin registered than the control. Histometric analysis documented significant changes in blood vessel diameter, primary lamellae width and secondary lamellae length, and the appearance of hemorrhage foci in all concentrations tested. Even at low Dimilin registered concentrations, the histopathological alteration index was mild to moderate, thereby indicating that the function of this tissue was compromised. These findings indicate that indiscriminate use of Dimilin registered can adversely affect the structural integrity of the gills of H. eques, which can cause numerous problems for fish farming systems.