ABSTRACTThe present study aimed to investigate the histological alterations in common carp gills caused by a fosetyl-Al and fenamidone based fungicide tested in laboratory conditions at 30, 38 and 50 mg/L concentration. In general, all the tested concentrations activated compensatory-adaptive mechanisms, which caused pathological changes in the fish gills. Results showed different histological alterations in the gill structure, which included lamellar lifting, edema, proliferation of the glandular cells and epithelium, covering the gill filament, fusion and degenerative alterations. Blood circulatory system showed vasodilatation of the secondary lamellae and aneurysms. Overall, there was enhancement of the gill histological changes, which was dose-dependent, i.e., proportional to the increasing fungicide concentrations. Thus, based on the results, it was concluded that the histological alterations in common carp gills could be applied as possible biomarkers in risk assessment and monitoring programs for pesticide contamination of aquatic ecosystems.

This work aimed to study the effect of new neonicotinoid thiamethoxam on the histological structure of common carp (Cyprinus carpio, L.) gills. Three experimental groups of fish were treated with 6.6, 10 and 20 mg/l thiamethoxam in laboratory conditions. Results showed different histological changes in the gill epithelium, which included lamellar lifting, edema, proliferation of the glandular cells and epithelium, covering the gill filament, fusion and degenerative alterations. The blood circulatory system showed mainly vasodilatation. All thiamethoxam concentrations activated compensatory-adaptive mechanisms, which caused pathological changes in the gills. Moreover, there was a tendency towards the enhancement of the gill histological changes, whose degree of expression was proportional to the increasing thiamethoxam concentrations.