RESUMO
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.
RESUMO
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.
RESUMO
The influence of increased zinc concentrations (0.1, 0.5, 1.0, 1.5 and 2.0 mg(-1) ZnSO4 x 7H2O) on the total number and the morphology of the erythrocytes, as well as the processes related to their formation and destruction in the spleen of Carassius gibelio were investigated ex situ. It was found that zinc concentrations caused pathological alterations in the erythrocytes that were not identical in the different concentrations-poikilocytosis; ruptures in cell membranes in the concentrations of 0.5mg(-1) and 1.5 mg(-1); cells with double nuclei (symplasts); in the concentration of 1.0 mg(-1); in the highest concentrations (1.5 mg(-1) and 2.0 mg(-1)) presence of erythrocytes at initial stage of atypical mitotic division. Against the background of those various alterations, the total number of the erythrocytes in the peripheral blood increased simultaneously with the increase of zinc concentrations (p < 0.001). Morphological alterations in the spleen were also observed, indicating a compensational tendency against the toxic influence of zinc upon the fish erythrocytes-hyperplasia of the red pulp and lack of hemosiderin. These results show that the alterations in the total number and the morphology of the erythrocytes are connected with the relevant compensatory histopathological alterations in the spleen. The use of the ascertained alteration could be valuable in monitoring zinc-polluted waters.