Respiratory profile and gill histopathology of Carassius auratus exposed to different salinity concentrations

The aim of this study was to evaluate the chronic salinity tolerance of Carassius auratus and the effects on blood parameters, gill morphology, and survival. In the first test, nine different concentrations (0.0, 0.5, 1.0, 2.5, 5.0, 10, 15, 20, and 25 g L-1) of NaCl were used with nine repetitions for 96 h. The survival of fish subjected to 15 g L-1 NaCl was 4 h, and 5 min at a concentration of 25 g L-1. The mortality of fish with 15 g L-1 NaCl was 100%. Morphological analyses of the gills showed hyperplasia of the coated cells in the interlamellar space and hypersecretion of mucus in fish exposed to 10 g L-1 of NaCl. At concentrations of 20 and 25 g L-1, necrosis of the support collagen caused the cells to detach from the lamellar structure mucosa. In the chronic test, two concentrations were used, with four replications containing nine fish in each aquarium for a period of 21 days. Blood samples and gills from the fish were collected, and it was observed that the fish showed a decrease in the concentration of bicarbonate (NaHCO3) in the blood, indicating hypernatremia. Acute exposure of C. auratus to sodium chloride (NaCl) should be at a maximum of 10 g L-1 of NaCl, after which level there would be a loss in animal performance and/or mortality. Chronic exposure to 5 g L-1 of NaCl promotes acidemia, ionic imbalance, and pathological changes in the gills; therefore, it is not recommended.

A Gill Histopathology Study in two Native Fish Species from the Hydrographic Douro Basin

Gill histopathology is a valuable tool to evaluate ecosystems health, because the gill is a key site of waterborne pollutant uptake and the first target organ to their toxicity. Consequently, this makes it important in biomonitoring programs. This study aims to evaluate gill histopathological differences in Douro basin native fish species and determine possible associations with water quality and the ecological status classifications. Two native fish species (Pseudochondrostoma duriense and Luciobarbus bocagei) were sampled in four points of the Douro basin: two reference points, Ameixiosa (Paiva River) and Covelas (Bestança River), both classified with an excellent ecological status; and two disturbed points, Castro Daire (Paiva River) and Alvações do Corgo (Corgo River), categorized with a good and a moderate ecological status, respectively. Gill histopathological differences were qualitative and quantitatively analyzed. The histological analysis showed that, in all sampling locations, both species presented some degree of gill differences, such as epithelial lifting, lamellar fusion, and/or necrosis. The histopathological differences evaluation emphasized some variances in the responses between the two species. In nase, the filament and lamellar epithelium proliferation were the histopathological differences that better reflected the river ecological status classification, proving their usefulness in biomonitoring programs.

Toxicological perturbations of zinc oxide nanoparticles in the Coelatura aegyptiaca mussel

More research is needed to understand the interactions of nanoparticles (NPs) with aquatic organisms and their mechanism of toxic action. Zinc oxide nanoparticles (ZnONPs) are the most used engineered metal oxide NPs in consumer products. The present study was designed to evaluate the cytotoxicity, genotoxicity and digestive gland (DG) as well as gill histopathology of the freshwater molluscan bivalve Coelatura aegyptiaca following exposure to ZnONPs (2, 10 and 50 mg/L) for 6 consecutive days. Exposure to ZnONPs (10 and 50 mg/L) induced a significant increase in malondialdehyde, superoxide dismutase and nitric oxide with a concomitant decrease in reduced glutathione, glutathione-S-transferase and catalase levels in the haemolymph, DG and gills of the treated mussels. Following exposure to ZnONPs (50 mg/L), the DG exhibited gradual changes in glandular activity showing hypertrophy and hyperplasia in the glandular cells and irregularity of lamellae and swelling of filaments in the gills. The present investigation revealed that oxidative stress induction, genotoxicity in the haemocytes and histological alterations in the DG and gills of C. aegyptiaca could be the main mechanisms involved in ZnONPs toxicity in aquatic organisms. Thereby, it is suggested that ZnONPs should be applied with more precautions in relevant industries, and occupational health surveillance should be necessarily considered.

KONTAMINASI MERKURI (Hg) DALAM ORGAN TUBUH IKAN PETEK (Leiognathus equulus) DI PERAIRAN ANCOL, TELUK JAKARTA

Mercury (Hg) which is contained in aquatic ecosystem can enter and be accumulated to organism’s body, like on petek fish (Leiognathus equulus). The research aimed to see mercury concentration in aquatic ecosystem, to see mercury concentration in organ of petek fish by AAS (Atomic Absorption Spectrophotometer) and its histopathology response in organs of petek fish. The research was done at Ancol, Jakarta Bay on October-December 2004. There are 16 samples of water and fish from 3 stations.The analysis result of water quality is compared by standard quality of sea water for sea organism life (Kepmen LH No. 51, 2004), mercu ry concentration in fish organ is compared by maximum mercury concentration in fish body by classification of Palar (2004). Ancol water quality is still on normal condition. Mercury concentration in water and petek fish organs had low concentration. Gill and lever contaminated by mercuryis only in station 1 fish, but it is still on normal concentration. Histopathology of petek fish gill is not abnormal, while the lever is necrosis. Water and petek fish is not a good indicator to detect mercury in aquatic ecosystem.Keywords: mercury, petek fish, water, lever, gill, histopathology, accumulation,indicator