Changes in plasma electrolytes and gill histopathology in wild Liza saliens from the Esmoriz-Paramos coastal lagoon, Portugal

The Esmoriz-Paramos is a lagoon of great ecological significance located on the Northwest coast of Portugal. The quality of water and sediment within this ecosystem has been gradually degraded due to the discharges of mostly untreated industrial waste and domestic sewage. Contaminants include heavy metals that can be taken up by fish from water, food, sediments, and suspended particulate material. Fish inhabiting polluted water bodies tend to accumulate many chemicals in high concentrations, even when the environmental contamination levels are low (Colombo et al. 1995). The leaping grey mullet (Liza saliens) is one of a few dominant species living in this environment. This species may contact xenobiotics in the water column or, when feeding, in the sediments

Oxidative stress enzymes and mitochondrial bioenergetics in wild Liza saliens exposed to heavy metals

The Esmoriz-Paramos coastal lagoon represents an ecosystem of great physical and ecological significance. However, as a result of industrial, agricultural and antropogenic activities this habitat has been progressively degrading over the last decades. The heavy metal contamination is an important factor to the decline of sediments quality and may adversely affect fish health. In the present work the leaping grey mullet Liza saliens was studied because it is the dominant endemic species in the lagoon. It is a filter feeder and also being a detritus-mud feeder, it is therefore exposed to contaminated sediments

Bioaccumulation of metals by Mugil saliens under chronic exposure to contamined sediments: Gill histopathological changes

The Esmoriz/Paramos coastal lagoon, is a habitat of ecological importance due to the presence of unique animal and plant species. During the past few years its immersed area has been gradually reduced due to effluent discharges and siltation. The major contaminants in the lagoon are derived from a multitude of nonpoint sources associated with urbanization and industrial activities within the watershed. Heavy metals are probably a class of pollutants contributing to the observed decline of fish species. The metal content in the water and sediments in the lagoon were investigated as well as gill metal bioaccumulation and gill histopathological changes of the grey leaping mullet, Mugil saliens

Oxidative stress responses and histological hepatic alterations in barbel, Barbus bocagei, from Vizela river, Portugal

Barbel (Barbus bocagei) a common species in Portuguese rivers was studied to assess the impact of water contamination on hepatic oxidative stress response, lipid peroxidation and histology. The Vizela River is a tributary of the Ave River, located in one of the most industrialized areas of Portugal. The oxidative stress biomarkers analyzed included superoxide dismutase, catalase, glutathione S-transferase, glutathione reductase, glucose 6‑phosphate dehydrogenase and xanthine oxidase activities. Levels of reduced glutathione and lipid peroxidation were also evaluated. Except xanthine oxidase activity, that did not show any alteration, all the other enzymatic activities were increased in the liver of barbel captured in the Vizela River when compared with reference barbel. While, no differences were observed for glutathione reductase content, lipid peroxidation was higher in barbel from the Vizela River. Liver histological alterations were determined and their severity scored. Though lymphocyte foci were only observed in Vizela River barbel, macrophage aggregates were also present in reference barbel, although the severity score was higher in Vizela fish. The results of this study show that barbel liver oxidative stress responses, lipid peroxidation and histology are sensitive to the contaminants present in Vizela River water and are valuable biomarkers for monitoring purposes.Barbos (Barbus bocagei), una especie común en los ríos portugueses, se utilizó para evaluar el impacto de la contaminación del agua en la respuesta hepática al estrés oxidativo, en la peroxidación lipídica y en la histología del órgano. El río Vizela es un afluente del río Ave, situado en una de las regiones más industrializadas de Portugal. Los biomarcadores de estrés oxidativo analizados fueron la actividad de las enzimas superóxido dismutasa, catalasa, glutatión S-transferasa, glutation reductasa, glucosa 6 fosfato deshidrogenasa y de la xantina oxidasa. Los niveles de glutatión reducido y de la peroxidación lipídica también fueron evaluados. Excepto la xantina oxidasa, que no mostró ninguna alteración, todas las otras actividades enzimáticas han sufrido incrementos en el hígado de los barbos capturados en el río Vizela, cuando se comparan con los barbos de referencia. No se observaron diferencias para el contenido de glutatión reductasa, pero la peroxidación lipídica fue mayor en los barbos del río Vizela. Las alteraciones en la histología hepática fueron identificadas y clasificadas de acuerdo con su gravedad. Mientras que los linfocitos de focos se observaron sólo en barbos del Río Vizela, los agregados de macrófagos también estuvieron presentes en barbos locales de referencia, aunque la gravedad de las alteraciones fue mayor en los peces del río Vizela. Los resultados de este estudio muestran que las respuestas de estrés oxidativo, la peroxidación lipídica y la histología hepática son sensibles a los contaminantes presentes en el agua del Río Vizela, demonstrando ser biomarcadores valiosos para propósitos de monitoreo

Heavy metal contamination in a mugil wild population of a coastal lagoon

Polluted sediments usualy contain complex chemical mistures that may have synergistic and/or antagonistic effects on target organisms. Establishing causality in the 1ieId, is thus, particularly difficulty and the biomarker responses recorded in whole sediment toxicity assays are o correlactive nature onl