Affiliation:
1. Adaptive Biology Laboratory
2. Universidade Federal de Santa Catarina
Abstract
Abstract
When exposed to high temperatures, changes in the respiration rate of fish occur, leading to an increase in the formation of reactive oxygen species. Thus, enzymatic and non-enzymatic responses of antioxidant defense may be altered to avoid cellular-level stress. Rhamdia voulezi is an endemic species of the Iguaçu River in Paraná, Brazil, and is of great economic interest for fish farming. The aim of this study was to evaluate the activity of enzymatic biomarkers of antioxidant defense (superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase, glutathione reductase, glucose-6-phosphate dehydrogenase), the concentration of non-protein thiols (reduced glutathione), and markers of oxidative damage (lipoperoxidation and carbonylation) in the livers, gills, and kidneys of R. voulezi after acute exposure to an elevated temperature (31°C) for 2, 6, 12, 24, and 96 hours. Control animals were kept at 21°C. In the liver, there were increases in superoxide dismutase up to 12 h and glutathione S-transferase at 12 h and 96 h at the high temperature (31°C). In the gills, there were increases in superoxide dismutase after up to 24 h of exposure and lipoperoxidation after 2, 6, 12 and 96 h of exposure to the high temperature. Among the fish maintained at 31°C, there was also an induction of a heat stress response in the kidneys at 12 h, with increased activity of superoxide dismutase and catalase. Lipid peroxidation was also observed after 2 and 6 h of exposure to a temperature of 31°C. The three tissues evaluated responded differently to heat stress, and the liver showed a greater ability to adjust to the high temperature. The expression patterns of multiple biomarkers of antioxidant defence and oxidative damage in response to exposure to a high temperature suggest that R. voulezi exhibited oxidative stress.
Publisher
Research Square Platform LLC