Assessing physiological responses and oxidative stress effects in Rhamdia voulezi exposed to high temperatures

Abstract

When exposed to high temperatures, changes in the respiration rate of sh 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 sh 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-6phosphate 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 Stransferase 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 sh 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.

Investigating the Impact of Disrupting the Glutamine Metabolism Pathway on Ammonia Excretion in Crucian Carp (Carassius auratus) under Carbonate Alkaline Stress Using Metabolomics Techniques

“…Glutathione manifests in two forms within the cell-oxidized glutathione (GSSG) and reduced glutathione (GSH), with GSH being synthesized from GSSG through the enzymatic action of glutathione reductase. Serving as a crucial cellular antioxidant, GSH effectively neutralizes free radicals and other harmful oxidants, thereby safeguarding cells from oxidative damage [44]. Peroxides and free radicals, which are the products of oxidative stress, can have toxic effects on cells.…”