Impact of Temperature Stress on Adaptive Mechanisms in Zebra Fish (Danio rerio)

Abstract

Environmental temperature plays a crucial role in regulating physiological and biochemical processes in ectothermic organisms such as Zebra fish (Danio rerio). Thermal stress can disrupt homeostasis by elevating reactive oxygen species (ROS), leading to oxidative damage in vital tissues. The present study investigates the impact of gradual temperature stress on antioxidant and metabolic enzyme responses in Zebra fish, with a focus on key antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and metabolic markers such as acid phosphatase (ACP), alkaline phosphatase (ALP), Β amylase, and Acetylcholinesterase (AChE) along with the lipid peroxidation marker malonaldehyde (MDA). Results demonstrated a significant increase in oxidative stress markers, with MDA levels rising by approximately 6.20-fold at 32°C and 6.48-fold at 38°C relative to control, indicating enhanced lipid peroxidation. Antioxidant responses were markedly elevated, with SOD activity increasing by 1.87-fold and 2.43-fold, CAT by 1.97-fold and 2.41-fold, and GSH by 1.97-fold and 2.02-fold at 32°C and 38°C, respectively compare to control. Metabolic enzymes exhibited temperature-dependent upregulation, with ALP increasing by 1.63-fold and 2.09-fold at 32°C and 38°C, respectively compare to control, ACP by 1.57-fold and 1.66-fold at 32°C and 38°C, respectively, and β-amylase by 1.20-fold and 1.70-fold at 32°C and 38°C, respectively as compare to control, suggesting enhanced metabolic turnover and energy mobilization. AChE activity also increased moderately (1.18-fold and 1.56-fold at 32°C and 38°C, respectively, indicating altered neurophysiological dynamics under thermal stress. These findings highlight the sensitivity of Zebra fish antioxidant systems to temperature fluctuations and underscore the importance of rate and duration of thermal exposure. This study contributes to understanding how climate-induced temperature changes can affect aquatic vertebrate physiology at the molecular and biochemical levels.