Developmental-induced changes of metabolic and antioxidant responses in the skeletal muscles of sea trout (Salmo trutta L.)
The goal of the current study was to characterize developmental-induced changes of the metabolic and antioxidant responses in the skeletal muscles of the anadromous sea trout (Salmo trutta L.) from the Baltic Sea and its catchment area rivers. Activities of the metabolic enzymes, i.e., lactate dehydrogenase, succinate dehydrogenase, alanine and aspartate aminotransferases, their ratios representing aerobic, anaerobic, and amino acid metabolisms, the level of the metabolites (pyruvate and lactate), the activities of several key antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase, and reductase), and a marker of lipid peroxidation (2-Thiobarbituric acid reactive substances, TBARS) were evaluated. The current study revealed the impact of the sex and different developmental stages of the sea trout (parr, smolts, spawners, adults, and kelts) on the effective formation of adaptive oxygen-dependent mechanisms. A stable developmental-related tendency toward increased lipid peroxidation in muscle tissues was observed. Glutathione peroxidase in muscle tissues played a leading role in the different stages of trout development. A switch of the muscle cytosolic redox potential from the aerobic pathway to anaerobic glycolysis was observed. These results indicated that energy-related cellular components and metabolic enzymes could compensate for adaptive mechanisms without any serious damage to muscle tissues. The differences in the enzyme activities were associated with the reorganization of the energy-related metabolic pathways (anaerobic and aerobic pathways) during spawning. This process was one of the adaptation mechanisms of this fish.