Antioxidants, lysosomes and elements status during the life cycle of sea trout Salmo trutta m. trutta L.

The aim of our study was to elucidate the effects of both development stages (parr, smolt, adult, spawner), and kelt as a survival form and sex (male, female) on the functional stability of the lysosomal complex, biomarkers of oxidative stress, and element contents in the muscle tissue of the sea trout (Salmo trutta m. trutta L.) sampled in the Pomerania region (northern Poland). We have evaluated the maximal activities of lysosomal enzymes (alanyl aminopeptidase, leucyl aminopeptidase, β-N-acetylglucosaminidase, and acid phosphatase), lipid peroxidation level, and protein carbonyl derivatives as indices of muscle tissue degradation. The relationship between lysosomal activity and oxidative stress biomarkers estimated by the lipid peroxidation level and protein carbonyl derivatives was also assessed, as well as the relationships between element levels and oxidative stress biomarkers. Trends of the main effects (i.e., the development stages and sex alone, the interaction of the sex and development stage simultaneously) on oxidative stress biomarkers, lysosomal functioning, and element contents in the muscle tissue were evaluated. The study has shown sex-related relationships between the pro- and antioxidant balance and the tissue type in the adult stage as well as modifications in the lysosomal functioning induced by long-term environmental stress associated with changing the habitats from freshwater to seawater and intense migrations. The highest level of toxic products generated in oxidative reactions and oxidative modification of proteins was noted in both the spawner stage and the kelt form. The holistic model of analysis of all parameters of antioxidant defense in all development stages and sex demonstrated the following dependencies for the level of lipid peroxidation, oxidative modification of proteins, lysosomal activities, and element contents: TBARS > OMP KD > OMP AD > TAC, AcP > NAG > LAP > AAP and Cu > Fe > Ca > Mn > Zn > Mg, respectively.