Profiling the antioxidant biomarkers in marine fish larvae: a comparative assessment of different storage conditions to select the optimal strategy.

Abstract

Research on antioxidant biomarkers can generate profound insights into the defense mechanisms of fish larvae against different stressors and can reveal manipulation strategies for improved growth and survival. However, the number of samples to process and unavailability of required infrastructure in larval-rearing facilities limit the immediate processing, requiring the preservation of specimens. Silver pompano (Trachinotus blochii), a potential marine aquaculture species, shows a low larval survival rate due to poorly developed antioxidant mechanism. In this context, 39 storage conditions, including three storage temperatures and different buffers, were scrutinized to select the most suitable preservation strategy for five important antioxidant biomarkers of fish larvae, viz. catalase activity, superoxide dismutase (SOD) activity, measurement of lipid peroxidation, reduced glutathione (GSH), and ascorbic acid contents. The paper proposes the optimum larval storage conditions for these five evaluated antioxidant biomarkers to generate similar results in preserved and non-preserved larval samples. Larval samples preserved in PBS at lower temperatures (- 20°C and - 80°C) are recommended for evaluating catalase activity and ascorbic acid content. Catalase activity can also be evaluated by preserving the larval samples at - 20°C or - 80°C without buffers. Larval samples held in PBS or without any buffers at - 20°C and at - 80°C were found to be suitable for SOD and GSH evaluation, respectively. Preservation in 50% glacial acetic acid at - 80°C or - 20°C was preferred for the lipid peroxidation assays. Apart from methodological perspectives, the paper provides insights into the dynamics of larval antioxidant profiles of T. blochii, for the first time.