Anti-oxidative properties of lipids extracted from rainbow trout (Oncorhynchus mykiss) fed with carotenoids and conjugated linoleic acid

Abstract

A commercial diet supplemented with carotenoids and conjugated linoleic acid was fed to rainbow trout (Oncorhynchus mykiss) for 8 weeks. To investigate the anti-oxidative properties of these compounds, lipids from the muscle and viscera of the fish were subjected to different assays. At 10 μg/mL, L-ascorbic acid exhibited 95% 2,2-diphenyl-l-picrylhydrazyl (DPPH) radical-scavenging activity, while the tissue lipids showed little radical scavenging activity. At 50 and 100 μg/mL, the lipids of the muscles and viscera showed 11.7-22.6% and 11.3-24.9% DPPH radical-scavenging activity, respectively. A lipid peroxidation inhibitory assay using the ferric thiocyanate method was also performed in comparison with α-tocopherol at a concentration of 6.0 mg/mL. Our results indicate that the anti-oxidative property of the lipids in fish muscle, which was 85.2% compared to 85.3% for the visceral lipids, was stronger than that of α-tocopherol (74.3%) following 3 days of storage at 40°C.