THE EFFECT OF PIGMENTS OF RHODOBACTER-CAPSULATUS ON FREE-RADICALS AND APPLICATION OF THE BACTERIUM AS FEED TO FISH LARVAE

The possible role of carotenoids as free radical scavengers during development of fish larvae has not been completely elucidated. To gain further insight, we used a photosynthetic bacterium Rhodobacter capsulatus (PSB) as a secondary feed for Japanese flounder larvae and juveniles. In the administration group of rotifers reared with PSB, the amount of lipid peroxides in the juveniles on day 30 after starting the feed was lower than that in the administration group without PSB (control). The mortalities on day 30 were also lower than those in the control. The PSB pigments inhibited the Fe2+-induced lipid peroxidation of egg phosphatidylcholine liposomes. These findings suggest that the pigments, especially X1 and X3 fractionated by reversed-phase HPLC, inhibited the initiation and progression of lipid peroxidation.