EFFECTS OF ACUTE IRON OVERLOAD ON ATLANTIC SALMON (SALMO-SALAR) AND RAINBOW-TROUT (ONCORHYNCHUS-MYKISS)

Distribution of radioiron to various tissues after intraperitoneal inj ections was examined in Atlantic salmon and rainbow trout. Liver and s pleen were found to be the major iron storage tissues. Injections of 1 or 5 mg iron as ferric ammonium citrate led to a fall in hemoglobin l evels in both species after 2 d. Hemoglobin levels returned to normal levels in rainbow trout after 8 d, but Atlantic salmon had not recover ed, and Hb levels fell below 3 g/100 mL. In both species, the fall in Hb was associated with a raise in iron levels in spleen and liver, sug gesting damage to erythrocytes. Atlantic salmon liver ferritin showed a two-to threefold increase, while rainbow trout showed a sixfold incr ease, and a more rapid response. The toxic effect of iron in fish appe ars to be different from the effect in other vertebrates.