DEPOSITION AND METABOLISM OF DIETARY CANTHAXANTHIN IN DIFFERENT ORGANS OF ARCTIC CHARR (SALVELINUS-ALPINUS L)

A diet containing 65 mu g canthaxanthin (Carophyll red, Hoffmann-La Ro che) per kg diet was fed to post-juvenile, immature Arctic charr, weig hing approximately 150 g each, for a 24 week period. Fish flesh was th e major tissue for storing carotenoids, followed by skin, liver and go nads. Canthaxanthin was the main carotenoid deposited in the flesh and its content reached 4.3 mu g g(-1) of wet tissue after 24 weeks of fe eding. The flesh also contained lutein (0.2 mu g g(-1)) and some reduc tive metabolites of canthaxanthin, namely, echinenone (0.7 mu g g(-1)) and 4'-hydroxyechinenone (0.7 mu g g(-1)). beta-Carotene, the final p roduct of canthaxanthin reduction, was only present in the skin at 4.6 mu g g(-1), corresponding to 48% of the total pigments present. Other carotenoids found in charr skin were isocryptoxanthin, echinenone, ca nthaxanthin, 4'-hydroxyechinenone and lutein/lutein esters. The conten t of carotenoids in the charr liver was 5.23 mu g g(-1), which consist ed mainly of echinenone (2.9 mu g g(-1)) and 4'-hydroxyechinenone (1.3 mu g g(-1)). The gonads of charr contained 2.2 mu g g(-1) carotenoids , only 17.8% of which was canthaxanthin and was dominated by 4'-hydrox yechinenone (33.5%) and lutein/lutein esters (37.7); isocryptoxanthin was a minor carotenoid (11.0%) present.