ASTAXANTHIN AND CANTHAXANTHIN KINETICS AFTER INGESTION OF INDIVIDUAL DOSES BY IMMATURE RAINBOW-TROUT ONCORHYNCHUS-MYKISS

Kinetics of a 100 mu g oral dose of astaxanthin (AX) or canthaxanthin (CX) was determined from serum AX or CX concentration-time curves in 2 34 immature rainbow trout, Oncorhynchus mykiss, with a mean body weigh t of 300 g. Carotenoid concentrations in serial serum were measured us ing HPLC. The net change in mean peak serum concentrations in rainbow trout fed AX or CX reached 4.4+/-1.0 nmol/mL of serum at 18 h post-dos ing for AX and 2.9+/-0.5 nmol/mL of serum at 12 h post-dosing for CX. The maximum level of CX serum was 1.6 lower than that of AX.;ln terms of absorption speed, AX and CX are Likely equivalent. The relative bio availability of CX, with respect to AX taken as the reference, corresp onds to 33.5%. AX was more slowly removed from the serum than CX. The mean retention time of AX (56.4 h) was 2.4-fold that of CX (23.1h).