Dynamics of dietary canthaxanthin utilization in sexually maturing female rainbow trout (Salmo gairdneri Rich.) compared to triploids

Dynamics of canthaxanthin in rainbow trout was studied through a feeding experiment of 37 weeks by following canthaxanthin deposition and retention in muscle and ovary of maturing diploid females compared to sterile triploids. In the first 4 weeks canthaxanthin retention in diploids (3.6%) was about three times that of triploids. Later on, canthaxanthin retention in triploid muscle and diploid muscle and ovary reached similar and rather constant levels (2%) while the level in the diploid muscle was lower. The canthaxanthin deposit in the flesh of fish was higher in triploids than in diploids. Furthermore, the canthaxanthin concentration in muscle plus ovary from diploids did not differ significantly from the concentration in the muscle of triploids. After spawning, canthaxanthin concentration in the muscle of female diploids reached a level as high as that of triploids after 4 weeks.