Dietary esterified astaxanthin effects on color, carotenoid concentrations, and compositions of clown anemonefish, Amphiprion ocellaris, skin

This study examined the effects of dietary esterified astaxanthin concentration on coloration, accumulation of carotenoids, and the composition of carotenoids over time in the skin of Amphiprion ocellaris. Juveniles of 30 days-post-hatch were fed 40, 60, 80, or 160 mg esterified astaxanthin per kg diet (mg kg^?1) for 90 days. Skin coloration was analyzed using the hue, saturation, and luminosity model. Increased astaxanthin concentrations and duration on diet lead to improvements in skin color, that is, lower hues (~27–29 to ~14–17; redder fish), higher saturation (~77 to ~87 %), and lower luminosity (~43 to ~35 %). Fish fed 80 and 160 mg kg^?1 astaxanthin feed showed significant coloration improvements over fish fed lower astaxanthin feeds. Increasing both dietary astaxanthin concentration and time on the feed resulted in significant increases in total skin carotenoid concentration (0.033–0.099 μg mm^?2). Furthermore, there was a significant linear relationship between hue and total skin carotenoid concentration. Compositionally, free astaxanthin and 4-hydroxyzeaxanthin were the major skin carotenoids. 4-hydroxyzeaxanthin was previously unreported for A. ocellaris. Carotenoid composition was affected by duration on diet. Fraction 4-hydroxyzeaxanthin increased by ~15 %, while free astaxanthin decreased equivalently. The transition from 4-hydroxyzeaxanthin to free astaxanthin appears to follow a reductive pathway. Results suggest that managing coloration in the production of A. ocellaris juveniles requires manipulation of both dietary astaxanthin concentration and period of exposure to astaxanthin containing diet. In order to achieve more orange–red-colored fish, feeding 80–160 mg kg^?1 esterified astaxanthin for an extended duration is recommended.