Growth performance, mortality and carotenoid pigmentation of fry offspring as affected by dietary supplementation of astaxanthin to female rainbow trout (Oncorhynchus mykiss) broodstock

Growth performance, mortality and carotenoid pigmentation were studied in triplicate groups each with 1000 swim-up larvae of rainbow trout (Oncorhynchus mykiss), derived from five groups of female broodstock fed diets with 0.07, 12.5, 33.3, 65.1 or 92.9 mg astaxanthin kg(-1), respectively. The first feeding fry ( initial weight range from 113 to 148 mg) were fed a diet not supplemented with carotenoids in an experiment lasting 45 days. Fry were initially sampled for astaxanthin content and initial weight, and in subsequent 15-day intervals to determine weights, condition factors (CF), specific growth rates (SGR) and thermal growth coefficients (TGC). Total carotenoid concentration of the larvae was highly linearly correlated to that of the eggs (r(2) = 0.97, P = 0.002). About 59-67% of fry carotenoids consisted of esterified astaxanthin, and on average 39.7% of the egg carotenoids were recovered in the fry. Overall (0-45 days) SGRs and TGCs were significantly higher (P < 0.05) in the offspring of the four groups of females fed supplemented diets (12.5-92.9 mg astaxanthin kg(-1)) than in offspring of females fed the non-supplemented diet. TGCs (0-45 days) within groups derived from broodstock supplemented with astaxanthin were similar (P > 0.05), but higher than in the group derived from females fed the diet not supplemented with astaxanthin ( P < 0.05). Mortality (average 0.76%) was not significantly affected by treatment. The study indicates that dietary supplement of astaxanthin (> 12.5 mg kg(-1)) to maternal broodstock diets improves offspring SGR and TGC with up to 33 and 38%, respectively.