Carotenoids in diets for salmonids. IV. Pigmentation of Atlantic salmon with astaxanthin, astaxanthin dipalmitate and canthaxanthin

Abstract

Diets supplemented with synthetic astaxanthin, astaxanthin dipalmitate and canthaxanthin at concentrations of 0, 30, 60 and 90 mg/kg, as carotenoid equivalents, were fed to groups of Atlantic salmon (Salmo salar L.) for 56 weeks. The mean initial and final fish weights were 62 and 406 g respectively. There was a tendency for astaxanthin to be more efficiently utilized than canthaxanthin, which in turn was more efficiently utilized than astaxanthin dipalmitate, for flesh pigmentation. These differences were partly explained by differences in the apparent digestibility of the carotenoids. The flesh pigmentation increased with increasing dietary carotenoid concentration. The visual assessments of flesh colour by means of a colour scale correlated well with the chemical determination. The carotenoid content of the skin was higher for the fish fed diets containing carotenoids than for the control groups, but there was no significant difference in the carotenoid concentration in the skin of the fish fed the different carotenoids. © 1987.