Effects of the levels of astaxanthin in the diet on the flesh pigmentation of rainbow trout

A feeding trial was conducted to study the effects of dietary astaxanthin concentration on muscle pigmentation of rainbow trout (Oncorhynchus mykiss) with a mean initial weight of 270 g fed diets supplemented with astaxanthin in diet concentrations of 60 (group II) and 90 mg/kg (group III) for 35 days. A control (I) group received a diet without astaxanthin. At the end of the experiment, the trout showed average body weight increases of 250.660 g, 261.675 g and 234.410 g, and the flesh reached a level of 0.695 mg/kg. 10.539 mg/kg and 11.954 mg carotenoid/kg in groups I. II and III, respectively (initially, 0.595 mg/kg). Fish pigmentation increased with increasing dietary carotenoid concentration. But the retention coefficients decreased as the pigment dose in the diet increased.