The influence of dietary astaxanthin and temperature on flesh colour in Arctic charr Salvelinus alpinus L.

Arctic charr Salvelinus alpinus L. averaging 150 g were fed six diets containing from 0 to 192 mg astaxanthin per kilogram dry diet al two temperatures (8 C and 12 C), After reaching an average weight of 320 g (102 days at 12 C and 126 days at 8 C), the fish were killed for evaluation of flesh pigmentation using instrumental colour measurement. There was a positive relationship between dietary astaxanthin and muscle redness up to a dietary concentration of around 70 mg kg^-1, where a plateau in pigmentation was reached. Tail sections were more intensely pigmented compared with the neck and dorsal regions. Within each temperature regime, flesh coloration was positively correlated to specific growth rate. Fish maintained at 8 C had significantly higher pigmentation compared to those grown at 12 C.