How Apparent Digestibility of Carotenoids,Macronutrients, and Minerals are Differently Affected by Ration Level in Atlantic Salmon,Salmo Salar

The main objective of this field experiment was to investigate whether ration level affected utilization of carotenoids, macronutrients, and minerals in 1,300 g Atlantic salmon (Salmo salar) during rapid growth. Salmon fed ration levels of either 1.2% or 0.6% of biomass of a commercial diet supplemented with astaxanthin and canthaxanthin (37 and 39 mg kg^?1, respectively) in two consecutive 6-day feeding periods had carotenoid digestibility coefficients of 11.8% and 32.1% at the high and low feed rations, respectively. Thus, low carotenoid digestibility, but good macronutrient digestibility, may explain poor pigmentation and good feed conversion in rapidly growing salmon. Practical implications are illustrated.