Impact of Different Dietary Phospholipid Levels on Cholesterol and Canthaxanthin Lipoprotein -Serum Transport and Muscle Deposition in Rainbow Trout

The study was designed to assess the effect of a progressive increase of dietary phospholipid (PL) levels in the transport of cholesterol and canthaxanthin by serum lipoproteins and their deposition in trout muscle. Three groups of 30 immature rainbow trouts, in triplicate, with a mean body weight of 195 g were fed three experimental diets containing 0, 4, and 8% extra PL contents for 6 weeks. The two major lipoprotein classes in rainbow trout were HDL and LDL. Both lipoproteins were the main transporters of serum canthaxanthin, whereas cholesterol was transported principally by LDL. Serum cholesterol contents remained constant, whereas serum canthaxanthin was increased when the PL amount augmented. In muscle, PL seemed not to have an effect on cholesterol and canthaxanthin deposition. Therefore, as an extra-PL contribution in the diet did not increase relative percentages of cholesterol and/or canthaxanthin in trout muscle, the results support the hypothesis that dietary extra-PL addition is not necessary to increase cholesterol and canthaxanthin and thus fish flesh pigmentation. However, a saturation effect of diet PL contents was found on muscle canthaxanthin deposition.