Relationship between blood and muscle levels of astaxanthin in dorsal aorta cannulated Atlantic salmon

Twelve previously unpigmented Atlantic salmon with a body weight of 545 39 (SE) g were kept individually and fed a diet containing 69 mg-kg(-1) astaxanthin for 63 days. On day 35 each fish was fitted with a dorsal aorta cannula. During the last 28 days blood levels of astaxanthin were measured on three separate occasions. At 63 days the fish were slaughtered and muscle content of astaxanthin was analysed. The fish had grown by an average of 171 29 g, with an SGR of 0.61 +/- 0.08, with a feed conversion ratio of 0.84 +/- 0.10 and astaxanthin retention of 7-10%, during the 63-day period. The average blood concentration of astaxanthin was 0.65 +/- 0.09 mu g(.)g(-1) and muscle content was 0.68 +/- 0.12 mg(.)kg(-1). Muscle content and retention of astaxanthin varied closely with that of blood concentration (R-2 = 0.92, p < 0.0001, R-2 =0.88, p < 0.0001, respectively) independent of fish size and feed intake. On the other hand, the effect of feed intake on astaxanthin blood level was less clear. Only SGR (R-2 < 0.1) among the other factors measured, such feed conversion, body size or feed intake (expressed as percent of body weight) were significant (P > 0.05) related to either astaxanthin blood or muscle level. On the basis of the data and provided that feed intake and fish is included in the analysis, we concluded that the level of astaxanthin in blood is indicative of long-term muscle deposition and can be used as a rapid scanning method to distinguish between the effects of different dietary treatments on long-term deposition of astaxanthin in muscle. (c) 2005 Elsevier B.V. All rights reserved.