Astaxanthin deposition in fillets of Atlantic salmon Salmo salar L. fed two dietary levels of astaxanthin in combination with three levels of α-tocopheryl acetate

Abstract

The influence of alpha-tocopheryl acetate (alpha-TOAc) on plasma concentration and fillet deposition of dietary astaxanthin was investigated in Atlantic salmon Salmo salar L. The diets were added 30 or 50 mg kg(-1) astaxanthin, and 200, 400 or 800 mg kg(-1) alpha-TOAc at each astaxanthin level. Improved flesh deposition of astaxanthin by 8-14% was achieved for fish fed diets with 30 and 50 mg kg(-1) astaxanthin, respectively, by the dietary addition of 800 compared with 200 mg kg(-1) alpha-TOAc. These results were supported by CIE[1976]L*a*b* tristimulus redness measurements (a* value). Plasma astaxanthin concentration mirrored the muscle astaxanthin concentration in the groups of fish fed a diet containing 30 mg kg(-1) astaxanthin. The salmon fed a high astaxanthin and low alpha-TOAc diet had the highest plasma concentration of idoxanthin (P < 0.05). Astaxanthin retention was significantly higher (P < 0.001) in salmon fed 30 mg kg(-1) astaxanthin than in those fed 50 mg kg(-1) astaxanthin, but was not significantly affected by dietary alpha-TOAc. Liver weight, body weight, specific growth rate, feed/gain ratio and mortalities were not affected by dietary alpha-TOAc levels. In conclusion, the dietary addition of alpha-TOAc appears to increase astaxanthin fillet deposition in salmonids and may reduce the demand for astaxanthin supplementation. The effect was rather small and requires verification.