Pigmenting efficacy of astaxanthin and canthaxanthin in fresh-water reared Atlantic salmon, Salmo salar

A 25-week feeding trial was performed to evaluate the efficacy of astaxanthin versus canthaxanthin, at mixed, graded levels in diets of freshwater reared Atlantic salmon, growing from an initial body weight of 408 g to a final weight of 1.2 kg. ietary pigment ratios were tested in five replicates. Dietary treatments were set-up to provide pigment ratios ranging from 1.00 of pigment from astaxanthin (45 mg/kg feed), to 1.00 from canthaxanthin (72 mg/kg feed). and feed utilisation parameters were unaffected by dietary treatment (P>0.05). trast to work on rainbow trout, there was no difference in the flesh pigment deposition of astaxanthin or canthaxanthin (P>0.05) in Atlantic salmon. Flesh deposition was linearly related to feed dose for both carotenoids, indicating that even at 70 mg/kg, canthaxanthin deposition had not reached a plateau in the fish under test. This could support the practice of feeding of levels of carotenoid at around 70 mg/kg in early grow-out phases of salmon since a significant incremental flesh response was observed (P<0.05). Linearity of the dose/ deposition relationship indicated that feed astaxanthin and canthaxanthin did not interact. e the relatively low flesh pigment levels attained, raw fillet colour was seen to be close to colour targets adopted for harvest-size fish.