FLESH LIPID AND CAROTENOID COMPOSITION OF SCOTTISH FARMED ATLANTIC SALMON (SALMO-SALAR)

Samples of steaks from market-size salmon (2.5-5 kg), produced under t he requirements of the Product Certification Scheme for Scottish Quali ty Farmed Salmon, were obtained from five Scottish salmon producers on a weekly basis for over 2 years. Samples were assayed for total lipid content, lipid class composition, fatty acid composition, vitamin E c ontent, and carotenoid pigment [astaxanthin (AX) and canthaxanthin (CX )] content. In addition, samples were obtained from the same producers to assess loss of carotenoid pigment in the period up to 120 h post-h arvest and to measure lipid and pigment content of different body regi ons. The analyses showed a positive correlation between dietary lipid and deposition of lipid in flesh, although there was great variation i n flesh lipid content within each dietary lipid level. The average lip id content of Scottish salmon was 10.1 +/- 2.9% (n = 495). Salmon fles h was rich in the n-3 highly unsaturated fatty acids, 22: 6n-3 and 20: 5n-3, with average values of 11.3 and 5.4% of total fatty acids or 10. 2 and 4.8 g/kg flesh, respectively. Vitamin E content of salmon flesh was around 30 mg/kg but was significantly higher in fish fed the lowes t dietary lipid level. Studies investigating changes in carotenoid pig mentation up to 120 h post-harvest suggested that fish fed AX alone sh owed a loss of pigment over time that did not occur in fish fed either CX alone or a combination of AX and CX. Measurement of lipid content of different body regions showed that the highest levels were found in the region immediately in front of the dorsal fin and that the lowest lipid levels were in the tail region. Total lipid content of all five body zones was positively correlated with dietary lipid. Carotenoid p igment levels were the same across all body zones and were not affecte d by dietary lipid.