LIPID AND FATTY-ACID COMPOSITION OF NORMAL AND MALPIGMENTED ATLANTIC HALIBUT (HIPPOGLOSSUS-HIPPOGLOSSUS) FED ENRICHED ARTEMIA - A COMPARISON WITH FRY FED WILD COPEPODS

Atlantic halibut larvae originating from a single spawn of one female and one male were fed either Super Selco(TM) enriched, enrichment-grad e Artemia nauplii or extensively grown zooplankton. The feeding experi ment was conducted in 1.5-m(3) outdoor tanks to evaluate if diet affec ted pigmentation. Pigmentation rates were found to be higher in the zo oplankton-fed fish: 99.2% compared to 66.4% in the Artemia-fed halibut . Lipid and fatty acid analyses were performed on five malpigmented Ar temia-fed fry, five normally pigmented Artemia-fed fry and 10 copepod- fed fry after 43 days feeding. Lipid class analysis was carried out on the eyes and carcasses of the halibut fry by HPTLC and densitometry. Fatty acid analyses of the same tissues were performed by gas liquid c hromatography. Copepod-fed fry showed significantly higher levels of d ocosahexaenoic acid (22:6n - 3; DHA) than their Artemia-fed counterpar ts (54.9% and 15.8% DHA in eye phosphatidylethanolamine (PE), respecti vely). Ratios of DHA: eicosapentaenoic acid (20:5n - 3; EPA) were also higher in the copepod-fed fish: 11.1, 4.1 and 2.3 in, respectively, P E, phosphatidylcholine (PC) and triglyceride (TAG) in the eye lipid fr actions of copepod-fed fry compared to 0.7, 0.3 and 0.1 in the same li pid of eyes of Artemia-fed fry. Within the Artemia-fed population, DHA and EPA levels were slightly, but significantly, raised in the eye PC fractions of normally pigmented fish compared to malpigmented ones. H owever, there was no significant difference in DHA:EPA ratios between normal and malpigmented fish fed Artemia. EPA: arachidonic acid (ARA) ratios were higher in zooplankton-fed fish but there was no significan t difference in these ratios between normal and malpigmented Artemia-f ed halibut. (C) 1998 Elsevier Science B.V. All rights reserved.