EFFECTS OF BROODSTOCK DIETARY-LIPID ON FATTY-ACID COMPOSITIONS OF EGGS FROM SEA BASS (DICENTRARCHUS-LABRAX)

Samples of sea bass (Dicentrarchus labrax) eggs from broodstock which had been fed either a formulated pelleted feed, containing fish and co rn oil, or a local trash fish, bogue (Boops boops) were analysed for l ipid class compositions, fatty acid compositions of phosphatidylcholin e (PC), phosphatidylethanolamine (PE) and phosphatidylinositol (PI) an d wax ester and fatty alcohol compositions of wax esters. The pelleted feed contained 1.3 mg g(-1) of arachidonic acid (20:4n-6; AA) and an AA/eicosapentaenoic acid (20:5n-3; EPA) ratio of 0.1 while the trash f ish contained 4.8 mg g(-1) AA and an AA/EPA ratio of 0.7. Docosahexaen oic acid (22:6n-3; DHA) concentrations were similar for both diets (ab out 23 mg g(-1)). The fatty acid compositions of PC, PE and PI from eg gs of fish fed trash fish contained significantly more AA, 22:5n-6 and DHA compared to fish fed the pelleted feed. The AA/EPA ratios in thes e phospholipids were around five-fold higher in the trash fish-fed gro up compared to those fed the fish and corn oil containing diet. In PI, which contains characteristically high levels of AA, the AA/EPA ratio s were 1.5 and 8.6 for eggs derived from broodstock fed the pelleted d iet and the trash fish, respectively. Determination of lipid class com positions of sea bass eggs revealed the presence of high levels of wax esters which were previously unrecorded in this species. The use of b roodstock diets containing blends of corn oil and Northern hemisphere fish oils may be undesirable in that they contain high levels of 18:2n -6 and have low ratios of DHA/EPA and of AA/EPA. In an effort to impro ve egg quality and larval viability, efforts should be directed toward s establishing the best ratio of DHA/EPA/AA in formulated feeds such t hat requirements for neural function and visual performance are maximi sed and that production and efficacy of eicosanoids are adequate to pe rmit physiological functions to operate efficiently. (C) 1997 Elsevier Science B.V. All rights reserved.