Study of the n-3 highly unsaturated fatty acids requirement and antioxidant status of Dentex dentex larvae at the Artemia feeding stage

This study was designed to investigate the requirements of Dentex dentex la rvae for n-3 highly unsaturated fatty acids (HUFA) at the Artemia feeding s tage. Artemia were enriched using mixtures of experimental emulsions contai ning (a) 500 mg g(-1) n-3 HUFA, 0.6 DHA/EPA ratio, based on ethyl esters an d (b) 0 mg g(-1) n-3 HUFA, based on coconut oil, to give five dietary treat ments which contained different levels of n-3 HUFA from 0.72 to 6.23 as dry wt.%. Optimal growth, as evidenced by total length, individual dry weight, specific growth rate and thermal growth coefficient, was achieved when die tary n-3 HUFA was 3.97% on a dry weight basis. Larvae fed Artemia enriched with apparently super-optimal levels of n-3 HUFA (5.67-6.23%) showed signif icantly lower vitamin E content and higher malondialdehyde (MDA) levels com bined with their eyes having maximum n-3 HUFA values and DHA/EPA ratios. Po orer performance of larvae was associated with increased dietary and larval MDA and decreased larval vitamin E, indicating increasing oxidation of n-3 HUFA in Artemia and larval utilization of vitamin E with increasing levels of dietary n-3 HUFA, particularly at supraoptimal levels of enrichment. Th e activities of antioxidant enzyme in the larvae was generally not greatly affected by the dietary treatments in this study. A balance is required bet ween growth-promoting essential fatty acids (EFA) qualities of n-3 HUFA and their potentially growth-inhibiting (pro-oxidant) qualities which must be counter-balanced with adequate dietary antioxidants. (C) 1999 Elsevier Scie nce B.V. All rights reserved.