1 SEPTEMBER 1999
G. Mourente, D.R. Tocher, E. Diaz-Salvago, A. Grau, E. Pastor-1999
Aquaculture, 179(1-4)-Special Issue: Proceedings of the VIII International Symposium on Feeding and Nutrition in Fish (recent Advances in Finfish & Crustacean Nutrition): 291-307
Abstract:
This study was designed to investigate the requirements of Dentex dentex larvae for n-3 highly unsaturated fatty acids (HUFA) at the Artemia feeding stage. Artemia were enriched using mixtures of experimental emulsions containing (a) 500 mg g-1 n-3 HUFA, 0.6 DHA/EPA ratio, based on ethyl esters and (b) 0 mg g-1 n-3 HUFA, based on coconut oil, to give five dietary treatments 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 dietary 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 significantly lower vitamin E content and higher malondialdehyde (MDA) levels combined with their eyes having maximum n-3 HUFA values and DHA/EPA ratios. Poorer 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. The activities of antioxidant enzyme in the larvae was generally not greatly affected by the dietary treatments in this study. A balance is required between 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.
(Department of Animal Biology, Vegetal Biology and Ecology, Faculty of Marine Sciences, University of Cadiz, Centro Andaluz Superior de Estudios Marinos (CASEM), Apartado 40, E-11510 Puerto Real, Cadiz, Spain)