Effects of varying dietary docosahexaenoic acid levels on growth, proximate composition and tissue fatty acid profile of juvenile silver pomfrets, Pampus argenteus (Euphrasen, 1788)

This study investigated the effects of varying dietary levels of decosahexaenoic acid (DHA) on growth performance, proximate composition and whole body fatty acid profiles of juvenile silver pomfret, Pampus argenteus. Triplicate groups of fish (30.55 +/- 0.08g) were fed diets containing 5.2%, 9.31% and 13.38% DHA (% of total fatty acids) or 0.85%, 1.52% and 2.18% DHA on dry diet weight for diets 1, 2 and 3 respectively. Survival was not affected by dietary DHA levels. The growth performance and feed utilization parameters of fish fed diets 2 and 3 were significantly (P<0.05) higher than those fed diet 1, although these parameters in diets 2 and 3 did not differ significantly (P>0.05). Whole body lipid and fatty acid profiles were influenced by dietary DHA levels. Significantly higher n-3 fatty acids particularly DHA, DHA:EPA(eicosapentaenoic acid) ratios and n-3:n-6 ratios were observed in fish fed diets 2 and 3 compared to those fed diet 1. Better growth performance and higher whole body DHA:EPA (2.31, 2.29) ratios and n-3:n-6 ratios (2.17, 2.12) observed in fish fed diets 2 and 3, respectively, suggests that silver pomfret juveniles have a higher requirement for n-3 fatty acids, notably DHA for optimum growth and survival.