Optimization of Artemia Metanauplii on Growth and Survival of Gilthead Sea Bream Larvae Sparus aurata

–Growth, feed efficiency and survival of gilthead sea bream Sparus aurata larvae fed exclusively various levels of enriched Artemia during the period 25 DPH-34 DPH were investigated. Larvae had an average initial fresh body weight (BW) of 4.99 mg and were fed on Artemia at rates of 20, 35, 50, 65, and 80% of their body weight per day, in two equal meals. Each ration was administered to duplicate groups of 1,000 larvae, with ration readjusted every second day. Feeding rate had a significant effect on larval survival, which was lower in larvae fed the 20 and 35% BS/d rations. The specific growth rate (SGR) showed a curvilinear significant increase when the feeding rate was increased from 20 to 65% BW/d, but there was no improvement when the feeding rate was increased from 65 to 80% BW/d. Percent feed efficiency (FE) decreased significantly from a maximum value at 20% ration to 80% BW/d but at 65% and 80% rations the values of FE were not significantly different. Optimum ration (minimum quantity of Artemia concomitant with maximum larval growth) was estimated close to 65% BW/d. The significance of the results is discussed in relation to potential economics of Artemia cysts use in commercial hatcheries.