Optimum feeding rates in juvenile olive flounder, Paralichthys olivaceus, at the optimum rearing temperature

Two feeding trials were carried out to determine the optimum feeding rates in juvenile olive flounder, Paralichthys olivaceus, at the optimum rearing temperature. Fish averaging 5.0 +/- 0.11g (mean +/- SD) in experiment 1 and 20.2 +/- 0.54g (mean +/- SD) in experiment 2 were fed a commercial diet at the feeding rates of 0%, 3.0%, 4.0%, 4.25%, 4.5% and 4.75% body weight (BW) day1 and satiation (5.52%BWday1) in experiment 1 and 0%, 1.0%, 2.0%, 3.0% and 3.5% BW day1 and satiation (4.12%BWday1) in experiment 2 at 20 +/- 1 degrees C. Both feeding trials lasted for 2weeks. Results from experiment 1 indicated that weight gain (WG) and specific growth rate (SGR) of fish fed to satiation were significantly higher than those of fish fed at other feeding rates while feed efficiency (FE) and protein efficiency ratio (PER) of fish fed at 4.25%BWday1 were significantly higher than those of fish fed to satiation and fish fed at 3.0%BWday1 (P<0.05). In experiment 2 WG, SGR and PER leveled out after the feeding rate of 3.5%BWday1 whereas FE reached a plateau at 3.0%BWday1. anova of FE indicated that the optimum feeding rates in 5.0 and 20g juvenile olive flounder could be 4.25% and 3.0%BWday1, respectively. Broken line analysis of WG suggested the optimum feeding rates of 5.17% and 3.47%BWday1 in 5.0 and 20g fish, respectively. Therefore, these results indicated that the optimum feeding rates could be >4.25 but <5.17%BWday1 for 5.0g, and it could be >3.0 but <3.47%BWday1 for 20g size of juvenile olive flounder at the optimum rearing temperature.