The influence of different dietary energy content and feeding regimes on growth and feed utilization of European sea bass (Dicentrarchus labrax, L.)

The growing importance of European sea bass in aquaculture poses the problem to find suitable and efficient feeding for this specific fish. In order to assess the influence of different dietary energy content and feeding regimes, it has been carried out a trial on ongrowing European sea bass at average initial weight of about 68g. 744 fish were randomly allocated to 12 800L tanks in a closed recirculation system provided by biofilter and UV lamps. Marine water was kept at a temperature of about 22 °C and dissolved oxygen level never falls below 90% of saturation. Isoproteic (47% crude protein) extruded experimental diets were formulated with three different lipid levels i.e. 16% (diet 16:D16), 24% (diet 24:D24) and 32% (diet 32:D32). For each diet, two feeding regimes were set up in duplicate: satiation and 80% of satiation. Feed intake (FI) were recorded daily. After 77 days, fish were bulk weight and growth, SGR and FCR were calculated. Furthermore, after diets chemical analyses, protein and lipid intake were determined. Finally, in order to check feeding costs, the economic efficiency ratio was calculated. Statistical analyses of all data were performed using a two-way analysis of variance (ANOVA). When p values showed significance, individual means were compared using Tukey’s multiple range test to detect intergroup significant differences. On a statistical basis, feeding regimes influenced all parameters analysed, whereas diet only FCR, FI, protein and lipid intake and EER. In the group of fish fed to satiation, the diet with the lowest energy content (D16) gave very interesting results for feed intake, FCR and EER. They scored the highest feed intake, a FCR slightly higher than satiation groups fed D24 and D32 but not statistically different from them and the lowest EER.