Effects of three diets on growth and body composition of gilthead sea bream, Sparus aurata

Wild gilthead sea bream fingerlings (4.3p 1.8 g) were reared to portion size (250 g) in an ambient seawater system with varying temperature (10.3-24.3o C) for 15.0-16.6 months. They were fed commercial crumbels and pellets alone (F1), or mixed with 35% chicken eggs (F2), or mixed with 35% blue mussel flesh (F3). The daily feeding rate, daily protein feeding rate, daily growth rate, feed efficency (FE), protein efficency ratio (PER), protein productive value (PPV) and specific growth rate (SGR) were calculated monthly after weighing. Fish fed diet F3 grew to 250 g significantly (P<0.05 ; ANOVA) faster than those fed F2 or F1, in 15.0 months rather than 16.6 months. The daily feeding rates significantly differed (P<0.05) between groups and was highest in group F3 (3.80p 0.18%) and lowest in group F1 (1.72p 0.34%). There were no significant differences in daily growth rate (P=0.58-0.11). The daily growth rate, FE, Per and PPV were negative in winter. The final body composition of the tested fish had significantly less moisture (65.0-68.5%) and higher lipids (8.4-10.3%) than initially and than specimens from a native environment (73.6-71.6% and 0.6-3.7%, respectively).