The effect of feeds containing different protein levels on growth and survival rates of European sea bass (Dicentrarchus labrax L., 1758) juveniles grown in freshwater

In this study, the effect of the use of feeds containing different protein ratios on the growth performance of juvenile sea bass (Dicentrarchus labrax L., 1758) reared in freshwater was investigated. Sea bass fry with an average body weight of 1.0 ± 0.03 g were stocked in 120 liter tanks in triplicate after their adaptation to freshwater. The feeds used in the study had different protein/similar fat content. Accordingly, the experimental groups were named as 45CP (45% CP / 18% CF), 50CP (50% CP / 18% CF) and 55CP (55% CP / 18% CF). At the end of the experiment, the highest body weight gain was 5.84 ± 0.03 g in the 55CP group, while the other groups were 5.73 ± 0.09 g (45CP) and 5.8 ± 0.08 g (50CP). SGR rates were similar for all three groups and there was no statistical difference between the groups (P>0.05). SGR values of the groups were calculated as 1.94 ± 0.04 (45CP), 1.89 ± 0.01 (50CP), 1.91 ± 0.02 (55CP), respectively. There was no statistical difference between the 45CP and 55CP groups, while the 50CP group showed a statistically lower FCR rate than the other groups (P<0.05). FCR values were calculated as 1.36 ± 0.05, 1.29 ± 0.03, 1.37 ± 0.04, respectively. There was no difference between the survival rates of the groups. According to the results of the study, it was concluded that sea bass fish can be raised in freshwater, especially in the fry stage, and that it is more effective than the commercial feeds currently used.