Effects of protein and lipid content of three artificial foods on survival and growth of common dentex during the on-growing phase (Dentex dentex Linneaus, 1758).

The purpose of this work is to highlight the effects of three different foods containing protein and lipids on the survival and growth of common dentex during the on-growing phase. Common dentex fingerlings weighting 5-6g were grown for one year in polyester tanks. Three diets were used (A1, A2 and A3), respectively, had a protein content of 55%, 45%, 33% and lipid level of 10%, 15% 23%. At the end of the experiment, fishes have reached a weight of 310.20 ± 7.76, 406.24 ± 11.01, 230.20 ± 6.41g, respectively, for A1, A2 and A3. The respective survivals were of 60%, 80% and 88%. The specific growth rates were of 1.04, 1.13 and 1.04 while the respective food conversion rates were of 1.45, 1.30 and 2.0. Diet containing 45% protein and 15% lipid gave the highest specific growth rate and the lowest food conversion rate with an intermediate survival of 80%. Results obtained during this phase are encouraged to undertake large-scale farming in sea cages, knowing that to transfer the fries into cages must have a weight greater than 6g. This study showed that during one year common dentex reached commercial size despite a thermal profile whose values have not reached the optimum temperatures for the majority of sparidae.