Effect of protein and lipid dietary levels on the growth of juvenile meagre (Argyrosomus regius)

This study investigates the effects of dietary lipid and protein levels in the growth, feed utilization and body composition of meagre (Argyrosomus regius). Triplicate groups of juvenile fish (23.4 ± 4.9 g average weight ± SD) were fed four isolipidic diets (17.5% crude lipids) containing 40, 45, 50 and 54% of protein, while in a separate experiment, fish (21.8 ± 3.7 g average weight ± SD) were fed four isonitrogenous (50% crude protein, dry matter) each containing 12, 15, 17 or 20% of crude lipids. In the protein requirement experiment, the increase in crude protein in the diet from 40 up to 50% positively affected SGR (Specific growth rate) and FCR (Feed conversion ratio). The increase in crude lipids in the diet from 12 up to 17% showed a tendency for improvement in SGR and FCR. In both experiments, the fastest growing fish exhibited higher lipid depots. Overall, the present investigation showed that juvenile meagre has an estimated protein requirement of 50% and it does not seem to require high dietary lipid levels.