Nivel óptimo de proteína dietaria para juveniles de lenguado paralichthys adspersus (Pisces: Pleuronectiformes)

Abstract

This study establishes the dietary protein level for maximum growth in Paralichthys adspersus juveniles. According with this purpose, three diets based on fish meal were formulated with increasing protein levels (48, 57 and 60%), which were compared with a commercial diet (54% protein; BIOMAR S.A.). Furthermore, the optimal protein level were determined and compared through bioassays using growth indicators, fitness, and regression analysis. A total of 156 juveniles (131.3 ± 23 g), separated in 13 individuals per group, were maintained in black conical tanks with a flat base, with 5.5 kg m-2 initial densities, and with a circulation system of open water for 175 days. The fish were fed daily to satiety twice per day with diets based on fish meal and oil, starch, vitamins and minerals. Based on the results of this study, we conclude that the optimal dietary protein level was obtained in diets with 54 and 57% of protein. If production costs are prioritized in flounder culture, the 54% protein diet is optimal for juveniles. However, considering the flounder growth, then 57% protein diet contains the optimal level. This study is a precedent for further research on the nutritional requirements of P. adspersus in order to improve their growth in captivity.