Effect of dietary amino acid composition from proteins alternative to fishmeal on the growth of juveniles of the common snook, Centropomus undecimalis

Abstract

This study investigated the effect of dietary amino acid composition from proteins alternative to fishmeal on the growth performance of the common snook, Centropomus undecimalis. Fish of 10.79±0.71 g (n = 150) were stocked in 15 shaded outdoor tanks of 1 m3. The basal diet contained 643.4 g kg-1 salmon byproduct meal (SML) and 200.0 g kg-1 soy protein concentrate (SPC). Two other diets replaced 39 and 29% of the SML with poultry byproduct meal (PBM, 170.1 g kg-1) and SPC (334.9 g kg-1), respectively. Fish were fed twice daily for 84 days under 32±1 g L-1 water salinity and 27.3±0.9 °C temperature. Final survival (99.5±2.6%) was unaffected by dietary treatment. Snook grew slower (0.24±0.03 and 0.27±0.04 vs 0.35±0.06 g day-1) and achieved the lowest body weight (31.1±6.62 and 33.3±10.20 vs 40.4±13.18 g) and the highest feed conversion ratio (3.69±0.29 and 3.11±0.51 vs 2.33±0.34) when fed SPC and basal diets compared with PBM, respectively. Retention of dietary crude protein varied from 36 to 38% for fish fed the basal and SPC diets, but exceeded 51% in fish fed PBM. Results indicate a greater ability of the common snook to gain weight and increase retention of nutrients when dietary protein is of terrestrial animal origin. Dietary protein from PBM yields a more balanced dietary amino acid composition relative to fish muscle, but possibly in excess of the species requirements.