Weaning of the common snook (Centropomus undecimalis) early juveniles reared in laboratory using commercial and experimental diets

Abstract

Laboratory-reared early juveniles (48 days after hatching) of the common snook (Centropomus undecimalis) were fed for 30 days using three different diets in order to evaluate transition from live to inert diet (weaning): 1) an experimental dry diet (46% crude protein), 2) a commercial dry diet (57% crude protein), and 3) only enriched Artemia metanauplii, used as a control group. The fish were placed in 80 L cylindrical tanks (three replicates) equipped with aeration and flow-through water (34 ± 1 salinity), and kept at 26.0 ± 0.5°C. The specific growth rates obtained in treatments 1 (5.62% day^-1) and 2 (6.13% day^-1) were similar (P = 0.32) and higher than the specific growth rate verified in the control group (3.71% day^-1) (P = 0.002). The feed conversion ratio was more efficient with the commercial diet (0.85 ± 0.04) when compared to the experimental diet (1.41 ± 0.15) (P = 0.003). There were no significant differences among the survival rates observed in the different treatments (P = 0.05) with values of 61.00 ± 1.00%, 83.66 ± 5.77% and 77.33 ± 14.57% for experimental, commercial and control diets, respectively. This study demonstrates that the inert diets tested were appropriate for weaning the common snook early juveniles.