Effects of fishmeal replacement by feather meal in practical diets for juvenile crayfish ( Pacifastacus leniusculus Dana, Astacidae).

The aim of this study was to evaluate different replacement levels of fishmeal ( FM) by feather meal (FeM) on survival and growth of juvenile crayfish ( Pacifastacus leniusculus). An 80-day experiment was conducted with stage 2 juveniles from the onset of exogenous feeding. Four practical diets (500 g kg⁻¹ protein) differing in the level of replacement of FM protein by FeM protein were prepared: 0% (control diet), 15% (8.2% dietary FeM), 25% (13.7% dietary FeM) or 35% (19.2% dietary FeM). Each diet was tested on grouped or individually isolated crayfish. Crayfish fed the control diet or 15% replacement achieved the highest survival (average of grouped and isolated: 88.2%) and growth (grouped and isolated: 13.58 mm carapace length, 523.2 mg weight) and the lowest feed conversion ratio (average of grouped and isolated: 1.11). Final growth of isolated crayfish was significantly higher than that of grouped crayfish for all diets. This study provides the first data on the substitution possibilities of FM by FeM in diets for freshwater crayfish. An 8.2% of FeM (15% replacement of FM protein) can be included in extruded diets for juvenile P. leniusculus during the first 80 days of intensive rearing without impairing growth or feed conversion. [ABSTRACT FROM AUTHOR]