Response of juvenile astacid crayfish (Pacifastacus leniusculus) to three commercial dry diets with different protein levels during the first 6 months of intensive rearing

Abstract

A 180-day experiment was carried out under controlled conditions to compare the effects of three commercial dry diets on survival, growth and body composition of juvenile Pacifastacus leniusculus from the onset of exogenous feeding (stage 2). Protein levels in the diets were 55.5% [high-protein content (HP) diet], 40.3% [medium-protein content (MP)] and 33.2% [low-protein content (LP)]. Diets were supplemented with restricted amounts of live fresh Artemia nauplii up to day 120. No significant differences in survival among diets were found along the trial, with final values around 68.5%. During the live feed supplementation, growth was similar with the three diets. At the end of the trial, weight with HP or with MP was similar (around 2.32 g) and significantly higher than with LP (1.97 g). Thus, a diet with 40% of protein can be suitable, as it allowed similar results as the diet containing 55%. Levels of protein in diets and in crayfish muscle were positively correlated (r=0.8). This study also shows that an intensive rearing up to 180 days with good survival and growth rates is possible using dry diets for finfish species supplemented with live feed.