Inclusion of poultry by-product meal in the diet of Sparidentex hasta: Effects on production performance, digestibility and nutrient retention

A 60-day experiment was conducted to evaluate the effect of replacement of fish meal (FM) with poultry by-product meal (PBM) on growth performance and feed utilization of juvenile sobaity sea bream (Sparidentex hasta). PBM replaced 0, 15, 25, 35, 45 and 55% of dietary FM in the isoproteic (500 g kg−1) and isocaloric (21 kj g−1) experimental diets. Sobaity sea bream with an average initial weight of 29.27 ± 0.06 g were randomly assigned to 18 tanks (6 treatments with triplicates each) at an initial stocking density of 20 fish per tank. The final body weight, weight gain, specific growth rate, protein efficiency ratio and nitrogen retention efficiency were higher in fish fed PBM15, 25 and 35 diets than in fish fed the control, PBM45 and 55 diets. Feed conversion ratio, nitrogen and phosphorus wastage did not show significant differences in PBM0, 35, 45 and 55. Increased retention of arginine, lysine, methionine, histidine and taurine was observed at lower dietary content of the respective amino acids. The morphometric indices, body proximate composition and amino acid profile were not significantly affected by the dietary treatments. Apparent digestibility coefficients (ADC) of dry matter, lipid and calcium in fish fed PBM diet did not show significant differences with PBM0. Protein ADC was significantly decreased with increased PBM level from 35%. Our results indicated that using fish meal and PBM in combination lead to improved growth and feed utilization of sobaity sea bream when compared to treatments using FM alone as the dietary protein source. Fish meal protein could be replaced up to 55% by PBM in the formulated diets of S. hasta juveniles without any negative effects on growth performance, feed utilization and whole body amino acid profile.