Evaluation of poultry by-product meal as partial replacement of fish meal in practical diets for juvenile tench (Tinca tinca L.)

Abstract

The aim of this study was to evaluate different replacement levels of fish meal (FM) by poultry by-product meal (PBM) on survival, growth performance and body composition of juvenile tench (Tinca tinca). A 90-day experiment was conducted with 5 month-old juveniles (31.95 mm total length, 0.396 g weight). Eight practical diets (50% crude protein) differing in the level of replacement of FM protein by PMB protein were tested: 0% (control), 25%, 31%, 37%, 43%, 49%, 55% and 61% corresponding to 0, 184.8, 229.2, 273.5, 317.8, 362.1, 406.5 or 450.8 g PBM kg−1 diet respectively. Significant differences were not found (P > 0.05) between 25% replacement of FM protein by PBM protein (184.8 g kg−1 PBM in diet) and control diet. At higher replacement levels, fish had significantly lower growth, higher feed conversion ratio and lower protein productive value (P < 0.05). Fish with externally visible deformities ranged from 1.1% to 3.3%. The relation among amino acid profiles of the diets, body composition, growth performance of juveniles and amino acid requirements of other fish species is discussed. Up to 184.8 g PBM kg−1 diet can be included in diets for juvenile tench without impairing growth performance.