Performance response of broilers to feeding pelleted diets is influenced by dietary nutrient density

Abstract

The influence of nutrient density (ND) and feed form (FF) on the performance, coefficient of apparent ileal digestibility (CAID) of nitrogen (N), starch, fat, calcium (Ca), phosphorus (P), gross energy (GE) and the N-corrected apparent metabolisable energy (AMEn) in broilers fed wheat-based diets was examined in a 35-day trial. A completely randomised design was used, with a 5 × 2 factorial arrangement of 10 treatments (6 replicates per treatment, 8 birds per replicate) involving 5 dietary nutrient densities (VL, very low ND; L, low ND; M, medium ND; H, high ND and VH, very high ND) and 2 FF (mash and pellet). Significant (P < 0.01) interactions between ND and FF were observed for weight gain and feed intake during the whole grow-out period. Birds fed pelleted diets outperformed mash-fed birds at each ND level, but the pellet-induced benefits were of higher magnitude at the lowest ND. Increasing ND lowered (P < 0.001) the feed conversion ratio from 1.540 in VL to 1.381 in VH diets. Increasing dietary ND progressively increased (P < 0.001) the CAID of N, fat and P. Feeding pelleted diets lowered (P < 0.05) the CAID of N, starch, fat and, AMEn. The absolute weight of gizzard was lower (P < 0.05) in pellet-fed birds than mash-fed birds and the opposite was observed (P < 0.05) for the gizzard pH. The current results showed that the performance benefits associated with feeding pelleted diets to broilers are diluted at higher dietary ND, highlighting the importance of determining optimum dietary ND in broiler diets to maximise the expected beneficial outcomes of feeding pelleted diets.