Influence of nutrient density and feed form on growth performance, nutrient digestibility and gastro intestinal tract development in broilers fed wheat-based diets : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Animal Science at Massey University, Manawatu, New Zealand

Abstract

Figures 2.1.& 2.2 have been removed for copyright reasons but may be accessed via their source.This study investigated the influence of nutrient density and feed form, and their interaction on growth performance, nitrogen-corrected apparent metabolisable energy (AMEn) and upper gut components of broilers fed wheat-based diets for 35 d post-hatch. A completely randomised design was used, with a 5 x 2 factorial arrangement of 10 treatments (with 6 replicates, 8 birds per replicate) involving five dietary nutrient density, VL, very low nutrient density (11.71 MJ/kg AMEn, 13.44 g/kg lysine); L, low nutrient density (12.13 MJ/kg AMEn, 13.92 g/kg lysine); M, medium nutrient density (12.55 MJ/kg AMEn, 14.40 g/kg lysine); H, high nutrient density (12.97 MJ/kg AMEn, 14.88 g/kg lysine); VH, very high nutrient density (13.39 MJ/kg AMEn, 15.36 g/kg lysine) and two feed forms, mash vs. pellet. Nutrient density x feed form interaction was significant (P 0.05) on these parameters in other nutrient density diets. Feeding pellets lowered (P < 0.05) the CAID of N and starch. Pelleting significantly (P < 0.001) reduced the absolute weight of gizzard compared to mash diets. The gizzard pH of birds fed pellet diet was higher (P < 0.001) than those fed mash diets. In general, the current results show that the pellet-induced benefits on growth performance reduce as the nutrient density levels increase, highlighting the importance of considering nutrient density to maximise the benefits associated with pellet feeding