Energy losses in the excreta of poultry: a model for predicting dietary metabolizable energy

Abstract

Twenty-four poultry diets with gross energy values ranging from 18.43 to 21.54 MJ kg-1 DM were fed to chickens using a standard metabolizable energy (ME) assay procedure. Gross energy as determined by bomb calorimetry was significantly related to gross energy as calculated from chemical composition (protein, fat, and carbohydrate), with an RSD of ± 0.25 MJ kg-1 DM. Energy loss via faeces and urine (range 4.1 1 to 5.91 MJ kg-1 diet DM) was significantly related to crude fibre expressed as a percentage of the total dietary carbohydrate (range 3.7 to 8.6). The RSD was ± 0.29 MJ. By treating the components of ME (gross energy and energy loss) separately, bias of biological origin was separated from random error in the prediction of ME from chemical composition.