Prediction of bioavailable energy of feed for poultry by estimation of organic matter digestibility

Abstract

One of the most important parameters of feed quality is energy. Not all energy of feed (gross energy) will be utilized by the animal, but only its bio-available portion, i.e. metabolisable energy (ME). The accepted method for direct determination of ME of feeds is by in vivo trials. These are often time-consuming and expensive why there has been a need for in vitro methods for predicting the in vivo ME values of feeds. The aim of this study was to develop linear equations to predict the in vivo true metabolisable energy (TME) of poultry feeds based on digestibility of organic matter as determined by an in vitro method. Sixteen diets and fifty seven samples of feedstufs for poultry were used. In vivo determination of TME was based on digestibility of nutrients, by use of the adult rooster assay. Same feed samples were analysed by an enzyme incubation based laboratory procedure for estimating the enzymatic digestible organic matter (EDOM). Obtained EDOM values were regressed against the in vivo TME results, which generated the prediction equation TME = 0.191 × EDOM, with R2 = 0.704 (RSD = 0.127). When other predictors were included, prediction was improved and the following equations and R2 have been generated: TME = 0.177 × EDOM + 0.168 × Fat, with R2 = 0.766 (RSD = 0.113) and TME = 0.191 × EDOM + 0.209 × Fat - 0.044 x Protein, with R2 = 0.830 (RSD = 0.098). The conclusion was that in vivo ME of feeds for poultry can be sucessfully predicted by use of organic matter digestibility.