Losses of Energy and Nitrogen on Drying Poultry Excreta

INTRODUCTION METABOLIZABLE energy has generally been accepted as the most useful practical measure of the energy value of a poultry diet. In the biological determination of ME value whether by the chromic oxide indicator method or by the total collection method it is usual to desiccate the mixed excreta before determining its gross energy content. Concern about serious possible errors arising from losses of energy and nitrogen when drying poultry excreta was expressed by Manoukas et al. (1964) and these authors suggested a method of determining the energy content of undried excreta. Manoukas et al. (1964) reported significant losses of energy and nitrogen ranging from 1.2 to 20.2% and −7.1 to 15.2%, respectively, when excreta samples were dried in a convection oven at 65°C. for 24 hours. Losses of this magnitude would lead to serious errors in normally determined ME values and it was decided to reinvestigate these findings. EXPERIMENTAL