The metabolizable energy of poultry feeding stuffs in relation to their chemical composition

Abstract

The metabolizable energy values of 17 samples of cereals, cereal by‐products and mixed rations have been determined with laying hens. They ranged from 1300 to 3500 kg.‐cal. per kg. and, where comparison with the findings of other workers has been possible, agreement has been generally satisfactory. The same samples were subjected to the standard methods of proximate analysis, and also analysed for their content of starch and reducing sugars using a specially modified anthrone method. Statistical analysis of the results showed that the formula −53 + 38 (% crude protein + 2.25 × % ether extract + 1.1 × % starch + % sugar) gave predicted figures for the metabolizable energy (in kg.‐cal./kg.) of the materials tested with a standard deviation of ± 190 kg.‐cal./kg. from the determined figures. This was a superior prediction to any that could be made with the data from proximate analysis alone, and the method may prove of use when an estimate of the energy value of a material or mixture for feeding to poultry has to be made from results of chemical analyses that can be carried out in a routine laboratory.