A proposed experimental method for the determination of the digestible energy of ingredients in pig feeds

For the purposes of compounded feed formulation an important assumption with regard to the digestible energy (DE) content of ingredients is made. It is assumed that the energy contents of individual ingredients in a feed are additive and therefore that, irrespective of the combinations in which the various ingredients occur, the energy contributed per unit of a particular ingredient remains constant. This implies that the DE content per unit of that ingredient is the same at all concentrations of the ingredient in the feed mixture. In other words, as one ingredient is substituted in increasing amounts for another in a dietary mixture, there is a linear change in the DE content of the whole feed. The purpose of this experiment was to determine whether this assumption is valid.