The protein and energy nutrition of the bacon pig:IV. Digestible energy values of cereals in pig diets

Abstract
For optimal growth and production animals require an adequate supply of each nutrient in the diet. This means that within the total of the ration every constituent is allocated its own appropriate proportion and that all the components fit into an ideal balance one with the other. It is reasonably straightforward to define the principles of allocation for vitamins and minerals where a particular chemical entity serves a reasonably well-defined specific function. The definition of the protein component reflects a requirement for certain essential amino acids and for the materials necessary to synthesize the non-essential ones. There remains, however, a major portion of the diet that is not amenable to such specific definition. This fraction includes various chemical entities—fats, carbohydrates and fibrous materials—which are not in themselves indispensable nutrients. It is now accepted, however, that the nutritive value of these components can for convenience be expressed as a whole in terms of their capacity to release energy upon oxidation.