Meeting the energy needs of poultry.

The most popular way is to evaluate the diet in terms of its metabolizable energy (ME) content measured in kcal ( I kcal=4-184 kJ). The problems associated with the determination of ME have been recently reviewed by Miller (1974). Unfortunately, the ME of a diet is not always equal to the sum of the ME values of its constituent parts (Vohra, 1972). It is reduced by the presence of toxicants, but is improved by certain fats, owing to the low energy cost of digestion, absorption, transport and deposition of dietary fats relative to the energy requirements for fat synthesis. The topic of carbohydrates and fats as dietary energy sources was reviewed by Annison (1974). The only practical way of predicting the ME of a diet would be from its chemical composition, but no single regression equation fulfills that role as yet. We