Lysine: Making progress in the nutrition of broilers

Genotypes used in the broiler industry have changed significantly in the past 40 yr, and continue to change at the same rate today. Different selection criteria are used by the major breeding companies, leading to widely different genotypes being available to the broiler industry, yet nutritionists have largely ignored these changes when formulating feeds and designing feeding strategies for broilers. The method presently used to formulate feeds for broilers relies on tables of nutrient requirements for different phases in the life of the broiler. These tables do not reflect either the requirements of broilers capable of growing at different rates, or that these strains have different genetically determined degrees of fatness. No further progress can be made with this approach. Progress can be made only by integrating information about the bird, the feed, and the environment into an accurate theory that can then be used in a simulation model to make accurate predictions of feed intake and growth rate for any given bird, in any given state, and in any given environment. With such a model, it is possible to determine the most economical method of feeding broilers under a wide range of economic conditions. The only defensible way in which nutritionists can improve the efficiency of feeding broilers is by the use of simulation modeling.