Effects of protein and energy intake on body fat and growth rate of broilers

Abstract

Four experiments were conducted with Indian River broiler chicks in which the protein and energy levels were fed in different combinations in an attempt to produce a broiler at 49 days of age with reduced body fat while maintaining a constant level of performance. Feeding a starter diet with no added fat during the first seven days of age was found to reduce total body fat present in the broiler at 49 days of age. As the percent body fat was reduced by early energy restriction, percent body moisture increased. Feeding a lower energy starter and finisher diet to 56 days of age was found not to reduce total body fat in the market age bird. Early energy restriction was not found to be detrimental to bird performance. Birds fed a starter diet with no added fat during the first seven days of age weighed more at seven and 49 days of age than birds fed diets with added fat from one day of age. Dietary energy restriction during the first seven days of age was found to be detrimental to the 49-day feed conversion. This difference in feed efficiency due to early energy restriction was smaller than that of past research. A high protein finisher diet fed to birds reared on an energy restricted starter produced a 49-day feed conversion equal to the control. A high protein finisher diet was found to overcome the adverse effect of early energy restriction. The vitamin level of the feed was found to affect the percent body fat. Birds fed starter and finisher diets with twice the normal vitamin levels were found to have less total body fat than the controls at 49 days of age.