Effects of Levels of L-Leucine Supplementation with Sub-Optimal Protein in the Diet of Grower-Finisher Broiler Chickens on Carcass Composition and Sensory Characteristics (Report‪)‬

INTRODUCTION It is now well documented that dietary composition can have a major effect on performance and body composition of chickens (Busye et al., 1992; 1997; Nieto et al., 1997; Collin et al., 2003). As a broiler chicken grows, its carcass composition changes. The most evident change is the increase in carcass fat. Some researchers reported that lowering dietary CP did not affect growth performance (Morran and Stilborn, 1996), however carcass composition becomes inferior in broilers fed diets in which CP has been reduced by more than 3%, even with adequate nutrient requirements (Sterling et al., 2005; Waldroup et al., 2005). Generally, amino acids (AA) and CP in the diet influence the carcass composition of broilers, and reducing dietary CP effects a decrease in carcass fat content (Si et al., 2004). On the other hand, increasing dietary leucine decreases carcass fat content (Donato et al., 2006).