Branched-chain amino acids supplementation in low-protein broiler diets: A review

Chicken meat has been one of the most important sources of quality animal protein in human diets, and the increasing human population has increased its demand. However, nitrogen excretion has been one of the challenges of increased production in poultry. Protein is one of the most expensive nutrients, and the use of synthetic amino acids improves feed efficiency in poultry. Therefore, nutritionists have sought to adopt low-protein diets supplemented with essential amino acids as a nutritional strategy to limit nitrogen excretion, reduce the cost of production, and improve feed efficiency in poultry. Branched-chain amino acids (BCAA), including isoleucine, leucine, and valine, are essential amino acids that cannot be synthesized endogenously in animals, and the diet remains the main source. Branched-chain amino acids supplementation in low-protein broiler diets is progressing. This review summarizes the effects of BCAA in low-protein broiler diets and finds that the dietary protein level, age of the broilers, and composition of the experimental diets have constituted inconsistencies in the response of the broilers across studies. Supplementation of balanced and optimal BCAA levels in low-protein diets improved broiler performance, carcass traits, and meat quality, but BCAA antagonism remains a concern.