Amino Acid Nutrition in Poultry: A Review.

Amino acids (AA) play a crucial role in poultry production, directly influencing feed efficiency, growth, immune function, and environmental impact. Over the years, advancements in feed formulation, digestibility assessments, and precision nutrition have contributed to improving poultry performance through AA nutrition while reducing nitrogen (N) excretion. Standardized ileal amino acid digestibility (SIAAD) has become a key tool for accurately evaluating AA bioavailability, moving beyond less precise estimate of apparent ileal digestibility (AID), to ensure that dietary formulations precisely meet the specific needs of poultry at different production stages, while correcting for basal ileal endogenous amino acid losses (BIEAAL) and providing more accurate, additive values for feed formulation. Additionally, innovations in synthetic amino acids (SAA), exogenous enzyme supplementation, and alternative protein sources have further enhanced AA utilization, offering sustainable solutions for modern poultry farming. However, challenges remain in optimizing AA metabolism, minimizing N excretion, and refining feeding strategies to optimize efficiency. This review explores the physiological significance of AAs in poultry, discusses factors affecting their digestibility and utilization, and examines emerging technologies for improving AA nutrition. Understanding these aspects is essential in advancing poultry production while ensuring sustainability and economic viability.