L-Carnitine and Its Use as A Feed Additive in Broiler Chicken Diet: A Review

L-carnitine is an amino acid–derived, vitamin-like compound that plays a crucial role in intermediary metabolism, particularly in mitochondrial fatty acid transport and energy production. Although endogenously synthesized from lysine and methionine, its production may be inadequate in poultry under intensive production systems due to high metabolic demands and limited dietary availability. In broiler chickens, L-carnitine facilitates the transport of long-chain fatty acids into mitochondria for β-oxidation, thereby enhancing energy utilization, sparing essential amino acids and supporting protein synthesis. Dietary supplementation with L-carnitine has been widely investigated for its effects on growth performance, feed efficiency, fat metabolism, immune response and antioxidant capacity, although responses vary depending on dietary composition, supplementation level and physiological conditions in birds. Overall, L-carnitine supplementation represents a promising nutritional strategy to improve metabolic efficiency, health status and productive performance in broiler chickens.