L-Carnitine in Broiler Chickens: Mechanistic Roles in Energy Metabolism, Oxidative Stress, and Gut Health with Implications for Sustainable Poultry Production

Abstract

This article reviews the mechanical role of L-carnitine in broilers, focusing on three main axes: energy metabolism, oxidative stress, and gut health. L-carnitine is made in the body from the amino acids lysine and methionine, and is also supplemented from feed. It plays a pivotal role in transporting long-chain fatty acids to the mitochondria for oxidation and ATP production, enhancing energy efficiency, especially in the late growth stages and at high-energy feeding. L-carnitine also exhibits protective effects against oxidative stress caused by heat, transport, or feed stress, as it reduces the production of reactive oxygen species and restores antioxidant balance, maintaining the quality of the meat. In terms of gut health, L-carnitine regulates acetyl-CoA metabolism, coordinates glycolysis pathways and the TCA cycle, and improves nutrient allocation. It has been observed that the embryonic chick has a physiological deficiency of carnitine and needs supplementation from day 7.5 after hatching. However, the effects of carnitine on growth performance and trophic conversion factor vary (positive, negative, or insignificant) depending on age, breed, management conditions, and climate. The article recommends standardized methodological studies to fill in knowledge gaps and enhance the role of carnitine in the sustainability of broiler production.