Early life nutrition and prenatal programming: Shaping carcass composition and meat quality.

Early life development plays a crucial role in shaping skeletal muscle development in livestock offspring through fetal programming mechanisms, which refers to developmental adaptations induced by environmental and nutritional stimuli during gestation. This review synthesizes recent research on the effects of maternal nutrition during gestation and early-life nutrition on muscle development and metabolism, carcass composition, and meat quality. Key developmental processes, including myogenesis and adipogenesis, occur predominantly during prenatal life and are highly sensitive to maternal nutrient supply. Consequently, nutritional interventions during gestation, such as protein and energy supplementation, can program muscle mass, adiposity, and metabolic characteristics of skeletal muscle, ultimately influencing growth potential and carcass composition. In addition, early postnatal nutrition, particularly during the "marbling window," which extends from the late fetal-neonatal stage to approximately 250 d of age in beef cattle, may enhance intramuscular adipocyte development and increase marbling potential. These developmental adaptations are associated with changes in muscle fiber type, metabolic pathways, and energy utilization, driven by alterations during critical windows of fetal development that define muscle fiber number, adipocyte formation, and metabolic flexibility. However, although these changes often result in differences in growth performance and carcass composition, their effects on meat quality attributes remain inconsistent. Overall, the impact of maternal and early-life nutrition on final meat quality depends on its interaction with postnatal management, highlighting the importance of integrated nutritional strategies throughout the animal's life.