Synchronized Dietary Glucose and Amino Acid Supply Promotes Broiler Growth by Redirecting Metabolic Flux and Activating the AKT/mTORC1 Signaling Pathway

This study elucidated how synchronized glucose and amino acid availability regulates muscle deposition. 540 21 day-old broilers followed a 3 × 3 factorial design: AM/AP ratios (0.19, 0.29, 0.41) and SID Lys levels (1.00%, 1.20%, 1.40%). Significant interactions between AM/AP ratios and SID Lys levels on BW, BWG, breast and thigh muscle percentage, and protein deposition, 0.19 AM/AP with 1.20% SID Lys was highest, whereas 0.41 AM/AP with 1.40% SID Lys was lowest. These represented synchronized (RDS) and asynchronous (SDS) model, respectively. Compared to SDS, RDS increased serum glucose and IGF-1 levels, nutrient digestibility, and transporter expression (GLUT2, SGLT1, CAT1). Metabolomics revealed RDS optimized glycolytic and TCA flux while attenuating Lys catabolism (AASS, ALDH7A1, AADAT). Molecularly, RDS activated AKT/mTOR-mediated synthesis and suppressed AMPK/FoxO3a-mediated degradation. Collectively, synchronizing nutrients via rapidly digestible starch (0.19 AM/AP) optimizes metabolic flux and mitigates amino acid wastage, offering a critical strategy for enhancing performance in low-protein diets.