“…Dietary amino acids are best known as building blocks for proteins and substrates for synthesis of small molecular substances and tissue growth, and have profound biological importance, crucial for whole body homeostasis ( Eugenio et al, 2022 ). Among them, the branched-chain amino acids ( BCAA ), including isoleucine ( Ile ), leucine, and valine, in addition to precursor function, also play important roles in control of energy homeostasis, nutritional metabolism, immunity, and intestinal health in animals ( Zhang et al, 2017 ; Nie et al, 2018 ; Brown et al, 2022 , Kriseldi et al, 2022 ). It has been noted that the requirement for BCAA is influenced by the diet type, breed, and age of the birds.…”