High leucine levels affecting valine and isoleucine recommendations in low-protein diets for broiler chickens

Very nice work and interesting, applicable, and relevant topic. Thank you very much indeed . We recently published a paper with BCAA using new statistical approach. In case anybody interested please fins it as below: Optimizations of branched-chain amino acid requirements for 15–21-day-old broiler chickens by using the Taguchi method M.Sedghi et al. , 2022 Animal Production Science , https://doi.org/10.1071/AN21238 One comment from my side: In low CP diets (ex. corn-soy), usually the amount of soybean is reduced, the amount of cereals increases, the amount of oil decreases and the overall amount of supplemented amino acids increases. It is also a very valid point mentioned in the paper that the ratio of Leu to other BCAA , Val and Ile is high in most of the raw materials we are currently use in feed industry. But with my experience in Corn-SBM diets, when we reduced SBM and add more supplemented AA's the excess LEU is reduced. I just made an exercise of feed formulation, Broiler Grower diet and using Ideal profile digestible SID AA , with 4 levels of CP , 21.5 , 19.5 , 17.5 and 15.5% respectively. With lower CP%, Lower SBM, Higher Corn, Lower Fat , Higher crystalline AA's and less excess of Leu are seen in the diets. In 15.5% CP diet, Leu becomes limiting AA and need to be added as crystalline AA from to reach the minimum requirement. With my understanding, the excess of Leu is possibly less problematic in Low CP diets .