The optimum ratio of standardized ileal digestible leucine to lysine for 8 to 12 kg female pigs

The objective of the study was to estimate Leu requirement for weaned piglets to balance indispensable AA in reduced CP diets. A dose-response experiment was conducted to estimate the standardized ileal digestible (SID) Leu to Lys ratio required for the maximum growth of young pigs after weaning. In this study, 96 female pigs (initial BW of 8 kg) were allotted to 1 of 6 dietary treatments with 16 individually penned pigs per treatment. Graded levels of crystalline l-Leu were added to a basal diet to provide diets containing 0.70, 0.80, 0.90, 1.00, 1.10, and 1.20 SID Leu: Lys. Lysine was limiting and fulfilled 90% of the current recommendations. The ADFI, ADG, and G: F were determined during a 2 wk experimental period. Blood and urine samples were taken at the end of each wk. The ADFI increased linearly (P