An experiment was carried out as a completely randomized design, with seven treatments, and six replicates of six birds to determine the lysine nutritional requeriments for 252 semi-heavy laying hens. The diets were formulated to be isonitrogenous (17.1%CP) and isoenergy (2,800 kcal/kg-ME) and to meet all bird nutrient requeriments, with the exception of lysine, that was supplemented with L-lysine HCl (78.4% of lysine) and resulted in the following levels: 0.79, 0.83, 0.87, 0.91, 0.95, 0.99, and 1.03% of total […]