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 lysine. The performance variables were evaluated from 30 to 46 weeks of age, that correspond to the peak of egg production in commercial hens. Quadract effect of treatments on egg production, egg weight and egg dozen:feed ratio was observed. The total lysine requeriments were of 0.92, 0.91, and 0.90, that was correspondent to the estimate of 0.84, 0.83, and 0.82% of digestible lysine, respectively. It is recommended levels of 0.92 or 0.84% or intake of 996 or 910 mg of total and digestible lysine/bird/day, during the peak of egg production.
nutrition; performance; total amino acids
