The objectives of this work were to estimate the requirement of lysine from 7 to 12 weeks and to evaluate their effect on the egg production phase. Two hundred egg-white pullets (EW), and two hundred egg-brown pullets (EB) strains were allotted in randomized block design, and fed a basal diet with 16.0% of crude protein (CP) and 2,900 kcal/kg metabolizable energy (ME), supplemented with L-lysine HCl for the level of 0.50, 0.55, 0.60, 0.65, and 0.70% of total lysine in the diet. In the laying period, 160 birds from each trademark were fed with a production diet, contained 16.5% CP, 2,900 kcal ME/kg, and 2.9% Ca+2 and 0.755% of lysine. The pullets requirement of lysine based on weight gain was 0.64% or intake of 368 mg daily for EW, and 0.66% or intake of 395 mg daily for EB. The egg production, egg mass and Feed: egg dozen of the two trademarks were affected by a quadratic relation by the lysine levels in the diet. The feed intake of EW during the laying phase was affected by a quadratic relation, and EB was affected by linear relation. During the growing phase, the EW presented lower weight gain and feed intake and the worst feed:gain ratio than EB. During the laying phase, the EB showed higher egg production and egg mass, lower feed intake and better egg mass and feed:egg dozen than EW.
amino acid; egg mass and production; growth
