The nutritional requirement of digestible lysine was determined in 180 Lohmann LSL white-egg laying hens raised from 79 to 95 weeks of age. The birds were allotted to five levels (0.555; 0.605; 0.655; 0.705 and 0.755%) of digestible lysine, six replicates and six birds per experimental unit. Quadratic effect of digestible lysine levels on feed intake, average weight gain, feed conversion/egg mass, the egg weight and the egg mass was observed. For the characteristics digestible lysine intake, feed conversion/dozen eggs and egg production a positive linear effect of digestible lysine levels was observed. The percentage of the components of the eggs and the internal quality were not affected by the digestible lysine levels, except for percentages of shell and yolk index, which showed linear negative effect. Although it was observed quadratic effect on egg mass and feed conversion/egg mass, these characteristics were not used to determine digestible lysine requirements for the white-egg birds, since these traits did not meet the requirement of digestible lysine observed for the other traits. Thus, the estimated requirement of digestible lysine for the white-egg laying hens, using linear effect was higher or equal to 0.755%, corresponding to an intake of at least 885 mg of digestible lysine/bird/day.
amino acids; egg quality; egg production
