An experiment study was carried out to establish the nutritional requirement of methionine + cystine (met + cyst) for brown-egg laying hens, in the second production cycle. One hundred and eighty Lohmann Brown birds from 79 and 95 weeks of age were used fed a base diet deficient in met + cyst, supplemented with 0.00; 0.053; 0.108; 0.161 and 0.214% DL-Methionine (98%), providing 0.490; 0.542; 0.594; 0.648 and 0.698% digestible met + cyst. The levels supplementation of met + cyst followed the lysine relations (0.653%) of 75, 83, 91, 99 and 107. A complete randomized design with five levels of met + cyst, six replications/treatment and six birds per experimental unit was used. The feed intake, met + cyst intake, feed conversion per dozen eggs and egg mass, weight gain, egg production, egg weight, egg mass, percentage of the egg components and the internal quality of the eggs were evaluated. A positive linear effect was obtained for food conversion per dozen eggs. A quadratic effect was observed of the met + cyst levels on diet intake, weight gain and food conversion. The met + cyst levels had a positive linear effect on the laying rate and quadratic effect on egg weight and mass. A quadratic effect was also observed of the on the Haugh unit and linear effect on yolk index. The requirement of met + cyst is higher or equal to 0.698%, that corresponds to a minimum intake of at least 786 mg digestible met + cyst/bird/day.
amino acids; egg production; egg quality
