Exigência de metionina + cistina para frangas de reposição na fase cria de sete a 12 semanas de idade

Abstract

The methionine + cystine requirement was determined for pullets from seven to 12 weeks of age and its effect was verified on the laying phase. The experiment was divided into two phases, growing and production, which lasted from 22 to 33 weeks of age. In the first experimental phase we used 640 birds (50% and 50% Lohmann LSL Lohmann Brown) allotted in a completely randomized factorial scheme 5x2 (methionine + cystine levels and lineages), with four replications and 16 birds per repetition. The levels of total methionine + cystine studied were 0.471; 0.541; 0.611; 0.681 e 0.751%. When they reached 22 weeks of age, 240 birds were used to verify the residual effect of the diets fed during the growth period. The level of methionine + cystine for white-egg and brown-egg pullets in the period from 1 to 6 weeks of age were 0.710% of total methionine + cystine (0.639 % met+cis digestible) and 0.706 % of total methionine + cystine (0.635 % of met+cis digestible), respectively.