Exigência de metionina+cistina para aves de reposição leves e semipesadas de 1 a 4 semanas de idade alimentadas com rações farelada e triturada

Abstract

The objective of this study was to evaluate the total methionine+cystine requirements in function of crushed and ground diets and pullet strain (light and semi-heavy) from 1 to 4 weeks of age. One thousand and sixty 1-day-old pullets were used as follows: 800 Dekalb White pullets and 800 Bovans Goldline pullets, weighting 34.52 ± 0.26 g and 36.41 ± 0.22 g, respectively. The experimental design was completely randomized in a 5 × 2 × 2 factorial scheme (0.65; 0.70; 0.75; 0.80 and 0.85% total Met+Cys × pullet strain × two physical forms), with twenty treatments, four repetitions of twenty birds. The basal diet was supplemented with DL-Met (99%) to provide five total Met+Cys levels. The experimental rations presented the same contents for ME (2.900 kcal/kg), CP (21%), Ca (0.94%) and available P (0.44%). The total feed consumption (TFC), daily feed consumption (DFC), total weight gain (TWG), daily weight gain (DWG) and feed conversion (FC) were measured up to 28 days of age. The averages were analyzed through the F test and regression model. SH strain presented better TFC, DFC, TWG, DWG and FC. The crushed ration provided better TWG, DWG and FC for both strains. The Met+Cys levels affected TWG, DWG and FC in a linear way. Semi-heavy pullets presented better performance than light pullets. The ground diet improved TWG, DWG and FC of light and SH pullets from 1 to 4 weeks of age. Supplementation with 0.85% of Met+Cys is recommended for light and semi-heavy pullets from 1 to 4 weeks of age or average Met+Cys consumption of 159 and 174 mg, respectively.