Lysine levels in starter and grower-finisher diets affect broiler performance and carcass traits

Providing adequate dietary lysine (Lys) to broilers is critical of the amou nt of saleable white meat is the economic objective. However, the period wh en Lys is most critical for breast development remains unclear. The objecti ve of this study was to determine if dietary Lys in the starter and grower- finisher diets interact to affect live performance, mortality, adn breast m eat in commercial broilers. This study records two levels of Lys in the sta rter diets (95 and 115% of 1994 NRC) and three levels of Lys in the grower- finisher diets (85, 105, and 125% of 1994 NRC) fed to male broilers in diet s composed of corn, soybean meal, corn gluten meal, poultry meal, and poult ry oil. Increasingly Lys in the starter or grower-finisher diets increased both per formance and mortality. Breast meat weight and yield increased when broiler s received the highest Lys levels in the starter and grower-finisher diets. Feeding broilers inadequate dietary Lys in the starter period decreased fi nishing live performance and breast meat responses, irrespective of grower- finisher Lys levels. Dietary Lys levels above that considered adequate (125 % of 1994 NRC) in the grower-finisher diets compensated for loss of breast meat due to Lys inadequacy in the starter diet, but compensatory breast mea t accretion was not complete.