Lysine Level Increases Live Performance and Breast Yield in Male Broilers

Abstract

Recent data have clearly demonstrated that feeding starting broilers diets containing higher levels of lysine (lys) than recommended by the NRC improves broiler performance. In addition, there are data suggesting the Lys requirement for meat yield is higher than the level considered adequate for feed conversion. Two experiments evaluated the effects of adequate and supplemental Lys levels (93 to 133% of the 1984 NRC for birds 1 to 48 days old in Experiment 1; 97 to 157% of the 1984 NRC for birds 21 to 52 days old in Experiment 2) on broiler performance and carcass muscle development. Body weight was maximized in birds feed 113% of the NRC in Experiment 1 and 109% of the NRC in Experiment 2. Feed conversions were optimized by feeding 103% and 121% of the NRC Lys recommendation in Experiments 1 and 2, respectively. Breast meat weight and proportional yield were significantly increased in Experiment 1, with the greatest improvement achieved by feeding broilers 113% of the NRC Lys recommendation. In Experiment 2, increasing dietary Lys up to 121% of the NRC recommendation significantly increased breast meat weight and proportional yield, with no improvement at higher levels. The results of this study indicate that male broiler performance and breast meat yield are improved by feeding Lys levels well above what is considered adequate by the NRC.