Impact of feeding varying grower digestible lysine and energy levels to female Cobb MV × Cobb 500 broilers from 14 to 28 D on 42 D growth performance, processing, and economic return

Abstract

Summary: Previous research in our laboratory has revealed that feeding crumbled diets with various levels of starter digestible Lys (dLys) and AME affects early feed conversion ratio (FCR) of Cobb MV × Cobb 500 broilers. However, overall performance was not affected, likely due to treatment application occurring in the starter phase. Therefore, the objective of this study was to evaluate a 3 dLys (1.00, 1.08, and 1.18%) × 4 AME (2,937, 3,028, 3,116, and 3,206 kcal/kg) factorial arrangement of pelleted grower diet treatments (Gdiets) and their impact on 42-day-old Cobb MV × Cobb 500 females. Significant dLys × AME interactions demonstrated a stepwise decrease in FCR (day 14–28 and 14–35) when dLys increased at 2,937, 3,116, and 3,206 kcal/kg but not at 3,028 kcal/kg AME. A significant dLys × AME interaction was also observed for day 14–28 total Lys intake/bird. Overall data exhibited improvements in BW and BW gain (BWG) when feeding Gdiets of 1.08 or 1.18% dLys. Feeding Gdiets of 1.18% dLys or ≥3,028 kcal/kg AME optimized day 14–41 FCR. Processing data demonstrated improved breast yield when feeding Gdiets formulated to ≥1.08% dLys or formulated to 2,937 or 3,028 kcal/kg AME. The most profitable Gdiet was 1.18% dLys +3,028 kcal/kg AME. To determine the best feeding regime for this new cross, future research should evaluate the effects of varying dLys and AME levels during the finisher phase on broiler performance.

Keywords

• lysine
• energy
• broiler
• live performance
• processing yield