Effect of Early Protein and Energy Restriction of Large Turkey Toms Fed High-Fat or Low-Fat Realimentation Diets. 2. Carcass Characteristics

Diets were fed to toms from 10 days to 6 wk of age to compare two levels of protein [100% (HP) or 70% (LP) of 1984 National Research Council (NRC) recommendations] in a factorial arrangement with two levels of energy [100% (HE) of 90% (LE) or 1984 NRC reference levels]. Subsequently, the four treatment groups were fed diets containing either 4 or 8% fat, allowing caloric density to increase as the level of fat increased and keeping other nutrients equivalent among the diets. Sample toms were killed at 6, 12, and 20 wk of age to determine carcass composition and organ size. Percentages of dry matter and fat in the carcasses of 6-wk-old toms were increased by LP and decreased by LE (P<.005). There were no protein or energy carry-over effects on body composition at 12 or 20 wk of age. The amount of protein consumed, relative to the amount of protein retained in the carcass, was reduced by LP before and immediately after realimentation (P<.005). From 10 days to 6 wk of age, growth of the skeleton and gut was not affected by dietary protein or energy. Breast muscle development, however, was reduced by LP, and this persisted until 12 wk of age. After 6 wk of age, added dietary fat significantly increased weight gain accompanied by greater body fat and equivalent body protein content levels, irrespective of early nutrition.