Effect of Dietary Protein and Lysine on Performance and Carcass Yield of Turkeys

Problem statement: There is a concern related to loss of nitrogen to the environment from animal manure and the high cost of the protein supplement. Thus, the current study was undertaken to determine the effect of reduction of CP and increased of lysine on growth and carcass yield in turkeys. Approach: A factorial experiment was carried out with commercial turkeys to evaluate the effect of two dietary levels of CP (90 and 100% of the NRC recommendations) and three dietary lysine levels (90, 110 and 130% of the NRC recommendations) on performance and carcass yield of male turkeys evaluated from 8-16 week of age. Results: The CP × lysine interaction was significant (p<0.05) for daily gain and Food Conversion Ratio (FCR). 100% CP level increased daily gain (0.13, 0.15 and 0.15 kg day^-1) and improved FCR (3.43, 3.12 and 3.01) as dietary levels of lysine in the diet increased (p<0.05), but the opposite was true for the birds fed 90% CP. The CP × lysine interaction (p<0.05) observed at 16 week of age showed that carcass weigh, breast weight, leg weight and thigh weight increased as the lysine level increased in the diet with 100% CP and the contrary occurred in the 90% CP treatment. Conclusion: The results of this experiment suggest a positive relationship between amino acids and CP; however, the increment of amino acids in the diets with low CP should be made keeping a proportional relationship among the dietary amino acids.