Digestible lysine and threonine requirements of male turkeys from days 8 to 21 and days 29 to 42

SUMMARY Two experiments were conducted to determine the digestible lysine (dLys) and digestible threonine (dThr) requirements of Nicholas White male turkeys from d 8 to 21 (experiment 1) and d 29 to 42 (experiment 2). In experiment 1, the reduced-CP (25% CP) basal diet supplied 1.14% dLys and 0.56% dThr. To determine the requirement for dThr, the level of dLys was kept at 1.50%, and the 7 dietary dThr treatment levels ranged from 0.56 to 1.04%, in 0.08% increments. For the dLys requirement, the level of dThr was kept at 1.04%, and the 7 dietary dLys treatment levels ranged from 1.14 to 1.50%, in 0.06% increments. When BW gain and feed conversion were used as response variables and the results of the break-point analyses were considered, the dLys requirements were estimated to be 1.36 and 1.39%, respectively, and the dThr requirements were estimated to be 0.74 and 0.81%, respectively, in experiment 1 (d 8 to 21). In experiment 2 (d 29 to 42), the reduced-CP (24% CP) basal diet supplied 1.06% dLys and 0.50% dThr. To determine the requirement for dThr, the level of dLys was kept at 1.42%, and the 7 dietary dThr treatment levels ranged from 0.51 to 0.99%, in 0.08% increments. For the dLys requirement, the level of dThr was kept at 0.99%, and the 7 dietary dLys treatment levels ranged from 1.06 to 1.42%, in 0.06% increments. When BW gain and feed conversion were used as response variables and the results of the break-point analyses were considered, the dLys requirements were estimated to be 1.27 and 1.29%, respectively, and the dThr requirements were estimated to be 0.72 and 0.76%, respectively, in experiment 2 (d 29 to 42).