Nitrogen maintenance requirements and potential for nitrogen retention of pullets in growth phase

• DOI: 10.1111/jpn.13117
• Publication Date: 2019-05-07T05:04:18Z
• Authors: Letícia Soares; Nilva Kazue Sakomura; Juliano Cesar de ...; Frank Liebert; Mariana Quintino ...; João Batista Koch...
• Keywords: Starter; Nitrogen balance; Dilution

Abstract Experiments were conducted to estimate daily N maintenance requirements (NMRs) and the genetic potential for retention (NR max T) of pullets in growth phase. Three nitrogen balance trials conducted, a total 48 Hy‐line W‐36 used each trial age periods (starter: 14–28, grower: 56–70 developer: 98–112 days). The treatments consisted six graded levels diets (L1 = 8, L2 16, L3 24, L4 32, L5 40 L6 g N/kg feed), formulated using dilution technique. regression analyses between intake excretion performed fit exponential function determine NMR. NMRs that estimated at 294, 331 355 mg/BW kg 0.67 initial, grower developer periods, respectively, applied further calculation NR T as threshold value balance. was by statistical procedure following several iteration steps Levenberg–Marquardt algorithm until sum squares residual minimized. 3,200, 2,633 1,826 starter, respectively. determined model parameters precondition modelling amino acid requirement based on an N‐utilization depended performance dietary efficiency. This will be developed subsequent study.