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. 2024 Feb 20;103(5):103572. doi: 10.1016/j.psj.2024.103572

Table 10.

Nitrogen intake, excretion, and litter ammonia concentrations of Ross × Ross 708 male broilers fed reduced crude protein diets while maintaining amino acid concentrations from 1 to 33 d of age.1

Dietary treatments Calculated CP2, % N Intake, g/bird N excretion
 NH3, mg/kg5
g/bird3 % Intake g/kg BW gain g/kg total meat4
1) Control (DL-Met, L-Lys, L-Thr) 23.23, 20.69, 19.13 79.22a 21.42a 27.00 10.87a 20.24a 93.68a
2) Control + L-Val 22.31, 19.95, 18.58 81.47a 21.70a 26.61 10.57ab 19.94ab 86.25ab
3) Control + L-Val, Gly6 22.44, 19.95, 18.58 79.40a 20.86ab 26.30 10.31ab 19.22ab 76.42ab
4) Control + L-Val, Gly, L-Ile6 21.95, 19.52, 18.28 80.36a 21.23ab 26.54 10.47ab 19.69ab 70.94ab
5) Control + L-Val, Gly, L-Ile, L-Arg6 21.23, 18.95, 17.80 76.81b 20.31ab 26.38 10.24ab 19.06ab 56.35ab
6) Control + L-Val, Gly, L-Ile, L-Arg, L-Trp6 19.81, 17.31, 16.87 70.21c 18.00b 25.68 9.27c 17.51c 48.85b
Pooled standard error 0.83 1.04 1.25 0.48 0.86 16.15
Preplanned orthogonal contrast Probabilities
 Treatment 1 vs. 2 0.06 0.80 0.77 0.55 0.75 0.73
 Treatment 1 vs. 3 0.88 0.61 0.60 0.27 0.27 0.42
 Treatment 1 vs. 4 0.34 0.87 0.74 0.47 0.58 0.29
 Treatment 1 vs. 5 0.044 0.31 0.64 0.22 0.21 0.09
 Treatment 1 vs. 6 < 0.001 0.003 0.32 0.003 0.005 0.041
 Diet < 0.001 0.02 0.95 0.06 0.07 0.34
1

Values represent least-square means for 10 replicate pens.

2

Calculated CP content in the starter (1–14 d of age), grower (15–25 d of age), and finisher (26–33 d of age) diets, respectively.

3

Litter N concentration at the conclusion of the experiment (day 33) was subtracted by litter N concentration before bird placement (day 0).

4

Total meat includes the sum of wings, drums, thighs, and total breast meat.

5

Values were determined using temperature as a covariate. Temperature was included as a covariate to account for any ammonia concentration variation as ammonia is temperature dependent and there was some variation in the room temperature while equilibrium concentrations were recorded.

6

Glycine was added to diets only from day 1 to 14.

a-c

Means within columns with different superscripts are significant (P < 0.05).