Table 1. Composition of experimental diets (% as fed)

Item Dietary protein content (%)
15 17 19 21 23 25
Corn 68.98 64.14 59.30 54.45 49.61 44.77
Wheat 10.00 10.00 10.00 10.00 10.00 10.00
Soybean meal (44%) 13.00 17.40 21.80 26.20 30.60 35.00
Fish meal 3.00 3.60 4.20 4.80 5.40 6.00
Vegetable oil 1.00 1.03 1.06 1.09 1.12 1.15
Limestone 1.00 1.00 1.00 1.00 1.00 1.00
Monocalcium phosphate 1.50 1.50 1.50 1.50 1.50 1.50
Vitamin-mineral premix1) 0.10 0.08 0.06 0.04 0.02 -
Salt 0.30 0.30 0.30 0.30 0.30 0.30
Lysine HCl 0.30 0.24 0.18 0.12 0.06 -
L-Arginine 0.25 0.20 0.15 0.10 0.05 -
DL-Methionine 0.15 0.16 0.17 0.18 0.19 0.20
L-Threonine 0.09 0.07 0.05 0.04 0.02 -
L-Tryptophan 0.10 0.10 0.09 0.09 0.08 0.08
L-Isoleucine 0.13 0.10 0.08 0.05 0.03 0.00
L-Valine 0.10 0.08 0.06 0.04 0.02 0.00
Calculated composition2)
 Metabolizable energy (kcal/kg) 3,196 3,197 3,198 3,199 3,200 3,201
 Crude protein (%) 15.43 17.29 19.15 21.01 22.87 24.73
 Calcium (%) 0.80 0.83 0.85 0.87 0.89 0.92
 Phosphorus (%) 0.39 0.40 0.40 0.41 0.42 0.42
 Lysine HCl (%) 0.98 1.08 1.18 1.28 1.38 1.47
 Methionine (%) 0.43 0.47 0.51 0.55 0.60 0.64
 Methionine + Cysteine (%) 0.70 0.77 0.83 0.90 0.97 1.03
 Isoleucine (%) 0.71 0.77 0.84 0.90 0.97 1.04
 Valine (%) 0.79 0.86 0.93 1.01 1.08 1.15
 Arginine (%) 1.08 1.18 1.28 1.38 1.48 1.58
 Leucine (%) 0.68 0.78 0.87 0.96 1.06 1.15
Analyzed composition
 Crude protein (%) 15.67 17.51 19.37 21.25 23.06 24.88
Supplied per kilogram of total diets: Fe (FeSO4 · H2O), 80 mg; Zn (ZnSO4 · H2O), 80 mg; Mn (MnSO4 · H2O) 80 mg; Co (CoSO4 · H2O) 0.5 mg; Cu (CuSO4 · H2O) 10 mg; Se (Na2SeO3) 0.2 mg; I, (Ca(IO3) · 2H2O) 0.9 mg; vitamin A, 24,000 IU; vitamin D3, 6,000 IU; vitamin E, 30 IU; vitamin K, 4 mg; thiamin, 4 mg; riboflavin, 12 mg; pyridoxine, 4 mg; folacine, 2 mg; biotin, 0.03 mg; vitamin B8, 0.06 mg; niacin, 90 mg; pantothenic acid, 30 mg.
The values are calculated according to the values of feedstuffs in NRC [14].