Table 1. Ingredients and nutrient composition of the experimental diets

Variable 0–14 days 14–32 days
PC NC1) PC NC
Ingredients (g/kg)
 Corn 547.9 568.2 490.6 512.8
 Soybean meal (46%) 411.3 391.0 354.7 335.2
 Wheat - - 100.0 100.0
 Limestone 12.3 12.4 12.3 12.4
 Soybean oil 7.0 7.0 22.9 20.0
 Monocalcium phosphate 7.6 7.8 6.4 6.6
 Sodium chloride 2.3 2.3 2.0 2.2
 Sodium bicarbonate 1.1 1.1 0.1 0.1
 L-Lysine HCl 1.9 1.9 2.2 2.2
 DL-Methionine 3.4 3.2 3.0 2.9
 L-Threonine 1.3 1.2 0.9 0.9
 Vitamin and mineral premix2) 2.0 2.0 2.0 2.0
 Choline chloride 60% 0.7 0.7 0.7 0.7
 Coccidiostat 0.6 0.6 0.6 0.6
 Bio-emulsifier3) 0.5 0.5 0.5 0.5
 NSP enzyme4) 0.05 0.05 0.05 0.05
 Phytase5) 0.1 0.1 0.1 0.1
Calculated nutrient composition (%, as fed basis)
 Dry matter 88.54 88.51 88.78 88.72
 ME (kcal/kg) 2940 2950 3075 3075
 Crude protein 23.80 23.00 21.93 21.18
 Crude fat 3.16 3.20 4.63 4.40
 Crude fibre 2.64 2.62 2.55 2.56
 Digestable lysine 1.28 1.23 1.18 1.14
 Digestable methionine 0.64 0.61 0.58 0.55
 Digestable methionine + cysteine 0.95 0.91 0.87 0.84
 Digestable threonine 0.87 0.83 0.76 0.73
 Digestable arginine 1.50 1.44 1.35 1.30
 Digestable tryptophan 0.26 0.25 0.24 0.23
 Ca 0.87 0.87 0.84 0.84
 Digestable phosphorous 0.40 0.40 0.37 0.37
 Na 0.16 0.16 0.14 0.15
 Cl 0.22 0.22 0.21 0.22
To create the experimental treatments, the different proteases were added at the expense of corn as follows: PR1, 300 g/t (3,000 U/kg, where 1 U of protease activity is defined as the amount of enzyme that releases 1 μg of trichloroacetic acid-soluble azo-casein peptides from a 1% azo-casein substrate solution per minute in the assay at pH 7.5 and at a temperature of 37°C); PR2, 200 g/t (15,000 U/kg, where 1 U of protease activity is defined as the amount of enzyme that releases 1 μmoL of p-nitroaniline from 1 mM substrate (Suc-Ala-Ala-Pro-Phe-pNA) per minute at pH 9.0 and temperature 37°C); PR3, 500 g/t (30,000 U/kg, where 1 U of protease activity is defined as the amount of enzyme that liberates 1 micromole of para-nitroaniline (pNA) from the Succinyl-Ala-Ala-Pro-Phe-pNA (C30H36N6O9) substrate per minute at pH 8.0 and 37°C).
Provided per kilogram diet: retinyl acetate, 3.50 mg; cholecalciferol, 0.1 mg; α-tocopherol acetate, 25 mg; menadione, 3 mg; thiamine, 2.0 mg; riboflavin, 7 mg; pyridoxine, 4.0 mg; cobalamin, 0.020 mg; niacin, 50 mg; calcium pantothenate: 15 mg; Cu (from copper sulphate), 9.0 mg; Fe (from ferrous sulphate), 35 mg; I (from potassium iodate): 1 mg; Mn (from manganese sulphate), 85 mg; Se (from sodium selenite), 0.35 mg; Zn (from zinc oxide), 80 mg.
LYSOFORTE® EXTEND, a proprietary combination of lysolecithin, synthetic emulsifier, and monoglycerides manufactured by Kemin Europa NV, Herentals, Belgium.
Endo-1,4-beta-xylanase 350,000 U/g, Endo-1,3(4)-beta-glucanase 23,500 U/g, Endo-1,4-beta-glucanase 180,000 U/g, Alpha-amylase 4,000, and Bacillolysin 17,000 U/g; KEMZYME Plus concentrate dry, Kemin Europa NV (Herentals, Belgium).
6-Phytase 10,000 FTU/g. KINGPHOS 10,000 FTU/g. Qingdao Vland Biotech Group (Qingdao, China).
PC, positive control; NC, negative control.