Table 4. Effects of crude protein level with protease supplementation level on growth performance in weaned piglets and growing-finishing pigs

Item Main effects SE p-value
Protein level Protease level CP Protease CP × protease
HP LP PT0 PT1 PT2
Body weight (kg)
 Initial 7.0 7.0 7.0 7.0 7.0 0.1 0.688 0.977 0.997
 4 wk 15.7 15.7 15.3a 15.4a 16.5b 0.2 0.944 0.010 0.941
 8 wk 32.2 32.3 31.9 32.0 32.8 0.4 0.875 0.695 0.803
 12 wk 57.8 57.1 57.6 56.8 58.0 0.7 0.662 0.786 0.706
 16 wk 88.4 88.4 88.4 88.1 88.6 0.9 0.980 0.974 0.958
 20 wk 114.2 113.6 111.9a 113.2ab 116.6b 0.8 0.730 0.049 0.987
Weeks 0–4
 ADG (g) 310 313 296a 300a 340b 6 0.779 0.003 0.917
 ADFI (g) 435 428 420 421 453 7 0.592 0.082 0.895
 G/F 0.71 0.73 0.70a 0.71a 0.75b 0.01 0.168 0.011 0.981
Weeks 4–8
 ADG (g) 587 592 594 594 581 12 0.860 0.885 0.785
 ADFI (g) 1,130 1,147 1,161 1,159 1,096 25 0.753 0.517 0.793
 G/F 0.52 0.52 0.51 0.52 0.53 0.01 0.890 0.615 0.958
Weeks 8–12
 ADG (g) 914 887 917 885 900 19 0.483 0.802 0.293
 ADFI (g) 2,104 2,124 2,164 2,113 2,066 34 0.779 0.519 0.411
 G/F 0.44 0.42 0.42 0.42 0.44 0.01 0.248 0.515 0.677
Weeks 12–16
 ADG (g) 1,094 1,115 1,101 1,118 1,095 24 0.679 0.926 0.790
 ADFI (g) 2,867 2,927 2,914 2,891 2,886 35 0.406 0.941 0.607
 G/F 0.38 0.38 0.38 0.39 0.38 0.01 0.855 0.861 0.889
Weeks 16–20
 ADG (g) 921 903 840a 799a 1,000b 15 0.472 < 0.001 0.667
 ADFI (g) 3,140 3,016 2,997 3,081 3,157 33 0.062 0.141 0.974
 G/F 0.29 0.30 0.28a 0.29a 0.32b 0.01 0.534 0.011 0.846
Weeks 0–8
 ADG (g) 449 453 445 447 460 7 0.813 0.673 0.773
 ADFI (g) 783 787 790 790 775 13 0.867 0.868 0.748
 G/F 0.58 0.58 0.57 0.57 0.60 0.01 0.886 0.134 0.989
Weeks 8–16
 ADG (g) 1,004 1,001 1,009 1,002 997 13 0.898 0.940 0.746
 ADFI (g) 2,486 2,525 2,539 2,502 2,476 22 0.377 0.512 0.314
 G/F 0.40 0.58 0.40 0.40 0.40 0.01 0.426 0.888 0.868
Weeks 0–20
 ADG (g) 806 802 789a 799ab 824b 6 0.750 0.044 0.987
 ADFI (g) 1,935 1,928 1,931 1,933 1,932 10 0.744 0.997 0.697
 G/F 0.42 0.42 0.41a 0.41ab 0.43b 0.01 0.889 0.049 0.843
Each value is the mean value of 4 replicates (4 pigs/pen).
Means in the same row with different superscripts differ (p < 0.05).
HP, high crude protein (19.00% [days 1–14 phase], 18.05% [days 15–28 phase], 17.10% [growing phase] and 16.15% [finishing phase]); LP, low crude protein (17.00% [days 1–14], 16.15% [days 15–28], 15.30% [growing phase] and 14.45% [finishing phase]); PT0, protease 0 ppm (weanling-finishing phase); PT1, protease 300 ppm (weanling phase) and 150 ppm (growing-finishing phase); PT2, protease 500 ppm (weanling phase) and 300 ppm (growing-finishing phase); CP, crude protein; ADG, average daily gain; ADFI, average daily feed intake; G/F, feed efficiency.