Table 3. Effect of supplemental protease on the ATTD of nutrients with different CP levels in weaned pig

Variables	Basal1)		Low		SE	CP		PT2)		p-value
	0%	0.1%	0%	0.1%		HP	LP	0	10	CP	PT	CP × PT
1 wk (%)
DM	78.98	80.22	80.80	82.09	0.82	79.60	81.45	79.89	81.16	0.036	0.138	0.976
CP	77.96	78.43	77.90	77.15	1.00	78.20	77.53	77.93	77.79	0.510	0.886	0.549
GE	81.18	81.34	82.30	81.20	0.82	81.26	81.75	81.74	81.27	0.561	0.571	0.455
2 wk (%)
DM	81.07	80.32	81.13	82.27	0.26	80.70	81.70	81.10	81.30	0.001	0.473	0.002
CP	76.57	78.41	77.06	78.79	0.37	77.49	77.93	76.82	78.60	0.246	< 0.001	0.884
GE	82.17	82.19	81.98	82.95	0.42	82.18	82.47	82.08	82.57	0.501	0.251	0.267

Basal, diet containing 18.78% CP; Low, diet containing 16.92% CP.
PT0, non-supplementation of protease; PT10, supplementation of 0.1% protease.
ATTD, apparent total tract digestibility; CP, crude protein; PT, protease; HP, high protein; LP, low crude protein; DM, dry matter; GE, gross energy.