Table 7.

Intestinal morphology in broiler chickens at 35 days of age when interactions between crude protein level and protease enzyme supplementation were significant¹⁾

Item	Diets2)				SEM	Contrast, p-values
	NP	LP1	LP2	LP3		Linear	Quadratic
Jejunal villus height
With protease	1,128	960	957	796	25.41	<0.001	<0.001
Without protease	962	1063	871	798	22.95	0.099	<0.001
Ileal absorptive surface area
With protease	0.119	0.174	0.151	0.142	0.066	<0.001	1.000
Without protease	0.135	0.152	0.118	0.106	0.006	0.386	0.004

SEM, standard error of mean.

¹⁾Data represent mean value of 8 birds.

²⁾NP, normal protein (starter CP21/finisher CP19); LP1, low protein diet 1 (starter CP19.7/finisher CP17.9); LP2, low protein diet 2 (starter CP18.5/finisher CP16.7); LP3, low protein diet 3 (starter CP17.2/finisher CP15.6).