Table 7.

Intestinal morphology in the duodenum and jejunum of pigs fed diets containing high, medium, and low levels of crude protein¹

	Dietary crude protein level, %
Item	22	19	16	SEM	P-value
Jejunum
Villus height, µm	278.33b	327.96a	300.82ab	11.82	0.023
Crypt depth, µm	212.67	192.30	209.81	13.10	0.504
Villus height:crypt depth ratio	1.44b	1.85a	1.54ab	0.11	0.040
Ileum
Villus height, µm	242.14	207.39	248.14	20.52	0.310
Crypt depth, µm	200.03a	161.00b	171.71b	7.89	0.002
Villus height:crypt depth ratio	1.22	1.30	1.37	0.12	0.684

¹Data are means of 11 to 12 observations per treatment.

^a,bMeans within a row lacking a common letter are different (P ≤ 0.05).