Table 5.

Effects of different dietary protein sources and levels in antibiotic-free diets on the intestinal morphology of weaned piglets.¹

Variable	Control	SPC19	FM19	SPC23	FM23	SEM	P-value2
							Diets	Basal	Source	Level	Source × level
Villous height, µm
Duodenum	379a	299b	330ab	298b	321b	11	0.001	0.001	0.016	0.621	0.660
Jejunum	406a	305bc	350ab	283c	297bc	14	0.001	0.001	0.041	0.011	0.263
Ileum	365	330	335	316	328	11	0.072	0.235	0.464	0.335	0.748
Crypt depth, µm
Duodenum	189c	228ab	208bc	248a	247a	9	0.001	0.001	0.224	0.002	0.280
Jejunum	184c	221abc	206bc	247ab	258a	14	0.006	0.004	0.891	0.009	0.336
Ileum	199	223	213	227	228	9	0.128	0.251	0.579	0.272	0.487
Villous height: crypt depth
Duodenum	2.01a	1.32c	1.59b	1.21c	1.31c	0.05	0.001	0.001	0.001	0.001	0.072
Jejunum	2.25a	1.39bc	1.71b	1.16c	1.15c	0.09	0.001	0.001	0.071	0.001	0.082
Ileum	1.73	1.46	1.58	1.40	1.41	0.09	0.111	0.229	0.499	0.220	0.567

SPC = soy protein concentrate; FM = fish meal.

^a,b,cWithin a row, values without a common superscript differ (P < 0.05), comparisons are from orthogonal contrasts.

¹Control = control diet of 17% CP; SPC19 = 19% CP diets formulated with more soy protein concentrate; FM19 = 19% CP diets formulated with more fish meal; SPC23 = 23.7% CP diets formulated with more soy protein concentrate; FM23 = 23.7% CP diets formulated with more fish meal.

²Diets, all five diets; Basal, control compared to supplemented diets; Source, additional soy or fish protein; Level, 19 and 23.7%. Values are least squares means for 6 replicate pens per treatment.