Table 4.

Effect of adding BP and colistin to the diets on histological changes of jejunum in infected chickens.

Morphometric parameters	Dietary treatments					SEM	P-value1
	Control	0.3 g colistin	0.4 g colistin	1.0 g BP	1.5 g BP		Trt	C vs BP	Lin	Quad
7 day post-challenge
Villus height (µm)	682.56b	744.20ab	733.24ab	798.55ab	827.15a	34.609	0.049	0.009	0.008	0.671
Crypt depth (µm)	92.85	88.73	90.94	89.76	79.74	7.151	0.732	0.381	0.260	0.546
VH: CD	7.58b	8.66ab	8.15ab	9.24ab	10.54a	0.585	0.013	0.009	0.004	0.703
Villus width (µm)	90.12	95.37	90.71	95.69	97.52	3.118	0.372	0.064	0.058	0.852
VSA (mm2)	0.19b	0.22ab	0.20ab	0.23ab	0.25a	0.012	0.017	0.002	0.002	0.648
Muscle thickness (µm)	203.24	231.67	221.90	230.83	231.22	13.680	0.539	0.072	0.086	0.554
14 day post-challenge
Villus height (µm)	823.58b	999.82a	851.27b	846.04b	919.74ab	34.864	0.007	0.161	0.074	0.327
Crypt depth (µm)	115.01a	109.65ab	104.61ab	95.52bc	92.09c	4.078	0.001	0.000	0.000	0.437
VH: CD	7.23c	9.19ab	8.16bc	8.87abc	10.07a	0.424	0.000	0.000	0.000	0.639
Villus width (µm)	110.14	116.31	111.98	111.98	113.12	5.838	0.960	0.743	0.724	0.984
VSA (mm2)	0.28	0.36	0.29	0.29	0.32	0.020	0.066	0.333	0.225	0.564
Muscle thickness (µm)	215.41	257.67	233.02	218.55	229.58	13.785	0.236	0.489	0.369	0.619

0.3 g colistin: 0.3 g/kg colistin in diet; 0.4 g colistin: 0.4 g/kg colistin in diet; 1 g BP: 1 g/kg bacteriophage in diet; 1.5 g BP: 1.5 g/kg bacteriophage in diet.

VH: CD villus height to crypt depth ratio; VSA villus surface area.

¹Trt: overall effects of treatments; C vs BP: contrasting birds not treated with BP or colistin versus birds treated with BP; Lin: linear effects of increasing inclusion levels of BP; Quad: quadratic effects of increasing inclusion levels of BP.

^abcValues within a row followed by different superscripts are significantly different. P < 0.05; Tukey's pairwise test.