Table 3.

Orthogonal and polynomial contrast analysis for counting of SE and coliform bacteria from cecum and liver at 7 and 14 day post-challenge.

P-value1	Salmonella Enteritidis				Coliform bacteria
	7 day post-challenge		14 day post-challenge		7 day post-challenge		14 day post-challenge
	Infected chickens	Exposed chickens	Infected chickens	Exposed chickens	Infected chickens	Exposed chickens	Infected chickens	Exposed chickens
Cecum
Control vs BP	< 0.000	0.027	< 0.000	0.021	0.004	0.002	< 0.000	0.002
BP vs Colistin	< 0.000	0.653	< 0.000	0.911	0.898	0.830	0.545	0.318
Lin	< 0.000	0.026	< 0.000	0.004	0.005	0.002	< 0.000	0.000
Quad	0.744	0.722	0.358	0.104	0.437	0.477	0.099	0.160
Liver
Control vs BP	0.063	0.012	0.034	0.006	< 0.000	0.027	0.000	< 0.000
BP vs Colistin	0.697	0.486	0.973	0.918	0.110	0.827	0.000	0.450
Lin	0.022	0.004	0.015	0.005	< 0.000	0.023	< 0.000	< 0.000
Quad	0.251	0.385	0.474	0.861	0.015	0.818	0.003	0.057

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