Table 2.

Growth performance of pigs fed diets with either antibiotics or increasing levels of BA¹

		BA, %				P value
Item	PC2	0.00	0.50	1.00	SEM	PC vs. 0.00	Linear3	Quadratic4
Body weight, kg
Initial	5.9	5.9	5.9	6.0	0.5	0.924	0.940	0.990
Phase 1	6.9	6.8	6.8	6.7	0.5	0.866	0.961	0.961
Phase 2	11.4	10.8	10.9	10.9	0.7	0.522	0.883	0.907
Phase 3	20.8	17.8	19.8	20.0	1.7	0.027	0.103	0.436
Phase 4	62.9	49.1	58.1	53.1	5.0	<0.001	0.149	0.005
Phase 5	96.3	81.1	93.0	88.3	5.2	<0.001	0.047	0.009
Phase 6	110.7	96.1	107.7	103.3	4.5	<0.001	0.059	0.015
Average daily gain, kg/d
Phase 1	0.142	0.119	0.117	0.108	0.014	0.169	0.505	0.823
Phase 2	0.319	0.283	0.294	0.295	0.017	0.143	0.612	0.813
Phase 3	0.450	0.337	0.423	0.435	0.060	<0.001	0.002	0.164
Phase 4	0.686	0.505	0.625	0.534	0.048	<0.001	0.393	<0.001
Phase 5	0.958	0.914	0.991	1.006	0.096	0.339	0.050	0.433
Phase 6	1.023	1.057	1.044	1.044	0.174	0.697	0.878	0.939
Overall	0.689	0.593	0.669	0.639	0.040	<0.001	0.039	0.007
Average daily feed intake, kg/d
Phase 1	0.200	0.205	0.190	0.187	0.017	0.757	0.313	0.709
Phase 2	0.574	0.597	0.556	0.600	0.084	0.510	0.929	0.159
Phase 3	0.651	0.576	0.617	0.638	0.022	0.016	0.043	0.715
Phase 4	1.090	1.110	1.054	1.066	0.096	0.645	0.317	0.366
Phase 5	2.593	2.726	2.618	2.730	0.208	0.199	0.965	0.220
Phase 6	2.864	3.050	2.997	3.110	0.355	0.226	0.697	0.530
Overall	1.450	1.495	1.448	1.495	0.137	0.345	0.999	0.256
Gain-to-feed ratio
Phase 1	0.71	0.58	0.62	0.58	0.08	0.016	0.911	0.383
Phase 2	0.59	0.49	0.56	0.51	0.06	0.010	0.634	0.069
Phase 3	0.70	0.58	0.70	0.69	0.10	0.030	0.048	0.190
Phase 4	0.64	0.47	0.61	0.53	0.08	<0.001	0.108	<0.001
Phase 5	0.37	0.33	0.38	0.37	0.02	0.111	0.115	0.111
Phase 6	0.35	0.36	0.34	0.34	0.03	0.852	0.523	0.789
Overall	0.48	0.40	0.47	0.44	0.03	<0.001	0.046	0.002

¹The experimental unit was a pen, consisting of 8 pigs per pen, and each least squares mean represents 15 observations.

²PC = a basal diet with antibiotics (chlortetracycline at 100 mg/kg [450 mg/kg of Aureomycin 100] during phases 1 to 3, and tylosin at 44 mg/kg [200 mg/kg of Tylan 100] during phases 4 to 6).

³Linear = linear effect of increasing levels of BA.

⁴Quadratic = quadratic effect of increasing levels of BA.