Table 6.

Effects of antibiotics and low-crude protein diets on the relative abundance of fecal associated microbiota at the family level in pigs¹

Item	ATB−2		ATB+3		SEM	P-value
	18.5% CP4	13.0% CP5	18.5% CP4	13.0% CP5		ATB	CP	CP × ATB
66 days of age
Prevotellaceae	17.2	19.7	14.6	14.3	2.383	0.076	0.629	0.523
Lachnospiraceae	12.5	13.3	14.6	15.2	0.902	0.027	0.437	0.969
Streptococcaceae	12.4	6.14	14.3	7.99	1.787	0.174	<0.001	0.984
Ruminococcaceae	7.66	6.62	8.14	8.26	1.007	0.215	0.582	0.494
Lactobacillaceae	7.80	6.96	3.79	5.89	1.528	0.031	0.580	0.201
Veillonellaceae	5.20	5.26	4.50	4.96	1.477	0.497	0.720	0.788
Oscillospiraceae	5.14	6.08	6.73	6.20	1.005	0.157	0.736	0.225
Selenomonadaceae	2.36	4.69	2.38	2.70	0.598	0.096	0.028	0.090
Muribaculaceae	3.71	3.52	4.12	4.45	0.672	0.281	0.908	0.679
Clostridiaceae	1.22	1.85	1.47	2.56	0.550	0.205	0.028	0.546
Others	24.7	25.9	25.3	27.6	1.825	0.515	0.324	0.751
87 days of age
Lachnospiraceae	15.4	16.1	14.9	15.6	0.861	0.453	0.258	0.983
Prevotellaceae	14.5	10.8	15.5	14.4	2.687	0.239	0.221	0.510
Streptococcaceae	11.0	5.01	9.43	4.73	1.219	0.356	<0.001	0.514
Ruminococcaceae	9.17	9.33	9.20	8.48	0.563	0.458	0.608	0.421
Lactobacillaceae	7.49	11.9	8.02	9.14	1.705	0.458	0.075	0.279
Veillonellaceae	7.19	6.94	7.52	9.09	0.970	0.165	0.454	0.305
Oscillospiraceae	6.13	6.17	5.40	6.37	0.569	0.635	0.365	0.405
Selenomonadaceae	4.17	4.19	3.94	6.36	1.136	0.326	0.221	0.228
Muribaculaceae	3.84	3.02	2.85	3.40	0.531	0.553	0.784	0.187
Clostridiaceae	2.58	4.66	2.53	3.57	0.601	0.331	0.011	0.377
Others	18.5	21.8	20.7	18.8	1.584	0.781	0.653	0.096

¹Experimental medicated diets (ATB+) were fed from 59 to 73 days old. In the postmedicated period, all pigs were fed their respective crude protein (CP) control diets from 73 to 87 days of age.

²ATB−, diet without antibiotics.

³ATB+, diet with 100 mg/kg tiamulin and 506 mg/kg oxytetracycline.

⁴18.5% CP, diet with 18.5% of CP.

⁵13.0% CP, diet with 13.0% of CP.