Table 2. The percentage of relative abundance of metal resistance group based on metal resistance genes in piglet faecal samples.

Metal resistance group	D2	12-hours post ETEC challenging						14-days post ETEC challenging
		Non-ETEC infection			ETEC infection			Non-ETEC infection			ETEC infection
		Negative control	Probiotic control	Antibiotic	Single-strain	Multi-strain	ETEC control	Negative control	Probiotic control	Antibiotic	Single-strain	Multi-strain	ETEC control
Multi-metal	57.11	67.27	67.50	59.07	47.83	66.15	55.56	55.62	61.78	57.14	60.77	56.79	55.88
Copper	13.31	10.12	8.93	14.65	35.75	10.76	12.59	11.23	15.53	42.86	12.10	12.00	19.80
Nickel	8.96	7.00	7.02	8.22	5.37	6.31	9.35	7.40	7.05	0.00	9.86	9.24	7.98
Zinc	8.52	6.38	6.84	7.77	4.17	7.17	9.45	12.05	7.38	0.00	6.57	8.42	7.54
Arsenic	5.41	5.65	4.91	5.36	3.36	5.42	5.59	6.58	4.96	0.00	6.64	6.89	4.90
Sodium	4.93	3.15	3.80	4.22	2.98	3.63	5.25	1.92	2.64	0.00	3.08	5.12	3.27
Iron	0.66	0.02	0.23	0.03	0.01	0.12	0.02	1.64	0.00	0.00	0.00	0.00	0.00
Chromium	0.62	0.41	0.54	0.43	0.50	0.41	0.64	1.10	0.00	0.00	0.56	0.62	0.49
Mercury	0.46	0.00	0.20	0.00	0.01	0.03	0.28	2.47	0.66	0.00	0.00	0.00	0.15
Tellurium	0.01	0.00	0.03	0.25	0.01	0.00	1.27	0.00	0.00	0.00	0.42	0.91	0.00

D2 refers to 2 days of age, before probiotic treatment.