Table 1 Relative distributions of bacterial phylotypes, families and genera in (i) the cecum content of mice orally exposed for 8 weeks to Cd (20 or 100 ppm) or Pb (100 or 500 ppm) salts and (ii) the fecal pellets for mice orally exposed for 8 weeks to Cd (20 ppm) or Pb (100 ppm)

Cecal content

Actinobacteria

0.25%

0.59%

1.19%

2.27%

0.25%

  (range)

(0.11-0.40)

(0.16-1.30)

(0.36-1.84)

(0.11-5.39)

(0.10-0.40)

  SEM

0.049

0.210

0.272

1.113

0.161

  P value

-

0.0775

0.0045

0.0537

0.478

Bacteroidetes

1.9%

2.58%

1.60%

1.47%

1.36%

  (range)

s(1.29-2.28)

(0.35-7.66)

(0.31-4.97)

(0.30-3.36)

(0.8-2.40)

  SEM

0.183

1.328

0.854

0.612

0.3

  P value

-

0.3131

0.3697

0.2578

0.0869

Firmicutes

97.8%

96.77%

97.2%

96.24%

98.36%

  (range)

(97.4-98.4)

(92.0-99.3)

(93.1-98.8)

(91.1-99.6)

(97.9-99.0)

  SEM

0.187

1.297

1.037

1.739

0.272

  P value

-

0.2269

0.2916

0.1986

0.1755

Fecal pellet

Actinobacteria

0.30%

0.39%

0.24%

  (range)

(0.18-0.50)

(0.13-0.65)

(0.08-0.42)

  SEM

0.053

0.089

0.058

  P value

-

0.2304

0.2188

Bacteroidetes

34.4%

38.8%

35.65%

  (range)

(12.5-50.8)

(30.1-7.5)

(22.4-51.5)

  SEM

6.56

10.84

8.65

  P value

-

0.3670

0.4553

Firmicutes

64.7%

60.44%

63.85%

  (range)

(48.2-71.3)

(47.5-90.9)

(38.2-77.5)

  SEM

6.73

10.86

8.72

  P value

-

0.3736

0.4701

Family

Cd0Pb0

Cd20

Cd100

Pb100

Pb500

Cecal content

Lachnospiraceae

72.6%

53.17%

25.9%

43.7%

67.5%

  (range)

(33.2-88.3)

(26.8-76.6)

(10.3-28.5)

(27.1-61.4)

(59.1-75.0)

  SEM

10.01

9.24

4.15

6.09

2.62

  P value

-

0.037

0.0081

0.0378

0.05859

Lactobacillaceae

22.34%

38.20%

54.68%

38.24%

26.1%

  (range)

(5.6-64.9)

(19.01-60.6)

(41.6-81.6)

(28.7-67.1)

(19.2-32.1)

  SEM

10.88

8.54

7.06

7.26

2.09

  P value

-

0.05859

0.0379

0.0379

0.05859

Ruminococcaceae

1.82%

2.15%

2.64%

2.15%

1.14%

  (range)

(0.72-3.01)

(0.76-5.91)

(0.81-7.21)

(0.63-3.22)

(0.58-1.67)

  SEM

0.442

0.836

0.876

0.934

0.939

  P value

-

0.3804

0.2627

0.3106

0.0997

Porphyromonadaceae

0.42%

0.63%

0.42%

0.49%

0.41%

  (range)

(0.0-1.25)

(0.0-2.24)

(0.0-1.41)

(0.0-1.65)

(0.05-1.24)

  SEM

0.228

0.438

0.433

0.415

0.411

  P value

-

0.3152

0.4774

0.4139

0.0641

Rikenellaceae

0.51%

0.42%

0.27%

0.21%

0.26%

  (range)

(0.0-1.32)

(0.0-1.32)

(0.0-0.92)

(0.0-0.6)

  (0.0-0.47)

  SEM

0.250

0.245

0.259

0.174

0.174

  P value

-

0.3883

0.2216

0.1564

0.1800

Coriobacteriaceae

0.49%

1.19%

2.38%

4.57%

0.36%

  (range)

(0.2-0.76)

(0.23-2.6)

(0.69-4.35)

(0.2-11.75)

(0.1-0.51)

  SEM

0.111

0.0939

0.107

0.433

0.138

  P value

-

0.1736

0.01414

0.0250

0.3

Streptococcaceae

0.3%

0.14%

0.15%

0.24%

0.04%

  (range)

(0.0-0.50)

(0.05-0.3)

(0.0-0.66)

(0–0.75)

(0–0.1)

  SEM

0.102

0.0239

0.0983

0.0894

0.0581

  P value

-

0.0901

0.1905

0.3711

0.0164

Erysipelotrichaceae

0.1%

2.32%

12.98%

6.89%

3.6%

  (range)

(0.0-0.24)

(0.42-8.02)

(3.82-28.12)

(2.13-14)

(1.73-6.05)

  SEM

0.044

0.232

0.219

0.268

0.02236

  P value

-

0.0182

0.0096

0.0096

0.00051

Family

Cd0Pb0

Cd20

Pb100

Fecal pellet

Lachnospiraceae

37.36%

23.67%

12.55%

  (range)

(18.8-86.9)

1.77-82.9)

(3.52-26.6)

  SEM

12.81

14.14

17.28

  P value

-

0.0453

0.023

Lactobacillaceae

32.99%

42.77%

50.88%

  (range)

(10.3-51.2)

(4.49-67.1)

(25.1-65.6)

  SEM

8.58

8.87

10.02

  P value

-

0.2782

0.1121

Ruminococcaceae

1.70%

1.4%

0.83%

  (range)

(0.24-3.46)

(0.08-4.58)

(0.11-1.61)

  SEM

0.65

0.65

0.86

  P value

-

0.3916

0.1275

Porphyromonadaceae

11.14%

13.01%

12%

  (range)

(3.46-16.25)

(1.60-22.04)

(4.88-19.6)

  SEM

2.22

3.11

3.84

  P value

-

0.3447

0.4075

Rikenellaceae

8.36%

4.99%

5.82%

  (range)

(5.71-14.18)

(1.93-16.07)

(0.45-18.5)

  SEM

1.92

2.47

2.87

  P value

-

0.1736

0.2626

Coriobacteriaceae

0.68%

0.67%

0.41%

  (range)

(0.03-0.99)

(0.32-1.32)

(0.16-0.67)

  SEM

0.137

0.114

0.159

  P value

-

0.4841

0.0677

Streptococcaceae

0.27%

0.26%

0.20%

  (range)

(0.0-0.68)

(0.02-0.69)

(0–0.36)

  SEM

0.127

0.129

0.09

  P value

-

0.4969

0.3060

Erysipelotrichaceae

0.33%

4.05%

6.56%

  (range)

(0.0-0.89)

(0.48-15.53)

(0.44-20.7)

  SEM

0.158

0.399

0.4033

  P value

-

0.0585

0.0107

Prevotellaceae

0.14%

1.06%

0.75%

  (range)

(0.0-0.25)

(0.08-4.14)

(0.11-1.22)

  SEM

0.058

0.806

0.812

  P value

-

0.1345

0.049

Clostridiaceae

0.00%

0.675%

1.55%

  (range)

(0.0-0.00)

(0.0-2.17)

(0.0-3.06)

  SEM

0.0

0.094

0.0940

  P value

-

0.0628

0.0086

Genus

Cd0Pb0

Cd20

Cd100

Pb100

Pb500

Cecal content

Lactobacillus

75.28

84.57%

77.4%

74.8%

83.82%

  (range)

(60–98.9)

(68–91.11)

(57.6-93.6)

(54.1-90.6)

(80.4-89.3)

  SEM

7.554

4.419

5.97

7.741

1.589

  P value

-

0.2229

0.1248

0.1234

0.1503

Blautia

5.39%

2.82%

0.36%

4.90%

0.78%

  (range)

(0–12.6)

(0.45-8.8)

(0–0.97)

(0–9.2)

(0.3-1.22)

  SEM

2.58

1.526

0.176

1.990

0.165

  P value

-

0.2456

0.1085

0.1136

0.2036

Coprococcus

3.49%

3.06%

0.46%

1.65%

0.64%

  (range)

(0–7.95)

(0.22-6.49)

(0.14-0.73)

(0.7-3.62)

(0.32-1.2)

  SEM

1.651

1.172

0.110

0.521

0.151

  P value

-

0.1874

0.2086

0.2677

0.2757

Alistipes

3.42%

1.40%

0.41%

0.40%

0.74%

  (range)

(0.0-12.5)(0.0-4.0)

(0.0-1.49)

(0.0-1.16)

(0.0-1.34)

  SEM

2.40

0.725

0.273

0.232

0.221

  P value

-

0.2084

0.0439

0.4421

0.0461

Steptococcus

2.84%

0.35%

0.24%

0.47%

0.11%

  (range)

(0.0-6.67)

(0.11-0.80)

(0.0-1.05)

(0.0-1.45)

(0.0-0.24)

  SEM

1.235

0.132

0.204

0.274

0.0514

  P value

-

0.4189

0.0522

0.1590

0.0616

Barnesiella

1.56%

0.34%

0.44%

0.66%

0.72%

  (range)

(0.0-6.67)

(0.0-0.8)

(0.0-1.35)

(0.0-2.6)

(0.0-2.27)

  SEM

1.295

0.152

0.244

0.503

0.404

  P value

-

0.1598

0.4157

0.4842

0.1505

Bacteroides

0.95%

0.44%

0.09%

0.11%

0.36%

  (range)

(0.0-3.33)

(0.0-1.6)

(0.0-0.37)

(0–0.54)

(0–1.29)

  SEM

0.631

0.292

0.071

0.108

0.236

  P value

-

0.0401

0.0356

0.0489

0.0229

Turicibacter

0.28%

4.02%

19.63%

14.34%

11.32%

  (range)

(0.0-1.15)

(0.76-11.8)

(4.48-41.3)

(3.09-22.15)

(6.37-15.4)

  SEM

0.222

1.987

6.566

4.599

1.749

  P value

-

0.0492

0.0092

0.0078

0.0001

Genus

Cd0Pb0

Cd20

Pb100

Fecal pellet

Lactobacillus

49.31%

58.0%

63.07%

  (range)

(8.96-73.18)

(22.4-88.4)

(34.4-82.9)

  SEM

10.71

12.14

11.67

  P value

-

0.3032

0.2053

Blautia

0.73%

0.75%

0.28%

  (range)

(0.0-2.99)

(0.0-3.28)

(0.0-0.64)

  SEM

0.570

0.634

0.143

  P value

-

0.4873

0.2331

Coprococcus

1.61%

0.83%

0.14%

  (range)

(0.0-5.97)

(0.0-3.48)

(0.0-0.32)

  SEM

1.101

0.664

0.065

  P value

-

0.2795

0.1091

Alistipes

17.5%

8.47%

7.20%

  (range)

(7.2-29.8)

(2.0-19.3)

(0.43-24.5)

  SEM

3.871

3.822

4.454

  P value

-

0.0678

0.0495

Steptococcus

0.50%

0.38%

0.28%

  (range)

(0.0-1.44)

(0.1-0.87)

(0.0-0.5)

  SEM

0.263

0.152

0.094

  P value

-

0.3494

0.2254

Barnesiella

14.18%

9.13%

7.38%

  (range)

(6.8-25.3)

(5.12-16.7)

(2.4-11.8)

  SEM

3.049

2.216

1.711

  P value

-

0.1086

0.0438

Bacteroides

11.17%

12.32%

10.46%

(range)

(4.7-19.6)

(2.08-39.9)

(3.76-24.8)

SEM

3.175

7.419

4.364

P value

-

0.4448

0.4492

Turicibacter

0.75%

4.81%

8.71%

  (range)

(0.0-1.49)

(0.82-17.6)

(2.84-28.24)

  SEM

0.307

3.236

4.996

  P value

-

0.0483

0.0281