Table 4 Effects of hay quality and concentrate supplementation on short-chain fatty acid (SCFA) profiles along the gastrointestinal tract of calves

Item

MQH¹

HQH²

MQH + C³

HQH + C⁴

SEM⁵

Hay quality

Concentrate

Hay quality × Concentrate

Reticulum

Total SCFA, µmol/g

74.9

106

85.7

94.6

12.8

0.13

0.99

0.38

Acetate, %

72.2

66.6

58.7

50.0

1.62

< 0.01

< 0.01

0.33

Propionate, %

16.7

20.5

32.0

38.6

1.42

< 0.01

< 0.01

0.32

n-Butyrate, %

7.66

9.21

4.78

5.54

0.78

0.14

< 0.01

0.60

Iso-Butyrate, %

1.25

0.92

0.66

0.71

0.13

0.28

0.02

0.16

n-Valerate, %

0.71

1.45

2.82

4.06

0.47

0.04

< 0.01

0.58

Iso-Valerate, %

1.34

1.03

0.69

0.64

0.16

0.27

0.01

0.41

Rumen liquid

Total SCFA, µmol/g

108

135

145

150

8.23

0.05

< 0.01

0.16

Acetate, %

70.6

65.1

54.2

48.5

1.56

< 0.01

< 0.01

0.92

Propionate, %

17.8

21.2

33.7

39.3

1.62

0.01

< 0.01

0.47

n-Butyrate, %

8.52

9.97

5.87

5.71

1.03

0.51

< 0.01

0.41

Iso-Butyrate, %

0.98

0.84

0.72

0.61

0.09

0.15

0.01

0.83

n-Valerate, %

0.81

1.67

4.18

4.78

0.81

0.34

< 0.01

0.86

Iso-Valerate, %

1.08

0.88

0.71

0.54

0.12

0.14

0.01

0.89

Rumen solid

Total SCFA, µmol/g

127

161

156

170

12.7

0.06

0.13

0.39

Acetate, %

70.9

65.7

54.7

48.4

1.58

< 0.01

< 0.01

0.72

Propionate, %

17.9

21.1

33.2

39.3

1.55

0.01

< 0.01

0.32

n-Butyrate, %

8.27

9.64

5.87

5.75

1.07

0.53

0.01

0.46

Iso-Butyrate, %

0.97

0.85

0.72

0.59

0.09

0.15

0.01

0.99

n-Valerate, %

0.81

1.65

4.20

4.88

0.87

0.36

< 0.01

0.92

Iso-Valerate, %

0.97

0.87

0.72

0.55

0.12

0.25

0.02

0.72

Abomasum

Total SCFA, µmol/g

13.7

18.8

27.8

16.0

8.44

0.66

0.48

0.14

Acetate, %

81.1

74.0

65.1

60.8

2.00

0.01

< 0.01

0.49

Propionate, %

13.1

16.8

27.7

32.5

1.32

0.01

< 0.01

0.72

n-Butyrate, %

3.76^b

6.43^a

3.87^b

3.58^b

0.56

0.05

0.03

0.02

Iso-Butyrate, %

1.17

1.05

0.33

0.11

0.14

0.24

< 0.01

0.75

n-Valerate, %

0.06

0.99

2.48

2.68

0.39

0.17

< 0.01

0.36

Iso-Valerate, %

0.83

0.69

0.28

0.10

0.21

0.46

0.01

0.93

Duodenum

Total SCFA, µmol/g

7.60

10.9

9.08

8.99

1.49

0.27

0.89

0.24

Acetate, %

87.3

78.1

78.2

64.6

4.34

0.01

0.02

0.60

Propionate, %

9.60^b

15.4^b

18.3^ab

30.3^a

5.14

< 0.01

0.12

< 0.01

n-Butyrate, %

2.50

4.52

2.01

3.23

1.00

0.11

0.36

0.68

Iso-Butyrate, %

0.31

1.46

0.18

0.00

0.50

0.31

0.11

0.18

n-Valerate, %

0.00

0.18

1.04

1.97

0.43

0.19

< 0.01

0.37

Iso-Valerate, %

0.27

0.38

0.26

0.00

0.29

0.79

0.49

0.49

Jejunum

Total SCFA, µmol/g

5.99

7.80

9.23

9.24

1.51

0.52

0.11

0.53

Acetate, %

97.9

83.9

92.9

90.3

6.13

0.18

0.91

0.34

Propionate, %

2.12

7.28

7.15

8.46

4.75

0.48

0.50

0.68

n-Butyrate, %

0.00

4.91

0.01

0.81

1.78

0.11

0.24

0.24

Iso-Butyrate, %

0.00

3.92

0.00

0.00

1.07

0.07

0.07

0.07

n-Valerate, %

0.00

0.00

0.00

0.47

0.22

0.27

0.27

0.27

Iso-Valerate, %

0.00

0.00

0.00

0.00

.

.

.

.

Colon

Total SCFA, µmol/g

63.3

93.5

67.2

81.2

17.0

< 0.01

< 0.01

0.89

Acetate, %

76.9

75.3

67.1

68.0

1.35

0.78

< 0.01

0.36

Propionate, %

14.6

14.8

19.2

20.6

1.06

0.49

< 0.01

0.58

n-Butyrate, %

4.17

5.98

11.6

10.1

1.08

0.92

< 0.01

0.14

Iso-Butyrate, %

1.48

1.30

0.73

0.49

0.11

0.06

< 0.01

0.76

n-Valerate, %

1.50

1.62

0.74

0.54

0.20

0.84

< 0.01

0.44

Iso-Valerate, %

1.26

1.01

0.59

0.37

0.11

0.04

< 0.01

0.87