Table 5 The effect of CAL on in vitro ruminal fermentation and methane production (Exp. 1)

 Redox potential, mV

− 335

− 336

− 329

− 333

2.11

0.35

0.34

 pH

6.89

6.89

6.91

6.91

0.001

0.12

0.08

 NH₃, mmol/L

9.19

9.19

9.11

9.18

0.25

0.99

0.96

 Total VFA, mmol/L

44.7

44.4

44.6

47.1

1.15

0.62

0.36

  Acetate (A)

61.3^a

59.7^ab

58.2^b

56.9^c

0.74

0.01

< 0.01

  Propionate (P)

22.9^bc

22.7^c

23.7^ab

24.7^a

0.37

< 0.01

< 0.01

  Isobutyrate

3.36

3.56

3.57

3.62

0.17

0.78

0.35

  Butyrate

8.19^b

9.10^a

9.36^a

9.36^a

0.14

0.02

< 0.01

  Isovalerate

1.01^ab

1.12^a

0.91^b

0.93^b

0.03

0.04

0.13

  Valerate

3.01^c

3.76^b

4.15^ab

4.22^a

0.14

< 0.01

< 0.01

  A/P ratio

2.75^a

2.69^a

2.51^b

2.35^b

0.07

< 0.01

< 0.01

  Dry matter

505

526

499

518

6.40

0.38

0.78

  Organic matter

516

530

504

524

6.36

0.47

0.99

  Crude protein

430^b

489^a

453^ab

489^a

7.82

0.01

0.03

  Neutral detergent fiber

491

506

483

488

7.11

0.66

0.59

  Gas, mL

2902^a

2984^a

2920^a

2534^b

51.0

< 0.01

0.01

  Gas, mL/g DM

264^a

271^a

265^a

230^b

4.63

< 0.01

0.01

  CH_4, mL

92.0^a

79.0^ab

71.1^b

46.6^c

3.84

< 0.01

< 0.01

  CH₄, mL/g DM

8.64^a

7.41^ab

6.45^b

4.22^c

0.34

< 0.01

< 0.01

  CH₄, mL/L gas

33.6^a

28.3^ab

24.2^b

18.2^c

1.24

< 0.01

< 0.01

  CH₄, mL/g DMD

17.1^a

14.0^b

14.9^ab

8.61^c

0.70

< 0.01

< 0.01

  CH₄, mL/g OMD

16.8^a

13.0^ab

12.4^b

8.90^b

0.69

< 0.01

< 0.01

  CH₄, mL/g NDF

15.6

14.4

13.9

8.46

0.80

0.08

0.02