Table 2.
Reaction equations used to estimate the production and consumption of metabolic hydrogen ([2H]) during the synthesis of major rumen fermentation end products (presented as underlined in the reaction equations).
| Fermentation end product | Reaction equation | Moles [2H] released/mole end product |
|---|---|---|
| Formate | [2H] + CO2
HCOOH
|
–1 |
| Acetate | C6H12O6 + 2 H2O 2 CH3COOH + 4 [2H] + 2 CO2
|
+2 |
| Propionate | C6H12O6 + 2 [2H] 2 CH3CH2COOH + 2 H2O |
−1 |
| Butyrate | C6H12O6
1 CH3(CH2)2COOH + 2 [2H] + 2 CO2
|
+2 |
| Valerate | C6H12O6 + [2H]
CH3(CH2)3COOH + CO2 + 2 H2O |
−1 |
| CaproateA | 3 C6H12O6
2 CH3(CH2)4COOH + 4 [2H] + 2 H2O + 6 CO2
|
+2 |
| CaproateB | C6H12O6 + 4 [2H]
CH3(CH2)4COOH + 4 H2O |
−4 |
| Heptanoate | 2 C6H12O6 + 2 [2H]
CH3(CH2)5COOH + 2 CO2 + CH3CH2COOH + 4 H2O |
–2 |
| Methane | CO2 + 4 [2H]
CH4 + 2 H2O |
−4 |
A
Acetyl-CoA as intermediate.
B
Propionyl-CoA as intermediate.