Table 4. Molar proportion of volatile fatty acids (VFA) in cultures
| Incubation times (h) | SEM | Contrast |
24 | 48 | 72 | Linear | Quadratic |
Total VFA (mM) | | | | | | |
Ec | 33.5a | 45.9b | 70.9a | 5.54 | < 0.001 | 0.008 |
AAFB | 23.1b | 28.0c | 32.3b | 1.40 | < 0.001 | NS |
Ec + AAFB | 33.9a | 59.2a | 75.8a | 6.15 | < 0.001 | NS |
VFA (moL/100 moL) | | | | | | |
Acetate | | | | | | |
Ec | 76.3a | 67.0b | 53.8b | 3.28 | < 0.001 | 0.002 |
AAFB | 76.5a | 73.5a | 72.7a | 0.60 | < 0.001 | 0.011 |
Ec + AAFB | 72.5b | 53.8c | 46.8c | 3.84 | < 0.001 | < 0.001 |
Propionate | | | | | | |
Ec | 15.2b | 24.1b | 37.8b | 3.30 | < 0.001 | 0.0115 |
AAFB | 12.10c | 16.1c | 15.3c | 0.61 | < 0.001 | < 0.0001 |
Ec + AAFB | 17.1a | 37.2a | 43.4a | 3.98 | < 0.001 | < 0.0001 |
Butyrate | | | | | | |
Ec | 6.61c | 7.29b | 6.74c | 0.15 | NS | NS |
AAFB | 8.75a | 8.00a | 9.24a | 0.19 | 0.006 | < 0.001 |
Ec + AAFB | 8.24b | 7.34b | 7.79b | 0.14 | 0.021 | 0.002 |
Valerate | | | | | | |
Ec | 0.66b | 0.49b | 0.35b | 0.05 | < 0.001 | NS |
AAFB | 1.00a | 0.84a | 0.76a | 0.04 | < 0.001 | NS |
Ec + AAFB | 0.67b | 0.44c | 0.37b | 0.05 | < 0.001 | < 0.001 |
Total BCVFA | | | | | | |
Ec | 1.21b | 1.15b | 1.36 | 0.06 | NS | NS |
AAFB | 1.61a | 1.54a | 1.97 | 0.09 | NS | NS |
Ec + AAFB | 1.51a | 1.27ab | 1.64 | 0.07 | NS | 0.017 |
Acetate:Propionate ratio | | | | | | |
Ec | 5.03b | 2.79b | 1.43b | 0.53 | < 0.001 | < 0.001 |
AAFB | 6.33a | 4.57a | 4.74a | 0.28 | < 0.001 | < 0.001 |
Ec + AAFB | 4.25c | 1.45c | 1.08c | 0.50 | < 0.001 | < 0.001 |
Means within a row with different superscripts differ (p < 0.05).
Ec, Entodinium caudatum alone; AAFB, amino acid-fermenting bacterial consortium alone; NS, not significant (p > 0.05); Ec + AAFB, co-culture of both Ec and AAFB; BCVFA, branched-chain VFAs.