Table 3. Effects of dietary CP levels or oscillating dietary CP on ruminal pH, total VFA concentration and individual VFA proportions in dual-flow continuous culture system.
| Item1 | Treatment, CP% | SEM | P-value | |||||
|---|---|---|---|---|---|---|---|---|
| 10% | 12% | 14% | OSC | 12% vs. OSC | Linear | Quadratic | ||
| pH | 6.1 | 6.1 | 6.4 | 6.1 | 0.08 | 0.70 | <0.01 | 0.12 |
| Total VFA, mM | 60.5 | 64.7 | 64.7 | 63.0 | 3.37 | 0.58 | 0.17 | 0.41 |
| VFA, % total | ||||||||
| Acetate | 35.6 | 34.5 | 30.9 | 38.8 | 2.99 | 0.29 | 0.25 | 0.72 |
| Propionate | 28.9 | 31.2 | 33.2 | 28.9 | 2.38 | 0.41 | 0.14 | 0.95 |
| Butyrate | 29.1 | 29.1 | 30.5 | 26.1 | 3.37 | 0.51 | 0.76 | 0.85 |
| Valerate | 2.7 | 2.4 | 2.7 | 2.6 | 0.39 | 0.58 | 0.99 | 0.47 |
| Iso-Butyrate | 0.1 | 0.4 | 0.5 | 0.5 | 0.51 | 0.23 | 0.70 | 0.36 |
| Iso-Valerate | 3.1 | 2.5 | 2.3 | 3.0 | 0.54 | 0.38 | 0.19 | 0.64 |
| BCVFA, mM | 2.2 | 1.9 | 1.8 | 2.2 | 0.40 | 0.49 | 0.34 | 0.75 |
| Acetate: propionate | 1.3 | 1.1 | 1.0 | 1.4 | 0.12 | 0.07 | 0.05 | 0.83 |
1VFA = volatile fatty acids; BCVFA = Branched-chain VFA.