Table 3.
Effects of 0%, 5%, 10%, and 20% of dietary crude glycerin on ruminal fermentation and volatile fatty acid profiles in goats
| Item | Dietary crude glycerin (%) | SEM2 | Contrasts, p-value1 | |||||
|---|---|---|---|---|---|---|---|---|
|
|
|
|||||||
| 0 | 5 | 10 | 20 | L | Q | C | ||
| Ruminal pH | 6.53 | 6.51 | 6.48 | 6.48 | 0.06 | 0.70 | 0.89 | 0.93 |
| NH3-N (mg/dL) | 21.27ab | 21.86a | 21.83a | 20.29b | 0.42 | 0.99 | 0.82 | 0.56 |
| BUN (mg/dL) | 21.26ab | 24.50a | 20.47ab | 19.35b | 1.36 | 0.26 | 0.26 | 0.24 |
| Total VFA (mmol/L) | 66.80 | 70.19 | 81.32 | 75.63 | 4.38 | 0.21 | 0.49 | 0.41 |
| Proportion of individual VFA (%) | ||||||||
| Acetate (C2) | 66.27 | 63.65 | 59.39 | 58.62 | 2.63 | 0.05 | 0.74 | 0.69 |
| Propionate (C3) | 19.11b | 21.30b | 24.85ab | 28.00a | 1.81 | 0.01 | 0.84 | 0.87 |
| Butyrate (C4) | 12.31 | 12.40 | 13.47 | 10.84 | 1.21 | 0.69 | 0.47 | 0.58 |
| Other VFA3 | 2.30 | 2.64 | 2.25 | 2.82 | 0.49 | 0.43 | 0.69 | 0.52 |
| C2: C3 ratio | 3.49a | 3.15ab | 2.78ab | 2.25b | 0.25 | 0.03 | 0.80 | 0.94 |
| Methane4 (%) | 29.49a | 27.75ab | 25.28ab | 23.01b | 1.40 | 0.01 | 0.87 | 0.90 |
a–c
Means within rows followed with different superscript letters are statistically different (p<0.05).
1
Linear (L), quadratic (Q), and cubic (C) effects of CGLY.
2
SEM = Standard error of the mean (n = 4).
3
Sum of isobutyrate, isovalerate, valerate and caproate.
4
CH4 = (0.45×acetic acid)−(0.275×propionic acid)+(0.40×butyric acid) (Moss et al., 2000).