Table 4.
Effect of slow-release urea (SRU) supplementation on microbial N production in Rusitec
| Item | Treatmenta | Pb | ||||||
|---|---|---|---|---|---|---|---|---|
| Control | U28 | U56 | MU35 | SEM | L | Q | C vs. MU35 | |
| Microbial Nc, mg/d | ||||||||
| Total | 78.9 | 84.5 | 83.8 | 83.4 | 1.88 | 0.14 | 0.05 | 0.03 |
| LAB | 52.8 | 56.0 | 55.6 | 55.3 | 1.69 | 0.38 | 0.61 | 0.20 |
| FPA | 15.0 | 15.7 | 14.9 | 15.3 | 0.81 | 0.97 | 0.47 | 0.79 |
| FPB | 9.8 | 11.4 | 11.5 | 11.5 | 0.65 | 0.06 | 0.32 | 0.08 |
| Efficiency of microbial Nd | 9.5 | 11.5 | 11.7 | 10.2 | 0.30 | 0.03 | 0.12 | 0.17 |
aControl (no SRU), U28 = control plus 0.28% SRU, U56 = control plus 0.56% SRU, and MU35 = control diet was modified by partially replacing soybean protein with 0.35% SRU (DM basis);
bL, Q = linear and quadratic effects of SRU (control, U28 and U56); C vs. MU35 = Contrast between Control and MU35
cLAB = liquid associate bacteria; FPA = feed particle-associated bacteria; FPB = feed particle-bound bacteria
dEfficiency of microbial N, mg of microbial N production/g of OM fermented