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. 2021 Sep 22;99(10):skab269. doi: 10.1093/jas/skab269

Table 3.

Effect of calcium-ammonium nitrate and bismuth subsalicylate on in vitro fermentation parameters (Exp.1)

Item Treatments1 SEM2 P-value3
CTL CAN CTLB CANB NPNS BSS BSS × NPNS
TGP4, mL/g incubated OM 159a 220b 223b 221b 32.6 0.029 0.016 0.005
IVOMD, % 70.4 72.5 66.1 70.5 5.20 0.230 0.241 0.661
pH 5.95 5.95 5.95 5.97 0.118 0.754 0.624 0.788
CH4, mmol/g incubated OM 0.13 0.19 0.18 0.20 0.082 0.477 0.644 0.753
NH3-N, mM 5.31 5.86 5.39 6.25 0.968 0.092 0.551 0.687
H2S, µmol/g fermented OM 3.76 6.47 5.67 3.99 1.085 0.617 0.781 0.055
VFA, mol/100 mol
 Acetate 50.50 53.47 52.12 53.26 3.278 0.052 0.464 0.346
 Propionate 29.48 30.03 30.98 30.29 5.330 0.908 0.179 0.326
 Butyrate 13.88 10.48 10.88 10.44 2.572 0.215 0.317 0.331
 BCVFA5 2.83 3.20 3.17 3.19 0.708 0.318 0.401 0.372
 Valerate 2.37 2.44 2.47 2.42 0.904 0.762 0.292 0.178
 Total VFA 115.7 125.9 120.2 125.5 8.31 0.293 0.773 0.728
 A:P 1.91 2.02 1.89 1.99 0.451 0.003 0.456 0.758

1CTL, Control (Urea at 0.74%); CAN, Nitrate (CAN at 2.22%); CTLB, Urea-Bismuth (Urea at 0.74% and BSS at 0.33%); CANB, Nitrate-Bismuth (CAN at 2.22% and BSS at 0.33%).

2n = 4 experimental units/treatment mean.

3NPNS, Effect of non-protein nitrogen source; BSS, Effect of BSS; BSSS × NPNS, Interaction between BSS and NPNS;

4TGP after 24 h.

5BCVFA, Branched-chain volatile fatty acids: isobutyrate + isovalerate + 2 methylbutyrate.