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. 2023 Jan 6;101:skad001. doi: 10.1093/jas/skad001

Table 7.

Relative abundance of bacterial taxa (phyla and genera level, sequenced targeting the V4 region of the 16s rRNA gene) associated rumen content (solid and liquid phase) collected at different sampling times (0, 6, and 12 h) from beef heifers fed a high forage diet (45% finely chopped grass hay and 45% barley silage) supplemented without 3-nitrooxypropanol (3-NOP, control) and with 3-NOP (150 mg/kg DM, 3-NOP)

Item Treatment (treat) Sampling time (hour, H)4 Rumen content (RC) P-value3
Control 3-NOP SEM 0 6 12 SEM Liquid Solid SEM Treat H RC
Observed amplicon sequence variants (ASV) 695 611 17.4 675a 654ab 630b 15.8 633 673 12.9 <0.01 0.02 <0.01
Chao1 value 696 612 17.5 676a 655ab 630b 15.9 634 674 13.0 <0.01 0.02 <0.01
Shannon index 5.56 5.32 0.089 5.47 5.44 5.41 0.029 5.36 5.52 0.024 0.04 0.09 <0.001
Relative abundances1, %
P Bacteroidates 50.8 50.9 3.31 49.2 50.4 53.0 1.65 58.4 43.3 1.51 0.98 0.07 <0.001
 g Prevotella 39.0 35.3 3.20 34.5a 37.3ab 39.5b 1.45 43.7 30.5 1.18 0.32 <0.01 <0.001
 g Rikenellaceae RC9 gut group 3.83 5.05 0.290 5.35a 4.32ab 3.65b 0.390 4.24 4.64 0.318 0.01 <0.001 0.20
 g Prevotellaceae UCG-001 3.12 3.25 1.001 3.50 2.61 3.46 0.482 3.35 3.03 0.394 0.90 0.12 0.42
 g Prevotellaceae UCG-003 1.08 1.68 0.355 1.11 1.52 1.50 0.360 1.89 0.87 0.296 0.12 0.43 <0.01
 g Prevotellaceae NK3B31 group 0.78 0.96 0.346 1.18 0.70 0.73 0.285 0.79 0.95 0.227 0.62 0.16 0.48
 g Prevotellaceae UCG-004 1.14 2.13 0.425 1.14 1.64 2.12 0.345 1.62 1.65 0.260 0.06 0.02 0.92
 g Bacteroidales BS11 gut group 0.33 0.37 0.074 0.41 0.34 0.31 0.097 0.33 0.38 0.074 0.57 0.47 0.92
 g Bacteroidates RF16 group 1.27 1.47 0.180 0.97b 1.45a 1.68a 0.176 1.58 1.16 0.141 0.32  <0.01 <0.01
 g Muribaculaceae 0.53 0.63 0.102 0.76a 0.27b 0.70a 0.141 0.62 0.54 0.093 0.40 <0.01 0.40
 g Paraprevotella 1.04 1.85 1.424 1.09 1.33 1.91 0.863 2.28 0.60 0.681 0.58 0.64 0.02
 g Uncultured 0.73 0.86 0.070 0.86 0.76 0.77 0.111 0.86 0.74 0.089 0.11 0.62 0.17
P Firmicutes 32.6 31.1 1.49 33.1a 32.9a 29.6b 1.20 27.6 36.1 0.98 0.36 0.01 <0.001
 g Succiniclasticum 15.6 18.0 1.34 17.9 16.6 15.8 1.13 16.0 17.6 0.92 0.10 0.18 0.10
 g Christensenellaceae R-7 group 2.98 2.67 0.303 3.11 2.81 2.56 0.282 2.12 3.53 0.228 0.34 0.16 <0.001
 g Ruminococcaceae 0.61 0.55 0.159 0.62 0.60 0.53 0.137 0.40 0.76 0.105 0.69 0.77 <0.01
 g Lachnospiraceae NK3A20 group 1.60 1.80 0.284 1.60 1.94 1.52 0.307 1.14 2.26 0.250 0.50 0.38 <0.001
 g Saccharofermentans 1.34 0.79 0.240 1.44a 1.09a 0.67b 0.146 0.75 1.38 0.116 0.04 <0.001 <0.001
 g uncultured f Ruminococcaceae 2.14 0.26 0.636 0.88 1.44 1.27 0.685 1.20 1.19 0.484 0.02 0.60 0.98
 g Lachnospiraceae XPB1014 group 1.29 0.67 0.246 0.90 1.19 0.84 0.201 0.65 1.30 0.160 0.06 0.16 <0.001
 g Lachnospiraceae AC2044 group 0.81 0.52 0.115 0.77 0.70 0.51 0.132 0.41 0.91 0.108 0.04 0.14 <0.001
 g NK4A214 group f Oscillospiraceae 1.50 1.04 0.163 1.35 1.39 1.07 0.194 1.11 1.43 0.158 0.02 0.21 0.05
 g Pseudobutyrivibrio 0.94 0.78 0.135 1.02 0.79 0.77 0.126 0.47 1.25 0.098 0.29 0.09 <0.001
 g Veillonellaceae UCG-001 0.79 0.71 0.093 0.86a 0.80a 0.60b 0.093 0.71 0.80 0.075 0.46 0.02 0.26
 g Mogibacterium 1.08 0.58 0.066 0.70 0.95 0.84 0.098 0.58 1.08 0.082 0.01 0.05 <0.001
P Proteobacteria 2.42 2.83 0.963 0.32c 2.42b 5.13a 0.671 3.67 1.57 0.533 0.68 <0.001 <0.001
P Fibrobacteres 7.55 8.73 1.852 10.54a 7.97b 5.91b 1.260 4.81 11.5 1.02 0.54 <0.01 <0.001
P Spirochaetae 4.82 4.70 1.667 3.68b 4.66b 5.95a 0.517 3.81 5.72 0.422 0.95 <0.001 <0.001
 g Treponema 4.59 4.60 1.593 3.45b 4.50ab 5.82a 0.524 3.65 5.54 0.427 0.99 <0.001 <0.001
P Verrucomicrobia 0.95 0.68 0.170 1.14a 0.71b 0.59b 0.165 1.04 0.59 0.133 0.15 <0.01 0.001
 g WCHB1 41 0.90 0.53 0.087 1.03a 0.60b 0.52b 0.140 0.90 0.54 0.110 0.01 0.001 0.002
P Planctomycetota 0.43 0.49 0.111 0.65a 0.41b 0.38b 0.118 0.42 0.54 0.107 0.97 0.04 0.26
P Patescibacteria 1.67 1.39 0.692 2.08a 1.26b 1.25b 0.297 1.74 1.32 0.232 0.69 <0.01 0.08
Protozoa, 105 cell/mL2 4.71 5.73 0.612 6.52a 4.65b 4.53b 0.314 na na na 0.14 <0.001 na

1 p = phylum, g = genus, f = family.

2Protozoa were identified and counted under microscope following Ogimoto and Imai (1981). Identified ruminal protozoa genera included: Isotricha spp., Dasytricha spp., Entodinium spp., Diplodinium spp., Ostracodinium spp., Metadinium spp., Polyplastron spp., and Osphyrscolex spp.

3Significance was declared at P ≤ 0.05 and a tendency to significance was declared at 0.05 < P ≤ 0.10.

4Mean values with a different superscripted letter differ significantly among sampling times.