Table 2.
Identification of significant differential metabolites in yak rumen fluid by comparison of the concentrate and forage groups using a VIP threshold of 1 (P < 0.05).
| Metabolite name | VIP | RT (min) | Mass error (ppm) | Ion (m/z) | Fold change | p value | Positive/negative |
|---|---|---|---|---|---|---|---|
| AMINO ACIDS, PEPTIDES, AND ANALOGS | |||||||
| β-Alanine | 1.57953 | 0.90 | 27 | 90.06 | 1.36 | <0.05 | ESI+ |
| Ornithine | 1.12637 | 0.82 | 15 | 155.08 | 1.67 | <0.05 | ESI+ |
| N6,N6,N6-Trimethyl-L-lysine | 1.19657 | 8.52 | 15 | 189.16 | 1.37 | <0.05 | ESI+ |
| L-Valine | 1.84756 | 10.15 | 4 | 140.07 | 0.88 | <0.05 | ESI+ |
| L-Tyrosine | 1.67342 | 0.99 | 18 | 182.08 | 1.30 | <0.05 | ESI+ |
| L-Proline | 1.73136 | 0.84 | 0 | 116.07 | 1.08 | <0.05 | ESI+ |
| L-Phenylalanine | 1.90725 | 1.54 | 2 | 166.09 | 2.98 | <0.05 | ESI+ |
| L-Methionine | 1.67356 | 0.97 | 0 | 150.06 | 1.74 | <0.05 | ESI+ |
| L-Leucine | 1.86254 | 1.13 | 20 | 132.10 | 2.63 | <0.05 | ESI+ |
| L-Glutamate | 1.78202 | 0.87 | 11 | 148.06 | 1.19 | <0.05 | ESI+ |
| L-Dopa | 1.59629 | 5.45 | 15 | 198.07 | −0.25 | <0.05 | ESI+ |
| L-Arginine | 1.12843 | 6.87 | 35 | 197.09 | −0.15 | <0.05 | ESI+ |
| Pyroglutamic acid | 1.4513 | 0.94 | 12 | 128.03 | 2.06 | <0.05 | ESI− |
| Citrulline | 1.00457 | 3.13 | 25 | 174.08 | −0.34 | <0.05 | ESI− |
| L-Aspartic acid | 1.02264 | 0.02 | 24 | 132.03 | 2.09 | <0.05 | ESI− |
| L-Threonine | 1.18916 | 2.84 | 35 | 154.02 | −2.19 | <0.05 | ESI− |
| FATTY ACIDS AND CONJUGATES | |||||||
| L-Palmitoylcarnitine | 1.35173 | 10.22 | 18 | 400.35 | 1.22 | <0.05 | ESI+ |
| β-Hydroxyisovaleric acid | 1.34658 | 2.45 | 22 | 119.07 | −0.19 | <0.05 | ESI+ |
| Stearic acid | 1.88003 | 10.73 | 2 | 283.26 | 2.68 | <0.05 | ESI− |
| Oleic acid | 1.71181 | 10.22 | 5 | 283.26 | 2.20 | <0.05 | ESI+ |
| Myristoleic acid | 1.58974 | 4.93 | 14 | 249.18 | −0.94 | <0.05 | ESI+ |
| Myristic acid | 1.16514 | 5.99 | 12 | 251.20 | −1.37 | <0.05 | ESI+ |
| FATTY ACIDS AND CONJUGATES | |||||||
| Eicosadienoic acid | 1.1918 | 6.44 | 10 | 331.26 | −0.60 | <0.05 | ESI+ |
| Arachidonic acid | 2.26453 | 6.37 | 3 | 305.25 | −1.87 | <0.05 | ESI+ |
| Tetradecanedioic acid | 1.34647 | 5.99 | 2 | 257.18 | −1.19 | <0.05 | ESI− |
| Palmitic acid | 1.54094 | 10.05 | 3 | 255.23 | 1.82 | <0.05 | ESI− |
| Adrenic acid | 1.76404 | 9.68 | 12 | 367.25 | 2.32 | <0.05 | ESI− |
| PURINES AND PURINE DERIVATIVES | |||||||
| Xanthine | 1.61396 | 0.99 | 16 | 153.04 | 4.64 | <0.05 | ESI+ |
| Hypoxanthine | 2.07019 | 0.98 | 4 | 137.05 | 3.83 | <0.05 | ESI+ |
| Guanine | 1.63166 | 0.98 | 15 | 152.05 | 1.74 | <0.05 | ESI+ |
| Adenine | 1.52322 | 0.85 | 2 | 136.06 | 1.89 | <0.05 | ESI+ |
| NUCLEOSIDES, NUCLEOTIDES, AND ANALOGS | |||||||
| Deoxyadenosine monophosphate | 1.33723 | 4.47 | 13 | 332.08 | 0.74 | <0.05 | ESI+ |
| Adenosine monophosphate | 1.17168 | 0.96 | 8 | 348.07 | 1.56 | <0.05 | ESI+ |
| Inosine | 1.67438 | 0.79 | 2 | 291.07 | 3.29 | <0.05 | ESI+ |
| Guanosine | 1.63239 | 1.01 | 1 | 284.10 | 2.33 | <0.05 | ESI+ |
| Deoxyadenosine | 1.16584 | 3.61 | 9 | 274.09 | −1.24 | <0.05 | ESI+ |
| Flavin mononucleotide | 1.96572 | 2.60 | 0 | 455.10 | 1.76 | <0.05 | ESI− |
| OTHER LIPIDS AND LIPID-LIKE MOLECULES | |||||||
| Linoleic acid | 1.3075 | 8.51 | 5 | 281.25 | 1.93 | <0.05 | ESI+ |
| 9-HODE | 1.48486 | 8.16 | 4 | 297.24 | 0.93 | <0.05 | ESI+ |
| 9-HOTE | 1.01731 | 5.70 | 5 | 295.23 | 0.45 | <0.05 | ESI+ |
| Taurallocholic acid | 1.11887 | 3.78 | 24 | 516.31 | −0.14 | <0.05 | ESI+ |
| Glycoursodeoxycholic acid | 1.60604 | 3.69 | 38 | 472.29 | −0.22 | <0.05 | ESI+ |
| OTHER LIPIDS AND LIPID-LIKE MOLECULES | |||||||
| Glycocholic acid | 1.04578 | 9.04 | 25 | 466.33 | 2.49 | <0.05 | ESI+ |
| LysoPC(16:0) | 1.06905 | 7.07 | 2 | 518.32 | 2.63 | <0.05 | ESI+ |
| LysoPC(15:0) | 1.19348 | 8.75 | 4 | 482.32 | 2.17 | <0.05 | ESI+ |
| LysoPC(14:0/0:0) | 1.0021 | 8.19 | 3 | 468.31 | 1.19 | <0.05 | ESI+ |
| LysoPE(0:0/16:1(9Z)) | 1.20375 | 7.17 | 2 | 452.28 | 1.92 | <0.05 | ESI+ |
| MG(0:0/18:2(9Z,12Z)/0:0) | 1.43675 | 7.33 | 5 | 355.28 | −0.25 | <0.05 | ESI+ |
| MG(17:0/0:0/0:0) | 1.0881 | 7.55 | 4 | 367.28 | −0.72 | <0.05 | ESI+ |
| MG(16:1(9Z)/0:0/0:0) | 1.10433 | 9.83 | 20 | 329.26 | 1.08 | <0.05 | ESI+ |
| Ubiquinone-1 | 1.39176 | 6.64 | 28 | 251.13 | −0.21 | <0.05 | ESI+ |
| Vitamin D3 | 1.23479 | 7.48 | 14 | 385.34 | 2.11 | <0.05 | ESI+ |
| MG(0:0/15:0/0:0) | 1.03958 | 7.04 | 0 | 315.25 | 1.59 | <0.05 | ESI− |
| Deoxycholic acid | 1.00367 | 6.86 | 1 | 391.29 | 1.44 | <0.05 | ESI− |
| Leukotriene D4 | 1.0961 | 7.82 | 37 | 495.27 | −0.51 | <0.05 | ESI− |
| LysoPA(8:0/0:0) | 1.10951 | 4.75 | 9 | 297.11 | 0.67 | <0.05 | ESI− |
| Glycerol 3-phosphate | 1.2641 | 1.06 | 25 | 206.99 | 2.01 | <0.05 | ESI− |
| LysoPE(0:0/16:0) | 1.4543 | 7.83 | 1 | 452.28 | 1.92 | <0.05 | ESI− |
| LysoPE(0:0/18:1(9Z)) | 1.48044 | 8.07 | 1 | 478.29 | 2.36 | <0.05 | ESI− |
| Corticosterone | 2.10136 | 10.19 | 23 | 381.18 | 2.85 | <0.05 | ESI− |
| Auxin a | 1.053 | 5.99 | 3 | 327.22 | 0.98 | <0.05 | ESI− |
| OTHERS | |||||||
| Dopamine | 1.37056 | 3.68 | 9 | 176.07 | 0.78 | <0.05 | ESI+ |
| Vanillic acid | 1.22091 | 2.64 | 3 | 169.05 | −0.83 | <0.05 | ESI+ |
| Hippuric acid | 1.15937 | 2.45 | 21 | 202.04 | −0.18 | <0.05 | ESI+ |
| 4-Aminosalicylic acid | 1.66214 | 0.76 | 22 | 176.04 | 2.55 | <0.05 | ESI+ |
| Succinic acid | 1.52258 | 14.25 | 14 | 119.03 | −0.18 | <0.05 | ESI+ |
| Phosphoglycolic acid | 1.55235 | 14.27 | 4 | 156.99 | −0.20 | <0.05 | ESI+ |
| Sphinganine | 1.80699 | 8.51 | 3 | 324.29 | 1.82 | <0.05 | ESI+ |
| 1-Phenylethylamine | 1.39625 | 14.05 | 1 | 122.10 | −0.21 | <0.05 | ESI+ |
| Phosphorylcholine | 1.04631 | 2.31 | 9 | 206.06 | 0.77 | <0.05 | ESI+ |
| Choline | 1.6994 | 0.75 | 0 | 104.11 | 2.99 | <0.05 | ESI+ |
| Myo-Inositol | 1.27085 | 2.45 | 28 | 203.05 | −0.19 | <0.05 | ESI+ |
| D-Mannitol | 1.63547 | 6.35 | 27 | 183.08 | −0.19 | <0.05 | ESI+ |
| D-Maltose | 1.26031 | 0.78 | 4 | 365.10 | 2.49 | <0.05 | ESI+ |
| Phosphohydroxypyruvic acid | 1.8193 | 14.23 | 2 | 184.99 | −0.19 | <0.05 | ESI+ |
| Riboflavin | 1.32022 | 2.78 | 2 | 377.15 | 1.06 | <0.05 | ESI+ |
| L-Tryptophan | 2.05113 | 2.39 | 8 | 205.10 | 1.28 | <0.05 | ESI+ |
| Niacin | 2.32403 | 0.99 | 1 | 124.04 | 1.87 | <0.05 | ESI+ |
| Thymine | 1.29367 | 1.14 | 3 | 127.05 | 1.94 | <0.05 | ESI+ |
| Kynurenic acid | 1.21658 | 2.50 | 2 | 190.05 | −0.70 | <0.05 | ESI+ |
| Gentisic acid | 1.10152 | 2.84 | 10 | 153.02 | −2.32 | <0.05 | ESI− |
| Salicylic acid | 1.02709 | 3.74 | 11 | 137.02 | −2.62 | <0.05 | ESI− |
| Homogentisic acid | 1.68695 | 0.89 | 3 | 203.01 | 2.88 | <0.05 | ESI− |
| Sphingosine | 1.25312 | 8.62 | 17 | 334.25 | −1.37 | <0.05 | ESI− |
| Indoleacetic acid | 1.65101 | 2.38 | 13 | 210.03 | −0.51 | <0.05 | ESI− |
| 2-Acetolactic acid | 1.34723 | 1.84 | 12 | 131.03 | 0.58 | <0.05 | ESI− |
| MG(22:2(13Z,16Z)/0:0/0:0) | 1.33733 | 8.24 | 2 | 433.33 | 1.40 | <0.05 | ESI+ |
RT, retention time; fold change, concentrate group vs. forage group. Mass Error in ppm, the difference between a theoretical m/z and an experimentally observed m/z. ESI+, positive ion mode; ESI−, negative ion mode.