. 2020 Feb 24;10:3318. doi: 10.1038/s41598-020-60150-y

Table 2.

Effect of dietary protein content on blood metabolomics profile.

Metabolites	CON^1,2	18% CP^1,2	12% CP^1,2	SEM³	P-value
Microbiome Metabolism
4-hydroxyhippuric acid	333.9^a ± 55.7	335.0^a ± 49.0	186.2^b ± 35.3	18.2	<0.001
Indole-3-acetate	1288.4^a ± 523.3	949.3^ab ± 257.9	776.2^b ± 217.7	85.5	0.008
Carbohydrate Derivatives
Arabitol	9536.1^a ± 2895.9	12458.1^a ± 2777.1	26265.7^b ± 4795.0	1786.3	<0.001
Pinitol	6066.4^a ± 1439.3	5577.4^a ± 1678.6	1711.4^b ± 442.4	504.4	<0.001
Hexitol	3156.6^a ± 583.4	4568.1^a ± 1257.4	6908.6^b ± 1165.3	403.6	<0.001
Xylitol	4949.9^a ± 446.6	4736.9^a ± 890.5	3712.0^b ± 458.1	174.7	<0.001
Lactobionic Acid	2661.0^a ± 834.8	2188.4^ab ± 875.6	1246.9^b ± 611.8	204.1	<0.001
Conduritol-beta-epoxide	15246.9^a ± 6484.8	17466.1^a ± 8838.6	4229.9^b ± 1388.0	1802.1	<0.001
N-acetylmannosamine	325.9^a ± 161.6	561.4^ab ± 220.9	756.9^b ± 165.7	53.8	0.001
Saccharic acid	2087.3^a ± 719.1	2438.6^a ± 732.9	1391.9^b ± 288.8	155.7	0.002
Carbohydrate Metabolism
UDP-glucuronic acid	593.6^a ± 152.8	485.6^a ± 91.4	309.7^b ± 108.2	35.5	<0.001
2-hydroxyglutaric acid	1026.1^a ± 300.2	1375.6^a ± 479.5	1910.5^b ± 380.4	113.2	0.001
Aconitic acid	1414.9^a ± 362.3	1233.7^ab ± 225.9	1024.9^b ± 231.5	66.5	0.002
Glucose-1-phosphate	1139.6^a ± 278.4	1368.1^ab ± 229.3	1719.6^b ± 273.8	74.9	0.008
Carbohydrates
Glucose	60566.9^a ± 7699.4	109757.0^b ± 42503.7	147801.5^c ± 32350.6	10082.5	<0.001
Protein Metabolism
Hydroxycarbamate	3102.6^a ± 1508.9	6206.6^a ± 2725.3	10706.1^b ± 2107.4	818.4	<0.001
N-acetylglutamate	221.1^a ± 90.1	223.7^a ± 94.3	381.6^b ± 74.7	24.2	0.003
Orotic acid	297.7^a ± 59.5	252.4^b ± 49.3	238.7^b ± 52.3	12.2	0.007
Amino Acids
Isoleucine	311769.7^a ± 28746.2	292147.1^a ± 57318.2	189372.3^b ± 32707.5	14567.1	<0.001
Tryptophan	94968.1^a ± 31926.0	85616.6^a ± 26084.5	47116.6^b ± 8808.5	6667.3	<0.001
Oxoproline	818178.6^a ± 55568.7	712547.7^b ± 92182.9	643733.8^b ± 81095.4	22308.1	<0.001
Glutamic acid	43575.4^a ± 17906.9	62658.3^a ± 30741.2	103193.4^b ± 31564.9	7869.2	0.002
Glycine	670979.7^a ± 77092.1	622914.1^a ± 180096.8	414781.3^b ± 104649.7	35718.3	0.002
Valine	411978.9^a ± 49889.2	381391.3^ab ± 74580.3	294508.4^b ± 35679.9	15683.7	0.004
Tyrosine	341122.9^a ± 100236.5	311482.7^ab ± 43414.8	226762.3^b ± 39620.8	17163.5	0.004
Fatty Acid Metabolites
Isohexonic acid	2325.6^a ± 275.0	2302.3^a ± 688.3	1412.5^b ± 338.3	133.5	<0.001
Amino Acids Metabolism Metabolites
2-ketoisocaproic acid	17449.9^a ± 2218.4	14123.1^b ± 3060.5	11027.1^b ± 1627.7	747.8	<0.001
Aminomalonate	2319.7^a ± 1180.8	7096.4^b ± 3853.0	9997.9^b ± 3377.5	930.0	<0.001
Phenylethylamine	7534.6^a ± 4235.9	7324.0^a ± 2537.3	15673.0^b ± 3443.1	1116.0	<0.001
Putrescine	991.3^a ± 189.7	1671.3^b ± 395.3	2035.4^b ± 554.4	127.0	0.001
Amino Acid Derivatives
Trans-4-hydroxy-L-proline	116148.9^a ± 18749.9	92179.4^b ± 16517.4	46283.7^c ± 21204.3	7496.0	<0.001
Pyrrole-2-carboxylic acid	2869.1^a ± 384.5	2591.3^ab ± 651.9	2025.7^b ± 323.9	122.8	0.003
N-acetylaspartic acid	1388.3^a ± 461.0	1300.1^a ± 673.8	718.9^b ± 156.6	115.7	0.003
Vitamins
Dehydroascorbic acid	1446.7^a ± 430.3	2488.0^b ± 786.9	1334.2^b ± 477.9	162.9	0.002
Lipid Metabolites
Cholesterol	275695.1^a ± 28637.7	305711.7^a ± 76128.6	396785.3^b ± 43574.5	15668.9	0.002

¹CON, control diet with 24% crude protein (CP); 18% CP, low protein diet with 18% CP; 12% CP, low protein diet with 12% CP.

²Average peak height.

³SEM: standard errors of means.

^a,bWithin a row, values with different superscripts are different (P < 0.05). The values are the mean ± standard errors.