Batch effect exerts a bigger influence on the rat urinary metabolome and gut microbiota than uraemia: a cautionary tale

Table 1 Normalised relative concentrations of selected urinary metabolites (relative units)

Substance	Batch 1	Batch 2	p ^ǂ	Uraemic	Control	p ^ǂ
Acetamide	28.803	28.126	0.930	24.867	34.845	0.001
Acetate	192.187	105.217	0.010	160.957	138.128	0.776
Acetoin	9.593	8.767	0.192	8.957	9.674	0.188
Alanine	29.330	18.013	0.001	23.765	24.923	0.809
Allantoin	28.996	29.158	0.967	25.391	35.508	0.054
Benzoate	110.964	52.071	< 0.001	82.269	87.564	0.809
Betaine	55.595	39.399	0.129	47.318	49.834	0.809
Citrate	119.823	112.407	0.752	126.188	99.414	0.127
Creatinine	140.283	152.104	0.642	131.066	171.189	0.027
Dimethylamine	21.667	21.548	0.967	19.390	25.504	0.054
Dimethylglycine	15.669	12.643	0.124	14.725	13.538	0.677
Formate	2.873	3.007	0.967	1.995	4.575	0.127
Glucose	43.856	19.678	0.018	34.385	30.208	0.809
Glycine	141.491	68.457	< 0.001	105.888	112.505	0.809
Hippurate	6.559	34.509	0.010	14.556	27.501	0.533
Lactate	571.659	188.265	0.005	402.362	388.686	0.922
m-Hydroxyphenylacetate	7.086	5.944	0.827	5.387	8.632	0.600
2-Oxoglutarate	167.931	182.841	0.642	183.945	158.543	0.533
Phenylacetate	13.308	8.148	0.001	10.380	11.982	0.600
Pyruvate	5.064	6.344	0.659	4.855	7.028	0.600
Succinate	97.877	72.642	0.044	85.106	88.682	0.809
Taurine	37.782	29.758	0.573	23.957	51.946	0.009
Trimethylamine	5.214	16.793	0.124	13.864	4.549	0.159
Trimethylamine N-oxide	42.391	32.387	0.253	34.013	44.547	0.267
Trigonelline	− 0.013	− 0.024	0.218	− 0.023	− 0.009	0.059
Urocanate	2.764	1.001	< 0.001	2.056	1.799	0.776

^ǂp values calculated using Student’s t test with Welch’s correction for unequal variances, subsequently adjusted to limit the false discovery rate to 0.15 using the Benjamini-Hochberg procedure [8]. Values in italic are significant at this level

ISSN: 2049-2618