Table 2.

Metabolic parameters and concentrations of tryptophan and its metabolites in stools, portal blood and systemic blood in Sprague Dawley rats maintained on standard laboratory diet and treated with either a water solution of neomycin, an antibiotic (neomycin group) or tap water (controls) for two weeks.

Group	Controls	Neomycin Group
Metabolic Parameters
Body mass at the beginning of the experiment (g)	279.37 ± 15.81	276.07 ± 16.16
Weight gain (g)	36.16 ± 2.17	42.56 ± 3.99 *
Food intake (g)	22.40 ± 0.61	22.16 ± 0.72
Caloric intake (kcal)	61.51 ± 1.56	61.24 ± 1.71
Water intake (mL)	33.97 ± 1.61	34.80 ± 1.05
Urine output (mL)	17.29 ± 1.23	13.20 ± 1.29 *
Stool output (g)	9.10 ± 1.00	13.30 ± 0.78 *
Tryptophan and Tryptophan Metabolites Concentration
Tryptophan
Diet (intake mg/24 h)	44.80 ± 1.23	44.60 ± 1.44
Diet (intake mg/kg b.w./24 h)	143.57 ± 6.17	141.14 ± 6.00
Stools (µg/mL)	2.15 ± 0.47	2.22 ± 0.33
Portal blood (µg/mL)	10.74 ± 1.08	9.04 ± 0.97
Systemic blood (µg/mL)	8.09 ± 0.46	6.73 ± 0.47
Kynurenine
Portal blood (µg/mL)	0.36 ± 0.04	0.41 ± 0.03
Systemic blood (µg/mL)	0.48 ± 0.03	0.38 ± 0.01 *
Serotonin
Portal blood (µg/mL)	0.74 ± 0.10	0.58 ± 0.05
Systemic blood (µg/mL)	0.69 ± 0.02	0.63 ± 0.04
Indole
Stools (µg/mL)	63.61 ± 18.74	6.63 ± 1.60 *
Indoxyl Sulfate
Portal blood (µg/mL)	4.76 ± 0.47	1.96 ± 0.44 *
Systemic blood (µg/mL)	4.80 ± 0.31	3.00 ± 0.44 *
Indole-3-Acetic Acid
Stools (µg/mL)	1.51 ± 0.27	0.96 ± 0.09
Portal blood (µg/mL)	0.14 ± 0.02	0.23 ± 0.07
Systemic blood (µg/mL)	0.08 ± 0.01	0.11 ± 0.03
Indole-3-Propionic Acid
Stools (µg/mL)	1.89 ± 0.37	LQQ
Portal blood (µg/mL)	1.10 ± 0.09	0.08 ± 0.02 *
Systemic blood (µg/mL)	0.96 ± 0.04	LQQ
Indole-3-Lactic Acid
Stools (µg/mL)	0.88 ± 0.41	2.34 ± 0.51 *
Portal blood (µg/mL)	0.09 ± 0.01	0.10 ± 0.01
Systemic blood (µg/mL)	0.07 ± 0.01	0.10 ± 0.01
Indole-3-Carboxylic Acid
Stools (µg/mL)	LQQ	LQQ

LQQ—below the limit of quantification; * p < 0.05 for comparison between the groups. Means ± SE are presented.