Fig. 5: Giardia diminishes free amino acids in protein deprived mice, and early childhood Giardia infection differentially alters serum free amino acid profiles in geographically distinct populations.

a PCA score plot comparing fecal amino acids profiles between infected and uninfected Rag2^−/− mice fed a PD diet. b Concentrations of fecal amino acids in biologically independent Rag2^−/− mice fed a PD diet 25 days after Giardia (N = 9) or PBS (N = 8)-challenge (median ± IQR; *P < 0.05 (P = 0.021 for isoleucine and phenylalanine, P = 0.011 for threonine, P = 0.015 for valine), **P < 0.01 (P = 0.0037 for leucine, P = 0.0079 for tyrosine), ***P = 0.0008 for methionine for PBS vs Giardia, two-sided Mann-Whitney U-test). c Concentrations of circulating amino acids measured in biologically independent plasma samples from children from Peru with concurrent Giardia detection at 15 months (median ± IQR, N = 49 with Giardia detection, N = 53 without Giardia detection). d Concentrations of circulating amino acids measured in biologically independent plasma samples from children from Bangladesh with concurrent Giardia detection at 15 months (median ± IQR, N = 46 with Giardia detection, N = 117 without Giardia detection). In Bangladesh, lysine, alpha-aminobutyric acid, ornithine and taurine were below the set limits of detection. For (b–d), statistical significance was determined using Mann-Whitney U-tests. For (b) *P < 0.05 (isoleucine P = 0.021, phenylalanine P = 0.021, threonine P = 0.011, valine P = 0.015; **P < 0.01 (leucine P = 0.0037, tyrosine P = 0.0079); ***P = 0.00084 for methionine). For (c), Histidine P = 0.027, Isoleucine P = 0.0037, Leucine P = 0.0056, Lysine P = 0.0022, Methionine P = 0.35, Threonine P = 0.002, Tryptophan P = 0.0057, Valine P = 0.0028, Arginine P = 0.029, Tyrosine P = 0.025, Citrulline P = 0.034, Ornithine P = 0.002, Taurine P = 0.0038. Source data are provided in the Source Data file.