title: Physiological variability in volatile organic compounds (VOCs) in exhaled breath and released from faeces due to nutrition and somatic growth in a standardized caprine animal model.
abstract: Physiological effects may change volatile organic compound (VOC) concentrations and may therefore act as confounding factors in the definition of VOCs as disease biomarkers. To evaluate the extent of physiological background variability, this study assessed the effects of feed composition and somatic growth on VOC patterns in a standardized large animal model. Fifteen clinically healthy goats were followed during their first year of life. VOCs present in the headspace over faeces, exhaled breath and ambient air inside the stable were repeatedly assessed in parallel with the concentrations of glucose, protein, and albumin in venous blood. VOCs were collected and analysed using solid-phase or needle-trap microextraction and gas chromatograpy together with mass spectroscopy. The concentrations of VOCs in exhaled breath and above faeces varied significantly with increasing age of the animals. The largest variations in volatiles detected in the headspace over faeces occurred with the change from milk feeding to plant-based diet. VOCs above faeces and in exhaled breath correlated significantly with blood components. Among VOCs exhaled, the strongest correlations were found between exhaled nonanal concentrations and blood concentrations of glucose and albumin. Results stress the importance of a profound knowledge of the physiological backgrounds of VOC composition before defining reliable and accurate marker sets for diagnostic purposes.
authors.affiliation: Institute of Molecular Pathogenesis at 'Friedrich-Loeffler-Institut' (Federal Research Institute for Animal Health), Naumburger Str. 96a, 07743 Jena, Germany.
authors.forename: Sina
authors.initials: S
authors.lastname: Fischer
authors.forename: Phillip
authors.initials: P
authors.lastname: Trefz
authors.forename: Andreas
authors.initials: A
authors.lastname: Bergmann
authors.forename: Markus
authors.initials: M
authors.lastname: Steffens
authors.forename: Mario
authors.initials: M
authors.lastname: Ziller
authors.forename: Wolfram
authors.initials: W
authors.lastname: Miekisch
authors.forename: Jochen S
authors.initials: JS
authors.lastname: Schubert
authors.forename: Heike
authors.initials: H
authors.lastname: Köhler
authors.forename: Petra
authors.initials: P
authors.lastname: Reinhold
mesh_terms: D000821:Animal Feed; D000818:Animals; D015415:Biomarkers; D001786:Blood Glucose; D001798:Blood Proteins; D001944:Breath Tests / Q000379:methods; D004032:Diet; D005243:Feces / Q000737:chemistry*; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006041:Goats / Q000254:growth & development; D008297:Male; D023421:Models, Animal; D012709:Serum Albumin; D055549:Volatile Organic Compounds / Q000032:analysis / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D001798:Blood Proteins; D012709:Serum Albumin; D055549:Volatile Organic Compounds