title: Metabolomic differentiation of nutritional stress in an aquatic invertebrate.
abstract: Poor diet quality frequently constrains the growth and reproduction of primary consumers, altering their population dynamics, interactions in food webs, and contributions to ecosystem services such as nutrient cycling. The identification and measurement of an animal's nutritional state are thus central to studying the connections between diet and animal ecology. Here we show how the nutritional state of a freshwater invertebrate, Daphnia magna, can be determined by analyzing its endogenous metabolites using hydrogen nuclear magnetic resonance-based metabolomics. With a multivariate analysis, we observed the differentiation of the metabolite composition of animals grown under control conditions (good food and no environmental stress), raised on different diets (low quantity, nitrogen limited, and phosphorus limited), and exposed to two common environmental stressors (bacterial infection and salt stress). We identified 18 metabolites that were significantly different between control animals and at least one limiting food type or environmental stressor. The unique metabolite responses of animals caused by inadequate nutrition and environmental stress are reflective of dramatic and distinctive effects that each stressor has on animal metabolism. Our results suggest that dietary-specific induced changes in metabolite composition of animal consumers hold considerable promise as indicators of nutritional stress and will be invaluable to future studies of animal nutrition.
authors.affiliation: Environmental and Life Sciences Graduate Program, Trent University, Peterborough, Ontario K9J 7B8, Canada; 2Environmental NMR Centre and Department of Chemistry, University of Toronto, Toronto, Ontario M1C 1A4, Canada; 3Department of Biology, Trent University, Peterborough, Ontario K9J 7B8, Canada.
authors.forename: Nicole D
authors.initials: ND
authors.lastname: Wagner
authors.forename: Brian P
authors.initials: BP
authors.lastname: Lankadurai
authors.forename: Myrna J
authors.initials: MJ
authors.lastname: Simpson
authors.forename: Andre J
authors.initials: AJ
authors.lastname: Simpson
authors.forename: Paul C
authors.initials: PC
authors.lastname: Frost
mesh_terms: D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001424:Bacterial Infections / Q000378:metabolism; D003621:Daphnia / Q000378:metabolism* / Q000382:microbiology; D004032:Diet; D009584:Nitrogen; D016226:Phosphorus, Dietary; D054712:Salinity; D013312:Stress, Physiological
chemical_list: D016226:Phosphorus, Dietary; D009584:Nitrogen