Nontargeted metabolomics reveals biochemical pathways altered in response to captivity and food limitation in the freshwater mussel Amblema plicata

Effective conservation of freshwater mussels (Mollusca: Bivalvia: Unionidae), one of the most endangered groups of animals in North America, is compromised by limited knowledge of their health. We address this gap in knowledge by characterizing the metabolic profile of Amblema plicata in the wild and in response to captivity and food limitation. Eight mussels brought into captivity from the wild were isolated for 18days without a food source. Hemolymph samples were taken prior to, and 9 and 18days after the start of the experiment; these samples were analyzed by gas chromatography–mass spectrometry and liquid chromatography–mass spectrometry. We detected and identified 71 biochemicals in the hemolymph of freshwater mussels; of these, 49 showed significant changes during captivity and/or food limitation (p