Correlations of microalgal fatty acid profiles with physiological and molecular indices in the freshwater mussel Hyriopsis cumingii.

Differences in dietary microalgal fatty acid (FA) profiles may affect mussel physiology, but the chemical basis of previously observed feeding effects remains unclear. We generated gas chromatography-mass spectrometry (GC-MS)-based FA profiles of three microalgae (Chlorella vulgaris, Cyclotella sp., and Navicula pelliculosa) and integrated these data with physiological and molecular results from a previously published feeding trial in the freshwater mussel Hyriopsis cumingii. This integrative approach enabled reinterpretation of earlier host responses in relation to dietary FA features. Higher proportions of saturated fatty acids (SFAs) and a higher dietary n-3/n-6 polyunsaturated fatty acid (PUFA) ratio were associated with more favorable physiological profiles, whereas higher proportions of monounsaturated fatty acids (MUFAs) and n-6 PUFAs were associated with less favorable responses. These findings suggest that algal FA composition, beyond total FA abundance, is associated with physiological variation in H. cumingii.