Myo-inositol enhances the resistance and alleviates inflammation of Cyprinus carpio to Aeromonas hydrophila infection

The metabolic state is closely related to the host's anti-infection ability, and metabolic modulation has been proved as a powerful strategy to improve the therapy for bacterial infection. The present study investigated the metabolic profiling between susceptible and resistant Cyprinus carpio upon Aeromonas hydrophila infection based on nuclear magnetic resonance (NMR) metabolomics approach, and myo-inositol as a metabolite with the most significant change, may be a candidate biomarker for host anti-infection ability. Consistent with our expectations, exogenous myo-inositol potentiated C. carpio against A. hydrophila infection in a dose-dependent manner. In addition, myo-inositol pre-treatment could inhibit the inflammatory response and alleviate oxidative damage of liver caused by bacterial infection. Furthermore, the underlying mechanism of myo-inositol enhances the resistance was investigated. Exogenous myo-inositol triggered metabolic shift, including alanine, aspartate and glutamate metabolism and arginine biosynthesis, and myo-inositol remarkably induced iNOS expression, iNOS activity and promote the production of nitrogen oxide (NO). The study disclosed a metabolic approach to enhance a host's ability to fight bacterial infection.