Myo-Inositol Restores Tilapia's Ability Against Infection by Aeromonas sobria in Higher Water Temperature

Bacterial infection presents severe challenge to tilapia farming, which is largely influenced by water temperature. However, how water temperature determines tilapias' survival to infection is not well understood. Here, we address this issue from the perspective of metabolic state. Tilapias were more susceptible to Aeromonas sobria infection at 33 degrees C than at 18 degrees C, which is associated with differential metabolism of the fish. Compared to the metabolome of tilapia at 18 degrees C, the metabolome at 33 degrees C was characterized with increased an tricarboxylic acid cycle and a reduced level of myo-inositol which represent the most impactful pathway and crucial biomarker, respectively. These alterations were accompanied with the elevated transcriptional level of 10 innate immune genes with infection time, where il-1b, il-6, il-8, and il-10 exhibited a higher expression at 33 degrees C than at 18 degrees C and was attenuated by exogenous myo-inositol in both groups. Interestingly, exogenous myo-inositol inactivated the elevated TCA cycle via inhibiting the enzymatic activity of succinate dehydrogenase and malate dehydrogenase. Thus, tilapias showed a higher survival ability at 33 degrees C. Our study reveals a previously unknown relationship among water temperature, metabolic state, and innate immunity and establishes a novel approach to eliminate bacterial pathogens in tilapia at higher water temperature.

Automated summary

This study investigated how water temperature affects the survival of tilapia to bacterial infection from the perspective of metabolic state. It was found that tilapia were more susceptible to infection at 33 degrees C, but the infection could be attenuated by exogenous myo-inositol. The exogenous myo-inositol inactivated the elevated TCA cycle, increasing the survival ability of tilapia at higher water temperature.