Temperature induces metabolic reprogramming in fish during bacterial infection

Area of Science:

• Aquatic animal health
• Fish immunology
• Environmental toxicology

Background:

• Global warming increases water temperatures, leading to higher incidence of bacterial diseases like edwardsiellosis in aquaculture.
• Edwardsiellosis, caused by Edwardsiella tarda, is a significant threat to farmed fish, including flounder (Paralichthys olivaceus).
• The impact of temperature on flounder's metabolic response to E. tarda infection remains poorly understood.

Purpose of the Study:

• To investigate the effect of elevated water temperature on the metabolic response of flounder to E. tarda infection.
• To identify key metabolites affected by temperature and bacterial infection in flounder.
• To explore potential therapeutic strategies using identified metabolite markers.

Main Methods:

• Comparative metabolomics analysis of flounder infected with E. tarda at different temperatures (15°C vs. 23°C).
• Identification of metabolites responsive to E. tarda invasion and temperature changes.
• Evaluation of the efficacy of L-methionine and UDP-glucose as exogenous supplements in flounder leukocytes.

Main Results:

• High temperature (23°C) significantly enhanced E. tarda dissemination in flounder tissues compared to low temperature (15°C).
• Elevated temperatures during infection led to decreased levels of amino acids and TCA intermediates, including the immune regulator succinate.
• Thirty-eight potential metabolite markers of temperature effect (MMTE) were identified, with L-methionine and UDP-glucose showing promise in modulating immune responses and suppressing infection.

Conclusions:

• Temperature significantly influences flounder metabolism during E. tarda infection, affecting disease progression and fish survival.
• Metabolite markers like L-methionine and UDP-glucose demonstrate potential for therapeutic intervention against bacterial infections in aquaculture.
• Understanding temperature-dependent metabolic shifts is crucial for managing fish health in the context of climate change.