Temperature induces metabolic reprogramming in fish during bacterial infection.

Abstract

Water temperature elevation as a consequence of global warming results in increased incidence of bacterial disease, such as edwardsiellosis, in fish farming. Edwardsiellosis is caused by the bacterial pathogenand affects many farmed fish including flounder (). Currently, the effect of temperature on the metabolic response of flounder toinfection is unclear. In this study, we found that compared to low temperature (15°C), high temperature (23°C) enhanceddissemination in flounder tissues. To examine the impact of temperature on the metabolism of flounder induced by, comparative metabolomics were performed, which identified a large number of metabolites responsive toinvasion and temperature alteration. Duringinfection, the metabolic profile induced by elevated temperature was mainly featured by extensively decreased amino acids and TCA intermediates such as succinate, a proven immune regulator. Further, 38 potential metabolite markers of temperature effect (MMTE) in association with bacterial infection were identified. When used as exogenous supplements, two of the MMTE, i.e., L-methionine and UDP-glucose, effectively upregulated the expression of pro-inflammatory cytokines and suppressedinfection in flounder leukocytes. Taken together, the results of this study indicate an important influence of temperature on the metabolism of flounder during bacterial infection, which eventually affects the survivability of the fish.