Taurine promotes Oreochromis niloticus survival against Edwardsiella tarda infection.

Edwardsiella tarda represents one of the most important pathogens that infects a variety of hosts including aquatic animals and humans. The outbreak of E. tarda infection is frequently reported in aquaculture that causes huge economic loss. Due to the widespread of antibiotic resistance, available antibiotics to treat bacterial infection are limited. Therefore, enhancing aquatic animals to survive upon E. tarda infection become an urgent issue. In this study, we profiled the metabolomic change of tilapia in-between the dying and survival fish upon E. tarda infection. The dying and survival fish mounts differential metabolic response, from which we identify a key metabolite, taurine, whose abundance is increased in both the survival group and the dying group but is more significant in the survival group. Exogenous taurine increases tilapia survival rate by 37.5% upon E. tarda infection. Further quantitative PCR analysis demonstrate taurine increases the expression of immune genes in liver, spleen and head kidney. Therefore, our study shows a new strategy to enhance fish immune response against bacterial infection.