Probiotics and Prebiotics

Fish has been recognized as the most promising and sustainable source of future food security. However, disease outbreak and slow and improper diagnosis often hinder the profitable blue-crop. Interestingly, global diseases like Edwardsiella affects much commercially important fish. To find common remedial measures to curb Edwardsiella infection in fish, a general idea of how the infection affects an individual, especially during early stages is highly essential. Using several in vivo experiments, we have previously shown that Hepcidin1, a gene critically involved in the starvation associated disease management, is a critical biomarker for E. tarda infection in Pagrus major. Owing to E. tarda’s vast infection terrain and enormous host susceptibility, in the present investigation, we aimed to determine the early molecular pathogenesis of E. tarda in a model (medaka) and commercially important (Red sea bream) fish. To achieve our goal, we infected medaka and red sea bream with E. tarda (@109CFU/ml water) and performed comparative transcriptome analysis using 6 and 24hours post infected liver samples. We found that infection altered the complement system gene expression, vitellogenin production, translation initiation, energy metabolism, cell death, iron homeostasis, ion balance pathways. Further real-time PCR analysis confirmed that several genes especially Hepcidin1, Ubiquitin1 (Autophagy regulator), HSP70 (stress management), SDF2 (cell maintenance), SLC41a (Ion balance) and EIF3d (translation initiation) were altered in a time-dependent manner. Although more thorough investigations are pertinent, our present data suggest the possibility of a general E. tarda molecular pathophysiology in fish.