GC/MS-based metabolomics approach to identify biomarkers differentiating survivals from death in crucian carps infected by Edwardsiella tarda

• GC–MS was used to characterize the metabolic profile of crucian carps infected with Edwardsiella tarda.
• Differential metabolome was determined between survivals and dead fish.
• Unsaturated fatty acid biosynthesis, fructose and mannose metabolism were identified.
• Increasing palmitic acid and decreasing d-mannose were the most key biomarkers.
• These highlight the importance of metabolic strategy against bacterial infections.

Microbial disease problems constitute the largest single cause of economic losses in aquaculture. An understanding of immune system in aquaculture animals how to function in defense against bacterial infections is especially important to control these diseases and improve food quality and safety. In the present study, we use a crucian carp model to explore which pathways and metabolites are crucial for the defense against infection caused by Edwardsiella tarda EIB202. We establish the metabolic profile of crucian carps and then compare the metabolic difference between survivals and dead fish by self-control. We identify elevating unsaturated fatty acid biosynthesis and decreasing fructose and mannose metabolism as the most key pathways and increasing palmitic acid and decreasing d-mannose as the most crucial metabolites differentiating survivals from death in these fish infected by E. tarda. Our findings highlight the importance of metabolic strategy against bacterial infections.