Metabolomics profiling for the identification of potential biomarkers in blood serum of Takifugu rubripes challenged with Cryptocaryon irritans

Abstract

Cryptocaryon irritans is a parasitic ciliate that causes cryptocaryonosis (white spot disease) in marine fish. Because the pathogenesis of cryptocaryonosis is unclear, and it is harmful to aquaculture, the identification of reliable biomarkers as a specific therapy for the disease is critical. To identify potential serum biomarkers in Takifugu rubripes infected by C. irritans, Agilent-QTOF/MS-6545 mass spectrometry-based untargeted metabolite profiling was applied to differentiate and identify potential biomarkers in blood serum samples we collected from 10 fish infected by C. irritans and 10 healthy controls. The results of untargeted metabolic pathway analysis showed that retinol metabolism, steroid hormone biosynthesis, purine metabolism, arachidonic acid metabolism and drug metabolism involving cytochrome P450 were significantly different between infected and control groups. Based on data from the receiver operating characteristic curve, we propose that retinoic acid, progesterone, xanthosine monophosphate, hepoxilin B3, tamoxifen and prostaglandin I2 are possible potential biomarkers for infected fish in terms of both sensitivity and specificity. Our study provides new insight into the underlying mechanisms of T. rubripes infected by C. irritans, and we suggest that metabolic pathways and metabolites identified in our work could make a major contribution to the prevention and treatment of this disease in aquaculture.