Enterocytozoon hepatopenaeiProliferate inProcambarus clarkii: A Warning for Crayfish and Shrimp Aquaculture

Abstract

AbstractThe pacific whiteleg shrimp (Litopenaeus vannamei) and the crayfish (Procambarus clarkii) are the most productive aquatic animals in the world. The prevalence of the microsporidiumEnterocytozoon hepatopenaei(EHP), an intracellular spore-forming unicellular parasite which leading retarded growth ofL. vannamei, has caused severe economic losses in most shrimp farming country. In this study, we found that the wildP. clarkii, living in shrimp ponds with EHP outbreak, excreted white faeces after temporary laboratory culture. The hepatopancreas (HP) of symptomatic crayfish exhibited a lighter color and severely atrophied. H&E-stain showed tissue lesions in both hepatopancreas and intestine, and clustered microsporidian spores were filled in the cytoplasm of the cells. PCR usingEHPptp2and two microsporidian-universal primers sets demonstrated the existence of EHP in the hepatopancreas, intestine and the white feces ofP. clarkii. The EHP loads of 103-104copies ofEHPptp2/50 ng HPgDNA were detected by qPCR. Developing stages and mature spores of EHP were observed in hepatopancreas ofP. clarkiithrough indirect-immunofluorescence assay (IFA) and transmission electron microscopy (TEM). Considering the large-scale cultivation ofL. vannameiandP. clarkii, overlap farming areas between these two species as well as the ability of crayfish to crawl on land and water, our finding indicates the potential role ofP. clarkiiin the transmission of EHP, and it is an early warning for crayfish and shrimp farming.