Effect of dietary fucoidan on innate immune response of Procambarus clarkii and disease resistance against white spot syndrome virus

Abstract

This study has been investigated the effect of dietary fucoidan on the innate immune response of crayfish (Procambarus clarkii) and the disease resistance against white spot syndrome virus (WSSV) infection. Adding fucoidan (30 mg/kg) to the diet can dramatically improved the survival rate of crayfish after WSSV infection and also can reduce the copy number of WSSV. The result of qRT-PCR demonstrated that fucoidan treatment can increase the expression profile of immune-related genes, such as NF-κB and prophenoloxidase. Further evidence indicates that fucoidan also had the influence on three immune parameters, which consist of the total number of hemocyte (THC), phenoloxidase activity (PO) and superoxide dismutase activity (SOD) in crayfish. The hemocytes apoptosis of crayfish post WSSV-infected and uninfected crayfish were both increased significantly after treating with 30 mg/kg fucoidan. Dietary fucoidan delayed and reduced the mortality after oral WSSV challenge, and decreased WSSV copies in 96 h after challenge. Our research demonstrated that fucoidan can be used to the regulation of innate immunity and induce immune protection effect of crayfish from WSSV infection, whether for treatment or prevention.