The prebiotic inulin increases the phenoloxidase activity and reduces the prevalence of WSSV in whiteleg shrimp (Litopenaeus vannamei) cultured under laboratory conditions

The effect of inulin on growth performance, survival, lactic acid bacteria (LAB) in the gut, WSSV prevalence, and immune response of Litopenaeus vannamei was evaluated under laboratory conditions. Inulin was sprayed onto feed at 0, 1.25, 2.5, 5.0, and 10gkgfeed ^-1. Two bioassays, performed with treatments in triplicate, were conducted for 62 and 73days, respectively. Feed supplemented with inulin did not improve growth, survival, and LAB in shrimp. However, inulin decreased the prevalence of WSSV in treated shrimp. The prebiotic significantly increased the phenoloxidase activity, but hemocyte number was not affected. Inulin increases the phenoloxidase activity in L. vannamei and, at concentrations of 2.5 and 5.0gkgfeed ^-1, is a good feed additive against WSSV in shrimp with low viral load.