Histological alterations and immune response in the crayfish Procambarus clarkii given rVP28-incorporated diets

► rVP28may suppress the apoptosis induced by WSSV challenge in a dose-dependent manner. ► Higher-dose rVP28 causes necrosis of hepatopancreatic epithelia and myocardial cells. ► Disease resistance of crayfish against WSSV depends on the dosage of rVP28. ► HyNPV-VP28 infected pupae at a dose of 5% has an optimal potential for crayfish immune system.