Safety and protective effect of a disinfectant (STEL water) for white spot syndrome viral infection in shrimp

摘要

ABSTRACT: The efficacy of STEL water for protection against white spot syndrome virus (WSSV) infection was evaluated using shrimp. The LC₅₀ of residual chlorine (Cl–) in STEL water for broodstock and 2-mo-old shrimp were 2.3 and 3.2 ppm, respectively. All 2-month-old shrimp raised in seawater containing more than 40 µl 2l–1 of a WSSV-infected tissue homogenate died within 3 d post-exposure (dpe). Thus, a 10-fold dose of 400 µl 2l–1 was used in the disinfection tests. Low concentrations of STEL water effectively prevented mortality of shrimp at this challenge dose. All 2-month-old shrimp exposed to seawater with 400 µl of viral homogenate disinfected with STEL water at Cl– concentrations over 0.125 ppm for 1 and 10 min, lived until 5 dpe. With 5-mo-old shrimp, all positive control shrimps died within 3 dpe, whereas most shrimp reared in seawater disinfected with STEL water for 1 h before addition of homogenate lived until 5 dpe. Results suggested that continuous disinfection of seawater with STEL water may be effective for preventing WSSV infection in shrimp.