Abstract:Acute hepatopancreatic necrosis disease (AHPND) has pathogenic diversity causing high mortality and economic losses in shrimp culture. We isolated PV130903A (Vibrio parahaemolyticus), PV140731A (V. harveyi), PV150526A (V. alginolyticus), and PV140821A (V. sp. Ex25) from the infected Litopenaeus vannamei, and designed a germicidal experiment on the isolated pathogens. Polyhexamethylene guanidine (PHMG), hydrogen peroxide (H2O2), povidone-iodine (PVPI), and chlorine dioxide (ClO2) were chosen to determine their concentration, killing rate, and killing time on the four pathogenic bacteria. Furthermore, an experiment was also conducted to determine the killing efficiency of PHMG on the Vibrios in the pond water. The results showed that 2 μl/L ClO2 killed all the bacteria in 1 h; 1 μl/L PHMG and H2O2 killed all the bacteria in 2 h; and 6 μl/L PVPI killed all the four bacteria in 6 h. It is noteworthy that the killing rate of PHMG and PVPI gradually increased with time. In contrast, the killing rate of H2O2 and ClO2 decreased after attaining the peak value. In the experiment carried out on the Vibrios in the pond water, 0.5 μL/L, 1 μL/L, and 2 μL/L PHMG decreased the total amount of Vibrios in the water to the minimal value of 79.14% on day 4, 82.48% on day 3, and 87.30% on day 3, respectively. Furthermore, the total amount of Vibrios in all the three concentration groups recovered slowly after reaching the minimal value. On day 11, the total amount of Vibrios in the three groups was still lower than the initial value of 3.58%, 5.53%, and 6.10%, respectively. The bactericidal ability of these four disinfectants was in the order: PHMG > H2O2 > ClO2 > PVPI. Based on the bactericide concentration, germicidal efficacy, duration, and cost, it was proved that PHMG has be efficiently used in aquaculture and it has a good application prospect in the future.
