Effects of potassium monopersulfate on nitrification activity and bacterial community structure of sponge biocarrier biofilm in Litopenaeus vannamei aquaculture system

Abstract

Abstract Effects of potassium monopersulfate (KMPS) on nitrification activity, growth performance of Litopenaeus vannamei and bacterial community structure of sponge biocarrier with pre-cultured biofilm (SBBF) were analyzed through shaking flask experiments and L. vannamei aquaculture experiment. The change of ammonia oxidation rate (AOR) and nitrite oxidation rate (NOR) of SBBF under six KMPS concentration treatments (0 mg/L, 1 mg/L, 2 mg/L, 3 mg/L, 4 mg/L and 5 mg/L) was studied, the results showed that the AOR and NOR of SBBF treated with high concentrations of KMPS (3 mg/L, 4 mg/L and 5 mg/L) were significantly lower than those of the control group (CK) (p < 0.05). However, compared with the first dosing of NH4Cl and NaNO2, the inhibition of KMPS on AOR and NOR was weakened after the second and third dosing times. The L. vannamei aquaculture experiment was set to four concentrations of KMPS (0 mg/L, 2 mg/L, 4 mg/L, 8 mg/L), the results showed that with the increase of KMPS dosage, the average and peak concentrations of NH4+-N and NO2−-N in each system significantly increased (P < 0.05). The final body weight of shrimps significantly decreased (P < 0.05), high dose (8.0 mg/L) of KMPS reduced the survival rate by 9.33% than CK. High-throughput sequencing analysis of the biofilm structure showed that the relative abundance of Nitrospirota, Nitrosomonas and Nitrococcus, which is related to nitrogen cycling, and beneficial bacteria including Firmicutes and Bacilli decreased with the addition of KMPS (p < 0.05).