天然水体中水质因子对虾肝肠胞虫(EHP)感染率影响的分析研究

Analysis on the Influence of Water Quality Factors in Natural Water Bodies on the Infection Rate of Enterocytozoon hepatopenaei (EHP) in Shrimp

摘要: 为明确天然水体中水质因子对虾肝肠胞虫(EHP)感染率的影响，本研究选取天津市5个已检出EHP的南美白对虾养殖室外池塘，于5月中旬起每20天采样1次，共开展4次采样(覆盖养殖早、中、中后及终末期)，每次采集20~30尾鲜活对虾及池塘水。通过测定水体中氨氮(${\text{NH}}_3^{+}{\text{NH}}_4^{+}$ )、亚硝酸盐(${\text{NO}}_2^{-}\text{-N}$ )、化学需氧量(COD)浓度，同时检测对虾EHP检出率，分析三者与EHP检出率的关系。结果表明：水体${\text{NH}}_3^{+}{\text{NH}}_4^{+}$ 、${\text{NO}}_2^{-}\text{-N}$ 、COD浓度与对虾EHP检出率整体呈正相关，且当${\text{NH}}_3^{+}{\text{NH}}_4^{+}$ < 1 mg/L、${\text{NO}}_2^{-}\text{-N}$ < 0.01 mg/L、COD < 18 mg/L时可抑制对虾体内EHP增殖，降低传播感染速率。该研究数据贴合生产实际，为对虾养殖中EHP的有效防治提供了理论依据。

Abstract: To clarify the impact of water quality factors in natural water bodies on the carriage of Enterocytozoon hepatopenaei (EHP) in shrimp, this study selected 5 outdoor Penaeus vannamei culture ponds in Tianjin where EHP had been detected. Starting from the middle of May, sampling was conducted once every 20 days, with a total of 4 samplings (covering the early, middle, mid-late, and final stages of culture). During each sampling, 20~30 live shrimp and pond water were collected. The concentrations of ammonia nitrogen (${\text{NH}}_3^{+}{\text{NH}}_4^{+}$ ), nitrite (${\text{NO}}_2^{-}\text{-N}$ ), and chemical oxygen demand (COD) in the water were determined, while the EHP detection rate in shrimp was tested to analyze the relationship between these three water quality indicators and the EHP detection rate. The results showed that the concentrations of ${\text{NH}}_3^{+}{\text{NH}}_4^{+}$ , ${\text{NO}}_2^{-}\text{-N}$ , and COD in water were generally positively correlated with the EHP detection rate in shrimp. Moreover, when ${\text{NH}}_3^{+}{\text{NH}}_4^{+}$ < 1 mg/L, ${\text{NO}}_2^{-}\text{-N}$ < 0.01 mg/L, and COD < 18 mg/L, the proliferation of EHP in shrimp could be inhibited, and the rate of transmission and infection could be reduced. The data from this study are in line with actual production conditions and provide a theoretical basis for the effective prevention and control of EHP in shrimp culture.