凡纳滨对虾商业苗种抗WSSV性能比较

白斑综合征病毒(WSSV)一直是甲壳类生物的高致病性病原。为了解市场上不同凡纳滨对虾(Litopenaeus vannamei)商业苗种病原携带情况及其抗WSSV性能,本研究收集了6个品牌的凡纳滨对虾商业苗种(分别简称为海南Z、海南S、广州P、广州Z、黄骅R和东营M),先进行包括WSSV在内的8种病原的检测,然后,采用单尾定量口饲感染方式进行抗WSSV性能测试,并比较各组苗种感染WSSV后的平均存活时间、存活率以及累积死亡率的差异。结果显示,6个商业苗种都不携带WSSV,部分苗种检测有潜在虾肝肠胞虫(EHP)和偷死野田村病毒(CMNV)。各苗种感染WSSV后,平均存活时间从长到短依次为海南Z、广州P、黄骅R、海南S、广州Z、东营M。东营M感染WSSV后第4天达到死亡高峰,而海南Z在第6~7天到达死亡高峰,比东营M晚了2~3d。感染实验结束后,海南Z和广州P存活率最高,同为72.5%,而东营M和黄骅R的存活率最低。本研究表明,海南Z和广州P抗WSSV性能最强,研究结果可为凡纳滨对虾抗病新品种的选育提供基础数据。

Comparison of WSSV-Resistant Traits of Different Commercial Larvae of Pacific White Shrimp Litopenaeus vannamei

The white spot syndrome virus (WSSV) is a highly virulent pathogen in crustaceans. The purpose of this study was to compare the WSSV-resistant traits of Pacific white shrimp Litopenaeus vannmei from different commercial brands. After detecting the infection status of eight different pathogens, including WSSV, infectious hypodermal and hematopoietic necrosis virus (IHHNV), taura syndrome virus (TSV), acute hepatopancreatic necrosis disease causing-Vibrio parahaemolyticus (VPAHPND), Yellow head virus (YHV), infectious myonecrosis virus(IMNV), Enterocytozoon hepatopenaei (EHP), and covert mortality nodavirus (CMNV), a quantitative feeding method to conduct a WSSV infection experiment on six commercial brands of juvenile L. vannamei (named Hainan Z, Hainan S, Guangzhou P, Guangzhou Z, Huanghua R, and Dongying M in the present study). The WSSV-resistant traits of each commercial brand were evaluated using the average survival time, survival rate, and cumulative mortality after infection. The results showed that no WSSV was found in shrimp of the six commercial brands, whereas some individuals were positive for EHP and CMNV. The average survival time for Hainan Z, Hainan S, Guangzhou P, Guangzhou Z, Huanghua R, and Dongying M was (150.18±25.92) h, (99.51±28.04) h, (122.32±43.59) h, (93.50±34.77) h, (100.99±26.84) h, and (71.70±23.79) h, respectively. The average survival time of Hainan Z was significantly higher than that of the other five brands. The average survival time of Guangzhou P was lower than that of Hainan Z, and was significantly higher than that of Dongying M, Guangzhou Z, Hainan S, and Huang Hua R. Dongying M had a significantly lower survival time than that of the other five brands. There was no significant difference between Guangzhou Z, Hainan S, and Huanghua R (P>0.05). The mortality peak for Hainan Z started on the 6th day and continued to the 7th day; whereas that of Dongying M was on the 4th day. The mortality peak for Hainan Z was 2 to 3 d later than that of Dongying M. At the end of the infection experiment, the survival rate of Hainan Z and Guangzhou P was the highest and was 72.5%. The survival rates for Dongying M and Huanghua R were the lowest, at 39.6% and 38.7%, respectively. The results suggested that Hainan Z and Guangzhou P have the strongest resistance against WSSV. The results could provide basic data for the selective breeding of L. vannamei.