Comparison of white spot syndrome virus quantification of fleshy shrimp Fenneropenaeus chinensis in outdoor ponds between different growing seasons by TaqMan real-time polymerase chain reaction

摘要

In the present study, we used TaqMan real-time polymerase chain reaction to quantify and compare infection of white spot syndrome virus (WSSV) with shrimp production of Fenneropenaeus chinensis cultured in outdoor ponds along the west coast of the South Korea. In 2007, a total of 60 specimens in summer and 116 specimens in autumn were collected from 12 growing-out ponds and 12 harvest ponds respectively. Pond harvest data were obtained from farmers. Of the summer samples, all specimens were WSSV positive, with a wide range of 12.4–7.0 × 107 (mean 7.5 × 106)?copies?ng?1 DNA; shrimp production was 1.7 metric tonnes per hectare (mt?ha?1). Of the 116 autumn-sample specimens, 81 (69.8%) were WSSV positive; WSSV infection had been decreased dramatically, to 0–7.2 (mean 3.5)?copies?ng?1 DNA. Shrimp production of autumn ponds was 2.1?mt?ha?1. Statistical analysis indicated that the difference in WSSV infections detected in summer and autumn was highly significant (P<0.01). In summer, seven ponds (58.3%) with low-WSSV infection loads (0–1000?WSSV?copies?ng?1 DNA) had shrimp production of 2.7?mt?ha?1; the others had shrimp production of only 0.2?mt?ha?1. The mean shrimp production between the two infection levels showed a highly statistically significant difference (P<0.01).