Performance of WSSV-infected and WSSV-negative Penaeus monodon postlarvae in culture ponds

[摘要] ABSTRACT: In a survey of 27 Penaeus monodon culture ponds stocked with postlarvae (~PL10) at medium density (~40 shrimp m^-2), single-step nested white spot syndrome virus (WSSV) PCR was used to measure the WSSV infection rates in theshrimp populations within 1 mo after stocking. Seven ponds were initially WSSV-free, and the shrimp in 5 of these were harvested successfully. In the ponds (n = 6) where detection rates were higher than 50%, mass mortality occurred during the growthperiod, and none of these ponds was harvested successfully. In a subsequent study, P. monodon brooders were classified into 3 groups according to their WSSV infection status before and after spawning: brooders that were WSSV-positive beforespawning were assigned to group A; spawners that became WSSV-positive only after spawning were assigned to group B; and group C consisted of brooders that were still WSSV-negative after spawning. WSSV screening showed that 75, 44 and 14%, respectively, ofgroup A, B and C brooders produced nauplii that were WSSV-positive. Most (57%; 16/28) of the brooders in group A produced nauplii in which the WSSV prevalence was high (>50%).When a pond was stocked with high-prevalence nauplii from 1 of these group Abrooders, an outbreak of white spot syndrome occurred within 3 wk and only ~20% of the initial population survived through to harvest (after 174 d). By contrast, 2 other ponds stocked with low-prevalence and WSSV-negative nauplii (derived respectivelyfrom 2 brooders in group B), both had much higher survival rates (70 to 80%) and yielded much larger (~3x by weight) total harvests. We conclude that testing the nauplii is an effective and practical screening strategy forcommercially cultured P. monodon.

[学科分类] 生物科学（综合）

[关键词] White spot syndrome virus;WSSV;Single-step nested WSSV PCR;Predictive power of screening;Penaeus monodon