Effects of shrimp density on transmission of penaeid acute viremia in Penaeus japonicus by cannibalism and the waterborne route

Diseases of Aquatic Organisms

K. Mushiake¹  J. L. Wu¹  A. Namikoshi¹  K. Muroga¹  K. Teruya¹  T. Nishizawa¹ 

关键词: Penaeus japonicus;    Penaeid acute viremia;    Density;    Cannibalism;    Waterborne transmission;    White spot syndrome;   

DOI  :  10.3354/dao047129

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: To investigate the effects of shrimp density on mortalities of Penaeus japonicus in experimental penaeid acute viremia (= white spot syndrome), shrimp injected intramuscularly with penaeid rod-shaped DNA virus (PRDV) were reared atdifferent densities. In Expt 1, challenged (10^-6 dilution of a PRDV preparation) shrimp were reared collectively in a tank or individually in separate chamber units. A significant difference in cumulative mortalities was found betweencollectively (75.6%) and individually (1.2%) reared groups after 30 d. In Expt 2, effects of density on mortality were clearly shown when challenged (10^-5 dilution) shrimp were reared collectively in tanks at high (260 shrimp m^-2),middle (135 shrimp m^-2) and low densities (73 shrimp m^-2). The cumulative mortalities for 14 d in the high, middle and low density groups were 72, 46 and 18%, respectively. In Expt 3, challenged (10^-5 dilution) shrimp werereared collectively in 3 tanks (Groups A, B and C) at the same high density (260 shrimp m^-2): Group A, dead shrimp were immediately removed to avoid transmission of the pathogen through cannibalism and the waterborne route; Group B, deadshrimp were removed at scheduled times but were separated from living shrimp by a net partition to avoid cannibalism; and Group C, dead shrimp were removed twice a day at scheduled times. Resulting cumulative mortalities for 20 d in Groups A, B and C were4, 24 and 64%, respectively. These results show that the higher mortalities occur in P. japonicus reared at the higher densities in experimental PRDV infection, and this phenomenon is caused mainly by a higher opportunity of horizontaltransmission of the virus through cannibalism and the waterborne route.

【 授权许可】

Unknown