Detection of Viral Pathogens in Shrimp Broodstock of Commercial Shrimp Hatchery in Cox’s Bazar Using Polymerase Chain Reaction

Abstract

Bangladesh enters into international shrimp market in early 1970s and now it occupies 2nd position in foreign currency earning. However, this sector facing a serious problem with White Spot Syndrome Virus (WSSV) which causes 100% mortality of shrimp in the shrimp farm within two weeks. Shrimps are also infected by Infectious Hypodermal and Hematopoietic Necrosis Virus (IHHNV), Monodon Baculo Virus (MBV), Hepatopancreatic Parvo Virus (HPV) and Yellow Head Virus (YHV) which may cause serious problem in farms. Therefore, the present study was conducted to identify these viral pathogens in brood stocks of Penaeus monodon and to assess the impact of temperature fluctuation on viral pathogen intensity to wild shrimp brood stocks using polymerase chain reaction (PCR). The study was conducted in five shrimp hatcheries of Cox’s Bazar area from January to March, 2014. Samples of pleopod, gill and feces were collected from 20 shrimp broods from each hatchery in every month. Among the tested viral pathogens, the highest and lowest prevalence was observed in IHHNV as 95% (Zamzam hatchery) and WSSV (Modern hatchery) and HPV (Zamzam hatchery) as 20%, respectively. However, there is no significant difference was found on viral contamination rate among the hatcheries except IHHNV (P>0.05). The significant difference was found among the virus prevalence rate with temperature changes (P<0.05). The trend of monthly infection rate was sequenced as March>February>January. The percentage of prevalence of WSSV, IHHNV, MBV and HPV were showed significant variation with the temperature changes (P<0.05). Tukey post-hoc HSD test stated that MBV and IHHNV, YHV, and WSSV and HPV were showed significantly (p<0.05) highest, moderate and lowest percentage of prevalence. However, there were no significant differences of contamination rate between MBV and IHHNV, and WSSV and HPV (P>0.05) in different hatcheries during the study period. This research signify the percentage of total carriage of different viruses by wild brood stock to hatchery and it will be a effective guidelines for national policy makers to take further steps on reducing the viral pathogens intensity in shrimp hatchery industries.