In order to validate the pathogen free status in shrimp, six individuals
were sampled and examined for bacterial and viral
infection. For bacteria isolation, the surface of shrimp was sterilized
with 70% alcohol. Shrimp hemolymph was withdrawn with sterilized
syringe and streaked onto tryptic soy agar (ST) supplementedwith 2% NaCl and thiosulphate-citrate-bile salt-sucrose agar (TCBS).
The shrimp was then cut aseptically. The tissues from hepatopancreas
and heart were collected with a sterilized loop and streaked
onto ST and TCBS plates. All samples were incubated at 28 C for
24e48 h and bacterial colonies were examined. For viral infection
diagnosis,WSSV was checked by universal PCR using primers listed
in Table 1 [30]. DNA extraction from whole body tissues was performed
as described by Jang et al. (2009) and PCR amplificationwas
conducted as follows: 95 C for 3 min; 35 cycles of 95 C for 30 s,
57 C for 45 s, and 72 C for 1 min; followed by 72 C for 10 min. The
PCR products were checked by electrophoresis on a 1.5% agarose
gel.