Effect of preservatives, temperature and storage duration on stability of nucleic acids of pleopod tissues of Penaeus vannamei (Boone) and screening of viral infections

In shrimp farming, screening for economically significant viral pathogens in nucleic acids of shrimps is vital for disease surveillance programmes and further, to take necessary precautions to ensure the sustainability of the farms and thereby the shrimp industry. Different preservatives, temperature and storage durations of the pleopod tissues of Penaeus vannamei broodstock were tested to investigate its effect on the quality and quantity of the nucleic acids. The pleopods were subjected to two preservation regimes and the yield and stability of the extracted nucleic acids were monitored over a time period of 12 months. Stability of the nucleic acids was assessed with nested polymerase chain reaction, and the yield was checked spectrophotometrically. Data was analysed by performing two way ANOVA and Tukeys Paired test. Preservation treatments included storage at -20 degrees C and 5 degrees C in RNAlater and in 70% ethanol. Significant variation (P < 0.05) was observed in both DNA and RNA yield and stability from ethanol and RNAlater stored pleopods at 5 degrees C. However, the yield and stability did not differ (P > 0.05) in both the preservatives at -20 degrees C. The RNA was degraded and yielded lesser quantity when pleopod tissues were stored in ethanol at -20 degrees C than when stored in RNAlater during storage duration of 9 months. This study would help the shrimp farmers and researchers to adopt better preservation strategy, vital for shrimp disease surveillance programmes and for traceability studies in the event of any disease outbreak.