Application of dsRNA VP24 vaccine by oral administration at different larval stages of Tiger Shrimp Penaeus monodon

This study aimed to evaluate the effect of dsRNA VP24 application on different stages of larvae. For mass production, cloned recombinant bacteria carrying the construction of the promoter T7VP24 are planted in Luria Bertani broth medium. The bacteria were inactivated using the heat-killed bacteria method by immersion in water at 80 °C for 5 minutes. The inactivated bacteria were mixed with larval commercial feed. The nauplii were produced from broodstock from Aceh waters and reared until postlarva 12 (PL12). The feed containing the dsRNA vaccine was applied to a different stage of larva, i.e: starting from zoea 1 (A), mysis 1 (B), PL 1 to PL 12 (C), and control without dsRNA (D). The PL 12 were challenged with WSSV by the immersion method and morphological characters were assessed. Results showed that inactivating bacteria was effectively done by immersion method without damaging the dsRNA construct in the plasmid. The survival rate was significantly influenced by different stages of larvae (P 0.05), in which the highest survival (26.0%) was obtained from mysis. The highest value of morphological characters (92.3) was also inhibited in the mysis. The results suggested that the dsRNA vaccine for larvae could be started to be applied in the mysis stage.