Silencing Pacific white shrimp Litopenaeus vannamei LvRab7 reduces mortality in brooders challenged with white spot syndrome virus

White spot syndrome virus ( WSSV ) is a major threat for farmed shrimp worldwide. RNA interference ( RNA i) is the most recent tool against viral diseases. Rab7 silencing effectively inhibited virus infections in juvenile shrimp, but the antiviral effect in brooders remains unknown. This study found a homologue Penaeus monodon Rab7 gene in Litopenaeus vannamei brooders from Mexico. Sequence identity was >99% to a Thai LvRab7 sequence and >94% to Rab7 sequences from P. monodon or Marsupenaeus japonicus . Animals treated with a partial (494 bp) or a complete (618 bp) LvRab7 ds RNA sequences and challenged 48 h post treatment (hpt) with a high WSSV dose showed 80–88% mortality respectively. Shrimp treated with 4 or 20 μg LvRab7 ds RNA and challenged with a WSSV high dose had 80% mortality each, but it was reduced to 33% and 40%, respectively, with a low dose. Efficacy of ds RNA to reduce shrimp mortality was dependent on virus dose used regardless of ds RNA concentration. A significant reduction in LvRab7 m RNA levels was observed at 120 hpt. In conclusion, silencing LvRab7 in brooders showed a mild antiviral effect against a WSSV challenge at 48 hpt.