Immune-Related Transcript Abundance and Survival of Penaeus vannamei Treated with an Acid Hydrolysate from WSSV-Infected Shrimp

This study characterized acid hydrolysates prepared from WSSV-infected (HS-WSSV) and non-infected (HS-noWSSV) Penaeus (Litopenaeus) vannamei Boone, 1931 muscle and evaluated immune-related transcript abundance and survival following WSSV challenge. Hydrolysates were maintained at pH 3.8 for 20 d, and their soluble protein profiles were assessed by SDS-PAGE. Shrimp received selected hydrolysate supernatants by intramuscular injection, and transcript abundance of Dorsal, Relish, Rab6, proPO, and PAP was evaluated at 3, 6, and 12 h post-injection. Survival was assessed after intramuscular and short-term immersion WSSV challenges. SDS-PAGE showed progressive changes in banding patterns consistent with protein degradation and distinct soluble protein profiles between HS-WSSV and HS-noWSSV preparations. Significant differences between HS-WSSV and the corresponding HS-noWSSV preparations were detected for several immune-related transcripts at specific hydrolysis and sampling times (p ≤ 0.05). Survival was evaluated using Kaplan–Meier analysis and Cox proportional hazards models with aquarium-clustered robust standard errors. In the intramuscular challenge, the 10 d HS-WSSV treatment showed the highest final survival (40.0%) and a lower mortality hazard than the WSSV-positive control (HR = 0.624, 95% CI: 0.349–1.115), although this difference was not significant (p = 0.112). In the short-term immersion challenge, the 10 d preparation produced the highest final survival (56.7%) and a significantly lower mortality hazard (HR = 0.472, 95% CI: 0.367–0.608, p < 0.001). Under the evaluated conditions, the 10 d HS-WSSV preparation was associated with early transcript-abundance changes and the most favorable survival profile, particularly following short-term immersion challenge.