Efficacy of <i>Lactobacillus plantarum CG02</i> Against <i>Vibrio parahaemolyticus</i> <scp>pVPA3</scp> ‐1 Infection in Whiteleg Shrimp ( <i>Penaeus vannamei</i> )

Thirty lactic acid bacteria (LAB) isolates were obtained from the digestive tracts of whiteleg shrimp (Penaeus vannamei) and screened for antagonistic activity against Vibrio parahaemolyticus, the causative agent of Acute Hepatopancreatic Necrosis Disease (AHPND). Among these, four isolates demonstrated strong inhibitory effects, producing inhibition zones of 16-20 mm in agar well diffusion assays. These four LAB isolates were reported to cause no shrimp mortality during the feeding trials. Notably, shrimp fed with the isolate CG02 for 4 weeks showed a significantly improved survival (p < 0.05) after the immersion challenge with V. parahaemolyticus strain pVPA3-1. Based on 16S rDNA sequencing, the isolate CG02 was identified as Lactobacillus plantarum. To improve its viability, the isolate CG02 was encapsulated into spray-dried microcapsules. The resulting probiotic powder exhibited high cell viability, with counts of 9 ± 1.45 × 10⁸ CFU g^-1 after 4 months at room temperature, and 4.11 ± 0.38 × 10⁸ CFU g^-1 after 8 months at 4°C. When incorporated into shrimp feed, the CG02 powder did not cause any shrimp mortality. Moreover, it provided a relative percent survival (RPS) of 34.78% compared to the control group following the immersion challenge with V. parahaemolyticus. These results highlight the potential of spray-dried L. plantarum CG02 as a probiotic feed additive for enhancing shrimp health and supporting sustainable aquaculture practices.