The growing threat of antimicrobial resistance has prompted a reduction in antibiotic use within aquaculture, where disease outbreaks and environmental stressors continue to compromise animal health and productivity. Functional feed additives have emerged as promising alternatives, offering benefits to gut health, immunity, and performance without contributing to antimicrobial resistance. This study assessed the efficacy of an enhanced organic acids-based feed additive (Biotronic® PX Top3) as a sustainable substitute for antibiotics in Pacific white leg shrimp (Litopenaeus vannamei). In total, 480 shrimp were randomly assigned to 24 tanks in a recirculating aquaculture system and fed one of four diets over 66 days (six replicates per group): (I) basal diet as control; (II) basal diet with the antibiotic Cefotaxime (0.15 g/kg feed, as a prevention dosage); (III) basal diet with Biotronic® PX Top3 at 0.5 g/kg; and (IV) at 1 g/kg. Growth performance and feed consumption were evaluated. Subsequently, a bath immersion challenge with Vibrio parahaemolyticus (1.2 × 10⁶ CFU/L) was conducted. The shrimp were fed the same experimental diets, except that the antibiotic dosage in group III was increased to 0.2 g/kg, representing the recommended treatment dose. Mortality was monitored daily for 14 days. Compared to the control, both dosages of Biotronic® PX Top3 significantly improved specific growth rate, tank yield, feed conversion ratio, and survival during the 66-day feeding period, achieving results comparable to the antibiotic group. Post-challenge mortality was lowest in the higher-dosage Biotronic® group (40.48 ± 10.75%, mean ± standard deviation), followed by the antibiotic group (57.14 ± 12.78%, p = 0.058), the lower-dosage Biotronic® group (59.52 ± 10.75%, p = 0.026), and the control (76.19 ± 7.37%, p < 0.001). These findings suggest that organic acid‑based feed additives may offer a promising and sustainable approach to supporting shrimp growth and resilience. Further studies should determine the mechanistic pathways.