Global farming of whiteleg shrimp Penaeus vannamei through aquaculture has created huge economic benefits. However, over the past decades, misuse of antibiotics to combat and prevent aquatic disease outbreaks such as vibriosis has led to different levels of antibacterial resistance in various countries. Essential oils (EOs) extracted from plants, and their purified components (EOCs) already proved to possess effective antimicrobial abilities towards aquatic microbial pathogens (e.g. Vibrio spp.) in laboratory conditions. Moreover, the benefits of EOCs were extensively studied before by the ARC lab, focusing on the crustacean model Artemia franciscana (Zheng et al., 2023) . The current study furt her validated the antibacterial activity and protective ability of EOCs in post-larvae (PLs ) of P . vannamei.
Three EOCs (citral, R-(+)-limonene and trans-cinnamaldehyde) we re applied through a broth microdilution assay at concentrations ranging from 2% to 0.0020%, with dimethyl sulfoxide at 1% as solven t, to determine the minimum inhibitory concentration (MIC) against V ibrio campbellii and V. parahaemolyticus (AHPND strain) at 5 x 105 CFU . The cell density was monitored hourly for 24 hours at OD 600nm. Pot ential synergistic effects of selected EOCs were analyzed in vitro. Finally, an in vivo assay involving toxicity assessment was performed , to investigate the LD50 of PLs exposed to different EOCs. C hallenge tests we re conducted to verify the protective effect of the selected EOCs on the shrimp PLs.
Initial results confirm that (0.5%, v/v) citral has a strong inhibitory effect on V. campbellii BB120 after 24 hours exposure (Figure 1). Trans-cinnamaldehyde significantly inhibits the growth of both Vibrio strains. The potential benefits of EOCs for miti gating and prophylaxis of vibriosis in shrimp farming practices is highlighted, and demonstrate a valuable and sustainable alternative for combating Vibrio during shrimp cultivation. By further exploring their protective efficacy, EOCs offer hope for ecological and sustainable health management in global aquaculture practice.