Phytobiotics as promising antimicrobial agents in aquaculture health management

As aquaculture continues to expand as a major food-producing sector, reliance on synthetic antibiotics raises concerns related to antimicrobial resistance, public health, and environmental sustainability. In response, the present study explores plant essential oils (EOs) as eco-friendly alternatives to conventional antimicrobials. The phytochemical composition, the antioxidant potential, antibacterial activity, and antibiofilm properties of EOs derived from Origanum vulgare L., Vitex agnus-castus L. and Mentha longifolia (L.) Huds. were investigated against common fish-pathogenic bacteria. Additionally, cytotoxicity was assessed using Epithelioma papulosum cyprini (EPC) cells to determine safety. Among the tested oils, Origanum vulgare L. EO ( Ov EO) exhibited the strongest bioactivity, showing potent antioxidant effects, broad-spectrum bactericidal action at low concentrations, significant antibiofilm inhibition, and minimal cytotoxicity. Mentha longifolia (L.) Huds. EO ( Ml EO) displayed moderate bioactivity, followed by Vitex agnus-castus EO ( Vac EO). These findings suggest that the varying antimicrobial and antioxidant capacities are attributable to differences in phytochemical composition, highlighting Ov EO as a promising natural candidate for sustainable disease management in aquaculture.