Enhancement of Vibrio parahaemolyticus resistance and immune responses in Exopalaemon carinicauda by synergistic bacteriostasis of Crataegus pinnatifida Bunge and oxytetracycline

Abstract

Abstract Natural plant extracts (NPEs) may offer an effective alternative to minimize the consequences caused by antibiotic resistance in the marine industry. In this study, the anti‐Vibrio parahaemolyticus activities of several antibiotics and NPEs alone and in combinations were evaluated. The results indicated that the best combination was the 1/4 minimum inhibitory concentration (MIC) oxytetracycline +1/4 MIC hawthorn extract with fractional inhibitory concentration of 0.50. As a result, the survival rate of Exopalaemon carinicauda challenged by V. parahaemolyticus was improved to 53.3 ± 4.7% (as compared to 23.3 ± 2.3% in control) because of exposure to the combination of oxytetracycline +1/4 MIC hawthorn extract. Furthermore, the combination of upregulated digestive enzyme activities (cellulose, lipase, and pepsin), Toll receptor expressions, and immune parameters (alkaline phosphatase, and lysozyme) improved tolerance of E. carinicauda to V. parahaemolyticus infection. The synergistic anti‐V. parahaemolyticus functions may be associated with improved digestibility and immunity of E. carinicauda. Therefore, as a supplementary therapy to inhibit V. parahaemolyticus, the combinations of NPEs + antibiotics will hold better application potential for reducing antibiotic dosage and resistance.

Keywords

• antibiotic adjuvant
• antibiotics
• aquatic industry
• herbal extracts
• Vibrio