Inactivation Mechanism and Apoptotic-Like Changes in Aeromonas hydrophila Induced by Slightly Acidic Electrolyzed Water in Freshwater

Abstract

Abstract. This study investigated the suppressive effect and the inactivation mechanism of slightly acidic electrolyzed water (SAEW) on . The experiment compared different inhibition effects with SAEW and two antibiotics, gentamicin and norfloxacin. The conditions of pH of 6.5, oxidation-reduction potential (ORP) of 890 mV, available chlorine concentration (ACC) of 28 mg L-1 of SAEW, and volume ratios of 1:10, 1:15, and 1:20 were used. Using exposure times of 5 and 10 min to analyze the inactivation mechanism of SAEW from the perspectives of cell membrane permeability, cell nuclear morphology, cell fluorescence staining, and other aspects, the anti-infection effects of SAEW were tested using tilapia () culture experiments. SAEW had a stronger bacteriostasis effect than the antibiotics used. SAEW can inhibit the ability to reproduce, causing abnormal cell morphology and cell elongation. The cell volume was increased with a change in the membrane permeability. The cell nuclear morphology was changed, further inducing apoptosis. Based on study of tilapia in a control group, the organs (intestine, stomach, and liver) developed different degrees of infection. No obvious infection was observed in muscle samples. After SAEW treatment, SAEW showed a better antibacterial effect and improvement effects on the inflammation and structural damage induced by , which could be helpful in aquaculture application. Keywords: A. hydrophila, Antibiotics, Anti-infection, Cell apoptosis, Membrane permeability, Slightly acidic electrolyzed water.