Evaluation of the Potential Use of Oxy-Hydrogen Gas for the Treatment of Lactococcus Garvieae Infected-Zebrafish in Hydrogen-Rich Water Aquarium

Abstract

This study aimed to evaluate the use of an oxy-hydrogen generator for preparing hydrogen-rich water (HRW) and studying its effects on the L. garvieae-affected zebrafish. 0, 10, 20, and 100% HRW were prepared to determine the effects of HRW on the mortality rate and gene expression levels of L. garvieae infected-zebrafish. After 48 hours of bacterial injection, the mortality rate of fish was 0, 0, 0, 66, 80, and 100% for the non-infected and non-HRW (G1), infected and 100% HRW (G5), non-infected and 100% HRW (G6), infected and 20% HRW (G4), infected and 10% HRW (G3), and infected without HRW (G2) groups. After 54 hours, there was a non-significant change in immunity-related gene expression levels (IL-1β and IL-6) between non-infected 100% HRW (G6) and non-infected non-HRW control (G1) groups. Gene expression levels were significantly upregulated for IL-1β (14, 13, and 9 times), IL-6 (48, 48, and 22 times), and SOD (9 times for each) genes in G2, G3, and G4 groups, respectively, but not for G5 comparing with control group G1. IL-1β and IL-6 gene expression levels decreased with the increase of hydrogen levels in the water. These results show that HRW could decrease (G3 and G4) and prevent (G5) the mortality of L. garvieae infected-zebrafish. This demonstrates the importance of the application of HRW for the treatment of bacterial infectious diseases of fish using a non-toxic compound as a green method without any residual effects on fish or water. © 2023 by the authors. Submitted for possible open access publication under the terms and conditions of the Creative Commons Attribution (CC BY NC) license (https://creativecommons.org/licenses/by-nc/4.0/).