Investigation of Spatial Distribution, Antimicrobial, and Histopathological Effects of Probiotics on Zebrafish Model Infected with Aeromonas Hydrophila Through Evaluation of IL-1β and TNF-α Genes Expression

Abstract

\n Background\n\nUsage of “probiotics” for treatment of food-borne pathogens associated diseases, makes a significant reduction in transmission of resistant bacteria, and antimicrobial resistance genes from aquaculture environments to humans. In this research, authors aim to evaluate immunomodulatory, and histological effects of two probiotic strains on Zebrafish model. Biometric tests, height, weight, and mortality rate of the fishes were assessed. Afterward, RT-PCR was conducted for bacterial existence of probiotic strains, and quantitative assessment of alterations in targeted immune genes. Subsequently, histological sampling was done for investigation of spatial distribution, and villus length in proximal, middle, and distal sections of intestinal tissues.\nResults\n\nBased on the results, there was an increased rate of goblet cells, and villus length in the middle and distal sections of intestinal tissue in case groups receiving both probiotic bacteria in 28th and 56th days. Furthermore, highest number of intraepithelial cells was observed in the proximal sections of intestinal tissue in groups receiving both probiotic bacteria in 56th days. The highest gene expression for Lactobacillus bulgaricus was found in groups only treated with this probiotic bacteria in 60th day. The highest gene expression for Lactobacillus acidophilus was found in case groups treated with both of probiotic bacteria in 28th day. The highest expression level of IL-1β, and TNF-α were found in control group (only infected by pathogen and receiving no probiotic). The highest survival rate was in case groups only treated with Lactobacillus bulgaricus.\nConclusion\n\nTo sum up, it seems that usage of probiotic for improvement of public health and fisheries industries can be helpful.