Introduction: Zebrafish is very similar to mammals in terms of physiology of digestive system, pharmacological and genetics. Also, the remarkable similarity of zebrafish immune system to mammals is as an alternative model for studying innate immunity and adaptive immunity as well as malignancies caused by immune cells. Therefore, this fish is an attractive model for investigating the basic inflammatory processes and damage to the intestine, which was used in this research and the results obtained can be generalized to humans. The purpose of this study is to investigate the effect of feeding with two probiotic strains of Lactobacillus bulgaricus and Lactobacillus plantarumseparately and in combination on the immune system, the presence of bacteria in the intestine and protection against the pathogen Aeromonas hydrophila in the zebrafish model, which is a successful model for studies on vertebrate developmental biology, physical and biomedical research, intestinal bacterial colonization and immune responses have been introduced. Materials & Methods: RT-PCR test was performed to prove the presence of probiotic bacteria in the intestine and quantitative evaluation of the expression of immune genes, and the mortality of fish after exposure to pathogenic bacteria was investigated. After preparation, probiotic bacteria were added to the feed at a concentration of 108 cfu/g at the rate of 3% of the body weight of the fish and were fed to 240 pieces of fish twice a day and the tests were evaluated for 60 (0, 28, 56 and 60) days. Results: According to the results, the highest gene expression of Lactobacillus plantarum bacteria in the intestine in LA.pba treatment was on day 28, and the highest gene expression of Lactobacillus bulgaricus bacteria in LA.ba treatment was on day 60. The highest level of expression of immune genes IL1β and TNFα as inflammatory cytokines was in the normal group and even after exposure to the pathogen on day 60, the lowest level of expression of these genes was in the LA.pba group. Also, the highest survival rate was seen in the LA.pba group. Conclusion: The obtained results indicate the appropriate effect of using two types of probiotics Lactobacillus plantarum and Lactobacillus bulgaricus in creating protection against the pathogen Aeromonas hydrophila. Also, it seems that the use of these two probiotics in combination has more beneficial effects in the zebrafish model.
Ehsannia S, Ahari H, Kakolaki S, Anvar S A A, Yousefi S S. Studying the effect of feeding Lactobacillus bulgaricus and Lactobacillus plantarum probiotics on the immune system and protection against the pathogen Aeromonas hydrophila in Zebrafish model. Journalaer 2025; 1 (2) :77-86 URL: http://journalaer.com/article-1-146-en.html