Akademik Veri Yönetim Sistemi
3rd AQUATIC BIOTECHNOLOGY SYMPOSIUM, İstanbul, Türkiye, 25 - 27 Eylül 2024, ss.1
In recent decades, the application of probiotics as a nutritional supplement in aquafarming aquaculture has been one of the modern advancements that could combat fish pathogens and control emerging fish diseases. The incorporation of probiotics in aquaculture aquafeeds can also modulate the gut microbiota, improve the immune system, and promote the growth parameters of aquatic organisms. Furthermore, they probiotics can help contribute to maintain the water quality parameters. The main objective of this study is to evaluate the probiotic potential of bacteria isolated from fish gut microbiota. The cultivable isolates from the randomly chosen Dicentrarchus labrax, Salmo trutta trutta, and Sparus aurata (n=6), from various local farms and sea in different regions of Turkey, Türkiye were investigated. The entire intestines were enriched, serially diluted, and then spread on MRS agar for the enumeration of commensal isolates. Following the incubation, 87 morphologically different colonies were randomly selected. Among them, four isolates exhibited significant antimicrobial activity against at least four out of five tested pathogenic strains, including Streptococcus agalactiae, Pseudomonas aeruginosa, Aeromonas salmonicida, Vibrio anguillarum, and Yersinia ruckeri. These potent isolates were genotyped by RAPD profiling, and then identified by 16S rRNA gene sequencingas Carnobacterium divergens EIR/FG1, Carnobacterium divergens EIR/FG2, Carnobacterium maltaromaticum EIR/FG3, and Enterococcus gallinarum EIR/FG4. According to the safety criteria of the European Food Safety Authority, all strains displayed non-hemolysis and no antibiotic resistance except streptomycin and clindamycin. Their tolerance to gastrointestinal conditions was evaluated using stimulated gastric fluid (3mg/mL pepsin, pH:3), and intestinal fluid (0.1% pancreatin, 0.03% bile salt, pH:8). Our results showed that all strains maintained their viability in simulated conditions. These findings indicate that isolates from the gut microbiota of fish have promising probiotic properties and may be suitable candidates for improving fish health. Our studies are still in progress to analyze their interaction with fish intestine and liver cells.