Evaluation of probiotic potential of bacteria isolated from black tiger (Penaeus monodon) for aquaculture application

Probiotics, live cells with different beneficial characteristics, have been extensively studied and explored commercially in many different products in the world. Their benefits to human and animal health have been proven in hundreds of scientific studies. Based on their beneficial effects, the marine shrimp Penaeus monodon was used as a potential source of probiotic bacterial strain isolation. The present study was aimed to isolate, characterize and identify bacterial strain with probiotic potential activities from gut sample of the marine shrimp Penaeus monodon. Among the samples twelve bacterial strains had been isolated and subjected for preliminary screening and two bacterial strains showed remarkable probiotic potential for acid, bile salt and NaCl tolerance assay and characterized by gelatine and hemolytic activity and subjected for antibiotic and antimicrobial activity and the potential strains were subjected for invitro colonization characterization and the strains were further confirmed using 16S rRNA identification as B. paramycoides and E. thailandicus . The isolates demonstrated strong tolerance at the pH of 2, bile salt concentration of 1.5% and NaCl of 2%. The isolated probiotic strains also showed remarkable activity against tested pathogenic organism in which bacterial strain BLTGUS2 showed maximum activity against clinical antibiotics and test pathogens. The strong auto and co-aggregation and cell surface hydrophobicity potential were produced by BLTGUS2 strain which was further subjected for immunomodulatory studies using RAW 264.7 cells. According to the results, BLTGUS2 was identified as the best possible in vitro probiotic isolates that have antimicrobial properties against infections. Additional in-vivo testing is required to determine the benefits of these isolates for human health in real-world scenarios.