Isolation and identification of bifidobacterium with probiotic potency from sheep intestines

Isolation and identification of bifidobacterium with probiotic potency from sheep intestines
Sorour Aalipanah,¹ Shohreh Nasiri poroj,^2,* Neda zamani,³
1. Department of Microbiology, Faculty of Life Sciences, Islamic Azad University, North Tehran Branch
2. Department of Microbiology, Faculty of Life Sciences, Islamic Azad University, North Tehran Branch
3. Department of Microbiology, Faculty of Life Sciences, Islamic Azad University, North Tehran Branch
Introduction: Probiotics are dietary supplements that contain live, non-pathogenic microorganisms that interact with the gastrointestinal microflora and directly with the immune system. Possible health effects of probiotics include modulating the immune system and exerting antibacterial and anti-mutagenic effects. The aim of this study was to isolate, identify and characterize Bifidobacterium strains from sheep intestines and also to determine some probiotic characteristics of the isolates.
Methods: In this study, a number of healthy-looking sheep were randomly selected and were sampled sterile from their intestines. After preparation of dilution and culture in MRS broth and agar medium, the samples were incubated in a CO2 incubator at 37 ° C for 24-72 hours. The bacteria were isolated and purified by phenotypic methods (gram staining, catalase test, biochemical tests including fermentation of carbohydrates and gas production from glucose). Then, these bacteria were studied based on initial probiotic indices including resistance to different concentrations of acid, bile salts and high salt concentrations. After the above experiments, three strains of Bifidobacterium from sheep intestine sample was isolated and the antimicrobial effect of these isolates on pathogenic bacteria was studied by using the well method. Then, one strain resistant to the high concentrations of acid, bile and salt that showed the best antimicrobial effect was identified by 16S rRNA gene sequencing.
Results: Among the isolated bacteria, five were gram-positive, anaerobic, non-spore forming, non-motile and catalase negative. They have various shapes including short, curved rods, club-shaped rods and bifurcated Y-shaped rods. Besides glucose, the isolated bacteria were able to utilize galactose, lactose, and usually, fructose as a carbon sources. The optimum growth temperature was 37-41 ° C, with maximum growth at 43-45 ° C and almost no growth at 25-28 ° C or below. The isolates were incapable of produce gas from glucose. The optimum pH for growth was 6-7 and from the above five isolates, three of the isolates were able to grow at pH 3-9 and also were resistant to bile salt with a concentration of 0.1-1.2 w / v and salt of 4.5 and 6.5%. All probiotic strains were able to inhibit the growth of pathogenic bacteria and Bifidobacterium bifidum had the maximum antibacterial effect.
Conclusion: Bifidobacterium is the common genus specified in sheep intestines. Therefore, probiotic bacteria isolated from sheep intestines have antimicrobial properties that can be utilized for industrial processes.
Keywords: Probiotic bacteria, Bifidobacterium, Intestinal flora, 16S rRNA, industrial processes