Characterization of Lactic Acid Bacteria Isolated from the Gastrointestinal Tract of Ethiopian Rhode Island Red Chicken and their Potential Use as Probiotics

Abstract

Background Chicken productivity and survival is affected by environmental stress and incidences of different diseases. After the ban of antibiotics growth promoters by different countries, the use of probiotics feed additives is mentioned as one alternative to antibiotics. The objective of this study was to isolate and identify potential probiotic lactic acid bacteria strains from the digestive tract content of Rhode Island Red chicken. Results The study was conducted in Gondar town of Amhara region, North West Ethiopia from November, 2018 to March, 2019. From the gastro intestinal content of 5 chicken 190 isolates were randomly selected. The isolates were identified and screened by their biochemical, morphological and 16S rRNA gene sequence. The in vitro probiotic potential of isolates was characterized by various tests. From 190 isolates 73 were found as gram positive, catalase negative and were able to grow at pH4. The bacteria were either rod (83.6%) or round (16.4%) shaped. Ten isolates were then randomly selected for further in vitro probiotic characterization due to higher cell surface hydrophobicity, good survival at pH2 and survival at 0.1% bile salt. From the 10 isolates 6 were able to survive at pH1 for 3hrs incubation. Five isolates (IS1, IS2, IS5, IS7 and IS8) were resistance to ampicillin, chloramphenicol, ciprofloxacin and erythromycin antibiotics. All the ten isolates showed antagonistic activity against Escherichia coli, Staphylococcus aureus, Salmonella typhimurium, Staphylococcus intermedius and Salmonella enteritidis. The optimum temperature for all ten isolates was 450C and all the isolates were able to grow at 0.69 mol/L of NaCl, and were able to ferment galactose, glucose, fructose, mannitol, sorbitol and sucrose. Using phylogenetic analysis of 16SrRNA gene sequence; IS3 was identified as Lactobacillus salivarius while IS4, IS6 and IS7 were identified as Lactobacillus reuteri. Conclusion The study concludes that the 10 selected isolates can be able to survive the stress conditions of gastrointestinal tract and can thus be considered as potential probiotics candidates for chickens.

Characterization of Nuvita Biosearch Center (NBC) Isolated Lactic Acid Bacteria Strains from Human Origin and Determination of Growth Kinetic Profiles of Selected Cultures by Lab-Scale Bioreactor Fermentation

“…The clean zone diameters formed around the wells by probiotic bacterial isolates against pathogens were measured in millimeters (mm). The experiment was duplicated (Tsega et al 2023).…”