In Vitro and In Vivo Evaluation of New Probiotic Lactobacillus Strains Isolated from Healthy and Colibacillosis diseased Broilers against Avian Pathogenic E.coli O78

Articles in Press

Document Type : Original Paper

Authors

1 Department of Wildlife and Ecology, University of Veterinary and Animal Sciences, Lahore 54000, Pakistan

2 Institute of Microbiology, University of Veterinary and Animal Sciences, Lahore 54000, Pakistan

Abstract

This study compares healthy and colibacillosis-diseased broilers to determine if disease conditions promote the selection of stronger or equally potent probiotic Lactobacillus spp. A total of 120 putative Lactobacillus colonies were recovered from chicken ileum samples from healthy (n=10) and diseased (n=10) poultry farms in District Kasur, Pakistan. The in vitro probiotic potential of isolates was assessed through antibiotic resistance, acid and bile tolerance, auto and co aggregation, and antimicrobial activity against E. coli O78 and laboratory-isolated Avian Pathogenic E.coli (APEC). Strains NK1, NK2, and NK3, identified as Lacticaseibacillus casei, Lactoplantibacillus plantarum, and Lacticaseibacillus paracasei from healthy (23H, 72H) and diseased (21D) sources, respectively, have been registered in National Center of Biotechnology Information (NCBI) with accession numbers PP831161, PP991318, and PP989450. For the feeding trial, broiler chickens (N=90) were randomly split into six experimental groups (A-F) with three replicates (n=5/replicate). Except for the control group (A), all groups (B–F) were challenged with APEC (105 CFU/mL) on day 11. Group C was treated with commercial probiotic, while groups D–F were treated with Lactobacillus strains 23H, 72H, and 21D, respectively. Results showed that isolates from diseased birds were more acid-tolerant (8.7%) and bile salt-tolerant (40%), with no significant difference in antibiotic resistance (p > 0.05). Diseased isolates also demonstrated higher auto-aggregation (21.4%) and co-aggregation with E. coli O78 and APEC (11.2%). Five strains significantly reduced APEC CFU/mL and enhanced their growth. Group D-F effectively decreased APEC levels in vivo, with growth performance comparable (p<0.05) to A and B groups and similar (p>0.05) to the C group, suggesting that isolates from diseased birds could also be promising probiotic candidates despite their lower incidence rate compared to healthy isolates. Probiotic isolates from diseased broilers demonstrated comparable probiotic potential to those from healthy broilers, effectively reducing APEC levels and enhancing growth performance. 

Keywords

Poultry Science Journal

Articles in Press, Corrected Proof
Available Online from 01 June 2025

Files

Share

How to cite

Statistics