Complete Genome Sequence Analysis and Probiotic Characterisation of Lactiplantibacillus plantarum Y300 Isolated from Traditional Free-Range Chickens

As a core strategy for antibiotic replacement, probiotics have two advantages insofar as they enhance both animal productivity and pathogen suppression. In this study, we screened the intestines of antibiotic-naïve chickens for broad-spectrum antimicrobial lactic acid bacteria (LAB) with natural adaptability, based on the host–microbiota coevolution theory, and systematically evaluated their potential for development as poultry probiotics. We isolated a LAB strain, Lactiplantibacillus plantarum Y300, from traditional native free-range chickens, which showed strong inhibitory activity against avian pathogenic Salmonella, Escherichia coli, and Staphylococcus aureus. In vitro experiments indicated that the Lpb. plantarum strain Y300 had no hemolytic activity; excellent acid-producing ability;an outstanding tolerance to bile salts, low-pH environments, and simulated gastrointestinal fluids; a positive hydrophobic interaction with xylene, and good auto-aggregation characteristics. It also displayed a relatively high antioxidant capacity. Whole-genome sequencing revealed that the genome of Lpb. plantarum Y300 was approximately 3.05 mb, with a GC content of 44.74%. The main carbohydrate-active enzyme and bacteriocin genes were predicted in the Y300 genome, and no virulence genes or drug-resistance genes were detected. In summary, this study suggests that Lpb. plantarum Y300 has potential utility as a probiotic, and lays the theoretical foundation for the further development of microecological preparations of avian-sourced LAB.