Probiotic characterization and whole genome sequencing of Limosilactobacillus reuteri CHF7-2 from Chahua chicken

Abstract:

Objective To study the probiotic properties and safety of Limosilactobacillus reuteri CHF7-2 isolated from Chahua chicken, providing a theoretical basis for the development of this strain as a microecological feed additive.Methods In vitro assays were conducted to evaluate the adhension, enzyme production, antibacterial activity, and antioxidant activity of strain CHF7-2. PacBio Sequel II and Illumina NovaSeq 6000 were used for whole genome sequencing of strain CHF7-2. Bioinformatics tools and databases were then used for genome annotation to explore the probiotic mechanisms and safety of this strain at the molecular level.Results Strain CHF7-2 possessed significant probiotic properties and safety. It exhibited high surface hydrophobicity, self-coagulation, and antioxidant activity. The strain inhibited the growth of Escherichia coli K88, Staphylococcus aureus ATCC 49521, Salmonella gallinarum CICC 21510, and Salmonella choleraesuis CVCC 3383. Strain CHF7-2 produced protease and lipase, and it was safe for use in feed since it did not exhibit hemolytic activity. Whole genome sequencing revealed that the genome size of CHF7-2 was 2 116 761 bp, with the G+C content of 38.8%, encoding 2 067 genes. Additionally, the genome carried the biosynthetic gene cluster of the class III bacteriocin EnlA and multiple genes involved in the acid tolerance, bile salt tolerance, heat stress tolerance, cold stress tolerance, adhesion, antioxidation, and organic acid synthesis, with no virulence or antibiotic resistance genes detected.Conclusion L. reuteri CHF7-2 is a potential probiotic strain and a promising candidate for use as a microecological feed additive.

Key words:Limosilactobacillus reuteri;whole genome sequencing;probiotic properties;microecological feed additive