Complete genome analysis of Bacillus velezensis TS5 and its potential as a probiotic strain in mice

Benhao Chen; Yi Zhou; Lixiao Duan; Xuemei Gong; Xingmei Liu; Kangcheng Pan; Dong Zeng; Xueqin Ni; Yan Zeng

doi:10.3389/fmicb.2023.1322910

Complete genome analysis of Bacillus velezensis TS5 and its potential as a probiotic strain in mice

Front Microbiol. 2023 Dec 6:14:1322910. doi: 10.3389/fmicb.2023.1322910. eCollection 2023.

Authors

Benhao Chen^#^{1

2}, Yi Zhou^#^{1

2}, Lixiao Duan^#^{1

2}, Xuemei Gong^{1

2}, Xingmei Liu^{1

2}, Kangcheng Pan^{1

2}, Dong Zeng^{1

2}, Xueqin Ni^{1

2}, Yan Zeng^{1

2}

Affiliations

¹ Animal Microecology Institute, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.
² Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People's Republic of China, Chengdu, China.

^# Contributed equally.

Abstract

Introduction: In recent years, a large number of studies have shown that Bacillus velezensis has the potential as an animal feed additive, and its potential probiotic properties have been gradually explored.

Methods: In this study, Illumina NovaSeq PE150 and Oxford Nanopore ONT sequencing platforms were used to sequence the genome of Bacillus velezensis TS5, a fiber-degrading strain isolated from Tibetan sheep. To further investigate the potential of B. velezensis TS5 as a probiotic strain, in vivo experiments were conducted using 40 five-week-old male specific pathogen-free C57BL/6J mice. The mice were randomly divided into four groups: high fiber diet control group (H group), high fiber diet probiotics group (HT group), low fiber diet control group (L group), and low fiber diet probiotics group (LT group). The H and HT groups were fed high-fiber diet (30%), while the L and LT groups were fed low-fiber diet (5%). The total bacteria amount in the vegetative forms of B. velezensis TS5 per mouse in the HT and LT groups was 1 × 10⁹ CFU per day, mice in the H and L groups were given the same volume of sterile physiological saline daily by gavage, and the experiment period lasted for 8 weeks.

Results: The complete genome sequencing results of B. velezensis TS5 showed that it contained 3,929,788 nucleotides with a GC content of 46.50%. The strain encoded 3,873 genes that partially related to stress resistance, adhesion, and antioxidants, as well as the production of secondary metabolites, digestive enzymes, and other beneficial nutrients. The genes of this bacterium were mainly involved in carbohydrate metabolism, amino acid metabolism, vitamin and cofactor metabolism, biological process, and molecular function, as revealed by KEGG and GO databases. The results of mouse tests showed that B. velezensis TS5 could improve intestinal digestive enzyme activity, liver antioxidant capacity, small intestine morphology, and cecum microbiota structure in mice.

Conclusion: These findings confirmed the probiotic effects of B. velezensis TS5 isolated from Tibetan sheep feces and provided the theoretical basis for the clinical application and development of new feed additives.

Keywords: Bacillus velezensis TS5; cellulose; complete genome; digestive enzyme activity; probiotic.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was supported by funding from the Sichuan Natural Science Foundation Project (2022NSFSC1771), China.