{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,16]],"date-time":"2026-07-16T08:11:51Z","timestamp":1784189511627,"version":"3.55.0"},"reference-count":41,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,7,16]],"date-time":"2026-07-16T00:00:00Z","timestamp":1784160000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Microbiol."],"abstract":"\n Introduction<\/jats:title>\n \n As a national second-class protected wild animal, the intestinal microbial community of\n Cygnus cygnus<\/jats:italic>\n is highly important for health status and ecological balance. The potential application value of probiotics in animal health and disease prevention has attracted much attention, but few studies have investigated probiotics derived from wild animals.\n <\/jats:p>\n <\/jats:sec>\n \n Methods<\/jats:title>\n \n We initially collected fecal samples before and after the migration of the\n C. cygnus<\/jats:italic>\n for macrogenomic sequencing. We subsequently isolated\n Bacillus<\/jats:italic>\n spp. from\n C. cygnus<\/jats:italic>\n feces and determined their hemolytic properties and tolerance to acid and bile salts to identify potential candidates. We subsequently studied the position of a candidate in phylogenetic trees using 16S rRNA sequences, as well as its susceptibility to antibiotics, toxicity, and effects on animal health.\n <\/jats:p>\n <\/jats:sec>\n \n Results<\/jats:title>\n \n Metagenomic analysis revealed that the abundance of the\n Firmicutes<\/jats:italic>\n phylum tended to decrease after the migration of\n C. cygnus<\/jats:italic>\n , whereas the relative abundance of the\n Fusobacteria<\/jats:italic>\n phylum increased. Although the diversity and abundance of the gut microbiota of\n C. cygnus<\/jats:italic>\n remained relatively balanced before and after migration, the microbial community structure changed significantly after migration. These changes were related to reductions in carbohydrate metabolism and energy metabolism, as well as a decrease in the abundance of genes encoding glycoside hydrolases. Twelve strains were isolated and screened, and two strains,\n Bacillus subtilis<\/jats:italic>\n S07a and N1B, without hemolytic activity were found to have good tolerance to acid and bile salts. It was sensitive to 14 kinds of antibiotics, but\n B. subtilis<\/jats:italic>\n S07a inhibited on three common pathogenic bacteria. Animal studies have shown that\n B. subtilis<\/jats:italic>\n S07a (1\u202f\u00d7\u202f10\n 9<\/jats:sup>\n \u202fCFU\/mL) is safe for use in mice. It also has anti-inflammatory potential and enhances intestinal barrier function to meet the probiotic and safety requirements of probiotics.\n <\/jats:p>\n <\/jats:sec>\n \n Conclusion<\/jats:title>\n \n Metagenomic analysis revealed reduced abundance of carbohydrate-degrading microbes in the gut of\n C. cygnus<\/jats:italic>\n post migration. The isolated\n B. subtilis<\/jats:italic>\n S07a exhibits desirable\n in vitro<\/jats:italic>\n probiotic potential and satisfactory\n in vivo<\/jats:italic>\n safety.\n <\/jats:p>\n <\/jats:sec>","DOI":"10.3389\/fmicb.2026.1898323","type":"journal-article","created":{"date-parts":[[2026,7,16]],"date-time":"2026-07-16T07:53:46Z","timestamp":1784188426000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Metagenomic analysis of the gut microbiota in Cygnus cygnus and isolation, identification, and safety assessment of Bacillus"],"prefix":"10.3389","volume":"17","author":[{"given":"Ying","family":"Xiao","sequence":"first","affiliation":[{"name":"College of Veterinary Medicine, Xinjiang Agricultural University","place":["\u00dcr\u00fcmqi, China"]},{"name":"Xinjiang Key Laboratory of New Drug Research and Development for Herbivorous Animals","place":["\u00dcr\u00fcmqi, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yabin","family":"Lu","sequence":"additional","affiliation":[{"name":"College of Veterinary Medicine, Xinjiang Agricultural University","place":["\u00dcr\u00fcmqi, China"]},{"name":"Xinjiang Key Laboratory of New Drug Research and Development for Herbivorous Animals","place":["\u00dcr\u00fcmqi, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yue","family":"Hu","sequence":"additional","affiliation":[{"name":"College of Veterinary Medicine, Xinjiang Agricultural University","place":["\u00dcr\u00fcmqi, China"]},{"name":"Xinjiang Key Laboratory of New Drug Research and Development for Herbivorous Animals","place":["\u00dcr\u00fcmqi, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rui","family":"Shi","sequence":"additional","affiliation":[{"name":"College of Veterinary Medicine, Xinjiang Agricultural University","place":["\u00dcr\u00fcmqi, China"]},{"name":"Xinjiang Key Laboratory of New Drug Research and Development for Herbivorous Animals","place":["\u00dcr\u00fcmqi, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Duo","family":"Mai","sequence":"additional","affiliation":[{"name":"College of Veterinary Medicine, Xinjiang Agricultural University","place":["\u00dcr\u00fcmqi, China"]},{"name":"Xinjiang Key Laboratory of New Drug Research and Development for Herbivorous Animals","place":["\u00dcr\u00fcmqi, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ruixue","family":"Lv","sequence":"additional","affiliation":[{"name":"College of Veterinary Medicine, Xinjiang Agricultural University","place":["\u00dcr\u00fcmqi, China"]},{"name":"Xinjiang Key Laboratory of New Drug Research and Development for Herbivorous Animals","place":["\u00dcr\u00fcmqi, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Juan","family":"Pan","sequence":"additional","affiliation":[{"name":"College of Veterinary Medicine, Xinjiang Agricultural University","place":["\u00dcr\u00fcmqi, China"]},{"name":"Xinjiang Key Laboratory of New Drug Research and Development for Herbivorous Animals","place":["\u00dcr\u00fcmqi, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuhan","family":"Pan","sequence":"additional","affiliation":[{"name":"College of Veterinary Medicine, Xinjiang Agricultural University","place":["\u00dcr\u00fcmqi, China"]},{"name":"Xinjiang Key Laboratory of New Drug Research and Development for Herbivorous Animals","place":["\u00dcr\u00fcmqi, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jiacheng","family":"Tan","sequence":"additional","affiliation":[{"name":"College of Veterinary Medicine, Xinjiang Agricultural University","place":["\u00dcr\u00fcmqi, China"]},{"name":"Xinjiang Key Laboratory of New Drug Research and Development for Herbivorous Animals","place":["\u00dcr\u00fcmqi, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhihui","family":"Hao","sequence":"additional","affiliation":[{"name":"College of Veterinary Medicine, Xinjiang Agricultural University","place":["\u00dcr\u00fcmqi, China"]},{"name":"Xinjiang Key Laboratory of New Drug Research and Development for Herbivorous Animals","place":["\u00dcr\u00fcmqi, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jinquan","family":"Wang","sequence":"additional","affiliation":[{"name":"College of Veterinary Medicine, Xinjiang Agricultural University","place":["\u00dcr\u00fcmqi, China"]},{"name":"Xinjiang Key Laboratory of New Drug Research and Development for Herbivorous Animals","place":["\u00dcr\u00fcmqi, China"]},{"name":"Xinjiang Key Laboratory of Animal Infectious Diseases","place":["\u00dcr\u00fcmqi, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,7,16]]},"reference":[{"key":"ref1","doi-asserted-by":"publisher","first-page":"493","DOI":"10.1093\/ajcp\/45.4_ts.493","article-title":"Antibiotic susceptibility testing by a standardized single disk method","volume":"45","author":"Bauer","year":"1966","journal-title":"Am. 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