{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T01:31:47Z","timestamp":1760059907581,"version":"build-2065373602"},"reference-count":42,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2025,7,20]],"date-time":"2025-07-20T00:00:00Z","timestamp":1752969600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Guangxi Science and Technology Program","award":["AD22080029","2021GXNSFBA075008","42106133","DTS-202305001","DTS-202503001"],"award-info":[{"award-number":["AD22080029","2021GXNSFBA075008","42106133","DTS-202305001","DTS-202503001"]}]},{"name":"Natural Science Foundation of Guangxi","award":["AD22080029","2021GXNSFBA075008","42106133","DTS-202305001","DTS-202503001"],"award-info":[{"award-number":["AD22080029","2021GXNSFBA075008","42106133","DTS-202305001","DTS-202503001"]}]},{"name":"National Natural Science Foundation of China","award":["AD22080029","2021GXNSFBA075008","42106133","DTS-202305001","DTS-202503001"],"award-info":[{"award-number":["AD22080029","2021GXNSFBA075008","42106133","DTS-202305001","DTS-202503001"]}]},{"name":"Institute of Green and Low Carbon Technology, and Green and Low Carbon Technology Program of Guangxi Institute of Industrial Technology","award":["AD22080029","2021GXNSFBA075008","42106133","DTS-202305001","DTS-202503001"],"award-info":[{"award-number":["AD22080029","2021GXNSFBA075008","42106133","DTS-202305001","DTS-202503001"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Microorganisms"],"abstract":"<jats:p>Streptococcus agalactiae (SA) is a severe prevalent pathogen, resulting in high morbidity and mortality in the global tilapia industry. With increasing bacterial resistance to antibiotics, alternative strategies are urgently needed. This study aims to investigate the antibacterial activity and the underlying mechanisms of the natural product xanthohumol (XN) against SA infection in tilapia (Oreochromis niloticus). The results showed that XN could significantly reduce the bacterial loads of SA in different tissues (liver, spleen and brain) after treatment with different tested concentrations of XN (12.5, 25.0 and 50.0 mg\/kg). Moreover, XN could improve the survival rate of SA-infected tilapia. 16S rRNA gene sequencing demonstrated that the alpha-diversity index (Chao1 and Shannon_e) was significantly increased in the XN-treated group (MX group) compared to the SA-infected group (CG group) (p &lt; 0.05), and the Simpson diversity index significantly decreased. The Bray\u2013Curtis similarity analysis of non-metric multidimensional scaling (NMDS) and principal coordinate analysis (PCA) showed that there were significant differences in microbial composition among groups. At the phylum level, the relative abundance of the phyla Actinobacteria, Proteobacteria and Bacteroidetes decreased in the MX group compared to the CG group, while the relative abundance of the phyla Fusobacteria, Firmicutes and Verrucomicrobia increased. Differences were also observed at the genus level; the relative abundance of Mycobacterium decreased in the MX group, but the abundance of Cetobacterium and Clostridium_sensu_stricto_1 increased. Metabolomics analysis revealed that XN changed the metabolic profile of the liver and significantly enriched aspartate metabolism, glycine and serine metabolism, phosphatidylcholine biosynthesis, arginine and proline metabolism, glutamate metabolism, urea cycle, purine metabolism, methionine metabolism, betaine metabolism, and carnitine synthesis. Correlation analysis indicated an association between the intestinal microbiota and metabolites. In conclusion, XN may be a potential drug for the prevention and treatment of SA infection in tilapia, and its mechanism of action may be related to the regulation of the intestinal microbiota and liver metabolism.<\/jats:p>","DOI":"10.3390\/microorganisms13071699","type":"journal-article","created":{"date-parts":[[2025,7,21]],"date-time":"2025-07-21T07:56:14Z","timestamp":1753084574000},"page":"1699","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Effects of Natural Ingredient Xanthohumol on the Intestinal Microbiota, Metabolic Profiles and Disease Resistance to Streptococcus agalactiae in Tilapia Oreochromis niloticus"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4153-0062","authenticated-orcid":false,"given":"Aiguo","family":"Huang","sequence":"first","affiliation":[{"name":"Guangxi Laboratory on the Study of Coral Reefs in the South China Sea, Coral Reef Research Center of China, School of Marine Sciences, Guangxi University, Nanning 530004, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yanqin","family":"Wei","sequence":"additional","affiliation":[{"name":"Guangxi Laboratory on the Study of Coral Reefs in the South China Sea, Coral Reef Research Center of China, School of Marine Sciences, Guangxi University, Nanning 530004, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jialong","family":"Huang","sequence":"additional","affiliation":[{"name":"Guangxi Laboratory on the Study of Coral Reefs in the South China Sea, Coral Reef Research Center of China, School of Marine Sciences, Guangxi University, Nanning 530004, China"},{"name":"School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Songlin","family":"Luo","sequence":"additional","affiliation":[{"name":"Guangxi Laboratory on the Study of Coral Reefs in the South China Sea, Coral Reef Research Center of China, School of Marine Sciences, Guangxi University, Nanning 530004, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tingyu","family":"Wei","sequence":"additional","affiliation":[{"name":"Guangxi Laboratory on the Study of Coral Reefs in the South China Sea, Coral Reef Research Center of China, School of Marine Sciences, Guangxi University, Nanning 530004, China"},{"name":"School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jing","family":"Guo","sequence":"additional","affiliation":[{"name":"Key Laboratory of Environment Change and Resources Use in Beibu Gulf, Ministry of Education, Nanning Normal University, Nanning 530001, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Fali","family":"Zhang","sequence":"additional","affiliation":[{"name":"Guangxi Laboratory on the Study of Coral Reefs in the South China Sea, Coral Reef Research Center of China, School of Marine Sciences, Guangxi University, Nanning 530004, China"},{"name":"Institute of Green and Low Carbon Technology, Guangxi Institute of Industrial Technology, Nanning 530000, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yinghui","family":"Wang","sequence":"additional","affiliation":[{"name":"Guangxi Laboratory on the Study of Coral Reefs in the South China Sea, Coral Reef Research Center of China, School of Marine Sciences, Guangxi University, Nanning 530004, China"},{"name":"Institute of Green and Low Carbon Technology, Guangxi Institute of Industrial Technology, Nanning 530000, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,7,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"526","DOI":"10.1016\/j.vetmic.2012.04.035","article-title":"PCR detection and PFGE genotype analyses of streptococcal clinical isolates from tilapia in China","volume":"159","author":"Chen","year":"2012","journal-title":"Vet. 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