{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,15]],"date-time":"2026-10-15T15:05:55Z","timestamp":1792076755621,"version":"4.4.0"},"reference-count":34,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2025,2,25]],"date-time":"2025-02-25T00:00:00Z","timestamp":1740441600000},"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":"<jats:sec><jats:title>Introduction<\/jats:title><jats:p>The intestinal dysfunction plays an important role in the decreased growth performance of broiler chickens under high stocking density. Gut microbiota plays an important role in maintaining intestinal health. However, the modulation pathway of gut microbiota by regulating the intestinal barrier and histomorphology remains unknown.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>One hundred and forty-four male Arbor Acres broilers (22-d-old) with similar weight were randomly assigned to two treatments: a high (HSD, 20 broilers\/m<jats:sup>2<\/jats:sup>) or low stocking density treatment (LSD, 14 broilers\/m<jats:sup>2<\/jats:sup>), with six replicates per treatment. The experimental period was 20 days, from 22 to 42 days of age.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>The final body weight at 42 days of age was lower in the HSD group (<jats:italic>P<\/jats:italic> = 0.0013) and average daily feed intake (<jats:italic>P<\/jats:italic> = 0.016) and weight gain of broilers from 22 to 42 days decreased (<jats:italic>P<\/jats:italic> = 0.012). In the HSD group on day 42, villus height and the ratio of villus height to the crypt depth in the ileum decreased (<jats:italic>P<\/jats:italic> &amp;lt; 0.05); mRNA expression of tight junction proteins, occludin (<jats:italic>P<\/jats:italic> &amp;lt; 0.01) and ZO1 (<jats:italic>P<\/jats:italic> &amp;lt; 0.05), were downregulated; whereas IL-6, TNF\u03b1, and NF\u03baB p65 (<jats:italic>P<\/jats:italic> &amp;lt; 0.05) and IL-1\u03b2 (<jats:italic>P<\/jats:italic> &amp;lt; 0.01) were upregulated. The HSD treatment increased the relative abundance of <jats:italic>Lactobacillus<\/jats:italic> (<jats:italic>P<\/jats:italic> = 0.045) and decreased that of <jats:italic>Alistipes<\/jats:italic> (<jats:italic>P<\/jats:italic> = 0.031). Cecal concentrations of acetic (<jats:italic>P<\/jats:italic> &amp;lt; 0.05) and butyric acids (<jats:italic>P<\/jats:italic> &amp;lt; 0.05) decreased. Gut metabolites co-metabolized by the host and gut microbiota were altered in the HSD group, with decreases in glycerophospholipid and tryptophan metabolites negatively correlated with <jats:italic>Lactobacillus<\/jats:italic> (<jats:italic>P<\/jats:italic> &amp;lt; 0.05). The metabolite content of conjugated bile acids decreased and free bile acids increased (<jats:italic>P<\/jats:italic> &amp;lt; 0.05) with HSD. Bile salt hydrolase (BSH) was increased in the intestine of HSD-treated broilers (<jats:italic>P<\/jats:italic> &amp;lt; 0.01). The total cholic acid content of the HSD group was lower in the jejunum and ileum (<jats:italic>P<\/jats:italic> &amp;lt; 0.05) but higher in the cecum than in the LSD group (<jats:italic>P<\/jats:italic> &amp;lt; 0.01).<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>HSD caused dysbiosis of the intestinal microbiota such as increased <jats:italic>Lactobacillus<\/jats:italic>, along with enhanced BSH activity and excessive unabsorbed free bile acids. This resulted in ileal epithelial cells damage, inflammation, decreased growth performance of broilers under high stocking densities.<\/jats:p><\/jats:sec>","DOI":"10.3389\/fmicb.2025.1542059","type":"journal-article","created":{"date-parts":[[2025,2,25]],"date-time":"2025-02-25T16:18:25Z","timestamp":1740500305000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":14,"title":["Effects of high stocking density on the growth performance, intestinal health and bile salts composition of broiler chickens"],"prefix":"10.3389","volume":"16","author":[{"given":"Yuanyang","family":"Dong","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuqi","family":"Zheng","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Haoyu","family":"Liu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yaru","family":"Wang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jiaqing","family":"Cui","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuan","family":"Wu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lei","family":"Yan","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhiqiang","family":"Miao","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Miaomiao","family":"Han","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chenxuan","family":"Huang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Peifeng","family":"Li","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuan","family":"Su","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yiru","family":"Shen","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Junzhen","family":"Zhang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jianmin","family":"Yuan","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bingkun","family":"Zhang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jianhui","family":"Li","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2025,2,25]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"873","DOI":"10.3923\/javaa.2012.873.877","article-title":"Impact and manipulation of gut microflora in poultry: A review.","volume":"11","author":"Adil","year":"2012","journal-title":"J. Anim. Veterinary Adv."},{"key":"B2","doi-asserted-by":"publisher","first-page":"431","DOI":"10.1017\/S0043933911000481","article-title":"Lipoprotein metabolism in poultry.","volume":"67","author":"Alvarenga","year":"2011","journal-title":"World\u2019s Poultry Sci. J."},{"key":"B3","doi-asserted-by":"crossref","first-page":"1729","DOI":"10.1128\/AEM.72.3.1729-1738.2006","article-title":"Bile salt hydrolase activity in probiotics.","volume":"72","author":"Begley","year":"2006","journal-title":"Appl. Environ. Microb."},{"key":"B4","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1016\/j.plefa.2015.07.004","article-title":"Relevance of dietary glycerophospholipids and sphingolipids to human health.","volume":"101","author":"Castro-G\u00f3mez","year":"2015","journal-title":"Prostaglandins Leukotrienes Essential Fatty Acids"},{"key":"B5","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1038\/s12276-018-0126-x","article-title":"Mechanisms regulating intestinal barrier integrity and its pathological implications.","volume":"50","author":"Chelakkot","year":"2018","journal-title":"Exp. Mol. Med."},{"key":"B6","doi-asserted-by":"crossref","first-page":"175","DOI":"10.1146\/annurev-nutr-082018-124344","article-title":"Bile acids as metabolic regulators and nutrient sensors.","volume":"39","author":"Chiang","year":"2019","journal-title":"Annu. Rev. Nutr."},{"key":"B7","doi-asserted-by":"publisher","first-page":"9","DOI":"10.1080\/00071660802538632","article-title":"Managing gut health through nutrition.","volume":"50","author":"Choct","year":"2009","journal-title":"Brit. Poultry Sci."},{"key":"B8","doi-asserted-by":"publisher","first-page":"1742","DOI":"10.1002\/pro.3484","article-title":"Bile salt hydrolases: Structure and function, substrate preference, and inhibitor development.","volume":"27","author":"Dong","year":"2018","journal-title":"Protein Sci."},{"key":"B9","doi-asserted-by":"publisher","first-page":"1153","DOI":"10.3382\/ps\/pey491","article-title":"Effect of stocking density and sex on growth performance, meat quality, and intestinal barrier function in broiler chickens.","volume":"98","author":"Goo","year":"2019","journal-title":"Poultry Sci."},{"key":"B10","doi-asserted-by":"crossref","first-page":"1878","DOI":"10.3382\/ps.2010-01311","article-title":"Effects of stocking density on the growth performance and digestive microbiota of broiler chickens.","volume":"90","author":"Guardia","year":"2011","journal-title":"Poultry Sci."},{"key":"B11","doi-asserted-by":"publisher","first-page":"427","DOI":"10.1016\/j.chom.2016.03.014","article-title":"Breathless in the gut: Implications of luminal o2 for microbial pathogenicity.","volume":"19","author":"Kelly","year":"2016","journal-title":"Cell Host Microbe"},{"key":"B12","doi-asserted-by":"publisher","first-page":"883","DOI":"10.2174\/1389200219666180427164731","article-title":"Indoles - Gut bacteria metabolites of tryptophan with pharmacotherapeutic potential.","volume":"19","author":"Konopelski","year":"2018","journal-title":"Curr. Drug Metab."},{"key":"B13","doi-asserted-by":"publisher","first-page":"1914","DOI":"10.5713\/ajas.18.0939","article-title":"Effect of stocking density and alpha-lipoic acid on the growth performance, physiological and oxidative stress and immune response of broilers.","volume":"32","author":"Li","year":"2019","journal-title":"Asian-Australas J Anim Sci."},{"key":"B14","doi-asserted-by":"publisher","first-page":"33","DOI":"10.3389\/fmicb.2014.00033","article-title":"Antibiotic growth promoters enhance animal production by targeting intestinal bile salt hydrolase and its producers.","volume":"5","author":"Lin","year":"2014","journal-title":"Front. Microbiol."},{"key":"B15","doi-asserted-by":"crossref","first-page":"10","DOI":"10.14336\/AD.2022.0104","article-title":"Functions of gut microbiota metabolites, current status and future perspectives.","volume":"13","author":"Liu","year":"2022","journal-title":"Aging Dis."},{"key":"B16","doi-asserted-by":"publisher","first-page":"skaa092","DOI":"10.1093\/jas\/skaa092","article-title":"Supplemental methionine and stocking density affect antioxidant status, fatty acid profiles, and growth performance of broiler chickens.","volume":"98","author":"Magnuson","year":"2020","journal-title":"J. Anim. Sci."},{"key":"B17","doi-asserted-by":"publisher","first-page":"573","DOI":"10.1038\/nrgastro.2017.88","article-title":"Gut microbiota and ibd: Causation or correlation?","volume":"14","author":"Ni","year":"2017","journal-title":"Nat. Rev. Gastro. Hepat."},{"key":"B18","doi-asserted-by":"publisher","first-page":"108","DOI":"10.4161\/gmic.26945","article-title":"Intestinal microbiome of poultry and its interaction with host and diet.","volume":"5","author":"Pan","year":"2014","journal-title":"Gut Microbes"},{"key":"B19","doi-asserted-by":"crossref","first-page":"867","DOI":"10.1021\/acscentsci.9b00147","article-title":"Chemoproteomic profiling of gut microbiota-associated bile salt hydrolase activity.","volume":"5","author":"Parasar","year":"2019","journal-title":"ACS Central Sci."},{"key":"B20","doi-asserted-by":"crossref","first-page":"802","DOI":"10.1111\/apt.13333","article-title":"Systematic review: Bile acids and intestinal inflammation-luminal aggressors or regulators of mucosal defence?","volume":"42","author":"Pavlidis","year":"2015","journal-title":"Aliment. Pharm. Ther."},{"key":"B21","doi-asserted-by":"crossref","first-page":"705","DOI":"10.5713\/ajas.2012.12633","article-title":"Influence of dietary fat source on growth performance responses and carcass traits of broiler chicks.","volume":"26","author":"Poorghasemi","year":"2013","journal-title":"Asian Austral. J. Anim."},{"key":"B22","doi-asserted-by":"publisher","first-page":"622","DOI":"10.1136\/gutjnl-2012-304241","article-title":"Claudin-1 regulates intestinal epithelial homeostasis through the modulation of notch-signalling.","volume":"63","author":"Pope","year":"2014","journal-title":"Gut"},{"key":"B23","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1016\/j.anifeedsci.2016.01.012","article-title":"Fats in poultry nutrition: Digestive physiology and factors influencing their utilisation.","volume":"213","author":"Ravindran","year":"2016","journal-title":"Anim. Feed Sci. Tech."},{"key":"B24","doi-asserted-by":"publisher","first-page":"341","DOI":"10.1038\/nri.2016.42","article-title":"Gut microbiota, metabolites and host immunity.","volume":"16","author":"Rooks","year":"2016","journal-title":"Nat. Rev. Immunol."},{"key":"B25","doi-asserted-by":"publisher","first-page":"1101","DOI":"10.1038\/nprot.2008.73","article-title":"Analyzing real-time pcr data by the comparative ct method.","volume":"3","author":"Schmittgen","year":"2008","journal-title":"Nat. Protoc."},{"key":"B26","doi-asserted-by":"publisher","first-page":"85","DOI":"10.1016\/j.vetmic.2013.01.030","article-title":"Identification of chicken intestinal microbiota correlated with the efficiency of energy extraction from feed.","volume":"164","author":"Stanley","year":"2013","journal-title":"Vet. Microbiol."},{"key":"B27","doi-asserted-by":"publisher","first-page":"1760","DOI":"10.1080\/10408398.2019.1598334","article-title":"Tryptophan (trp) modulates gut homeostasis via aryl hydrocarbon receptor (ahr).","volume":"60","author":"Sun","year":"2020","journal-title":"Crit. Rev. Food Sci."},{"key":"B28","doi-asserted-by":"publisher","first-page":"40","DOI":"10.1038\/s41577-019-0198-4","article-title":"The intestinal microbiota fuelling metabolic inflammation.","volume":"20","author":"Tilg","year":"2020","journal-title":"Nat. Rev. Immunol."},{"key":"B29","doi-asserted-by":"publisher","first-page":"671","DOI":"10.1016\/j.chom.2017.05.009","article-title":"Il-22 upregulates epithelial claudin-2 to drive diarrhea and enteric pathogen clearance.","volume":"21","author":"Tsai","year":"2017","journal-title":"Cell Host. Microbe"},{"key":"B30","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1080\/03079457.2014.1000820","article-title":"High stocking density as a predisposing factor for necrotic enteritis in broiler chicks.","volume":"44","author":"Tsiouris","year":"2015","journal-title":"Avian Pathol."},{"key":"B31","doi-asserted-by":"publisher","first-page":"769","DOI":"10.3945\/jn.110.135657","article-title":"Regulation of tight junction permeability by intestinal bacteria and dietary components1,2.","volume":"141","author":"Ulluwishewa","year":"2011","journal-title":"J. Nutr."},{"key":"B32","doi-asserted-by":"publisher","first-page":"1322","DOI":"10.1080\/10495398.2021.1898413","article-title":"Effect of stocking density on performance, meat quality and cecal bacterial communities of yellow feather broilers.","volume":"33","author":"Wang","year":"2022","journal-title":"Anim. Biotechnol."},{"key":"B33","doi-asserted-by":"publisher","first-page":"158","DOI":"10.1080\/19490976.2019.1674124","article-title":"Diversification of host bile acids by members of the gut microbiota.","volume":"11","author":"Winston","year":"2020","journal-title":"Gut Microbes"},{"key":"B34","doi-asserted-by":"publisher","first-page":"102829","DOI":"10.1016\/j.psj.2023.102829","article-title":"Effects of different stocking densities on organ development, blood biochemical indices, and antioxidative status of breeder pigeons during the rearing period.","volume":"102","author":"Xie","year":"2023","journal-title":"Poultry Sci."}],"container-title":["Frontiers in Microbiology"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fmicb.2025.1542059\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,2,25]],"date-time":"2025-02-25T16:18:30Z","timestamp":1740500310000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fmicb.2025.1542059\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,2,25]]},"references-count":34,"alternative-id":["10.3389\/fmicb.2025.1542059"],"URL":"https:\/\/doi.org\/10.3389\/fmicb.2025.1542059","relation":{},"ISSN":["1664-302X"],"issn-type":[{"value":"1664-302X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,2,25]]},"article-number":"1542059"}}