Avian Pathology最新文献

{"title":"Evolution of Newcastle disease virus subgenotype VII.1.1 in Iran, 2017-2024.","authors":"Fereshteh Sabouri, Tae-Hyeon Kim, Mohammad Abdoshah, Andrew Y Cho, Mohammad Hossein Fallah Mehrabadi, Sun-Hak Lee, Chang-Seon Song, Dong-Hun Lee, Mohsen Bashashati","doi":"10.1080/03079457.2025.2585135","DOIUrl":"10.1080/03079457.2025.2585135","url":null,"abstract":"<p><p>Newcastle disease (ND), caused by Newcastle disease virus (NDV), has posed a continuous threat to Iran's poultry industry since its first detection in the early 1950s, with subgenotype VII.1.1 currently recognized as the dominant circulating strain. To gain deeper insights into the evolutionary dynamics of NDV in Iran, we performed genome sequencing and phylogenetic analysis on 60 viruses isolated from domestic poultry and wild birds between 2017 and 2024. Maximum likelihood and Bayesian phylogenetic analyses of the fusion (F) and haemagglutinin-neuraminidase (HN) genes revealed that all viruses belong to subgenotype VII.1.1, forming a well-supported monophyletic group, indicative of independent evolution of this subgenotype within Iran after its introduction. The F and HN genes displayed high sequence identities of over 97% and 93%, respectively. All viruses contained a polybasic cleavage site in the F gene (R-R-Q/K-K-R↓F), consistent with virulent NDV strains. The estimated evolutionary rates for the F and HN genes were 1.31 × 10^-3 and 9.62 × 10^-4 substitutions/site/year, respectively. The most recent common ancestor of the subgenotype VII.1.1 F gene was dated to 2007 (95% highest posterior density: 2005-2009), likely originating from the Middle East. Bayesian skyride analysis showed an exponential increase in viral diversity between 2020 and 2024. Continuous surveillance of NDV in both poultry and wild birds in Iran is essential to track ongoing viral evolution, monitor potential changes in virulence or transmissibility, and identify emerging threats to poultry health and production.</p>","PeriodicalId":8788,"journal":{"name":"Avian Pathology","volume":" ","pages":"171-182"},"PeriodicalIF":2.2,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145430365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"HSP90α promotes fowl adenovirus serotype 4 replication in LMH cells via interacting with hexon.","authors":"Saimin Zhai, Xiaozhan Zhang, Keying Liu, Huichao Gao, Linyang Yu, Jianli Li, Xia Yang, Jun Zhao, Zeng Wang","doi":"10.1080/03079457.2025.2611109","DOIUrl":"10.1080/03079457.2025.2611109","url":null,"abstract":"<p><p>Heat shock protein 90 alpha (HSP90α), a conservative chaperone protein, is closely involved in signal transduction and virus proliferation, but how it engages the lifecycle of fowl adenovirus serotype 4 (FAdV-4) remains unknown. Here, we demonstrated that the expression of HSP90α was significantly upregulated in Leghorn male hepatoma (LMH) cells infected with FAdV-4. Functional study revealed that overexpression of HSP90α promoted FAdV-4 replication <i>in vitro</i>, whereas knockdown of HSP90α exerted the opposite effect. Subsequently, co-immunoprecipitation (Co-IP) assay showed that HSP90α, particularly the truncated HSP90α variant encompassing amino acid residues 286-542, interacted with hexon protein of FAdV-4. These findings collectively identify HSP90α as a critical host factor that modulates FAdV-4 replication through direct interaction with the viral hexon protein (via its 286-542 amino acid domain), thereby providing novel insights into the molecular crosstalk between FAdV-4 and host cells.</p>","PeriodicalId":8788,"journal":{"name":"Avian Pathology","volume":" ","pages":"220-230"},"PeriodicalIF":2.2,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146017240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation regarding the occurrence of fowl adenovirus (FAdV) in dead-in-shell chicks and young broiler breeders in Sweden.","authors":"Ylva Lindgren, Mikael Berg, Eva Berndtson, Anna Birgersson, Anne-Lie Blomström, Helena Eriksson, Siamak Zohari, Désirée S Jansson","doi":"10.1080/03079457.2025.2572968","DOIUrl":"10.1080/03079457.2025.2572968","url":null,"abstract":"<p><p>This paper describes the investigation of the epidemiology of fowl adenoviruses (FAdVs) among fast-growing meat-type breeder parent chickens in Sweden, based on serology, PCR and partial genome sequencing of samples collected during rearing and egg production. Blood samples (<i>n</i> = 1910) from breeder flocks at 16 (79 flocks), 24 and 36 (52 flocks) weeks of age were analysed for FAdV antibodies. Ninety-four percent of the flocks had seroconverted at 16 weeks of age, and at 36 weeks of age all 52 flocks were seropositive. From 35 of these flocks, dead-in-shell chicks (DIS, <i>n</i> = 949) from eggs laid at 26-27 and 36-37 weeks of age were sampled, and pooled liver and caecal tonsils were analysed by PCR. Nucleic acid from FAdV was not detected. Negative PCR results were confirmed by testing tissues from 62 broiler breeders and 80 DIS from four additional seropositive flocks, collected at age 24-26 weeks. From six other breeder flocks, liver and caecal tonsils were sampled from one bird (when available) per day during rearing from 1-112 days of age. From 6 weeks of age, in 4/6 flocks, FAdV species A and/or D were detected by PCR and partial hexon gene sequencing. In conclusion, FAdVs were detected during rearing in breeder birds but not in DIS. This suggests that vertical transmission of FAdVs was prevented by immunity acquired early in life. However, it should be noted that high antibody titres in breeder birds does not necessarily confer protection against vertical transmission.<b>RESEARCH HIGHLIGHTS</b>The majority of 16-week-old parent flocks were seropositive to FAdV.FAdV was not detected by PCR in dead-in-shell chicks from seroconverted flocks.FAdV-A and D were detected in broiler breeders during rearing from 6 weeks of age.Results suggest that vertical spread was prevented by immunity in breeder birds.</p>","PeriodicalId":8788,"journal":{"name":"Avian Pathology","volume":" ","pages":"137-145"},"PeriodicalIF":2.2,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145257136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determination of immune responses in mucosal lymphoid tissues following infectious laryngotracheitis virus (ILTV) eye drop and vent brush vaccination of chickens.","authors":"Thanh Tien Tran, Nicholas M Andronicos, Natkunam Ketheesan, Shahid Nazir, Stephen W Walkden-Brown, Priscilla F Gerber","doi":"10.1080/03079457.2025.2584351","DOIUrl":"10.1080/03079457.2025.2584351","url":null,"abstract":"<p><p>Eye drop (ED) and vent brush (VB) application of live infectious laryngotracheitis virus (ILTV) vaccine provides protective immunity against disease, but little is known regarding the immune responses following application. This study compared the gene expression of immune markers associated with VB and ED ILTV vaccination in the conjunctiva, trachea and cloaca at 3, 5, 7 and 10 days post-vaccination (dpv) and 3, 5 and 7 days post-revaccination (dprv). The relative gene expression of markers associated with inflammatory responses and their regulation (CCL4, CCR5, IL2, IL4, IL6, IL17C, IFNG), pathogen recognition receptors (TLR2-2, TLR4, TLR7) and cell surface markers (CD4, CD8A, CD14, CD80) was evaluated by RT-PCR after ED or VB vaccination and revaccination using the alternate route (ED/VB (primary/booster), VB/ED). There was increased expression of inflammatory markers at vaccination sites following primary vaccination. In the VB group, there was increased expression of IL6 and IFNG in cloaca (3 dpv) and IL2 in the conjunctiva (7 dpv) compared to the ED group (<i>P</i> < 0.05), while there was increased CCL4 expression in conjunctiva (5 dpv) in the ED group compared to the VB group. ED vaccination was associated with increased expression of IL2 and IL17C in trachea while VB vaccination was associated with increased expression of IL6 and IL17C in trachea. Similarly, ED/VB- and VB/ED-associated increases in IL2, IL6 and IL17C expression were observed at the revaccination sites. In conclusion, immune responses after the first and second ILTV vaccination were site-specific and associated with inflammatory responses in the mucosa of the vaccinated tissues and trachea.<b>RESEARCH HIGHLIGHTS</b>ILTV vaccination elicited inflammatory responses at the vaccination sites (conjunctiva and cloaca).Conjunctival or cloacal vaccination elicited similar inflammatory responses in the trachea after 3 and 5 days, respectively.Revaccination by a different route stimulated similar immune responses in conjunctiva, cloaca and trachea.</p>","PeriodicalId":8788,"journal":{"name":"Avian Pathology","volume":" ","pages":"146-160"},"PeriodicalIF":2.2,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145430314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anatomopathological and molecular characterization of avian reovirus in broilers condemned due to arthritis in Southern Brazil.","authors":"Elizabeth Baggio Batista, Jéssica Aline Withoeft, Anna Laura De Oliveira Cunha, Stephane Reinhold Dal Molin, André Fonseca, Patricia Hoepers, Renata Assis Casagrande","doi":"10.1080/03079457.2025.2610378","DOIUrl":"10.1080/03079457.2025.2610378","url":null,"abstract":"<p><p>Condemnations in slaughterhouses are a recurring cause of losses for the poultry industry. This study aimed to evaluate the involvement of avian reovirus (ARV) in arthritis-related condemnations in a broiler slaughterhouse under Brazilian Federal Inspection. A total of 150 pelvic limbs condemned for arthritis were collected from the inspection line at the time of condemnation, originating from 30 flocks not vaccinated against ARV. For the detection of ARV, real-time polymerase chain reaction following reverse transcription (RT-qPCR) was performed on a pool of five gastrocnemius tendons from each flock using the primers ReoS-F1, ReoS-R1, ReoS-F2, and ReoS-R2, followed by Sanger sequencing of the σC gene. For macroscopic and histopathological analyses, the gastrocnemius, digital flexor, and extensor tendons, as well as the articular cartilage of the tibiotarsometatarsal joint, were evaluated. Injuries were classified into four degrees, ranging from G0 (no changes) to G3 (highest degree of injury). Macroscopic injury scores revealed a higher percentage of injuries in the gastrocnemius tendon compared to the extensor and flexor tendons. Histological changes were observed in the peritendon and muscles adjacent to the tendons, including infiltration of heterophils, macrophages, lymphocytes, plasma cells with lymphoid aggregates, haemorrhage, and fibrinous exudate in the gastrocnemius, flexor, and digital extensor tendons. ARV was detected in 50% of the flocks by RT-qPCR, with no correlation to increased arthritis condemnations (<i>P</i> > 0.05). The sequence analysis identified the cluster as lineage VI, a strain not present in Brazil's commercial vaccination programmes. The study concludes that half of the investigated flocks were positive for ARV, identifying a cluster absent in current Brazilian vaccination programmes.</p>","PeriodicalId":8788,"journal":{"name":"Avian Pathology","volume":" ","pages":"210-219"},"PeriodicalIF":2.2,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146059191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental model for the reproduction of necrotic enteritis in turkeys using different <i>Clostridium perfringens</i> strains.","authors":"B Cordioli, M Vereecken, I Drigo, M Garbuio, C Zanardello, L Gagliazzo, L Palazzolo, L Zandonà, A Rizzardi, M De Gussem, K De Gussem, L Bano","doi":"10.1080/03079457.2025.2594442","DOIUrl":"10.1080/03079457.2025.2594442","url":null,"abstract":"<p><p>Necrotic enteritis (NE) is a disease affecting poultry caused by virulence factors, primarily toxins, produced by <i>Clostridium perfringens</i> (Cp). Although NE is well documented in turkey flocks, only one study describes its pathogenesis suggesting a protocol for the induction of the disease. The aim of this study was to set up a challenge model for the experimental reproduction of NE in turkeys, in line with clinical signs currently observed in the field. To this purpose, the disease was induced based on the administration of some well-known predisposing factors for chicken (sudden switch to a high protein diet, coccidia) and challenging the birds with Cp strains with different genetic virulence factors isolated from chicken and turkey affected by NE. The predisposing factors were administered to three experimental groups (T02, T03, T04). In addition, groups T03 and T04 were challenged with Cp isolated from chicken or turkey, respectively. Group T01 served as the negative control. Clinical signs, gross pathology and histopathological lesions were scored and compared between groups. The challenge with the chicken Cp strain induced clinical manifestations of NE (80% mortality) and reproduced lesions both macroscopically and microscopically. In groups challenged with Cp, gross pathology revealed more severe lesions (<i>P</i> < 0.001) when compared to the group challenged with the predisposing factors only. Histopathologically, those findings were confirmed only in group T03 in the jejunum (<i>P</i> < 0.001). This experimental model will be useful to test the efficacy of control/preventive measures and to better understand the virulence factors involved in the pathogenesis of NE in turkeys.<b>RESEARCH HIGHLIGHTS</b>Not all <i>Clostridium perfringens</i> (Cp) strains can reproduce severe necrotic enteritis (NE) in turkeys.The developed NE reproduction model caused 80% mortality.A reliable NE reproduction model is crucial to investigate pathogenic Cp strains.</p>","PeriodicalId":8788,"journal":{"name":"Avian Pathology","volume":" ","pages":"183-192"},"PeriodicalIF":2.2,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145740465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of management and air quality conditions on development of respiratory and gastroenteric disease, and antibiotics phenotypic resistance in domestic canaries (<i>Serinus canaria domesticus</i>).","authors":"Tiziano Iemmi, Giovanna Zanardi, Roberto Ramoni, Alicia Maria Carrillo Heredero, Alice Prosperi, Valentina Ravaioli, Elisabetta Lilliu, Camilla Torreggiani, Simone Bertini","doi":"10.1080/03079457.2026.2623655","DOIUrl":"https://doi.org/10.1080/03079457.2026.2623655","url":null,"abstract":"<p><p>Air quality plays a crucial role in maintaining the health of birds housed in indoor facilities. This study evaluated the impact of environmental and air quality parameters on the health of domestic canaries (<i>Serinus canaria domesticus</i>) in 102 Italian flocks, classified according to disease prevalence: healthy (H) and diseased (D), with D further divided into respiratory (RD) and gastrointestinal (GID) disorders. Environmental indicators included particulate matter (PM), carbon dioxide (CO₂), formaldehyde (HCHO), total volatile organic compounds (TVOC), temperature (T°), relative humidity (RH) and bird stocking density (<i>n</i>/m³). These variables were analysed alongside clinical status, the presence of canary circovirus (CaCV) and polyomavirus (CaPyV), microbiological findings, and antimicrobial resistance patterns. Significantly higher PM and CO₂ concentrations were detected in RD flocks, supporting the role of poor air quality in respiratory disease onset. CaCV and CaPyV circulation were detected in 30.4% and 6.9% of flocks, respectively. Flocks positive for CaCV showed significantly higher CO₂ levels and bird stocking density, suggesting a link between inadequate environmental management and viral persistence. Microbiological analysis revealed widespread antimicrobial resistance: 60.8% of Gram-negative and 54.4% of Gram-positive isolates were multidrug resistant (MDR). Moreover, correlations between environmental parameters and resistance profiles were identified, though highly variable by microbial type and health status. Overall, these results emphasize that maintaining optimal air quality and environmental conditions is essential for preventing disease and limiting antimicrobial phenotypic resistance in canary breeding facilities.</p>","PeriodicalId":8788,"journal":{"name":"Avian Pathology","volume":" ","pages":"1-14"},"PeriodicalIF":2.2,"publicationDate":"2026-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147442321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A systematic review of the aetiology and presentation of stunting diseases in broiler chickens.","authors":"Shen-Yuan Hsieh, Pauline M Sheridan, Victoria J Smyth, Ilias Kyriazakis","doi":"10.1080/03079457.2026.2632916","DOIUrl":"10.1080/03079457.2026.2632916","url":null,"abstract":"<p><strong>Research highlights: </strong>Specificity of histological lesions is key to differentiating broiler stunting syndromes.Differences are seen in the peak age of occurrence of different stunting diseases.Virus co-infection may play a role in stunting and may cause mixed stunted cases.</p>","PeriodicalId":8788,"journal":{"name":"Avian Pathology","volume":" ","pages":"1-17"},"PeriodicalIF":2.2,"publicationDate":"2026-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147269735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Protection against HPAI-H5N8 early challenge in commercial broilers with maternal immunity: prime-boost vs. single vaccination of a trivalent H5-inactivated vaccine.","authors":"Wael M K Elfeil, Marwa Safwat, Mohamed A Abaza, Ahmed R Elbestawy, Eslam Arafa, Manal Afify, Magdy F Elkady, Walid H Kilany","doi":"10.1080/03079457.2025.2603919","DOIUrl":"10.1080/03079457.2025.2603919","url":null,"abstract":"<p><p>HPAI viruses, especially the newly discovered H5N8 clade 2.3.4.4 strain, are the world's biggest concern. The HPAI virus challenge in broilers is a significant issue, especially for short-lived commercial broiler chickens. This study examined H5 inactivated vaccine regimens. Phylogenetic analysis was used to compare the genetic sequences of vaccination seeds, the challenge virus (H5N8 clade 2.3.4.4 strain), and the circulating HPAI H5N8 strain. Following this, a field investigation evaluated various vaccination schedules using the H5 inactivated vaccine against the HPAI virus in early-challenged commercial broilers with maternal immunity against the AIV-H5N8 virus. Three vaccination regimens were planned: a prime-boost regimen (days 1 and 9) in group 1 (G1), a single dose 1.5 times the manufacturer-recommended dosage on day 7 in G2, and the routinely recommended single dose on day 7 in G3. Weekly AI-H5 humoral immune response antibody titres were measured. Both vaccinated and unvaccinated positive controls were challenged with HPAI H5N8 virus clade 2.3.4.4b on day 28 of age. Clinical signs, survival, and virus shedding were monitored for 10 days post-challenge. After three weeks post-vaccination (WPV), prime-boost antibody titres were significantly higher than those in single-dose groups. After the challenge, G2 and G3 had high survival rates (91.7%) but a noticeably high shedding rate following the early challenge (3 WPV), while G1 had 100% survival and negligible viral shedding. HPAI H5N8 virus protection increased with prime-boost vaccination in early challenge. These findings highlight the importance of implementing optimal vaccination programmes to mitigate HPAI virus risks in commercial chicken production.<b>RESEARCH HIGHLIGHTS</b>A phylogenetic study has proven vaccine genetic match with circulating H5N8 strains.Prime-boost vaccine regimen provided 100% survival in H5N8-challenged broilers.Enhanced immunity observed in prime-boost groups, with minimal viral shedding.Single-dose groups achieved 91.7% survival and showed higher viral shedding.</p>","PeriodicalId":8788,"journal":{"name":"Avian Pathology","volume":" ","pages":"1-8"},"PeriodicalIF":2.2,"publicationDate":"2026-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145755143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Competitive exclusion strategies utilizing healthy caecal microbiota impair <i>Salmonella enterica</i> serovars colonization in broilers.","authors":"Isis M M Kolososki, Valdinete P Benevides, Heitor L S Rodrigues, Viviane A Ferreira, André L C Rabelo, Murilo C B Santos, Túlio S Lima, Isabella C Campos, Adriana M Almeida, Rafaela L Carvalho, Melissa F F Dix, Thais A Codognotto, Angelo Berchieri Junior, Mauro M S Saraiva","doi":"10.1080/03079457.2026.2630671","DOIUrl":"https://doi.org/10.1080/03079457.2026.2630671","url":null,"abstract":"<p><p>Avian non-typhoidal <i>Salmonella</i> (NTS) is the second most prevalent foodborne zoonotic pathogen worldwide, which is transmitted through poultry products. Human-infecting serovars exhibit genotypic and phenotypic diversity, which affect bacterial virulence, such as susceptibility to antimicrobial drugs. The emergence of antimicrobial-resistant strains further reduces treatment efficacy, underscoring the need for alternatives in food-producing animals. One promising strategy is the use of competitive exclusion (CE) products, formulated with naturally occurring microorganisms derived from the gut microbiota of healthy adult birds. Although this approach has shown proven efficacy in controlling <i>Salmonella</i>, its application is still limited, primarily due to the incomplete understanding of the specific interactions among pathogen, host, and microbiota. Considering this scenario, we compared three CE products formulated under distinct conditions (aerobic, anaerobic, and a combination of both), being administered to newly hatched broiler chicks before challenging them with <i>Salmonella</i> Typhimurium (STM) or <i>Salmonella</i> Enteritidis (SE), evaluating faecal excretion and caecal colonization. Regarding caecal colonization, the combined formulation conferred the greatest reduction in STM-challenged birds, whereas the aerobic formulation conferred better reduction in SE-challenged birds. Bacterial adhesion factors, mainly associated with <i>Salmonella</i> Pathogenicity Island 10 (SPI-10), were also identified in the SE genome and may have contributed to the observed differences in outcomes. These findings suggest that CE products have the potential to aid in controlling <i>Salmonella</i> spp. in poultry production. Still, their effectiveness likely depends on pathogen virulence factors and the dynamics of the intestinal microbiota.</p>","PeriodicalId":8788,"journal":{"name":"Avian Pathology","volume":" ","pages":"1-10"},"PeriodicalIF":2.2,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147353633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}