Frontiers in Veterinary Science最新文献

{"title":"Study on the skin structure, hair follicle cycle, and GSDMA protein expression in Ganxi goats.","authors":"Xue Yang, Dengxiang Ji, Caiyan Wen, He Chen, Zhangyong Jin, Luyun He, Lucheng Zheng, Ben Liu, Qingcan Fan, Wei Hu, Wenya Zheng, Qianqian Wang, Yan Hu","doi":"10.3389/fvets.2025.1661505","DOIUrl":"https://doi.org/10.3389/fvets.2025.1661505","url":null,"abstract":"<p><strong>Introduction: </strong>The Ganxi goat, a native Chinese breed inhabiting the hot and humid regions of western Jiangxi Province, displays notable adaptability to local climatic stress. This study aimed to investigate the morphological structure, hair follicle cycling pattern, and GSDMA protein expression in the skin of Ganxi goats, to elucidate the potential mechanisms underlying their environmental adaptation.</p><p><strong>Methods: </strong>Using histological (H&E, Sacpic, and melanin staining), immunohistochemical (Ki67 and GSDMA), and Western blotting techniques, we conducted a year-long analysis of skin samples from ten 6-month-old female Ganxi goats.</p><p><strong>Results: </strong>Results showed that total skin thickness ranged from 1,118 to 2088 μm, and epidermal thickness from 12 to 28 μm, with regional variation. Primary hair follicle depth averaged 1,056 μm. Hair follicle groups exhibited a typical trimeric structure, but were looser than in other goat breeds, with less-developed connective tissue sheaths, wider inter-follicular spaces, and well-developed sweat glands. Melanin was mainly localized in hair bulbs and outer root sheaths. Ki67-positive cells were concentrated in hair matrix regions. These structural features suggest that Ganxi goat skin is morphologically adapted to hot and humid environments. The secondary hair follicle cycle was divided into four phases: anagen (October-February), late anagen (March), catagen (April-August), and telogen (September). Ki67-positive cells were mainly located in the hair matrix, outer root sheath, and sebaceous glands, indicating active cell proliferation. Melanin was primarily distributed in the hair bulb and outer root sheath, but absent in the epidermis. GSDMA protein was cytoplasmically expressed in the epidermis, hair follicles, and sebaceous glands, with its level peaking in late anagen and decreasing through catagen and telogen phases.</p><p><strong>Discussion: </strong>These findings highlight the structural and molecular adaptations of Ganxi goat skin to hot and humid environments and suggest that GSDMA may be involved in regulating the hair follicle cycle and maintaining skin homeostasis, and that further functional studies are required to establish a direct role in environmental adaptation.</p>","PeriodicalId":12772,"journal":{"name":"Frontiers in Veterinary Science","volume":"12 ","pages":"1661505"},"PeriodicalIF":2.9,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12498022/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145244272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Traditional Chinese medicine and plant-derived bioactive compounds as sustainable alternatives to antibiotics in bovine mastitis: a review.","authors":"Xuewei Fan, Abdul Qadeer, Mohammed Asiri, Fuad M Alzahrani, Khalid J Alzahrani, Khalaf F Alsharif, Muhammad Zahoor Khan, Xin Jiang","doi":"10.3389/fvets.2025.1642647","DOIUrl":"https://doi.org/10.3389/fvets.2025.1642647","url":null,"abstract":"<p><p>Bovine mastitis, an inflammatory condition of the mammary glands caused by diverse etiological agents, represents a significant economic challenge to the global dairy industry, resulting in annual losses of approximately $35 billion. While antibiotic therapy remains the conventional intervention for both prophylaxis and treatment, the increasing prevalence of antimicrobial resistance (AMR), particularly the emergence of multidrug-resistant and methicillin-resistant strains, has compromised therapeutic efficacy. These developments pose substantial concerns regarding milk safety and public health implications. Consequently, research attention has shifted toward alternative therapeutic modalities, encompassing phytotherapeutic interventions, nutritional modifications, and traditional Chinese medicine (TCM). Numerous plant species demonstrate significant antimicrobial properties while maintaining favorable safety profiles for humans, animals, and ecological systems. Complementary therapeutic approaches, including acupuncture and traditional herbal formulations, have exhibited promising potential in enhancing treatment outcomes and improving milk quality parameters. This review synthesizes current evidence on the integration of traditional Chinese medicine and plant-derived bioactive compounds into sustainable, holistic strategies for mastitis management, with implications for animal welfare, economic sustainability, and public health safety.</p>","PeriodicalId":12772,"journal":{"name":"Frontiers in Veterinary Science","volume":"12 ","pages":"1642647"},"PeriodicalIF":2.9,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12498554/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145244267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A newly discovered sRNA is involved in the virulence regulation of <i>Salmonella pullorum</i>.","authors":"Ting He, Meiling Huang, Yuling Sun, Yonghui Ding, Nanlong Zhou, Meihong Fu, Tiansen Li","doi":"10.3389/fvets.2025.1651294","DOIUrl":"https://doi.org/10.3389/fvets.2025.1651294","url":null,"abstract":"<p><strong>Background: </strong><i>Salmonella pullorum</i>, the primary pathogen responsible for avian pullorum disease, has imposed substantial economic losses on the poultry industry. sRNAs, a class of small non-coding RNAs, have been identified in numerous bacterial species and serve as pivotal regulatory factors in bacteria.</p><p><strong>Methods: </strong>A bacterial infection assay was conducted to detect the differential transcription levels of sRNA12 in the macrophage cell HD11. Environmental stress tests, intracellular survival assays, target gene transcription analyses and chick virulence tests were conducted to compare the wild-type strain and the ΔsRNA12 deletion strain.</p><p><strong>Results: </strong>A significant 7.5-fold increase in the transcription level of sRNA12 was observed during the invasion of host cells by bacteria. Under hyperosmotic conditions, the survival ability of the deletion strain was markedly reduced, while in a highly oxidative environment, it was significantly enhanced. Compared with the wild-type strain, the colonization ability of the ΔsRNA12 deletion strain in HD11 cells was enhanced by 3.5-fold. The transcription levels of most target genes of sRNA12, such as <i>ompD</i>, <i>siiE</i>, and <i>prgH</i>, were significantly upregulated. The LD₅₀ of the deletion strain in chicks was approximately three times lower than that of the wild-type strain. Moreover, the colonization abilities of the deletion strain in the liver, spleen, and cecum of chicks were significantly enhanced and it induced more severe organ lesions.</p><p><strong>Conclusion: </strong>The findings suggest that the deletion of sRNA12 enhances the virulence of <i>S. pullorum</i>. This research provides novel insights into elucidating the pathogenic mechanism of <i>S. pullorum</i> and the associated regulatory signaling pathways.</p>","PeriodicalId":12772,"journal":{"name":"Frontiers in Veterinary Science","volume":"12 ","pages":"1651294"},"PeriodicalIF":2.9,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12498021/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145244343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Osteosarcoma of the appendicular skeleton in dogs: consensus and guidelines.","authors":"Gerry Polton, Juan F Borrego, Francisco Clemente-Vicario, Craig A Clifford, Dariusz Jagielski, Martin Kessler, Tetsuya Kobayashi, Didier Lanore, Felisbina L Queiroga, Lucas Rodrigues, Annika Tranaeus Rowe, Péter Vajdovich, Philip J Bergman","doi":"10.3389/fvets.2025.1633593","DOIUrl":"https://doi.org/10.3389/fvets.2025.1633593","url":null,"abstract":"<p><p>Osteosarcoma (OSA) in dogs poses a clinical challenge to veterinary practitioners across the globe. As knowledge evolves, so too do clinical practices. However, there remain uncertainties and controversies. There is value for the veterinary community at large in the generation of a contemporary wide-ranging guideline document. The aim of this project was therefore to assimilate the available published knowledge into a single accessible referenced resource and to provide expert clinical guidance to support professional colleagues as they navigate current OSA challenges and controversies. Primary bone tumors are common in dogs. The history and clinical signs relate to the anatomic site of the tumor. Most canine patients present with a sudden-onset lameness that can appear to improve temporarily in response to analgesia and rest. Most patients do not have detectable metastasis at the time of diagnosis, but most canine patients do develop metastasis within months without appropriate therapy. Surgical resection using wide margins is currently the mainstay of therapy for the local control of the primary tumor. Most commonly, this comprises limb amputation in dogs, but not all dogs are considered good candidates. Anti-metastatic therapy is vital in dogs if surgery is going to offer a good chance of achieving a durable benefit. While there are many limb-sparing and palliative therapy options for dogs with OSA, most have not been shown to achieve superior outcomes compared with amputation and adjuvant chemotherapy. There is a role for radiotherapy in the palliative treatment of OSA. Immunotherapy should be considered a developing treatment modality-multiple immunotherapeutic approaches have yielded positive results in dogs in small experimental studies. It is hoped that this document will serve as a useful resource to practitioners all over the world, to help them better understand this disease and provide the best options for patients to extend quality of life and survival, either within the primary care or referral hospital setting.</p>","PeriodicalId":12772,"journal":{"name":"Frontiers in Veterinary Science","volume":"12 ","pages":"1633593"},"PeriodicalIF":2.9,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12498955/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145244275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fermented cottonseed meal improves production performance, immune function and intestinal microecological environment of laying hens and its nutritional properties.","authors":"Mingyang Xu, Jia Li, Wei Wang, Tongguo Gao, Caixuan Zhang, Zhimin Hao, Cheng Zhou","doi":"10.3389/fvets.2025.1622229","DOIUrl":"https://doi.org/10.3389/fvets.2025.1622229","url":null,"abstract":"<p><strong>Introduction: </strong>Global population growth and consumption upgrades have led to an increase in demand for animal feed protein sources, which has prompted an urgent need to find economical alternative protein sources. In this study, the potential of partially replacing traditional protein source soybean meal (SBM) with fermented cottonseed meal (FCSM) in practical applications were evaluated.</p><p><strong>Methods: </strong>The 180 24-week-old Hyland Brown laying hens were randomly divided into a control group (CON, fed SBM) and an experimental group (FCSM, fed FCSM). The effects of FCSM on the production performance, immune system, intestinal morphology and microbiota composition of laying hens were investigated. Furthermore, the enrichment of FCSM for characteristic nutrient metabolites and key pathways was further explored.</p><p><strong>Results: </strong>The feed-to-egg ratio and egg quality indexes (eggshell thickness, eggshell strength, albumen height and Haugh units) of laying hens in the FCSM group were significantly better than those of the CON group (<i>p</i> < 0.05). Additionally, splenic index, immunoglobulins (IgG, IgM and IgA) and albumin/globulin ratio were stable in the FCSM group. FCSM significantly increased the species richness of the gut flora as well as the beneficial bacteria such as <i>Rikenellace_ae_RC9_gut_</i>group and <i>Romboutsia</i> (<i>p</i> < 0.05). Non-targeted metabolomics analyses indicated that microbial solidstate fermentation technology increased the levels of nutrients in CSM, such as L-glutamine, ornithine, citrulline, and D-galactose.</p><p><strong>Conclusion: </strong>FCSM promoted the absorption of nutrients and intestinal health in laying hens by regulating the intestinal flora, demonstrating superior efficacy over BSM in overall production performance, immune function, and intestinal morphology. These findings provides a theoretical basis for the resource reuse in CSM and the precise nutrition of laying hens.</p>","PeriodicalId":12772,"journal":{"name":"Frontiers in Veterinary Science","volume":"12 ","pages":"1622229"},"PeriodicalIF":2.9,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12497634/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145244336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization of the gut microbiome in Wuhuang pigs and their crossbred offspring.","authors":"Zhijuan Yan, Yiting Yang, Xinghong Yu, Ziling Hao, Yong Du, Yan Wang, Yuanyuan Wu, Ye Zhao, Lili Niu, Xiaofeng Zhou, Linyuan Shen, Mailin Gan, Li Zhu","doi":"10.3389/fvets.2025.1668076","DOIUrl":"https://doi.org/10.3389/fvets.2025.1668076","url":null,"abstract":"<p><strong>Introduction: </strong>As an indigenous Chinese breed, Wuhuang pigs are valued for their stress resistance, tolerance to coarse feed, and high lean meat yield, while Berkshire pigs serve as ideal sires due to superior meat quality and early maturity. To explore the microbial basis of hybrid vigor in these breeds, we compared the gut microbiota of purebred Wuhuang pigs and Wuhuang-Berkshire hybrids.</p><p><strong>Methods: </strong>Microbial composition was assessed via 16S rDNA sequencing, and predictive functional profiling was performed using PICRUSt2 analysis.</p><p><strong>Results: </strong>Hybrids exhibited significantly increased microbial <i>α</i>-diversity and altered <i>β</i>-diversity. Notably, hybrid ceca were enriched with probiotic genera involved in fiber degradation and short-chain fatty acid (SCFA) production-such as Prevotella, Ruminococcus, Lachnospiraceae, and Roseburia-accompanied by a higher Firmicutes-to-Bacteroidetes ratio and strengthened microbial network connectivity. Predictive functional profiling further revealed significantly elevated activity in hybrid pigs for key metabolic pathways including tryptophan synthesis, pyridoxal salvage, and galacturonic acid metabolism (FDR < 0.05).</p><p><strong>Discussion: </strong>These results imply that hybrid animals leverage enriched probiotic consortia to augment nutrient metabolism and immune function, thereby supporting improved stress resilience and feed efficiency. This study provides potential microbial targets for the future genetic improvement of indigenous pig breeds.</p>","PeriodicalId":12772,"journal":{"name":"Frontiers in Veterinary Science","volume":"12 ","pages":"1668076"},"PeriodicalIF":2.9,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12497601/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145244287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of dietary Trollius chinensis Bunge residue supplementation on growth performance, antioxidant status, intestinal morphology, and cecal microbiota in weaned rabbits.","authors":"Lingcong Deng, Juan Fang, Jiayu Yu, Yu Dong, Kailong Han, Xue Yang, Dongliang Fei, Xibin Han, Mingxiao Ma, Jieying Bai","doi":"10.3389/fvets.2025.1640419","DOIUrl":"https://doi.org/10.3389/fvets.2025.1640419","url":null,"abstract":"<p><strong>Background and objective: </strong>Weaning stress can cause decreased immunity and intestinal flora imbalance, leading to diarrhea and even death of the rabbits. The present study aimed to investigate the benefits from Trollius chinensis Bunge residues (TCBR) on growth performance, antioxidant capacity, intestinal health and cecal microbiota in weaned rabbits.</p><p><strong>Methods: </strong>Through the ultra performance liquid chromatography (UPLC) technology, the main active ingredients from TCBR were analyzed. And then, 48 30-day-old rabbits were randomly allocated into 4 groups, with 12 replicates per group. Four diets were formulated with graded levels of TCBR: 2.0, 4.0, and 6.0% represented as TCBR2, TCBR4, and TCBR6 groups alongside a Mock group without TCBR.</p><p><strong>Results: </strong>Our results showed that TCBR2 significantly alleviated adverse clinical manifestations in weaned rabbits and improved survival rate, growth performance, and reduced the feed conversion ratio compared with the Mock group. TCBR2 also enhanced carcass yield, partial-eviscerated carcass yield, and antioxidant capacity, and increased jejunal villus height and villus/crypt ratio compared with that in the Mock group, whereas no differences were observed between the TCBR4 and TCBR6 groups. Furthermore, TCBR2 significantly increased the expression levels of Occludin and ZO-1 in jejunal tissue while reducing the expression levels of TNF-<i>α</i> and IL-8. Notably, 16S RNA analysis revealed that <i>Bacteroidota</i> levels were significantly elevated in the TCBR2 groups, with <i>Akkermansia</i>, <i>Clostridium</i>, and <i>Succiniclasticum</i> also up-regulated in the TCBR2 group.</p><p><strong>Conclusion: </strong>TCBR2 supplementation improved growth performance and attenuated adverse clinical symptoms in rabbits, suggesting the potential of low-dose TCBR as a feed additive.</p>","PeriodicalId":12772,"journal":{"name":"Frontiers in Veterinary Science","volume":"12 ","pages":"1640419"},"PeriodicalIF":2.9,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12491828/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145232214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deep learning framework for vertebral heart size and cardiothoracic ratio estimation in dogs and cats using thoracic radiographs.","authors":"Habtamu Tilahun Mekonnen, Núria Puig, Alejandro Elson, Elena López, Paula Martínez, Selene Campos, Francisco Hernández, Daniel Mayor, Jorge Quilis, Xavier Cufí, Jordi Freixenet, Arnau Oliver, Xavier Lladó, Robert Martí","doi":"10.3389/fvets.2025.1612338","DOIUrl":"https://doi.org/10.3389/fvets.2025.1612338","url":null,"abstract":"<p><strong>Introduction: </strong>Heart disease is a major cause of mortality in aging dogs and cats, with cardiomegaly being the most frequent radiographic finding. While deep learning methods have shown potential in detecting and quantifying cardiomegaly, their integration into clinical veterinary practice remains limited due to challenges in interpretability and workflow alignment.</p><p><strong>Methods: </strong>We developed a deep learning framework for the automatic estimation of Vertebral Heart Size (VHS) and Cardiothoracic Ratio (CTR) from thoracic radiographs of dogs and cats. A diverse dataset collected from two veterinary institutions was used. Segmentation of cardiac and thoracic anatomical regions was performed using Mask R-CNN, followed by automatic measurement of VHS and CTR. Model performance was evaluated against expert radiologist annotations.</p><p><strong>Results: </strong>The proposed framework demonstrated strong agreement with manual evaluations. Pearson correlation coefficients reached 0.922 for VHS and 0.933 for CTR, with regression slopes close to unity and minimal intercepts. The method was validated on both lateral and ventrodorsal projections, confirming its versatility across common clinical views.</p><p><strong>Discussion/conclusion: </strong>This work introduces an automated, robust approach for cardiac size assessment in dogs and cats. By supporting objective and reproducible measurements of VHS and CTR, the framework has potential to aid in the early detection and monitoring of heart disease, particularly in veterinary settings with limited access to specialized radiology expertise.</p>","PeriodicalId":12772,"journal":{"name":"Frontiers in Veterinary Science","volume":"12 ","pages":"1612338"},"PeriodicalIF":2.9,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12492017/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145232145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Case Report: Presumptive spinal embryonal tumor in a cat.","authors":"Marieke van den Heuvel, Quinten Van Koulil, Dorien Willems, Ines Carrera, Wilhelmina Bergmann, Daniel R Rissi, Koen M Santifort","doi":"10.3389/fvets.2025.1633279","DOIUrl":"https://doi.org/10.3389/fvets.2025.1633279","url":null,"abstract":"","PeriodicalId":12772,"journal":{"name":"Frontiers in Veterinary Science","volume":"12 ","pages":"1633279"},"PeriodicalIF":2.9,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12492636/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145232196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mapping the spread of fluoroquinolone resistance: continued presence of non-susceptible <i>Escherichia coli</i> in broilers.","authors":"Moniek Ringenier, Filip Boyen, Bert Bogaerts, Mathieu Gand, Kevin Vanneste, Sigrid C J De Keersmaecker, Ilias Chantziaras, Nelima Ibrahim, Mathias Devreese, Jeroen Dewulf","doi":"10.3389/fvets.2025.1610997","DOIUrl":"https://doi.org/10.3389/fvets.2025.1610997","url":null,"abstract":"<p><strong>Introduction: </strong>Sustained resistance against fluoroquinolones (FQ), without the use of FQ in broilers, raises important questions about other possible factors contributing to the persistence in farms. Therefore, the current study investigates the prevalence of FQ non-susceptibility in <i>Escherichia coli</i> on broiler farms and examines the roles of day-old chicks, the farm environment, and the antimicrobial use (AMU) in the dynamics of the within-flock spread.</p><p><strong>Methods: </strong>On 29 Belgian broiler farms, AMU was monitored, while environmental and day-old chick intestinal samples (day 0) were collected before their arrival. On days 3 and 36 of the production round, 30 cloacal swabs were taken per farm. In all samples, total <i>E. coli</i> and FQ non susceptible <i>E. coli</i> isolates were quantified by non-selective and FQ selective isolation. A selection of the isolates was analyzed using whole-genome sequencing to characterize their resistance and virulence-associated determinants and to investigate their phylogenetic relatedness using core-genome multi-locus sequence typing (cgMLST) and whole-genome single-nucleotide polymorphism (SNP) analysis.</p><p><strong>Results: </strong>Before entering the stable, day-old chicks carried FQ non-susceptible <i>E. coli</i> on 79.3% of the farms, while FQ non-susceptible <i>E. coli</i> were found in 48.3% of the sampled environments. According to cgMLST, identical FQ non-susceptible isolates were found on day 0 and 36, suggesting that FQ non-susceptible isolates present in the environment at the start of a production round or in day-old chicks, can remain present until slaughter, even when no FQs were used. Total AMU was positively correlated with the proportion of FQ non-susceptible <i>E. coli</i> [<i>r</i> = 0.42, 95% CI (0.06, 0.68), <i>p</i> = 0.03], often also multidrug-resistant, at the end of the production cycle.</p><p><strong>Conclusion: </strong>The continued presence of FQ non-susceptible <i>E. coli</i> in broiler farms is likely the result of both a historical contamination at the farm level and a continuous influx along the production chain. AMU contributes to the continued presence of FQ non-susceptible <i>E. coli</i> in broiler farms, but accounted for only a small proportion of the variability in FQ non-susceptibility in currently investigated farms. The role of certain virulence-associated genes in the persistence of FQ non-susceptible <i>E. coli</i> in broiler farms deserves more in-depth research.</p>","PeriodicalId":12772,"journal":{"name":"Frontiers in Veterinary Science","volume":"12 ","pages":"1610997"},"PeriodicalIF":2.9,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12491820/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145232320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}