Avian diseases最新文献

{"title":"Note from Editor.","authors":"Randall Singer","doi":"10.1637/0005-2086-70.1.1","DOIUrl":"https://doi.org/10.1637/0005-2086-70.1.1","url":null,"abstract":"","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"70 1","pages":"1"},"PeriodicalIF":1.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147680087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of Quercetin and Thyme Oil Effect on Oxidative Stress Biomarkers and mRNA Expressions of Interleukin 6, 2, and 16 During <i>Eimeria tenella</i> Infection.","authors":"Rania A Mohamed, Haytham A Ali, Gamal A Salem, Ashraf Hussein","doi":"10.1637/aviandiseases-D-25-00048","DOIUrl":"10.1637/aviandiseases-D-25-00048","url":null,"abstract":"<p><p>Coccidiosis is a protozoan disease that causes serious economic losses annually worldwide. This study evaluated thyme oil and quercetin as natural anticoccidial treatments in broiler chickens experimentally infected with <i>Eimeria tenella</i>. In total, 450 one-day-old Hubbard broiler chicks were allocated into 10 groups. On the eighth day of age, five groups remained uninfected: a negative control group (-ve) and early-treated and late-treated groups treated with thyme oil or quercetin. The other five groups were infected with <i>E. tenella</i>: a positive control group (+ve) and early-treated and late-treated groups treated with thyme oil or quercetin. The clinical signs, parasitologic findings, oxidative stress biomarkers, and the relative expressions of interleukins 2, 6, and 16 were evaluated on the sixth, 11th, and 16th days postinfection (dpi). The infection induced bloody diarrhea, weight loss, and high lesion scores in +ve controls, while the infected, thymol-treated (ITE) group yielded the best clinical recovery, lowest lesion scores, and highest weight gain among infected groups. Oocyst shedding peaked at 8 dpi but was significantly reduced in early-treated groups, particularly ITE. Oxidative stress biomarkers and interleukin relative expressions were significantly altered, with early treatment improving antioxidant status and modulating immune responses. In conclusion, the results recommend the early administration of either thyme oil or quercetin to improve the productivity, oxidative stress, and birds' immune response against <i>Eimeria</i> infection.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"70 1","pages":"2-11"},"PeriodicalIF":1.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147679924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correlation Between Avian Pathogenic <i>Clostridium perfringens</i> Spore Load and Occurrence of Necrotic Enteritis on Broiler Chicken Farms.","authors":"Sydney R Kinstler, Margie D Lee, Eric A Wong, Joel Cline, John J Maurer","doi":"10.1637/aviandiseases-D-25-00080","DOIUrl":"10.1637/aviandiseases-D-25-00080","url":null,"abstract":"<p><p>Necrotic enteritis (NE) is a significant intestinal disease in poultry caused by the spore-forming, obligate anaerobe <i>Clostridium perfringens</i>. Historically, antimicrobials have controlled NE but growing concerns over antibiotic resistance have led to reduced use, resulting in disease resurgence. <i>Clostridium perfringens</i> spores persist in poultry environments, and their accumulation is believed to contribute to NE outbreaks. However, tools to assess spore load and predict outbreak risk are limited. To address this, a selective egg yolk agar medium was developed using potassium chlorate to inhibit aerobic bacteria, combined with heat treatment to enumerate <i>C. perfringens</i> spores in poultry litter. Matrix-assisted laser desorption-ionization time of flight mass spectrometry confirmed that 80% of lecithinase-positive colonies on chlorate-supplemented agar were <i>C. perfringens</i>. When comparing reinforced <i>Clostridium</i> agar and <i>Clostridium perfringens</i> agar (CPA) as bases, chlorate did not significantly reduce lecithinase-positive aerobes. Ninety-nine percent of lecithinase-positive black colonies on CPA were strict anaerobes, and 85% were confirmed as <i>C. perfringens</i> by PCR. A significant correlation (χ² test; <i>P</i> < 0.05) was observed between spore abundance in litter and a farm's NE history. However, spore abundance did not correlate with increased sporulation efficiency in <i>C. perfringens</i> isolates (<i>P</i> = 0.86). Notably, the presence of <i>netB</i>-positive <i>C. perfringens</i> was strongly associated with prior NE outbreaks (<i>P</i> < 0.01). This study demonstrated CPA-based egg yolk agar as an effective diagnostic medium for detecting <i>C. perfringens</i> in poultry litter.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"70 1","pages":"124-132"},"PeriodicalIF":1.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147679934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study of the Protective Effects of Baihu Decoction on Heat-Stressed Laying Hens on the Basis of Metabolomics Analysis.","authors":"Shuya Xu, Lihong Li, Lijie Zuo, Xianghui Li, Yingying Mei","doi":"10.1637/aviandiseases-D-25-00023","DOIUrl":"10.1637/aviandiseases-D-25-00023","url":null,"abstract":"<p><p>This study aimed to investigate the effects of dietary supplementation with Baihu decoction (BHD) on serum antioxidant indices and plasma metabolomic profiles in heat-stressed laying hens. One hundred eighty Hy-Line Brown laying hens were randomly divided into three groups. The normal control (NC) group and the heat stress (HS) group were fed with the basal diets, whereas the BHD group was supplemented with 0.75% BHD dry powder in the basal diet. The NC hens were kept at 26 ± 1 C, whereas HS and BHD groups' temperatures were raised to 32 ± 1 C on day 14. At the end of the experiment, blood samples were collected to assess antioxidant indices. The metabolic mass spectra were then analyzed using liquid chromatography-mass spectrometry. The results indicated that 1) heat exposure significantly decreased serum catalase (CAT) and superoxide dismutase (SOD) activities and increased malondialdehyde (MDA) levels compared with the NC group. BHD supplementation significantly restored CAT and SOD activities and reduced MDA content toward normal levels. 2) Plasma metabolomics identified 26 differentially expressed metabolites, among which 17 were potentially associated with BHD's protective effects. Enrichment analysis revealed significant alterations in several metabolic pathways, including Val, Leu, and Ile biosynthesis. These findings suggest that BHD alleviates HS by modulating antioxidant capacity and key metabolic pathways, providing new insights into the physiologic mechanisms underlying BHD's protective role from a metabolomic perspective.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"70 1","pages":"82-90"},"PeriodicalIF":1.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147680105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Immunohistochemical Detection of Serum Amyloid A-Derived Amyloid Deposits in Poultry Using a Synthetic Peptide-Based Antibody.","authors":"Aoi Kurokawa, Yu Yamamoto, Aya Terao, Shun Ishizuka","doi":"10.1637/aviandiseases-D-25-00101","DOIUrl":"10.1637/aviandiseases-D-25-00101","url":null,"abstract":"<p><p>Avian amyloidosis, mostly caused by the abnormal deposition of amyloid fibrils derived from serum amyloid A (SAA), is histologically diagnosed through the morphological identification of eosinophilic amyloid deposits in tissues. Congo red staining is a popular special staining method for detecting amyloid; however, immunohistochemical staining would allow precise identification and confirmation of SAA-derived amyloid by targeting its protein composition. The purpose of this study was to establish an immunohistochemical method for detecting amyloid deposits in poultry. A rabbit polyclonal antibody was generated against a synthetic peptide corresponding to the C-terminal region of chicken SAA. Immunohistochemistry was performed to detect amyloid deposits in six poultry species: chicken (<i>Gallus gallus</i>), helmeted guinea fowl (<i>Numida meleagris</i>), Japanese quail (<i>Coturnix coturnix</i>), mallard duck (<i>Anas platyrhynchos</i>), Muscovy duck (<i>Cairina moschata</i>), and turkey (<i>Meleagris gallopavo</i>). Positive signals of immunohistochemistry corresponded to histologically observed eosinophilic materials and Congo red-positive areas in all species. Our results indicate that the synthetic peptide-based antibody developed in the study is effective for detecting amyloid deposits in common poultry.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"70 1","pages":"112-116"},"PeriodicalIF":1.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147680111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular Characterization and Detection of <i>Brachyspira pilosicoli</i> Associated with Intestinal Dysbiosis of Layer Chickens on the Indian Subcontinent.","authors":"K Vigneshkumar, V Gowthaman, T R Gopala Krishna Murthy, G A Balasubramaniam, A Arulmozhi, P Srinivasan, K G Tirumurugaan, A Alagesan, A Balakrishnan","doi":"10.1637/aviandiseases-D-25-00052","DOIUrl":"10.1637/aviandiseases-D-25-00052","url":null,"abstract":"<p><p>Avian intestinal spirochetosis, caused by <i>Brachyspira</i> species, significantly impacts chicken flocks worldwide, leading to economic losses due to mortality, reduced egg production, and lower-quality eggs. Despite India's substantial poultry population, the importance of <i>Brachyspira</i> has been overlooked. This study investigated the significance of <i>Brachyspira</i> spp. in layer chicken flocks in India. This is a primary report to determine the incidence of <i>Brachyspira pilosicoli</i> from layer flocks in the country. The study sampled 25 layer chicken farms between March and December 2023 from which 250 cecal swabs were processed for <i>Brachyspira</i> isolation, molecular confirmation made using PCR and its phylogenetic analysis. The results showed that two out of 25 farms were positive for <i>B. pilosicoli</i> by culture and PCR. The positive flocks, aged between 50 and 72 wk, reared in a cage system in open-sided houses. The litter conditions were semisolid, with an abnormal odor and brownish color, indicating dysbiotic changes. The affected flocks experienced a drop in egg production of up to 12%-15%, fecal-stained eggs up to 0.4%-0.6%, and pasty vents and mortality rates of 1.5% and 5.7%, respectively. Postmortem examination revealed ballooning of the ceca with yellowish-light brown moist contents and inspissated, amorphous yolk material in the abdominal cavity. The histopathological examination of the cecum showed loss of villi and crypts along with infiltration of inflammatory cells. Sequencing and phylogenetic analysis showed 99.73% to 100% identity of the Indian <i>B. pilosicoli</i> sequences with the reference sequences from Australia, France, and the United States.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"70 1","pages":"42-46"},"PeriodicalIF":1.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147680093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Probiotic Prophylaxis for <i>Enterococcus cecorum</i> Prevalence in the Free Thoracic Vertebra of Broiler Chickens.","authors":"Matthew K Jones, Charles L Hofacre, M Mitsu Suyemoto, Enid T McKinley, Alexandra H Smith, Jodi Delago, Roy D Berghaus, Virginia A Baxter, John A Smith","doi":"10.1637/aviandiseases-D-25-00031","DOIUrl":"10.1637/aviandiseases-D-25-00031","url":null,"abstract":"<p><p><i>Enterococcus cecorum</i> has become a significant pathogen of broilers and broiler breeders worldwide, and there are few effective prevention, treatment, or control measures. Improved, preferably nonantibiotic tools are needed to control the disease. Two pen trials were conducted to assess the effectiveness of a day-of-age probiotic and a continuous direct fed microbial (DFM) in preventing colonization of the spleen and free thoracic vertebra after challenge with pathogenic <i>E. cecorum</i> in commercial broiler chickens. In Experiment 1, three treatment groups were administered either no treatment (challenge controls), a day-of-age probiotic gel plus DFM 1 continuously in the feed, or the probiotic plus DFM 2, and challenged orally on Day 0 with a known pathogenic strain of <i>E. cecorum</i> (SA3). Both treatments resulted in a significant decrease in prevalence of colonization of spleens and free thoracic vertebrae at Day 42 compared to the challenge controls, with no effects on performance parameters or total mortality. In Experiment 2, four treatment groups were administered either no treatment (challenge controls), the day-of-age probiotic gel alone, the probiotic gel plus DFM 1, or DFM 1 alone. At 42 days of age, both the probiotic alone and the probiotic plus DFM 1 resulted in a significant decrease in colonization of the free thoracic vertebrae compared to the challenge controls, with the DFM alone being statistically intermediate. There were no impacts on performance parameters, livability, or lameness compared to the challenge controls. These results suggest that the day-of-age probiotic and the DFM may be a useful tool in controlling enterococcal spondylitis, and further larger-scale trials are warranted to assess impacts on clinical signs and performance.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"70 1","pages":"91-98"},"PeriodicalIF":1.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147680103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Supplementation with Bee Antibacterial Peptides and Turmeric Essential Oil on Microbial Enumeration and Intestinal Integrity-Related Genes, Immunity, and Performance in Heat-Stressed Broilers.","authors":"Ahmed M Elbaz, Mohammed Al-Rasheed, Karima El-Naggar, Amin Tahoun, Ahmed Sabry Arafa, Mahmoud Kandeel, Hanem El-Sharkawy","doi":"10.1637/aviandiseases-D-25-00063","DOIUrl":"10.1637/aviandiseases-D-25-00063","url":null,"abstract":"<p><p>Heat stress (HS) is one of the many challenges facing the poultry industry. Many effective strategies reduce the harmful effects of HS on birds, the most important of which are feed additives due to their many beneficial properties. The present study investigated the effects of dietary supplementation with antibacterial peptides (melittin [MEL]) and turmeric essential oil on growth performance, cecum microbial content, immunity, and gene expression in heat-stressed broilers. The first experiment, a completely randomized design, used three levels of MEL (50, 100, and 150 mg kg ^-1), with five replicates of 10 chicks each. In the second experiment, a total of 600 one-day-old chicks were completely randomly distributed into five experimental groups. The five experimental groups included the following: the first group was fed a basal diet without feed additives or exposed to HS (the control group), the second group was fed a basal diet and exposed to HS without feed additives (COHS), while the other groups were exposed to HS and adding turmeric essential oil (TEO, 200 mg kg^-1), melittin (MEL, 150 mg kg^-1), and their mixture (MTC). Results of the first experiment indicated that body weight gain (1 to 28 days) increased linearly, while the feed conversion ratio decreased linearly (<i>P</i> < 0.05) with increasing MEL supplementation. In the second experiment, results indicated that dietary supplementation with MTC improved broilers' growth performance through lowering the feed conversion ratio and raising the body weight gain, and crude protein digestibility (<i>P</i> < 0.05). It also enhanced carcass characteristics (<i>P</i> < 0.05) by increasing carcass yield, breast meat, and thigh meat, while decreasing abdominal fat. Supplementing MTC boosted the immuno-antioxidant status by increasing IgA, IL-10, and superoxide dismutase levels (<i>P</i> < 0.05) and decreasing IL-6 and MDA levels. Additionally, MTC maintained intestinal integrity by increasing intestinal ZO-1 and MUC-2 gene expression (<i>P</i> < 0.05) and increasing <i>Lactobacillus</i> count. In conclusion, adding MTC mitigated the negative effects of HS by boosting growth performance and immune-antioxidant status, modifying intestinal microbiota, and up-regulating ZO-1 and MUC-2 gene expression in broiler chickens.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"70 1","pages":"12-22"},"PeriodicalIF":1.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147679880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluating the Effect of Acetylsalicylic Acid in Turkey Poults Experimentally Infected with Coccidia.","authors":"Aaliyah Gore, Pok Man Chan, James L Yeatts, Ronald E Baynes, Raveendra R Kulkarni, Rocio Crespo","doi":"10.1637/aviandiseases-D-25-00029","DOIUrl":"10.1637/aviandiseases-D-25-00029","url":null,"abstract":"<p><p>Acetylsalicylic acid (ASA), originally trademarked as Aspirin, is a common nonsteroidal anti-inflammatory drug (NSAID) used in human and veterinary medicine to mitigate pain and pyrexia caused by inflammatory processes. There is limited information on the effectiveness of ASA in turkey production. The objective of this study was to investigate the effect of ASA on turkey poults with induced coccidial enteritis. Two experimental trials were conducted. In both trials, the turkeys were divided into four groups: no coccidia + no ASA; no coccidia + ASA (NA); coccidia + no ASA (CN); and coccidia + ASA (CA). In both trials, turkeys in groups CN and CA were given 100× the dose of a commercial turkey coccida vaccine. Starting 48 hr postinoculation and for 7 days, the turkeys from groups NA and CA were given ASA (50 mg/kg per day). For Trial 1, ASA was given via oral gavage twice daily, whereas in Trial 2 (T2), ASA was in the drinking water. Poult weights and cloacal temperatures were recorded daily. Blood was collected daily from two randomly selected birds from each group for biochemical analysis and to assess the serum salicylic acid and nitric oxide (NO) levels. At the end of the trials, tissues were examined histologically, and immune gene expression was evaluated. Coccidia infection was the factor that had most significant influence on the majority of measured parameters. ASA had minimal to no effect on reducing clinical signs, minimizing weight loss, or controlling body temperature. These findings may be due to the rapid elimination of the drug or because sick birds did not consume sufficient ASA. In T2, it was estimated that the CA group poults consumed 31 mg/kg of ASA or less per day. Although the drinking water concentration was calculated to match the total daily intake (50 mg/kg per day), ASA's rapid metabolism meant that continuous low-level ingestion might not have reached the therapeutic plasma threshold achieved by two to three daily bolus doses. Because ASA is rapidly metabolized, a higher total daily dose may be required when provided in drinking water to maintain effective serum concentrations compared with bolus administration. Although the serum NO and tissue gene expression analysis showed that coccidia infection predominantly induces an inflammatory response, the anti-inflammatory effect of ASA administered to birds in the NA or CA groups were nil to minimal. This study highlights the complexity of ASA's effects on turkeys.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"70 1","pages":"99-111"},"PeriodicalIF":1.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147680041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of Vaccination Programs in Layer Pullets Using Recombinant Fowl-Pox <i>Mycoplasma gallisepticum</i> Vaccine in Comparison to Commercially Available F-Strain Live Vaccines.","authors":"Amro Hashish, Maria Chaves, Onyekachukwu Osemeke, Yuko Sato, Mohamed El-Gazzar","doi":"10.1637/aviandiseases-D-25-00005","DOIUrl":"10.1637/aviandiseases-D-25-00005","url":null,"abstract":"<p><p>Over the last few decades, recombinant vaccines have been increasingly used for disease control in commercial poultry production. This study assesses the efficacy of a recombinant fowl-pox virus-based vector vaccine (rFP-MG) in conferring protection against <i>Mycoplasma gallisepticum</i> (MG) in different prime-boost combinations with or without the live modified F-strain vaccine. Four different vaccination programs were evaluated using Hy-line W-36 layer pullets. Group 1 served as unvaccinated controls (<i>n</i> = 57). Group 2 (<i>n</i> = 30) received a single dose of rFP-MG at 8 wk of age, and group 3 (<i>n</i> = 31) received two doses of rFP-MG, one at 1 day of age and again at 8 wk. Group 4 (<i>n</i> = 30) received a single dose of F strain at 8 wk, and group 5 (<i>n</i> = 32) received rFP-MG at 1 day of age and F strain at 8 wk. Four weeks after the second vaccination, all groups, including the negative control group, were divided into two (challenged and unchallenged) subgroups. All challenged groups were then inoculated with the MG R_low strain at a dose of 3.11 × 10⁸ CCU/bird via the fine spray route. Unchallenged groups included the unvaccinated/unchallenged and four vaccinated/unchallenged control groups. Clinical scoring, air sac scoring, and tracheal mucosal thickness at 21 days postchallenge were used as the main parameters for the evaluation of each vaccination program. No mortalities were observed in any of the study groups after the challenge; however, challenged groups that received only rFP-MG showed clinical signs (ranged from a few snicks to some gurgling sounds) as early as 7 days postchallenge, while the F-strain-vaccinated/challenged groups did not show any clinical signs. Birds from all groups exhibited varying degrees of air sac lesions (ranging from air sacs with suds or small flecks of caseous exudate to cloudy and thickened air sacs), with a higher percentage of birds in the rFP-MG groups being affected. The tracheal mucosal thickness of the F-strain-vaccinated groups was not significantly higher than that of the unvaccinated/unchallenged (negative control) group. However, the tracheal mucosal thickness of the rFP-MG-vaccinated group was significantly lower (<i>P</i> < 0.05) than that of the unvaccinated/ challenged (positive control) group. Results from this trial showed that rFP-MG vaccine provided partial protection against the clinical signs compared to the unvaccinated/challenged positive control; however, it was less protective than the F-strain vaccine.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"70 1","pages":"47-56"},"PeriodicalIF":1.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147680079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}