Veterinary Sciences最新文献

C. pseudotuberculosis is a Gram-positive pathogenic bacterium that infects various animals, causing diseases such as caseous lymphadenitis, leading to significant economic losses in the livestock industry and posing zoonotic risks. This study targeted the conserved gyrA gene fragment of this bacterium, designed specific primers, optimized the reaction system and conditions, and established a high-resolution melting curve (HRM) detection method with potential utility for preliminary molecular screening. Validation showed that this method exhibits strong specificity, producing specific amplification only for the target biovars. The melting temperatures (Tm values) for the two biovars were 86.16 ± 0.05 °C and 86.92 ± 0.05 °C, respectively, allowing clear differentiation. It demonstrated high sensitivity, with minimum detection limits of 28 copies/μL and 25 copies/μL for standard plasmids of the ovis and equi biovars, respectively. The method also showed good reproducibility, with intra- and inter-batch coefficients of variation both below 1.0%. Applied to 133 clinical nasal swab samples from goats in Fujian Province, the method detected a positivity rate of 19.5% and indicates that a biovar equi-like gene fragment was detected in goat nasal swabs from Fujian Province via molecular screening. The HRM method developed in this study is sensitive, specific, simple, and cost-effective, enabling rapid detection and biovar differentiation of C. pseudotuberculosis. It is suitable for large-scale clinical sample screening and provides an efficient technical approach for epidemiological monitoring and precise control of the disease.

The infectious bursal disease virus (IBDV) can cause severe immunosuppression and high mortality in chickens, posing a significant threat to the poultry farming industry. Pyroptosis mediated by gasdermin E (GSDME) may be closely related to the tissue damage caused by IBDV. In this study, 3-week-old specific-pathogen-free (SPF) White Leghorns chickens were inoculated intranasally with 1000 copies/200 μL of very virulent IBDV (vvIBDV) Gx strain, and we analyzed GSDME expression in chicken tissues and the cleavage site of GSDME by Caspase-3. Tissue distribution results showed that GSDME and IL-1β transcription in the bursa of Fabricius and kidneys were significantly upregulated by more than five-fold (p < 0.01) following vvIBDV infection, indicating a close association with vvIBDV-induced tissue lesions. Further studies demonstrated that Caspase-3 could cleave GSDME at conserved sites (D270), releasing the active N-terminal fragment (GSDME-N) to induce pyroptosis. Furthermore, although IBDV proteins cannot directly cleave GSDME, the viral protein VP3 enhances Caspase-3-mediated GSDME cleavage, thereby triggering pyroptosis. The above results reveal the role of GSDME-dependent pyroptosis in the pathogenesis of IBDV and provide new ideas for the prevention and control strategies against IBDV.

Mortality events in commercial rabbit production can lead to significant economic losses, highlighting the need for earlier identification of elevated mortality risk at the group level using routinely collected production data. This study presents a machine learning-based framework for predicting mortality risk at future observation points using routinely collected production data. Models were developed using group-level variables and evaluated with StratifiedGroupKFold cross-validation to prevent information leakage. The selected XGBoost model achieved a balanced performance, with a recall of 0.78 ± 0.03, precision of 0.59 ± 0.04, and ROC-AUC of 0.72 ± 0.02. Predictions were translated into an alert system based on a predefined threshold, prioritising sensitivity while maintaining a moderate false alert rate. A scenario-based cost-benefit analysis indicated that economic outcomes are highly dependent on intervention effectiveness, with positive returns observed under moderate to optimistic assumptions. Overall, the framework demonstrates the feasibility of integrating predictive modelling with alert-based decision support in rabbit production, although real-world validation under commercial farm conditions is required to confirm its practical effectiveness.

The present work was designed to investigate the impacts of tartary buckwheat flavonoids (TBF) on the growth performance and physiological metabolism of Liangshan Yanying chickens. A total of 144 healthy 4-week-old Liangshan Yanying chickens of uniform body weight were randomly divided into four groups. Each group consisted of six replicates with six chickens per replicate. The control group was fed a basal diet, whereas the treatment groups received the same basal formulation supplemented with TBF at concentrations of 20, 40, and 60 mg/kg, respectively. The entire feeding trial lasted for 10 consecutive weeks. Growth performance, serum parameters, bone quality, slaughter traits, and hepatic lipid metabolism were determined and statistically analyzed. Results showed that dietary TBF supplementation had no significant impact on the overall growth performance (p > 0.05); however, final body weight and average daily weight gain displayed a positive linear trend in response to increasing TBF levels (0.05 < p < 0.1). For serum parameters, TBF supplementation significantly increased total antioxidant capacity (p < 0.05) and decreased malondialdehyde content (p < 0.05) in a linear manner. Specifically, compared with the control group, the 60 mg/kg TBF group increased T-AOC by approximately 64.6% and reduced MDA by approximately 67.9%, demonstrating a robust antioxidant effect. A linear increase in high-density lipoprotein cholesterol levels approaching significance (p = 0.055) was also observed. A significant quadratic regulatory effect of TBF was observed on serum glucose concentrations (p < 0.05), whereby the 60 mg/kg TBF dose reduced serum glucose by 15.6% relative to the control (p < 0.05), reflecting a robust hypoglycemic effect. Regarding bone quality, supplementation with 20 and 60 mg/kg TBF significantly elevated tibial phosphorus content relative to the 0 mg/kg TBF group (p < 0.05). Regression analysis showed that increasing dietary TBF levels linearly elevated tibial calcium content (p < 0.05) and resulted in linear increasing trends in tibial ash content, tibial phosphorus content, femur ash content, and femur calcium content (0.05 < p < 0.1). Concerning slaughter performance, dietary TBF inclusion resulted in a significant linear rise in breast muscle percentage (p < 0.05). At the molecular level, TBF upregulated the mRNA expression of hepatic AMPKα1 and CPT1, while concurrently downregulating the expression of FAS and ACC (p < 0.05). Collectively, dietary TBF supplementation in Liangshan Yanying chickens effectively improved antioxidant capacity, promoted tibial calcium and phosphorus deposition, regulated hepatic fatty acid oxidation and synthesis via AMPK-related genes, and enhanced lean meat deposition, with no adverse effects on growth performance under the experimental conditions.

S. suis is a major zoonotic infectious disease whose serological diversity brings challenges to vaccine development. Based on the whole-genome data of 169 S. suis strains, this study conducted a systematic bioinformatics analysis of the surface antigen protein HP0197 that reveals its distribution characteristics, sequence diversity, domain composition and antigenic epitope distribution. The results showed that the HP0197 gene, which has a detection rate of 91.72%, can be divided into seven major phylogroups (I-VII) and the following two structural types: short form (HP0197-S) and long form (HP0197-L). All sequences contained signal peptides, transmembrane structures, LPXTG anchoring motifs, as well as conserved GAGBD and G5 domains, among which tandem repeats of the G5 domain existed in the long HP0197-L type. Tertiary structure prediction indicated that HP0197 has a spatial architecture of "conserved at both ends and flexible in the middle", in which B-cell epitopes are mainly enriched near the GAGBD and G5 domains, suggesting these regions are the key targets for inducing cross-immune protection. It systematically elucidates the diversity and structural characteristics of the HP0197 protein from the perspective of population genetics, which provides a theoretical basis for optimizing existing subunit vaccines, designing broad-spectrum multi-epitope vaccines and exploring novel anti-infection strategies.

SARS-CoV-2 is a zoonotic virus with a proven ability to infect various animal species, including domestic cats. In the post-pandemic period of COVID 19, limited data still exist on the clinical course, shedding of infectious virus and diagnostic features in cats. The aim of this study was to investigate the spread of SARS-CoV-2 in cats in 2023, the clinical manifestations of the infection, the diagnostic algorithm, including molecular detection of viral components, the differential diagnosis of co-infection with FHV, FCV, Mycoplasma spp. and Chlamydia felis, serology, and the isolation of infectious SARS-CoV-2. The immunomodulatory therapy in animals with a standalone SARS-CoV-2 infection was applied. The study included oropharyngeal, conjunctival and nasal swab samples from 102 domestic cats with clinical signs. Of them, 20.6% (21/102) were positive for SARS-CoV-2, with 16.67% (17/102) of the cats showing various variants of co-infection with FHV, FCV, Mycoplasma spp. and Chlamydia felis. Four of the cats had a standalone SARS-CoV-2 with mild clinical manifestations that included serous discharges from the eyes, without change in the general condition. The virus was isolated from these samples. These four cats and their owners were positive for antibodies to the virus, and the owners were PCR-negative. The treatment of SARS-CoV-2 infection included the preparations Viusid, RX immunosuport, Vetomun and Lisymun. This is one of the first post-pandemic studies covering FHV, FCV, Mycoplasma spp. and Chlamydia felis in domestic cats with SARS-CoV-2 infection and further expands on the essential main idea including the specified pathogens of interest.

Background/objectives: Multidrug-resistant (MDR) Escherichia coli has increasingly been recognized as a pathogen capable of causing severe systemic infections in various animal species. However, reports describing respiratory and septicemic infections caused by MDR E. coli in guinea pigs remain scarce. The objective of this report was to describe the clinical, pathological, and microbiological findings associated with a fatal infection in a domestic guinea pig.

Case study: A 10-month-old female guinea pig (Cavia porcellus), kept as a companion animal in a household environment, presented with acute respiratory distress, lethargy, and anorexia, progressing rapidly to death within approximately 36 h of onset. Post-mortem examination revealed severe pulmonary congestion, diffuse inflammatory lesions in the trachea, and generalized vascular congestion in multiple organs. Bacteriological cultures obtained from lung and bone marrow samples yielded pure growth of Escherichia coli. Identification was confirmed using MALDI-TOF mass spectrometry. Antimicrobial susceptibility testing demonstrated resistance to several antibiotic classes, including β-lactams, fluoroquinolones, tetracyclines, sulfonamides, and phenicols, while susceptibility was retained only to aminoglycosides. Molecular analysis revealed the presence of virulence genes involved in adhesion and iron acquisition, supporting the pathogenic potential of the isolate.

Conclusions: This report highlights the ability of MDR E. coli to cause severe respiratory and systemic infections in guinea pigs. The findings underline the importance of early diagnosis, appropriate antimicrobial stewardship, and improved husbandry conditions in preventing such infections. From a One Health perspective, the circulation of resistant strains in companion animals may represent a potential risk for both environmental and human health.

Bovine ocular squamous cell carcinoma (BOSCC) is the most common ocular tumour in cattle, with a multifactorial aetiology involving ultraviolet (UV) radiation, genetic factors, pigmentation, and management practices. A detailed epidemiological characterisation of BOSCC in the Azores, Portugal, is provided, with particular emphasis on its spatial distribution and potential risk determinants. Data were obtained through an epidemiological questionnaire completed by field veterinarians between August 2023 and March 2025. A total of 85 BOSCC cases were recorded across 62 farms-45 on Terceira Island and 17 on São Miguel Island. All affected animals were adult Holstein Friesian dairy cows, managed under extensive pasture-based systems. The nictitating membrane was the most frequently affected structure (69.5%), and multiple lesions occurred in 20% of the cases. Farms located at 200-400 m of altitude presented the highest number of cases. Continuous exposure to UV under pasture-based management represents the main environmental risk factor. Although periocular pigmentation may provide partial protection, other environmental and genetic factors can also contribute to tumour development. Artificial insemination is considered a promising preventive tool, enabling genetic selection for protective traits such as periocular pigmentation. This research provides the first regional epidemiological characterization of BOSCC in the Azores, highlighting the interplay among environmental, genetic, and management-related factors in disease occurrence.

Heat shock proteins 70 (HSP 70) are molecular chaperonins ubiquitously expressed in both prokaryotes and eukaryotes and are involved in the modulation and exacerbation of the immune response. The present study aimed to assess the immunohistochemical expression of HSP70 and apoptosis markers, such as TUNEL and Caspase-3, in 17 cases of cutaneous lupus erythematosus (CLE) in dogs to determine whether HSP70 expression correlates with cell apoptosis and to highlight possible involvement of HSP70 in the pathogenesis of CLE. The results revealed positive HSP70 expression in epidermal and inflammatory cells across all cases, with a significant correlation between HSP70 expression score and TUNEL-positive cells but not with Caspase-3-positive cells. This correlation could indicate a possible role for HSP70 in cell death via a caspase-independent apoptotic mechanism or other programmed cell death mechanisms, such as pyroptosis or necroptosis. The precise mechanisms by which HSP70 acts in this specific pathological context remain incompletely understood, but the results of this study provide important information for future investigations into autoimmune skin disease in dogs.

Avian orthoavulavirus 1 (AOaV-1), commonly known as Newcastle disease virus (NDV), despite widespread vaccination, remains a significant threat to domestic chickens (Gallus gallus domesticus). Currently available live-attenuated NDV vaccines are derived from genotypes I and II lentogenic strains, whereas genetically divergent velogenic strains predominantly caused recent NDV outbreaks. This study examined the extent of genotypic divergence between NDV vaccine strains and field strains using phylogenetic and multivariate analyses of two major antigenic and virulence-associated genes: fusion (F) and haemagglutinin-neuraminidase (HN). A total of 121 full-length NDV-F and 81 NDV-HN gene sequences, representing reported NDV genotypes, were downloaded from GenBank and analysed using maximum-likelihood (ML) phylogenetic trees and principal coordinates analysis (PCoA). The phylogeny revealed genotype-specific clustering for both genes, consistent with current NDV classification. NDV vaccine strains belonging to genotypes I and II formed distinct clades, segregated from the majority of NDV field strains, including velogenic or virulent NDV genotypes. The principal coordinates analysis of both genes further confirmed the phylogenetic clustering of NDV genotypes, indicating increased genomic heterogeneity. These findings suggest genetic segregation of divergent velogenic or virulent genotypes from lentogenic NDV vaccines, requiring biological experiments for determining their efficacy against field strains. This study highlights the importance of molecular surveillance of NDV to monitor its genomic diversity, which is crucial for developing strategies to combat NDV outbreaks in domestic chickens. This study provides an updated, NDV-glycoprotein-gene-based comparative analysis across reported NDV genotypes using phylogenetic and multivariate approaches.