Veterinary Quarterly最新文献

Salmonella enterica subsp. Salmonella Pullorum is a concerned pathogenic microorganism that poses a serious threat to the global poultry industry due to high mortality in chicken. Acquired immunity is considered the most effective means to prevent and control Salmonella pullorum. However, safe and effective vaccines are still lacking worldwide. In this study, Saccharomyces cerevisiae was used as a chassis to design an oral vaccine for pullorum by displaying Salmonella fimbriae and outer membrane proteins on its surface. The results demonstrated that the engineered yeast EY-01 exhibited strong antigenicity as identification and capture by specific antibodies. In addition, oral administration of EY-01 significantly stimulated a 1.4- to 2.7-fold increase in antibody (IgG/A) and immune factors levels (IL-1β/2/4, IFN-γ) in chicks without affecting the growth performance. The ratios of CD4⁺/CD3⁺ and CD8⁺/CD3⁺ T cell subsets in peripheral blood were significantly increased by 2.1-fold. Importantly, 37.5% of chicks were protected from challenge with Salmonella pullorum after oral administration of EY-01. And the Salmonella load in various tissues, especially muscle, was significantly reduced by 7.2%-22.4%. Collectively, EY-01 is a safe and effective oral vaccine to against Salmonella infection in chicks and such surface display-based vaccine is potential to be used for decreasing the poultry diseases.

Salmonellosis is a major food safety challenge in poultry production, requiring effective antibiotic alternatives. We isolated a polyvalent Tequintavirus, vB_SalS_KY05, from a Taiwanese poultry farm and evaluated its biological properties and in vivo efficacy against Salmonella enterica serovars Typhimurium and Enteritidis, and Escherichia coli. The objective of this study was to comprehensively characterize vB_SalS_KY05 and assess its potential as a biocontrol agent for poultry farming. Genome analysis confirmed a lytic lifestyle with no detectable virulence or antimicrobial resistance genes. The phage remained stable at pH 4-10, at 41 °C, and in water for 7 days. For improved biosafety, large-scale amplification was achieved by switching the propagation host to non-pathogenic E. coli K12. In vivo, SPF chickens challenged with S. Typhimurium received low-dose (10⁵ PFU/mL) or high-dose (10⁸ PFU/mL) phage via drinking water. Low-dose treatment reduced splenic Salmonella, improved albumin-to-globulin ratios, and enriched beneficial taxa like Lactobacillus crispatus and Blautia coccoides. In contrast, high-dose treatment resulted in phage-bacteria coexistence and increased potentially harmful taxa including Erysipelatoclostridium. Overall, cecal microbiota composition remained largely unchanged. These findings indicate vB_SalS_KY05 is a promising biocontrol candidate, highlighting the importance of dose optimization to enhance pathogen control while preserving gut microbiota stability in poultry production.

A heart-convolutional neural network (heart-CNN) was developed and tested for the automatic detection of left atrial enlargement (LAE) from feline thoracic radiographs. A retrospective and multicenter study was performed. Right lateral and dorso-ventral and/or ventro-dorsal thoracic radiographs of cats with concomitant echocardiographic examination were selected from the internal databases of both academic and private referral institutions. Radiographic images were classified as no LAE, mild, moderate and severe LAE, based on echocardiographic reports. Heart-CNN performance was evaluated using confusion matrices and receiver operating characteristic curves for both radiographic projections considering a multiclass and a binary classification. Considering the multiclass classification, for the right lateral view, the area under the curve (AUC) was of 0.73, 0.68, 0.64 and 0.78 for the no LAE, mild, moderate and severe LAE groups, respectively. The AUCs for the dorso-ventral and/or ventro-dorsal images were 0.73, 0.64, 0.63 and 0.76 for the no LAE, mild, moderate and severe LAE groups, respectively. In the binary classification, AUCs were 0.83 and 0.81 for right lateral and dorso-ventral and/or ventro-dorsal projections, respectively. The developed AI-based tool seems to be a promising support for automatic identification of more advanced stages of LAE in cats.

Uterine luminal fluid influences embryonic development and the subsequent phenotype of offspring, yet its detailed metabolomic composition remains poorly characterized. Here, minimally invasive transcervical techniques were employed to collect neat uterine fluid from postpartum dairy cows and cyclic beef cows to allow for metabolomic profiling via targeted mass spectrometry. Objectives were to 1) compare the metabolomic profile of uterine fluid with plasma in dairy cows and 2) assess the impact of dietary rumen-protected methionine and stage of estrous cycle (day 0 vs 7) on plasma and uterine fluid metabolomic profile in beef cows. Results revealed that the concentrations of many metabolites, including amino acids, signaling molecules (e.g. dopamine, gamma-aminobutyric acid) and lipids (e.g. ceramides, diacylglycerols), were higher in uterine fluid than in plasma. An oral bolus of rumen-protected methionine increased uterine concentration of methionine on day 0 of the estrous cycle. The uterine metabolome remained relatively stable between days 0 and 7 although there was temporal variability for a select number of metabolites (cysteine, methionine, methionine sulfoxide, asymmetric dimethylarginine, ceramides, and glycerophospholipids). Correlations between plasma and uterine fluid concentrations were strong or moderate for many amino acids. Collectively, these findings highlight that the uterine lumen is a specialized, selectively regulated biochemical compartment.

Spotty liver disease in laying hens can be caused by Campylobacter hepaticus or by Campylobacter bilis. While C. hepaticus is widely distributed around the world, C. bilis has thus far only been documented in Australia and the USA. We investigated five outbreaks of spotty liver disease in laying hens in the Netherlands. In November 2020 C. bilis was cultured as the causal agent of the outbreak on one of these farms, while C. hepaticus was cultured from hens from the four other farms. Clinical and pathological features were indistinguishable, but MALDI-TOF and WGS identified these species unambiguously. To our knowledge, this is the first report of C. bilis outside Oceania and the USA.

Vaccination is routinely used in industrial poultry to control infectious diseases. Vaccines based on mRNA and self-amplifying RNA (saRNA) are approved for human use, but research on their application in poultry is limited. In this study the saRNA vaccine platform is evaluated in poultry. First, a luciferase-encoding saRNA (luc-saRNA) was tested as a model vaccine across different administration routes and doses in broilers. High luciferase expression, and anti-luciferase antibodies were observed after intramuscular (IM), subcutaneous (SC), and in ovo (IO) administration. After a second Luc-saRNA injection, seroconversion rates and antibody titers increased in the IM and SC group to almost 100%. Higher doses of Luc-saRNA increased luciferase production. However, they did not linearly increase antibody production, as all tested doses (0.20-5.0 µg) elicited an equipotent immune response. A vaccination experiment with saRNA encoding the hemagglutinin head-domain (HA-HD) of H5N1 avian influenza showed hemagglutinin inhibition (HI) titers that are indicative for protection after a single injection and these titers remained above the protective threshold during 6 weeks without boosting. When boosted, the HI titers increased four-fold. This study confirms effective protein translation and immune response induction in chickens with IM or SC administered saRNA-LNPs, even at the lowest dose of 0.20 µg.

Diagnostic ultrasound (US) is a noninvasive, cost-effective imaging modality widely used for evaluating the gastrointestinal (GI) tract in companion animals. It provides information on wall thickness and layer differentiation, allowing assessment of normal anatomy and pathological changes. Despite its diagnostic relevance, ultrasonographic reference values for the GI tract in dogs and cats remain inconsistent across publications. This study reviewed ultrasonographic characteristics of the normal GI wall in dogs and cats and compiled a consensus-based reference table for overall wall thickness and individual layer proportions to enhance clinical interpretation. A literature search of PubMed and Scopus identified studies assessing the ultrasonographic features of normal GI segments, from stomach to colon, in healthy dogs and cats. Twelve studies met the inclusion criteria: six focused on dogs and six on cats. Reference values for GI wall thickness and its layers were reported in both species. However, discrepancies were noted in weight-based classifications for dogs, and the stomach of adult dogs remains poorly studied. Moreover, evaluation of gastric rugal and inter-rugal folds remains limited in this species. US is valuable for GI assessment, but dispersion of reference values across studies may hinder accessibility. Establishing standardized ultrasonographic parameters could improve diagnostic accuracy and clinical decision-making.

Feline calicivirus (FCV) infection causes nasal discharge, oral mucosa inflammation, ulcerations, gingivitis, and conjunctivitis, often progressing to chronic gingivostomatitis, severe pneumonia, and fatal systemic infections. With no antivirals currently available, poly(sodium 4-styrene sulfonate) (PSSNa) was identified in 2019 as a safe inhibitor in vitro. In this preliminary single-center, randomized, double-blind, placebo-controlled field study, we further characterized the PSSNa's safety profile and tested its efficacy in cats after topical oral application. Twenty-eight cats were enrolled in the study, and they were initially treated with standard dental therapy, followed by adjuvant local oral application of PSSNa or placebo. After 4 weeks, PSSNa demonstrated a favorable safety profile with no adverse effects. The treatment group showed a significant decrease in viral load (p = 0.001) compared to placebo (p = 0.012). Disease symptoms improved significantly, though the oral health index remained unchanged. Additionally, PSSNa showed activity against multiple genetically diverse isolates, indicating a potential, exploratory link between genetic background and treatment outcome. Summarizing, this study presents initial data on the efficacy and tolerability of PSSNa treatment for FCV infections in cats. Nevertheless, several significant limitations should be acknowledged, including inconsistent drug administration by owners, non-sterile housing, sample size, variable oral disease severity, and concurrent treatments.

Staphylococcus aureus (S. aureus) evades host immunity by modulating macrophage functions, including immune regulation and phagocytosis, ultimately contributing to bovine mastitis. This study aimed to elucidate the molecular mechanisms of S. aureus-induced bovine mastitis from both host and pathogen perspectives, focusing on prostaglandin E₂ (PGE₂) as a key regulator. During bovine mastitis, macrophages were recruited into the mammary gland with elevated inflammatory mediators. S. aureus lipoproteins amplified inflammation by activating MAPK and NF-κB pathways via TLR2, TLR4, and NLRP3, leading to elevated secretion of mediators, including PGE₂, in bBMMs. Inhibition of TLR2, TLR4, or NLRP3 decreased COX-2 and mPGES-1 expression, suppressing PGE₂ synthesis, while inhibition of COX-2 or mPGES-1 can regulate the expression of TLR2 and NLRP3, as well as the activation of MAPKs and NF-κB signaling pathways. Excess PGE₂ can regulate inflammation and phagocytosis mediated by TLR2, TLR4, and NLRP3. S. aureus lipoproteins promote PGE₂ synthesis via TLR2, TLR4, and NLRP3 signaling, while PGE₂, in turn, modulates receptor activity, inflammation, and phagocytosis. These findings reveal crucial functional cross-talk between PGE₂ and innate immune receptors in S. aureus-induced mastitis, suggesting that targeting this interaction may provide novel therapeutic strategies.

Herein, we present novel quantitative loop-mediated isothermal amplification (qLAMP) and reverse-transcription qLAMP (RT-qLAMP) assays for the detection of five viruses implicated with the onset and progression of bovine respiratory disease (BRD): Bovine Alphaherpesvirus Type 1 (BHV-1), Bovine Adenovirus Type 3 (BAV-3), Bovine Respiratory Syncytial Virus (BRSV), Bovine Viral Diarrhea Virus Type 1 (BVDV-1), and Bovine Parainfluenza Virus Type 3 (BPIV-3). Using contrived samples spiked with whole viruses, our extraction-free assays have limits of detection between 30 and 1,057 copies per reaction (1.8% final sample concentration) with minimal sample processing. Using dual-tipped swabs and 1.4 mL resuspension volumes, limits of detection are on the order of 2 × 10⁵ copies per swab for BAV-3 and BHV-1 and between 6.31 × 10⁶ to 8.22 × 10⁶ copies per swab for BPIV-3, BRSV, and BVDV-1. Analytical sensitivities ranged from 73 - 100% and analytical specificities ranged from 90 - 100%. Additionally, we introduced a streamlined pipeline to minimize the experimental workload to design, screen, select, and characterize LAMP performance for developing assays. Our assays support the development of colorimetric LAMP assays that enable the sensitive and specific detection of these viruses' chute side to aid in diagnosing and treating BRD. The associated pipeline enables more rapid development of LAMP-based diagnostic tools targeting emerging pathogens.