Frontiers in Veterinary Science最新文献

Introduction: Pasteurella multocida (Pm) is a major pathogen that causes respiratory diseases in sheep, leading to high morbidity, high mortality, and significant economic losses. Current diagnostic methods, such as bacterial isolation, ELISA, and PCR, are limited by low throughput, complex procedures, and reliance on specialized equipment, making them unsuitable for field use.

Methods: In this study, we developed a rapid, visual, and sensitive method for detecting Pm by combining recombinase polymerase amplification (RPA) with CRISPR/Cas12a. The PCR method based on kmt1 is the "gold standard" for studying Pm. So this assay targeted the kmt1 gene and was optimized for primer selection, reaction conditions, and crRNA/Cas12a ratios. Specificity verification was conducted through common respiratory pathogens, and sensitivity verification was carried out using plasmid dilution solutions.

Results: The method showed a detection limit of 5 × 10^-1 copies/μL, and the reactions were completed within 30 min. When applied to 102 clinical samples, the RPA-CRISPR/Cas12a assay yielded a positive rate of 40.20% (41/102), which was 4.1 times higher than that of PCR. This assay offers a promising tool for rapid and instrument-free detection of Pm in frontline clinical settings.

Background: Ovine toxoplasmosis is a zoonotic disease that severely impacts the development of the sheep industry. The primary routes of Toxoplasma gondii infection in sheep are cyst infection and oocyst infection. However, current technologies are unable to distinguish between these two infection pathways.

Methods: In this study, we initially screened eight proteins that are highly specifically expressed during the oocyst stage. Through Western blot (WB) analysis, we identified a protein (TGME49_267410) that could serve as a diagnostic antigen. Subsequently, we optimized the conditions for an indirect enzyme-linked immunosorbent assay (iELISA) using TGME49_267410. Based on these optimized conditions, we collected 1,350 sheep serum samples from various prefecture-level cities in Hubei Province and compared the detection results using both GRA1-iELISA and Tg267410-iELISA.

Results: In this study, we successfully identified TGME49_267410 as a specific diagnostic antigen for Toxoplasma gondii oocyst-derived infections and established a Tg267410-based indirect enzyme-linked immunosorbent assay (Tg267410-iELISA) for antibody detection. This method exhibited excellent specificity with no cross-reactivity against ovine Haemonchus contortus infections, along with a low limit of detection and good stability of enzyme-linked plates. Serological testing of sheep serum samples from Hubei Province revealed an overall oocyst infection positive rate of 47.4%, where the positive rate in commercial fattening farms (39.9%) was significantly higher than that in breeding sheep farms (12.2%).

Conclusion: To summarize, the Tg267410-iELISA established herein enables specific, sensitive, and stable detection of ovine Toxoplasma gondii oocyst-derived infections. This method facilitates the differentiation of infection routes and epidemiological surveillance of ovine toxoplasmosis in Hubei Province and beyond, providing a robust scientific foundation for optimizing targeted prevention and control strategies in sheep farms.

Introduction: Ferroptosis is a distinct form of regulated cell death characterized by iron-dependent lipid peroxidation that damages cellular membranes and leads to the end of a cell's life. Glutathione peroxidase 4 (GPX4), the only enzyme capable of the reduction of lipid peroxidation products within cells, is a key regulator of this process.

Aims: The role of GPX4 in feline chronic kidney disease (CKD) has not been previously investigated. This study aims to determine whether urine GPX4 levels are associated with CKD severity in cats and to assess their potential as a progression biomarker.

Methods: Urine GPX4 levels were measured using a commercial feline ELISA kit. The urine-GPX4-to-creatinine ratio (UGCR) was calculated. Fifteen healthy cats, 61 cats with CKD, and six cats with acute-on-chronic kidney disease (ACKD) were included in the study.

Results: Compared with the control group (urine GPX4, median [IQR]: 25.21 [18.99-26.91]; UGCR: 0.072 [0.057-0.101] × 10^-4) and the early-stage CKD group (urine GPX4: 24.31 [22.00-24.07]; UGCR: 0.134 [0.070-0.260] × 10^-4), cats with late-stage CKD showed significantly higher levels of urine GPX4 (26.89 [25.11-31.66]; p = 0.011) and UGCR values (0.271 [0.197-0.457] × 10^-4; p < 0.001). Within the CKD subgroups, UGCR was significantly higher in cats with proteinuria, hypertension, anemia, and those receiving iron supplementation (all p < 0.003). Serum creatinine levels and WBC counts were identified as independent variables that were correlated with UGCR. Cats in the CKD progression group had higher UGCR than non-progressors, and an elevated UGCR was associated with an increased risk of CKD progression (hazard ratio [HR], 1.75; 95% CI, 1.20-2.54; p = 0.003).

Conclusion and clinical importance: UGCR increased with the severity of CKD and was significantly associated with serum creatinine concentration and disease progression. Urine GPX4 may thus serve as a novel biomarker for monitoring renal deterioration and progression in cats with CKD.

Periodontal regeneration around maxillary canine teeth in dogs remains challenging because of limited surgical access and the risk of postoperative complications associated with flap surgery. This article presents a minimally invasive, flapless protocol for periodontal regeneration using an Er: YAG laser-assisted minimally invasive non-surgical technique (MINST). The method enables efficient removal of granulation tissue, root surface conditioning, and blood-clot stabilization under microscopic magnification, without flap elevation. Detailed materials, equipment, and procedural steps are described to support reproducibility. Two representative clinical applications are summarized, showing complete reduction of probing pocket depth and stable healing up to 10 months. This technique may serve as a reproducible, low-invasive alternative to conventional flap-based regenerative surgery for preservation of the maxillary canine teeth in dogs.

Background: Echocardiography is the first choice for assessing the structure and function of the heart, but it is unclear for detecting subclinical changes. In recent years, abnormal heart rate variability (HRV) has received attention for its ability to identify patients at risk for developing heart failure. HRV analysis in veterinary medicine is predominantly limited to linear analysis, which primarily reflects advanced heart disease. In contrast, nonlinear HRV analysis holds the potential for early detection of heart disease, but its quantitative evaluation remains rare.

Objectives: This study aimed to evaluate the feasibility of using HRV for the early heart disease detection in clinical settings, with a focus on doxorubicin (DXR)-induced myocardial damage in dogs.

Animals and methods: Six healthy female dogs with no abnormalities on physical examination, blood pressure, electrocardiography (ECG) and echocardiography were selected in this study. The dogs had an average age of 1.2 years and an average body weight of 8.1 kg. After recording blood pressure, ECG and echocardiography, the dogs were fitted with a Holter ECG, and measurements were taken for 2 days. Following the removal of the Holter ECG, DXR at 30 mg/m² was administered over 30 min, repeated every 3 weeks, up to a maximum cumulative dose of 180 mg/m². Each measurement was taken before the first and after the final DXR dose.

Results: There were no changes in recommended parameters of left ventricular systolic function (FS: 34.4% [33.9-42.8] vs. 37.8% [34.7-42.8], p = 0.73, GLS EN: -19.1% [-21.3 - -17.5] vs. -18.0% [-19.3 - -17.3], p = 0.68). However, the Poincaré plot of nonlinear HRV significantly reflected increased sympathetic activity (SD1/SD2: 0.58% [0.57-0.60] vs. 0.42% [0.40-0.45], p = 0.008, SD2/SD1: 1.8% [1.76-1.82] vs. 2.5% [2.3-2.7], p = 0.008).

Conclusion: The finding that nonlinear HRV analysis reflected early increased sympathetic activity associated with DXR administration in dogs is an important step forward in enhancing the clinical application potential of HRV.

Objective: To develop and validate dual detection platforms integrating recombinase polymerase amplification (RPA) with Pyrococcus furiosus Argonaute (PfAgo) for the rapid and specific identification of Streptococcus suis serotype 2.

Methods: The conserved cps2J gene was selected as the molecular target. Key RPA parameters and PfAgo reaction conditions were systematically optimized, including temperature, reaction time, MnCl₂ concentration, gDNA design and probe concentration. Specificity and sensitivity were evaluated using plasmid dilutions and multiple S. suis serotypes together with other common swine pathogens. A total of 41 clinical samples were also tested and compared with the national standard PCR assay (GB/T 19915.3-2005).

Results: Two assay formats were established: real-time fluorescence system (RPA-PfAgo-RTF) and lateral flow dipstick system (RPA-PfAgo-LFD). The RPA-PfAgo-RTF assay achieved a detection limit of 10⁰ copies/μL, while the RPA-PfAgo-LFD assay detected 10² copies/μL. Both formats showed high specificity without cross-reactivity. Among 41 field samples, six were SS2-positive, and results showed 100% agreement with the reference PCR method. Total detection time for either assay was < 1 h.

Conclusion: Both assay formats provide rapid, sensitive, and accurate tools for SS2 detection suitable for laboratory use and on-farm point-of-care testing.

The extensive use of antimicrobials in livestock has accelerated the emergence of antimicrobial resistance (AMR), raising serious global concerns. Poultry feces are recognized as important reservoirs of antibiotic resistance genes (ARGs) and their associated mobile genetic elements (MGEs); however, the microbial community characteristics and ARG profiles of laying hens across different laying stages remain poorly understood. In this study, 40 fecal samples were collected from laying hens at five sampling points, including the early laying stage (HE), three peak laying stages (HPI, HPII, and HPIII), and the late laying stage (HL), with eight randomly selected samples per stage. Shotgun metagenomic sequencing was conducted to characterize the taxonomic structure and functional profiles of the intestinal microbiota and to systematically analyze the diversity and distribution patterns of ARGs. The results showed that most ARGs were harbored by bacteria belonging to the phyla Pseudomonadota and Bacillota, with Escherichia coli serving as the primary carrier of antibiotic resistance genes. Moreover, significant correlations were observed between the co-abundance and co-occurrence of ARGs and MGEs, suggesting that MGEs play a key role in facilitating ARG dissemination. Overall, these findings provide novel insights into the prevalence of ARGs in laying hens across different laying stages and may inform strategies to mitigate the spread of antimicrobial resistance in poultry production systems.

Introduction: Boxer dogs exhibit a distinctive skull morphology resembling scaphocephaly in humans. This study investigates the status of skull sutures in Boxer dogs in comparison with other brachycephalic and mesocephalic breeds.

Methods: Archival magnetic resonance images of the heads of 312 dogs with variable skull morphologies were examined. Sutures and synchondroses of the skulls were assessed as open or closed, and the presence or absence of ventricular dilation was noted.

Results: A total of 160 dogs belonged to the mesocephalic group, 103 were brachycephalic, and 49 were Boxer dogs. Age was a predictor for closed sutures and synchondroses (p < 0.05). Sutures and synchondroses were more likely closed in brachycephalic compared to mesocephalic dogs (p < 0.0001). In addition, brachy- and mesocephalic dogs were less likely to show a closed sagittal suture (S4), parietointerparietal suture (S9) (p < 0.0001), and lambdoid sutures (p < 0.05) than Boxer dogs. Cranial index was higher in brachycephalic dogs compared to mesocephalic dogs and Boxer dogs and significantly differed among all groups (p < 0.05). Width/height index of the skull was significantly different among all groups and lowest in Boxer group (p < 0.05). Boxer dogs more likely experienced ventriculomegaly than the other breeds (p < 0.0001).

Discussion/conclusion: The parietointerparietal and sagittal suture are more likely fused in Boxer dogs. A premature suture closure is most likely responsible for the Boxer dog's unique skull morphology or scaphocephaly and an associated ventriculomegaly, which resembles a non-syndromical craniosynostosis in humans.

[This corrects the article DOI: 10.3389/fvets.2025.1614761.].

Introduction: Fermented liquid feed (FLF) has been shown to improve feed efficiency and growth performance of pigs, however, its effects on porcine immune function remain poorly understood.

Methods: In this study, transcriptomic, metabolomic, and ELISA-based approaches were employed to systematically evaluate the effects of fermented liquid feed on immune factor levels, splenic metabolic profiles, and gene expression in pigs. A total of 64 commercial pigs were randomly assigned to two groups, fed a basal diet group (CON) and a fermented liquid diet group (LFF), for a feeding period of 60 days.

Results: The results showed that, compared with the CON group, the LFF group exhibited significantly higher serum concentrations of interleukin-6(IL-6, 767.88 ± 12.43 pg/ml), tumor necrosis factor-α(TNF-α 678.32 ± 15.37 pg/ml), complement C3(145.92±3.69 μg/ml), immunoglobulin A(IgA, 485.15 ± 9.13 μg/ml), and interferon-γ(IFN-γ 1966.76 ± 72.22 pg/ml). Meanwhile, transcriptome sequencing revealed that the expression levels of immune-related genes CXCL2, CXCL8, and SLA-5 were significantly upregulated in the LFF group. Further KEGG pathway analysis demonstrated a more pronounced enrichment of the chemokine signaling pathway and IL-17 signaling pathway in this group. The metabolomic analysis revealed that fermented liquid feed altered the metabolic profile of the spleen, primarily affecting the biosynthesis of unsaturated fatty acids and linoleic acid metabolism. Integrated analysis indicated that fermented liquid feed reprogrammed metabolic patterns by modulating the expression of immune-related genes.

Discussion: In conclusion, our findings indicate that fermented liquid feed significantly enhances immune function in pigs, providing a theoretical basis for its scientific application and promotion in healthy farming of pigs.