农林科学最新文献

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.

Shigella infection is a leading cause of diarrheal diseases, especially in developing countries like Bangladesh, contributing significantly to morbidity and mortality. Despite its importance, data on Shigella prevalence, serotype distribution, and antimicrobial resistance (AMR) patterns remained limited. This study aimed to explore the prevalence of Shigella among patients with acute diarrhea at Tangail Medical College and Hospital, Tangail, Bangladesh, and to analyze the serogroup distribution and AMR profiles of the isolated strains. Stool samples from 96 patients with diarrhea were collected from May 2018 to December 2018 and tested for Shigella using biochemical, molecular, and serotyping methods. The isolates were further examined for antibiotic resistance. In addition, pathogenicity of Shigella spp. was assessed using Caenorhabditis elegans in a solid agar infection assay. Of the total participants, 28.1% were Shigella-positive by culture, while 5.2% and 4.15% were positive by molecular and serotyping methods, respectively. All Shigella isolates exhibited varying degrees of resistance to common antibiotics. Shigella flexneri isolates exhibited high resistance for nalidixic acid only among the tested antibiotics. Shigella dysenteriae was resistant to amoxicillin-clavulanic acid, erythromycin, gentamicin, and nalidixic acid, while Shigella boydii showed resistance to ampicillin, amoxicillin-clavulanic acid, and nalidixic acid. However, no resistance was observed to azithromycin, tetracycline, levofloxacin, or ciprofloxacin. In the pathogenicity assay, a significant difference in survival was observed in C. elegans infected with Shigella spp. compared with the control group. S. dysenteriae exhibited the highest pathogenicity, with only 21.6% survival of C. elegans after 12 h postinfection, while S. boydii and S. flexneri exhibited 27.47% and 35.55% survival, respectively. This study highlights the importance of regular surveillance of Shigella prevalence and AMR patterns in Bangladesh. Furthermore, exploring genomic epidemiology and alternative treatments for Shigella infections is crucial in combating its spread and resistance in Bangladesh.

Clostridium perfringens is an important zoonotic pathogen that can be carried by both humans and small ruminants. This study aimed to investigate the virulence gene profiles and antibiotic resistance characteristics of C. perfringens isolates from farmed sika deer. A total of 10 isolates were obtained from fecal samples, with an overall isolation rate of 2.59%. All strains were identified as type A. Antimicrobial susceptibility testing revealed varying degrees of resistance to tetracycline (10%), tigecycline (50%), penicillin (50%), clindamycin (50%), and metronidazole (50%). Whole-genome sequencing identified 12 virulence-associated genes (including nagK, nagH, colA, cloSI, plc, and pfoA) and 8 resistance genes (tetA(P), tetB(P), ermQ, mprF, etc.). Molecular typing by multilocus sequence typing and core genome multilocus sequence typing uncovered limited clonal spread and substantial genetic diversity, with the majority of isolates (7/10) representing novel sequence types. These findings provide new insights into the genomic characteristics of C. perfringens in farmed sika deer and underscore the potential public health and animal health risks associated with antimicrobial-resistant strains.

Haemonchus contortus is a highly pathogenic gastrointestinal nematode that significantly impacts ruminant health and productivity. Despite extensive research, a comprehensive understanding of the global prevalence of H. contortus infections and associated risk factors remains lacking. A systematic review and meta-analysis were conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Literature on H. contortus in ruminants was retrieved from PubMed, Web of Science, ScienceDirect, Scopus, and Google Scholar up to January 1, 2025. Pooled prevalence and 95% confidence intervals were estimated using a random-effects model. A meta-analysis of 64 studies on H. contortus infection in ruminants worldwide revealed a pooled prevalence of 37%. Continent subgroup significantly influenced prevalence (p < 0.05), with the highest rate reported in Europe and the lowest in Oceania. Environmental factors played a critical role, with regions classified under the Cwb climate exhibiting significantly higher infection rates than other climate zones (p < 0.05). Higher prevalence was also associated with high-altitude areas, annual rainfall ≥800 mm, and lower temperatures. Host-related factors were equally important, with animals over 1 year of age and females showing greater susceptibility. These findings underscore the importance of developing control strategies adapted to different climates and host species, with a particular emphasis on targeted surveillance and deworming efforts against H. contortus in high-risk regions to reduce infection burden and support sustainable ruminant production.

While thyroid physiology has been studied in domestic ruminants, many uncertainties remain. In fact, this metabolism is rarely assessed in routine veterinary practice, and diseases of the thyroid gland or its metabolism are poorly documented in domestic ruminants. This scoping review aims to summarize current knowledge in anatomy, physiology, diseases, and diagnostic methods related to thyroid function in domestic ruminants. A structured research methodology was followed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for scoping reviews. Four databases were used: CAB Abstracts, Embase, PubMed and Scopus. Selection and screening process of the identified studies, as well as data extraction, were managed using Covidence software. Finally, 206 studies were included. Most studies involved cattle (n = 104), followed by sheep (n = 65) and goats (n = 28). The main study topic was on thyroid physiology (n = 127), followed by diseases (n = 48), diagnostic methods (n = 22) and histology (n = 9). Although many studies addressed the anatomy and physiology of the thyroid gland, few confirmed the euthyroid status (having a normally functioning thyroid gland) of these animals, warranting cautious interpretation of the results. Hypothyroidism is the most documented thyroid disease in ruminants, predominantly caused by iodine deficiency. The physiology of the thyroid gland has been extensively studied in relation to heat stress, reproduction, animal production and nutrition. However, there is much less literature available on diseases described in domestic ruminants and their diagnostic methods. Diagnostic tools for assessing thyroid metabolism in ruminants include assays for total thyroxine, total triiodothyronine, bovine thyroid stimulating hormone, total serum iodine, milk iodine, urine iodine, and plasmatic inorganic iodine.

Canine mammary tumors (CMTs) are the most common neoplasms in intact female dogs, yet early detection remains challenging due to the lack of clinically validated, noninvasive biomarkers. This study aimed to develop a noninvasive diagnostic model for CMT detection by integrating serum autoantibody biomarkers with machine learning. Serum samples from 154 dogs with mammary tumors (31 benign, 123 malignant) and 39 healthy controls were analyzed using a custom multiplex immunoassay detecting autoantibodies against AGR2, HAPLN1, IGFBP5, and TYMS, normalized to anti-BSA levels. Median fluorescence intensity (MFI), standardized autoantibody ratios, and their combination, together with clinical variables, were used to train random forest classifiers. The model based on standardized autoantibody ratios achieved the best performance, with an AUC of 0.79 (sensitivity 75.3%, specificity 74.4%) for overall CMT detection; 0.78 (92.7%, 61.5%) for malignant CMTs; and 0.77 (82.2%, 71.8%) for early-stagemalignancies. Assuming a CMT prevalence of 0.5 in the hospital-referred population, the positive and negative predictive values ranged from 0.74-0.75 and 0.75-0.91, respectively. This proof-of-concept study demonstrates that a machine learning-assisted multiplex autoantibody assay offers a feasible noninvasive approach for CMT detection. Further validation in larger, independent cohorts is warranted to support clinical translation in veterinary oncology.

The genus Listeria is heterogeneous and contains pathogenic and nonpathogenic species. Pathogenic L. monocytogenes and L. ivanovii have different environmental distributions, infect different hosts, and cause distinct syndromes. Here, we evaluated whether responses of different Listeria species to diverse host niches contribute to virulence heterogeneity and influence their environmental distribution. We assessed resistance to gastric and intestinal fluids, gut and uterus microbiota, and semen. L. monocytogenes was more resistant than L. ivanovii in gastric fluid, whilst L. seeligeri and L. valentina showed an intermediate phenotype. All the tested Listeria species resisted the intestinal fluid. Gut microbial communities outcompeted and eliminated L. ivanovii and L. valentina. However, L. monocytogenes and L. seeligeri outcompeted intestinal commensal bacteria. Our findings suggest that, unlike L. monocytogenes and L. seeligeri, the tested L. ivanovii are unlikely to colonize the gastrointestinal tract of ruminants, which would reduce replication, fecal shedding, and environmental distribution. However, the ability of L. ivanovii to survive within uterine microbiota and semen suggests that the tested clones could persist in the urogenital tract of ruminants. Then venereal transmission could be more probable than the oral route, which could explain why L. ivanovii is associated with abortion outbreaks and not encephalitic cases.

Xizang sheep are vital economic livestock in plateau regions. Traditional surgical castration often induces stress and infection. Although immunization presents an alternative method, the physiological mechanisms underlying its effects in Xizang sheep remain unclear. Therefore, this study integrated serum immune-antioxidant indicators with hypothalamus-pituitary transcriptomics to investigate molecular mechanisms of GnRH immunization. Results indicated that serum IgA, IgG, IgM, SOD, and GSH in the immunization (IM) group were significantly higher than in control (CON) and surgical castration (SN) groups, while IL-6 and TNF-α were significantly reduced (p < 0.05). RNA-seq analysis revealed that hypothalamic CYTB, ATP6, COX, ABLIM1, and ABI3 were significantly upregulated in IM group, whereas SHISA7 and PTPRO were significantly downregulated, with notable enrichment in prion disease, oxidative phosphorylation, and thermogenesis pathways. Pituitary RPL15 was upregulated while RPL10A, CACNA1D, ANK1, DDX3X, and KCNMA1 were significantly downregulated, showing enrichment in myofibril, contractile fiber, sarcomere, and cytosolic ribosome pathways. Association analysis revealed significant positive correlations between IgG and pituitary ATP6, CYTB, TNNI2, as well as hypothalamic COX1, COX, and ND4. In summary, GnRH immunization outperforms surgical castration by modulating hypothalamic-pituitary genes and enhancing immunity and antioxidants in plateau Xizang sheep, achieving integrated neuroendocrine-immune regulation for healthy husbandry of plateau Xizang sheep.

Quinolones are one of the most widely used antibiotics globally for the treatment of Staphylococcus aureus infections, and resistance to their various generations of drugs occurs. The present study aimed to investigate the inhibitory effect of quercetin on quinolone-resistant S. aureus, triggered by efflux pumps, to assess its potential value as an efflux pump inhibitor. The minimum inhibitory concentration of ciprofloxacin for resistant bacteria was determined by the micro broth dilution method, combined with UV spectrophotometry and high-performance liquid chromatography, to observe the changes in ciprofloxacin accumulation in the antibiotic-resistant bacteria after treatment with quercetin, quantitative real-time PCR (qRT-PCR) was used to analyze the transcript levels of some efflux pump genes, finally, the whole proteins of S. aureus were extracted by the action of quercetin, following bicinchoninic acid (BCA) quantification, proteins were separated by SDS-PAGE, stained with Coomassie Brilliant Blue, and overall changes in total protein bands were observed. The results showed that 64-256 µg/mL quercetin significantly increased the accumulation of ciprofloxacin in antibiotic-resistant bacteria, inhibited the efflux of ciprofloxacin by 2-10-fold downregulation of the expression of the efflux pump genes norA, norB, norC, and mepA, and modulated the protein expression profile of S. aureus. This study revealed that quercetin has the potential to act as an efflux pump inhibitor, providing a theoretical basis for the treatment of antibiotic-resistant bacterial infections.