Veterinary World最新文献

Background and aim: The inland aquaculture sector in Saudi Arabia has expanded rapidly, with Nile tilapia (Oreochromis niloticus) becoming the dominant cultured species. However, limited national surveillance has restricted early detection of parasitic infestations that could indicate breaches in farm-level biosecurity. This study aimed to evaluate low-cost parasitological screening as a practical indicator of biosecurity performance by assessing parasite prevalence, diversity, and predictors across inland farms during two seasons.

Materials and methods: A sample of 30 fish from each farm was examined from 25 inland aquaculture sites sampled in summer and winter (2022-2023). External and internal parasitic infestations were evaluated through wet smears of the skin, fins, and gills, and by compression techniques for digeneans. Water quality parameters, serum cortisol levels, and farm management data were recorded. Parasites were identified to the genus-level. Predictors of infestation were analyzed using binary logistic regression followed by generalized linear mixed models.

Results: Six parasite groups were detected, with infestations recorded on all farms. Trichodina spp. showed the highest farm-level prevalence (96%) and fish-level prevalence (54.3%), followed by Cichlidogyrus spp. (92% of farms; 56.9% of fish). Dactylogyrus, Ambiphyra, Gyrodactylus, and Centrocestus were variably present, with the eastern region displaying the lowest diversity. Most infestations were mild. Significant predictors varied by parasite type: summer season increased the likelihood of Centrocestus, Dactylogyrus, Cichlidogyrus, and Ambiphyra; low pH strongly predicted monogenean and sessile ciliate infestations; dissolved oxygen and fish length also contributed to parasite-specific patterns. No clear association existed between infestation and elevated cortisol levels.

Conclusion: This nationwide two-season assessment shows that simple parasitological screening, especially for Trichodina and Cichlidogyrus, offers quick, affordable signs of biosecurity breaches in inland O. niloticus aquaculture. The presence of parasites indicates past or current risks of pathogen introduction, highlighting the importance of better quarantine procedures, water quality management, and following national biosecurity guidelines. Regular quarterly parasitological checks, combined with water quality testing and improved farm hygiene, can enhance early detection and reduce the spread of disease across Saudi Arabia's aquaculture industry.

Background and aim: Microplastics (MPs) are persistent pollutants that build up in filter-feeding marine animals. Green mussels (Perna viridis), commonly eaten in Thailand, are effective bioindicators of water pollution. However, there are still limited standardized histopathological methods for detecting MPs and assessing lesions. This study aimed to develop a three-part histopathological exam using light microscopy, polarized light microscopy, and Nile Red (NR) fluorescence, and to analyze MP distribution and linked tissue effects in mussels collected from industrial shoreline areas in Rayong Province.

Materials and methods: Sixty-one mussels were collected from three coastal sites near an industrial estate. Target tissues were processed using a novel isopropanol-based, xylene-free protocol to prevent MP loss. Serial sections were stained with hematoxylin-eosin, evaluated under polarized light, and analyzed for NR fluorescence. Particle confirmation required co-localization across all three methods. Histopathological lesions were scored semi-quantitatively, and statistical associations were assessed using Fisher's exact test, McNemar's test, and generalized estimating equations.

Results: MP prevalence was 59.0% using light and polarized microscopy, 44.3% with NR fluorescence, and 39.3% with trimodal confirmation. The digestive tract showed the highest MP accumulation (64.1%), followed by the gills (33.3%) and the digestive glands (15.4%). Most MPs were irregular fragments (91.67%), mainly 10-100 μm in size. Mussel size was not significantly linked to MP contamination (p = 0.224). Notably, 88.9% of MP-positive tissues showed no observable histopathological changes; only 11.1% had mild to moderate lesions, including epithelial cell damage and hemocyte infiltration in digestive tracts, gills, and digestive glands.

Conclusion: The standardized trimodal histopathological approach offers a reliable, fast, and xylene-free method for MP detection in P. viridis. Digestive tracts, gills, and digestive glands are the most informative tissues for biomonitoring. Although many tissues did not show obvious lesions, the presence of mild pathological changes highlights the potential for sublethal effects in chronically exposed populations. This method improves diagnostic accuracy by reducing false positives and provides a consistent framework for MP surveillance in industrial coastal zones.

Background and aim: Corn is the main cereal used in broiler nutrition because of its high energy content and carotenoid richness, while wheat and barley offer alternative nutrient profiles that may increase production flexibility. However, their relative impacts on broiler performance, carcass traits, meat physicochemical properties, and consumer sensory perception under standardized enzyme-supplemented conditions remain unclear. This study examined the effects of partially replacing corn with wheat or barley on growth performance, carcass yield, meat quality, and consumer sensory evaluation in broiler chickens.

Materials and methods: A total of 525 male ROSS 308 broilers were randomly assigned to three dietary treatments: corn (C), corn-wheat (CW), and corn-barley (CB), with five replicates of 35 birds each. Diets were isocaloric and isonitrogenous and supplemented with a xylanase-β-glucanase complex. Birds were raised for 35 days under controlled environmental conditions. Growth performance, carcass traits, meat color (L*, a*, b*), pH, water-holding capacity, texture profile, and consumer sensory attributes were evaluated using standardized protocols. Data were analyzed using General Linear Model procedures with significance set at p < 0.05.

Results: Broilers fed with corn showed numerically higher body weight gain (+4.8% compared to CW; +4.4% compared to CB) and a tendency toward improved feed conversion ratio (1.52 vs. 1.56-1.58; p = 0.10). Including barley significantly increased abdominal fat (+36% vs. corn; p = 0.04), while wheat resulted in the lowest fat deposition. Meat yellowness (b*) was highest in the corn group at both 45 min and 24 h postmortem (p < 0.05, p < 0.01), reflecting the higher carotenoid content of corn. No significant differences were found among treatments for pH, drip loss, cooking and thawing loss, texture parameters, or sensory scores (p > 0.05). All sensory attributes scored above 4.3 on the 7-point scale.

Conclusion: Moderate inclusion of wheat (12%-20%) or barley (8%-15%) in enzyme-supplemented diets did not affect growth performance, carcass yield, meat physicochemical traits, or consumer sensory acceptance. Wheat might be used strategically to reduce abdominal fat, while corn remains preferred when enhanced yellowness is desired. These findings support the practical use of wheat and barley as viable alternatives to corn in commercial broiler feeding programs.

Background and aim: Methicillin-resistant coagulase-positive Staphylococci (MRCoPS), including methicillin-resistant Staphylococcus pseudintermedius (MRSP), methicillin-resistant Staphylococcus aureus (MRSA), and methicillin-resistant Staphylococcus coagulans (MRSC), are emerging zoonotic pathogens in veterinary hospitals, posing significant infection control challenges. This study aimed to investigate the molecular epidemiology, antimicrobial resistance profiles, and clonal dissemination of MRCoPS across environmental surfaces, veterinary personnel, and canine patients at the Veterinary Teaching Hospital, Chulalongkorn University (VTH-CU), Thailand.

Materials and methods: A cross-sectional study was conducted involving 216 environmental samples, 23 veterinary staff, and 14 canine patients. Isolates were identified using biochemical tests, polymerase chain reaction (PCR), and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry. Methicillin resistance was confirmed by mecA gene detection. Antimicrobial susceptibility was evaluated through disk diffusion following Clinical and Laboratory Standards Institute guidelines. Molecular typing was performed using staphylococcal cassette mec (SCCmec) PCR and pulsed-field gel electrophoresis (PFGE). Multivariate logistic regression identified environmental predictors of MRCoPS contamination.

Results: Among 88 coagulase-positive isolates, 62 (70.5%) were methicillin resistant, predominantly MRSP (91.9%), followed by MRSC (8.1%) and MRSA (1.6%). Floors represented the principal environmental reservoir, with significantly higher contamination odds than medical instruments (adjusted odds ratios [AOR] = 0.32; 95% confidence interval = 0.12-0.86; p = 0.024). The dermatological unit showed a six-fold higher risk of MRCoPS contamination than the medicine unit (AOR = 5.86; p = 0.027). All MRSC isolates carried SCCmec type V and displayed a consistent triple resistance pattern (gentamicin-clindamycin-erythromycin), while MRSP isolates exhibited diverse antibiograms and untypeable SCCmec elements. PFGE revealed clonal similarity (pattern A) between canine and environmental isolates, confirming the potential for nosocomial transmission.

Conclusion: MRCoPS, particularly MRSP, were widely distributed and persistent in the VTH-CU environment, despite routine cleaning. The clonal overlap among environmental and canine isolates highlights potential cross-contamination within the hospital. Strengthened disinfection protocols, antimicrobial stewardship programs, and regular environmental surveillance are imperative to mitigate the spread of multidrug-resistant staphylococci. This study highlights the importance of integrating environmental, animal, and human infection control practices in veterinary facilities within the context of One Health.

Background and aim: Hypertrophic cardiomyopathy (HCM) is the most common form of cardiomyopathy in cats and is often linked with diastolic dysfunction and progressive remodeling of the left atrium (LA). While LA strain analysis has been utilized to measure atrial function, LA stiffness (LASt), a load-adjusted marker that combines diastolic filling pressures and atrial deformation (E:E'/εS), has not yet been studied in feline patients. This study aimed to compare LASt between normal cats and those with HCM and to assess its correlation with traditional echocardiographic parameters of LA and left ventricular (LV) function.

Materials and methods: This retrospective cross-sectional study included client-owned cats evaluated at a university teaching hospital between August 2021 and August 2022. Cats were classified as normal or HCM based on LV wall thickness (≤5 mm vs. ≥6 mm). Standard echocardiographic parameters, doppler indices, tissue Doppler imaging (TDI) values, and two-dimensional speckle-tracking echocardiography (STE)-derived LA strain variables (reservoir, conduit, and active strain) were measured. LASt was calculated as E:E'/εS. Group comparisons were performed using t-tests or Mann-Whitney U tests, and correlations were assessed using Pearson's coefficient.

Results: Thirty-seven cats met the inclusion criteria (12 with HCM and 25 normal). Cats with HCM showed significantly higher LASt values compared to normal cats (median 2.26 vs. 0.30; p < 0.001), representing approximately a sevenfold increase. Reservoir strain (εS), conduit strain (εE), and active strain (εA) were all significantly lower in the HCM group (p < 0.001). LASt showed strong positive correlations with LA diameter and LA:Ao ratio (r ≥ 0.85; p < 0.001), and moderate-to-strong correlations with Doppler and TDI markers of diastolic dysfunction, including E:A ratio, MV A velocity, MV E', and MV S'.

Conclusion: LASt, measured by STE, provides a sensitive, load-inclusive index of LA mechanical dysfunction in cats with HCM and may detect atrial remodeling earlier than strain alone. Its strong association with established markers of diastolic impairment supports its potential clinical utility for identifying subclinical atrial dysfunction. Larger longitudinal studies are warranted to validate LASt as a prognostic biomarker and to define clinically relevant thresholds for disease staging and monitoring.

Background and aim: Free-range laying hens raised under tropical climates are susceptible to heat stress (HS), which compromises intestinal integrity, nutrient absorption, and egg quality. Ganoderma lucidum (Lingzhi) contains potent antioxidant compounds, but its efficacy in animal diets is limited by poor solubility and stability. This study evaluated the effects of dietary microencapsulated G. lucidum extract (MGE) on laying performance, antioxidant capacity, intestinal morphology, and nutrient digestibility in free-range hens under high-temperature conditions.

Materials and methods: A total of 256 Hy-Line Brown hens (25 weeks old) were randomly assigned to four dietary treatments with four replicates of 16 birds each: (i) basal diet (control [Con]), (ii) basal diet + free G. lucidum extract (1, 000 mg/kg), (iii) MGE at 1, 000 mg/kg (MGE0.1), and (iv) MGE at 500 mg/kg (MGE0.05). The trial lasted 12 weeks under natural tropical temperatures. Productive performance, egg quality, fatty acid profile, jejunal histomorphology, and antioxidant indices were analyzed. Statistical analysis was conducted using one-way analysis of variance with Tukey's test (p ≤ 0.05).

Results: MGE supplementation improved average egg weight and albumen height without affecting feed intake or feed conversion ratio. Both MGE0.1 and MGE0.05 increased jejunal villus height, width, surface area, and the villus height-to-crypt depth ratio compared with the Con. group. MGE diets significantly increased apparent ileal digestibility of dry matter, crude protein, gross energy, and ash. Enhanced antioxidant responses were observed, including higher total antioxidant capacity (15%-19%), superoxide dismutase (15%-22%), and catalase activity, with a concurrent 46%-47% reduction in malondialdehyde. Additionally, MGE diets reduced yolk cholesterol and the n-6/n-3 polyunsaturated fatty acid ratio.

Conclusion: MGE effectively enhances intestinal morphology, antioxidant defense, and nutrient utilization in free-range hens exposed to HS, thereby improving egg quality and the yolk lipid profile. MGE represents a promising natural antioxidant and feed additive for sustainable poultry production under tropical conditions.

Background and aim: The Ovar-DRB1 gene, a key component of the sheep main histocompatibility complex (MHC) class II region, plays a critical role in antigen presentation and immune responsiveness. Despite the well-documented hypervariability of exon 2 in many sheep breeds, no study has yet examined DRB1 allelic composition in Edilbay sheep, a Kazakh breed highly adapted to harsh continental steppe conditions. This study aimed to characterize the diversity of Ovar-DRB1 exon 2 alleles in Edilbay sheep and to identify novel allelic variants using Sanger sequencing.

Materials and methods: Blood samples from 50 Edilbay sheep reared at a breeding farm in Kazakhstan were subjected to DNA extraction and DRB1 exon 2 amplification using validated primers. Polymerase chain reaction products were purified and sequenced using Sanger sequencing. Allele identification was performed through pairwise sequence alignment in SnapGene and reference comparison with the Immuno Polymorphism Database of Major Histocompatibility Complex (IPD-MHC) database. Ambiguous chromatograms and overlapping nucleotide peaks were assessed for potential novel allelic patterns. Genetic diversity indices (Ho, He, Ne, and Shannon's H') were calculated.

Results: A total of 25 known DRB1 alleles were identified in the Edilbay sheep population. Genetic diversity parameters demonstrated extremely high immunogenetic variation, with observed heterozygosity (Ho) of 0.94, expected heterozygosity (He) of 0.90, an effective number of alleles (Ne) of 16.7, and Shannon's index (H') of 3. Several chromatograms showed overlapping peaks or substitution patterns inconsistent with known alleles, including variations at positions 243-244 and multiple additional polymorphic sites. These patterns indicate the presence of putative novel alleles that could not be unambiguously assigned by direct Sanger sequencing. Approximately 20% of samples contained undocumented variants or low-quality chromatograms requiring further resolution.

Conclusion: This study presents the first comprehensive molecular characterization of Ovar-DRB1 exon 2 in Edilbay sheep, revealing exceptionally high genetic diversity and strong evidence for previously undescribed alleles. These findings broaden the catalog of DRB1 variants and highlight the breed's adaptive immunogenetic potential. Further investigations using allele-specific amplification, cloning, or next-generation sequencing are recommended to precisely identify novel variants and explore associations with disease resistance and environmental adaptation.

Background and aim: Rabies remains a fatal zoonotic disease of major public health importance in Vietnam, with rising human and animal cases in recent years. Achieving effective control requires high vaccination coverage in dogs and cats, as well as a clear understanding of the behavioral factors influencing vaccination decisions. This cross-sectional analytical study aimed to assess vaccination coverage, examine determinants of proactive vaccination behaviors, and classify pet owners based on their knowledge, attitude, and practice (KAP) regarding rabies prevention in Duc Hue District, Long An Province, during the 2024 mass vaccination campaign.

Materials and methods: The study was conducted across 11 communes between January 10 and April 25, 2024. Data collection included a general household survey and a structured KAP questionnaire. Digital tools such as KoboToolbox, QGIS version 3.36, and RStudio version 4.5.1 were used for data entry, mapping, and statistical analysis. Logistic regression identified demographic and logistical variables associated with proactive vaccination behavior. Principal component analysis (PCA) and cluster analysis (CA) were used to classify pet owners into behavioral groups based on KAP score patterns. Ethical approval was obtained from Nong Lam University and the Long An People's Committee.

Results: A total of 6,899 of 8,776 pets were vaccinated, achieving a coverage rate of 78.6%, surpassing the national target of 70% for 2022-2025, although coverage varied widely across communes (60.63%-87.78%). Logistic regression revealed that higher education levels, specific occupations, shorter distance to veterinary services, and smaller total pet populations were significant predictors of proactive vaccination behavior. PCA and CA identified three distinct groups of pet owners. The group with higher education levels and farming occupations demonstrated the strongest KAP profile, while the lowest-performing group was associated with limited education and greater logistical challenges in accessing veterinary services.

Conclusion: This study presents the first integrated behavioral-statistical classification of pet owners in southern Vietnam using PCA and clustering, providing a data-driven foundation for more targeted rabies vaccination interventions. Addressing logistical barriers, improving equitable access to veterinary services, and tailoring educational activities toward low-performing groups are essential for sustaining vaccination gains and advancing Vietnam's goal of achieving 80% coverage by 2030.

Background and aim: Highly pathogenic avian influenza (HPAI) remains a global threat to poultry production, trade, and public health. While Morocco has not yet reported confirmed HPAI outbreaks, the endemic circulation of low-pathogenic avian influenza (LPAI) H9N2 since 2016, proximity to affected neighboring countries, and Morocco's position along migratory bird flyways highlight the country's vulnerability. This study aimed to identify high-risk areas for HPAI introduction and spread to inform risk-based surveillance and control policies.

Materials and methods: We applied a spatial multi-criteria decision analysis integrated with geographic information systems at the provincial scale. Relevant risk factors were identified through a literature review and expert consultation, and categorized into the introduction (wetlands, live poultry imports, recreational bird imports, and poultry products) and spread (poultry density and type, live bird markets, transport networks, and human population density) domains. Weights were assigned to factors using the analytic hierarchy process based on responses from 73 poultry-sector experts. Data were normalized, integrated into composite risk maps, and validated against historical LPAI H9N2 outbreak data (2016). Sensitivity and uncertainty analyses were used to assess model robustness.

Results: The final maps revealed that 25 provinces (33.3% of the national territory) exhibited high-to-very high risk of HPAI introduction, particularly along northern coastal provinces, border regions, and areas linked to recreational bird imports. For spread risk, 41 provinces (41.3%) were classified as high to very high, concentrated in the Casablanca-Settat, Rabat-Salé-Kenitra, Fès-Meknès, and Marrakech-Safi regions, which are characterized by dense poultry production, major trade hubs, and extensive transport networks. Sensitivity analyses confirmed the model's stability, with variations in weight producing a minimal impact on risk classifications.

Conclusion: This study provides the first comprehensive spatial risk maps of HPAI introduction and spread in Morocco, highlighting priority provinces for early detection, targeted surveillance, and preventive biosecurity measures. Despite limitations arising from reliance on LPAI data and expert judgment, the approach offers a robust decision-support tool for veterinary authorities. The methodology is adaptable to regional applications and can be refined with real-time surveillance data, enhancing Morocco's preparedness and resilience against future avian influenza incursions.