Veterinary World最新文献

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: 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: 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: Highly pathogenic avian influenza virus (HPAI) H5N1 continues to threaten poultry biosecurity worldwide due to rapid antigenic drift and reassortment. Since late 2020, clade 2.3.4.4b strains have dominated outbreaks across multiple continents. This study genetically characterized H5N1 isolates circulating in Upper Egypt during 2023-2025, clarified their phylogenetic origin, and compared them with vaccine strains used nationally.

Materials and methods: A total of 100 samples from 25 broiler flocks showing respiratory and neurological symptoms across New Valley, Assiut, and El-Minya governorates were examined. Specimens were screened for avian influenza subtypes (H5N1, H9N2, H5N8, H6N2) and differential viral pathogens (Newcastle disease virus, infectious bronchitis virus, infectious laryngotracheitis virus, infectious bursal disease virus) using reverse-transcription quantitative polymerase chain reaction (RT-qPCR). Positive isolates were propagated in specific-pathogen-free embryonated chicken eggs and identified through hemagglutination and hemagglutination inhibition assays. Partial hemagglutinin gene sequencing and phylogenetic analyses were performed using Molecular Evolutionary Genetics Analysis version 7.0.

Results: HPAI-H5N1 was detected in 16% (4/25) of flocks, showing 25%-50% mortality. Five isolates displayed high hemagglutination titers (7-8 log2) and were confirmed as H5N1 subtype by RT-qPCR. Phylogenetic analysis classified New Valley-1-H5N1-2023 and New Valley-2-H5N1-2024 within clade 2.3.4.4b. These strains shared 96%-99% nucleotide and amino acid identity with recent Egyptian and Eurasian H5N1 isolates but only 72%-84% with currently used Egyptian vaccine seeds (e.g., MEFLUVAC [Kemin Industries, Inc., USA], EgyFlu [Nagy Awad Group, Cairo, Egypt]). Mutations R72S, A83D, and T140A were identified in receptor-binding and antigenic regions of hemagglutination, implying potential antigenic drift.

Conclusion: This is the first documentation of clade 2.3.4.4b HPAI-H5N1 circulation in broiler flocks of Upper Egypt. The low genetic relatedness to existing vaccine strains indicates probable vaccine mismatch and reduced protection. Continuous molecular surveillance, integration of full-genome sequencing, and periodic vaccine seed updates are essential for effective containment. Enhanced monitoring at the domestic-wild bird interface will help mitigate cross-species transmission and align with One Health strategies for zoonotic risk reduction.

Background and aim: Feline coronavirus (FeCoV) is a widely circulating Alphacoronavirus that causes mild enteric infections and, in some cases, progresses to Feline infectious peritonitis, a fatal systemic disease. FeCoV consists of two genotypes (I and II) and two biotypes (FeCoV and feline infectious peritonitis virus [FIPV]). Despite its importance, whole-genome data, particularly for FeCoV genotype II, remain limited in Thailand. This study aimed to determine the prevalence of FeCoV in domestic cats and to genetically characterize circulating strains using whole-genome and S gene sequencing.

Materials and methods: A total of 471 rectal swabs were collected from domestic cats presented to private small animal hospitals in Bangkok and neighboring provinces from October 2022 to October 2023. FeCoV detection and genotyping were performed using one-step reverse transcription polymerase chain reaction targeting the 3'UTR and S gene, respectively. Selected FeCoV-positive samples were subjected to whole-genome sequencing (WGS) (n = 4) and complete S gene sequencing (n = 6) using Oxford Nanopore technology with Minimap2, Racon, and Medaka pipelines. Phylogenetic and genetic analyses were conducted using MEGA program.

Results: FeCoV positivity was 21.87% (103/471), with higher detection in young cats (<6 months; 28.46%), though age, clinical status, and season showed no significant association (p > 0.05). Genotype I was overwhelmingly predominant (99.03%), whereas genotype II was rare (0.97%). Phylogenetic analysis revealed that Thai FeCoV-I strains clustered closely with Chinese and Dutch FeCoV-I strains, while the FeCoV-II strain grouped with Chinese FeCoV-II. Whole-genome pairwise comparisons showed high nucleotide and amino acid identities with their respective genotype references. No mutations were detected in the S1/S2 or S2 cleavage sites of Thai FeCoV-I, indicating conserved spike characteristics typical of FECoV biotypes. FeCoV-II exhibited the characteristic deletion and insertion patterns known for this genotype. No evidence of recombination with other coronaviruses was observed.

Conclusion: This study provides updated molecular epidemiology of FeCoV in Thailand and reports the first complete FeCoV-II genome sequences from the country. The predominance of FeCoV-I and the detection of conserved spike regions highlight the need for genotype-specific surveillance and the reconsideration of vaccine strategies that currently target FeCoV-II. Expanded nationwide monitoring and detailed recombination analyses are warranted to better understand FeCoV evolution and transmission in feline populations.

Background and aim: Pregnancy and lactation place significant physiological demands on dairy goats, affecting red blood cell (RBC) indices, white blood cell (WBC) profiles, and platelet traits. Despite the diagnostic value of hematology (HA), there are no longitudinal, breed-specific reference values for Thuringian Forest goats. This study aimed to describe changes over time in differential blood counts and platelet indices in clinically healthy does kept under BIOLAND-certified organic management.

Materials and methods: A longitudinal study was conducted over one year using 25 clinically healthy Thuringian Forest does. Monthly blood samples were collected from 3 months prepartum through 12 months postpartum, resulting in 295 samples. Hematological analyses included RBC count, hematocrit (HCT), hemoglobin (HGB), mean corpuscular volume (MCV), mean corpuscular HGB (MCH), mean corpuscular HGB concentration (MCHC), RBC distribution width (RDW), and HGB distribution width (HDW). Platelet parameters, platelet count (PLT), mean platelet volume (MPV), and platelet distribution width (PDW), and differential WBC counts (neutrophils, lymphocytes, monocytes, eosinophils, and basophils) were measured using a validated automated analyzer. Repeated-measures analysis of variance evaluated the effects of reproductive stage, parity, milk yield, milk composition, and litter size.

Results: Significant stage-dependent hematological changes were observed. RBC, HGB, and HCT decreased during late gestation and reached their lowest levels before birth, then increased gradually during lactation. MCV and MCH remained stable. PLT increased around parturition, MPV declined before birth and rose after, and PDW decreased steadily from late gestation through lactation. Neutrophils and total WBC counts increased toward parturition, while lymphocytes and monocytes rose during lactation. Eosinophils peaked at the start of lactation, and basophils declined after birth. Parity and milk yield significantly influenced certain RBC, platelet, and leukocyte parameters, whereas litter size showed no significant effect.

Conclusion: Thuringian Forest goats show unique hematological changes during pregnancy and lactation, reflecting metabolic, hormonal, and immune adjustments related to reproduction and milk production. These breed-specific, stage-specific reference values improve clinical interpretation and diagnosis in dairy goat management. To our knowledge, this is the first longitudinal hematological study of this breed in organic farming conditions.