Veterinary World最新文献

Background and aim: Palmitic acid (PA) (C16: 0) is a rumen-inert long-chain fatty acid (FA) widely used in dairy cattle to increase dietary energy density and milk fat synthesis; however, its effects in dairy goats remain poorly characterized. This study evaluated whether supplementing 3% or 6% PA in the diet of mid-lactation goats could improve milk yield, composition, FA profile, and whole-animal energy balance under semi-arid Mexican production conditions.

Materials and methods: Twenty-one multiparous crossbred goats (45.8 ± 1.2 kg; 21 ± 3 days in milk) were randomly assigned to three treatments for 6 weeks after a 2-week adaptation: (1) Control diet (without PA), (2) diet + 3% PA, and (3) diet + 6% PA on a dry-matter (DM) basis. Diets were isoenergetic and isoproteic before PA addition. Individual DM intake (DMI), milk yield, and composition were measured daily; milk FA profiles and energy balance were determined on days 0, 21, and 42. Data were analyzed using a mixed-model with repeated measures, and means were compared using the Tukey test (p ≤ 0.05).

Results: PA inclusion did not affect DMI, body weight, or milk yield. However, milk fat concentration and yield increased significantly (p < 0.01) in both PA treatments, with the highest fat concentration observed at 6% PA. The milk FA profile shifted toward greater C16: 0 and C16: 1 proportion (p < 0.0001) and decreased short-chain (C16) FA fractions. Energy-corrected milk yield rose by ~40% in PA-fed goats, and energy balance improved markedly from week 3 onward, particularly in the 3% group (p < 0.01), indicating superior dietary energy utilization without intake suppression.

Conclusion: Moderate PA supplementation (~3% DM) effectively enhances milk fat synthesis and energy efficiency in goats while maintaining stable intake and yield. Increasing PA beyond 3% confers minimal additional benefit and may overly saturate milk fat. These findings provide species-specific evidence that rumen-inert fat inclusion can be an efficient strategy to support metabolic status and product quality in mid-lactation goats under variable forage systems.

Background and aim: An increased proportion of female piglets is desirable in commercial swine breeding to improve productivity, facilitate genetic selection, and reduce the need for male castration. However, currently available sex-selection techniques, such as flow cytometry, are costly and impractical for routine field use. This study evaluated the potential of rabbit serum albumin (RSA) as a low-cost biochemical modulator to influence the proportion of female offspring, comparing its effects with those of other albumin sources and determining optimal supplementation conditions for boar semen used for artificial insemination (AI).

Materials and methods: Eight Landrace boars were initially screened in vitro to assess sperm quality and the proportion of X- and Y-bearing sperm following incubation with albumin. Four boars (A, B, E, and G) showing a higher X-sperm proportion were subsequently selected for in vivo trials involving 130 sows. Semen was diluted in a conventional extender supplemented with albumin (RSA, porcine serum albumin, or bovine serum albumin) or left unsupplemented (control). The effects of albumin source, concentration (0.1-0.2 mg/mL), incubation temperature (25°C vs. 37°C), duration (5-15 min), and boar variation were examined. Offspring sex ratio and litter size were analyzed using the Kruskal-Wallis test, followed by Dwass-Steel-Critchlow-Fligner pairwise comparisons (p < 0.05).

Results: All albumin treatments significantly increased (p < 0.05) the proportion of female piglets compared with controls. RSA yielded the greatest effect, particularly at 0.1 mg/mL incubated at 37°C for 15 min, producing up to 61.8% female offspring compared with 24.8% in controls. Boars with an initial male-biased sex ratio showed the largest improvement after RSA treatment. Although litter size decreased slightly with albumin supplementation, the difference was not statistically significant (p ≥ 0.05).

Conclusion: Supplementation of semen extenders with RSA effectively increased the proportion of female piglets without compromising fertility. This method offers a practical, scalable, and economical alternative to conventional sex-sorting technologies for swine breeding. Further optimization and larger-scale validation are warranted to ensure consistent litter performance and broader adoption in commercial production systems.

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.

Background and aim: Aeromonas hydrophila is a zoonotic, antimicrobial-resistant pathogen that causes significant losses in aquaculture and raises important One Health concerns. Outer membrane protein (OMP)-based subunit vaccines provide a targeted, antibiotic-sparing alternative to traditional bacterins, but validation across mammalian species remains limited. This study assessed the immunogenicity, safety, and protective effectiveness of a native ~34 kDa Omp34 (nOmp34) subunit vaccine in BALB/c mice, comparing it to a formalin-killed cell (FKC) vaccine, and examined immune factors that may predict survival.

Materials and methods: Female BALB/c mice (n = 13 per group) received subcutaneous injections of phosphate-buffered saline (PBS), FKC, FKC + incomplete Freund's adjuvant (IFA), or native Omp34 + IFA on days 0, 14, and 28. Immune responses were assessed by measuring anti-Omp34 immunoglobulin (Ig)G2a levels via enzyme-linked immunosorbent assay, serum lysozyme activity, nitroblue tetrazolium (NBT) respiratory burst, and phagocytic activity at specified intervals up to day 42. On day 42, mice were challenged intraperitoneally with a lethal dose of A. hydrophila, causing 80% mortality, and observed for 14 days for survival, clinical scores, and body weight changes. Data analysis involved analysis of variance with Tukey post hoc tests, mixed-effects modeling, Spearman correlation, receiver operating characteristic curves, logistic regression, and Kaplan-Meier survival analysis.

Results: By day 42, all immune biomarkers showed clear separation (nOmp34+IFA > FKC + IFA > PBS; p < 0.05). NBT demonstrated the strongest correlation with survival (ρ ≈ 0.90) and the highest predictive performance (Area under the curve [AUC] ≈ 0.80), exceeding IgG2a and phagocytosis (AUC ≈ 0.70). Post-challenge survival rates were 84.6% for nOmp34 + IFA, 61.5% for FKC + IFA, and 23.1% for PBS, corresponding to relative percent survival values of 80% and 50% compared to PBS. The direct comparison between nOmp34 and FKC revealed a favorable but not statistically significant survival benefit (p = 0.238). Vaccination was well-tolerated, with stable body weight, minimal reactogenicity, and no severe clinical events.

Conclusion: The nOmp34 subunit vaccine elicited a strong, coordinated humoral and innate immune response, surpassing the matched bacterin in both efficacy and immune strength. NBT activity between days 35-42 proved to be a practical indicator of protection, aligning mechanistically with nicotinamide adenine dinucleotide phosphate -oxidase-mediated bacterial killing. These findings offer proof-of-concept for Omp34 as a scalable, antibiotic-sparing vaccine candidate and support its progression into aquaculture-relevant platforms within a One Health framework.

Viral infections continue to pose major challenges to pig health, farm productivity, and global food security. Early and accurate diagnosis is the cornerstone of disease prevention, surveillance, and control in swine populations. In recent years, remarkable progress has been achieved in molecular, serological, and digital diagnostic technologies, enabling more rapid, sensitive, and field-adaptable detection of important porcine viruses such as African swine fever virus, porcine reproductive and respiratory syndrome virus, and classical swine fever virus. This review summarizes current and emerging diagnostic approaches, highlighting polymerase chain reaction (PCR) and its advanced forms, quantitative PCR and digital PCR, as the gold standards for laboratory confirmation. The advent of next-generation sequencing and metagenomics has revolutionized pathogen discovery and genomic surveillance, providing comprehensive insights into viral evolution and transboundary transmission. Isothermal amplification techniques such as loop-mediated isothermal amplification and recombinase polymerase amplification have shown strong potential for on-farm diagnosis due to their simplicity, rapidity, and minimal equipment requirements. Innovations such as clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated-based assays, biosensors, lab-on-a-chip platforms, and point-of-care testing devices are bridging the gap between laboratory precision and field application, allowing rapid decision-making during outbreaks. The integration of artificial intelligence, machine learning, and geographic information systems has further enhanced diagnostic interpretation, real-time data sharing, and early outbreak prediction under the One Health framework. Despite these advances, challenges remain in ensuring assay standardization, affordability, and equitable access in resource-limited regions. Continued international collaboration, data sharing, and policy harmonization under the guidance of the Food and Agriculture Organization, the World Organization for Animal Health, and the World Health Organization are essential for the global control of swine viral diseases. Ultimately, combining molecular innovation with digital adaptability offers the most promising path toward resilient, cost-effective, and sustainable diagnostic systems for safeguarding animal and public health.

Background and aim: Canine monocytic ehrlichiosis, caused by Ehrlichia canis and transmitted primarily by Rhipicephalus sanguineus, is a common yet diagnostically challenging tick-borne disease in tropical regions. On the northern coast of Perú, environmental conditions favor vector persistence, but local data on clinical characteristics and risk determinants remain limited. This study aimed to determine the seroprevalence of E. canis in domestic dogs in Trujillo (La Libertad, Perú), describe associated clinical findings, and identify epidemiological risk factors linked to infection.

Materials and methods: A cross-sectional analytical study was conducted from December 2023 to August 2024 involving 462 dogs with compatible clinical signs and/or tick infestation from 18 veterinary clinics across three districts. Serological testing was performed with the CaniV-4® rapid test, and hematological parameters were analyzed with an automated analyzer. Epidemiological data were obtained through owner questionnaires. Associations were evaluated using chi-square tests, logistic regression (Odds ratio [OR], 95% CI), and Mann-Whitney U tests for hematological differences. A p-value < 0.05 with OR and lower CI >1 defined risk factors.

Results: The overall seroprevalence of E. canis was 51.3% (95% CI: 46.7%-55.8%). Sex and breed were not associated with infection. Dogs <1 year old (OR = 1.46), those lacking external deworming (OR = 1.99), fed homemade diets (OR = 2.26), and those frequently contacting stray dogs (OR = 4.33) were at significantly higher risk. Clinical predictors strongly associated with infection included lethargy (OR = 5.55), fever (OR = 5.52), anorexia (OR = 4.24), anemia (OR = 4.12), lymphadenopathy (OR = 3.46), and epistaxis (OR = 2.50). Seropositive dogs exhibited significantly reduced erythrocyte counts, hematocrit, hemoglobin, leukocyte counts, and platelet counts (p < 0.01). Although tick presence and park access were associated with seropositivity, their OR < 1 suggested confounding rather than true protective effects.

Conclusion: The high seroprevalence and significant clinical-hematological alterations highlight widespread exposure to E. canis among dogs in northern coastal Perú. Identified risk factors emphasize the need for integrated tick-control, improved owner awareness, and strengthened diagnostic protocols. Future research combining molecular confirmation, socioeconomic variables, and One Health-based surveillance is recommended to refine prevention and management strategies.

Background and aim: General anesthesia (GA) suppresses the blink reflex and lacrimal gland activity, making animals more vulnerable to precorneal tear film (PTF) issues. Although decreases in tear volume during GA are well documented, changes in PTF quality are not well understood. This study examined both the quantity and quality of PTF, including the Schirmer Tear Test-1 (STT-1), tear osmolarity (TO), tear ferning (TF), and punctate fluorescein staining (PFS), in healthy mesocephalic Canis familiaris undergoing routine non-ophthalmic surgery under GA.

Materials and methods: A prospective, randomized, pre-post study was conducted on 16 client-owned mesocephalic dogs (32 eyes). All subjects were clinically and ophthalmologically normal and classified as American Society of Anesthesiologists (ASA) I-II. Tear film parameters were evaluated at five perioperative time points: 30 min preoperatively (T0), 10 min post-premedication (T10), 5 min post-induction (T5), at first surgical incision (TS), and at discharge (TD). STT-1, TF, and TO were measured at each time point; PFS was performed at TD. GA consisted of methadone and dexmedetomidine premedication, propofol induction, and isoflurane maintenance. Mixed-effects regression, paired t-tests, and correlation analyses were applied, with p < 0.05 considered significant.

Results: STT-1 values significantly decreased from baseline (21.2 ± 3.3 mm/min) to T10 (13.5 ± 5.9 mm/min; p < 0.001), T5 (6.4 ± 6.3 mm/min; p < 0.001), and TS (0.8 ± 1.6 mm/min; p < 0.001). TO decreased from 374.4 ± 29.3 mOsm/L at T0 to 354.7 ± 28.2 mOsm/L at TS (p < 0.001). TF grades increased from 0.8 ± 1.0 at T0 to 1.5 ± 1.3 at T10 and 2.3 ± 1.4 at T5 (p < 0.001), indicating deterioration of PTF structure. Moderate correlations were observed among STT-1, TF, and TO. At TD, tear parameters remained significantly altered compared with T0, and PFS identified punctate epithelial lesions in 34.4% of dogs. Age showed a moderate negative relationship with STT-1 (b = -0.41 mm/min; p = 0.038).

Conclusion: GA causes a significant decline in the quantity and quality of the PTF, with incomplete recovery by discharge despite the return of spontaneous blinking. These findings emphasize the need for proactive perioperative ocular surface protection and highlight TF and TO as useful early indicators of anesthesia-related ocular surface impairment in mesocephalic Canis familiaris.

Background and aim: Genetically engineered pigs are invaluable biomedical models for xenotransplantation and the study of human diseases. Although electroporation (EP) and lipofection are individually effective for clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) ribonucleoprotein (RNP) delivery, their combined application in porcine embryos has not been systematically evaluated. This study aimed to determine whether packaging Cas9-guided RNA complexes in cationic lipids enhances EP-mediated gene editing efficiency without compromising embryonic development.

Materials and methods: Porcine zygotes with their zona pellucida removed were edited using RNPs targeting beta-1,4-N-acetyl-galactosaminyl transferase 2 (B4GALNT2) or growth hormone receptor (GHR) genes. Four treatment groups were tested: (1) EP with RNPs (EP), (2) EP with lipofectamine-packaged RNPs (EPL), (3) transfection with lipofectamine-packaged RNPs before EP (TL + EPL), and (4) EP followed by lipofection (EPL + TL). Blastocyst formation was evaluated morphologically, and mutation rates were assessed by Sanger sequencing followed by tracking of indels by decomposition (TIDE) analysis.

Results: Blastocyst formation rates were comparable across all treatments, indicating that lipofectamine packaging and EP caused no detectable cytotoxicity. For B4GALNT2, no mutations were induced by EP alone, whereas TL + EPL treatment significantly increased total and mosaic mutation rates (p < 0.05). For GHR, the total mutation and mosaic mutation rates were likewise higher in TL + EPL compared with EP, although mutation efficiency (indel percentage per edited embryo) remained unchanged. These results suggest that pre-EP lipofection promotes RNP uptake by facilitating lipid-membrane interactions that are potentiated by subsequent membrane destabilization through EP.

Conclusion: Packaging RNPs in cationic lipids and applying sequential lipofection followed by EP significantly enhances CRISPR/Cas9-mediated mutagenesis in porcine zygotes without affecting developmental competence. This dual-delivery approach provides a simple, reproducible, and low-toxicity workflow for generating gene-edited embryos, with potential applicability to large-animal biomedical models.