Journal of Veterinary Research最新文献

Introduction: Bovine leukaemia virus (BLV) is a Deltaretrovirus responsible for enzootic bovine leukosis, the most common neoplastic disease of cattle. It deregulates the immune system, favouring secondary infections and changes in the blood and lymphatic tissues. Blood homeostasis depends on functional haematopoietic stem cells (HSCs). Bone marrow is populated by these cells, which express CD34⁺ and CD35⁺ surface antigens and produce and release cytokines involved in the maintenance of haematopoiesis. The aim of the study was determination of the profile of cytokine production by CD34⁺ stem cells of cattle naturally infected with BLV.

Material and methods: The HSCs were generated from the blood and lymphoid organs of cows infected with BLV and healthy control cows with immunomagnetic separation and anti-CD34⁺ monoclonal antibodies. Isolated CD34⁺ cells were cultivated for two weeks with interleukin (IL)-4 and granulocyte-macrophage colony-stimulating factor. The levels of IL-6, IL-10, IL-12p40, IL-12p70, interferon gamma (IFN-γ) and tumour necrosis factor alpha (TNF-α) were determined in culture fluid by flow cytometry.

Results: The expression of IL-6, IL-12p70 and TNF-α in blood HSCs was higher in BLV⁺ cows than in the control animals. In bone marrow HSCs of infected cows, IL-12, TNF-α and IFN-γ were more concentrated, but in these cows' spleen HSCs only expression of IL-10 was elevated. In HSCs isolated from the lymph nodes of leukaemic cows, only TNF-α secretion was lower than in control cows, the other cytokines being more potently secreted.

Conclusion: Infection with BLV caused statistically significant differences in cytokine expression by HSC CD34⁺ cells.

Introduction: Carp oedema virus (CEV) is a relatively understudied poxvirus. It exhibits an affinity for gill and skin epithelial cells. Investigations were conducted into selected aspects of CEV biology, with a focus on determining cell and tissue tropism of CEV, acquiring gene sequences and updating CEV tests in fish tissues.

Material and methods: A total of 238 common carp tissue samples from nine aquaculture farms were analysed. The study evaluated the efficacy of intermediate detection of CEV by real-time PCR and in situ hybridisation. The genes encoding protein P4a were sequenced, analysed and aligned in a phylogenetic tree using a molecular evolution model.

Results: In situ hybridisation revealed the necessity to validate the Centre for Environment, Fisheries and Aquaculture Science protocols for sampling for CEV detection and to use the tissues for which the virus has the highest tropism, namely the skin and kidneys, rather than solely the gills. The level of genetic variability was determined, and it was shown that CEV mutates systematically. The creation of two distinct phylogenetic clades confirms certain strains' description as Polish isolates.

Conclusion: Determining the localisation of CEV genetic material in organs and tissues is pivotal for shaping the World Organisation for Animal Health guidelines. The utility of molecular diagnostics has been demonstrated in the skin and kidney of carp, in addition to the gills, impelling their inclusion in diagnostic protocols. The clusters identified in the phylogenetic tree offer valuable insights for developing the current PCR primers. The prevalence of CEV infection in aquaculture, juxtaposed with its notably lower detection in wild fish, underscores the significance of mandatory molecular diagnostic testing for CEV in carp farming.

Introduction: Since lagoviruses cannot be cultivated in vitro, using expression systems is an alternative and promising way of producing diagnostic viral antigens. It opens up their use as active immunogens for vaccine production.

Material and methods: Virus-like particles (VLPs) were produced in a baculovirus expression system in Spodoptera frugiperda 9 (Sf9) insect cells based on wild-type and mutated variants of the virus capsid VP60 protein from a Polish strain of European brown hare syndrome virus (EBHSV) and wild-type and mutated versions of this protein from a Polish strain of rabbit haemorrhagic disease virus 2 (RHDV2). The mutations were the substitution of an arginylglycylaspartic acid (Arg-Gly-Asp/RGD) motif in the P2 subdomain and, in the S or P2 domain, the substitution of three lysines. The VLPs were purified with sucrose gradient ultracentrifugation.

Results: Protein production was confirmed by Western blot analysis using rabbit or hare sera and ELISA tests with different types of monoclonal antibody. The haemagglutination properties of some VLPs were also evaluated. Electron microscopy of wild-type EBHSV, wild-type RHDV2 and the four VP60 variants produced in this experiment revealed the formation of characteristic VLP structures.

Conclusion: For the first time, mutated VLPs of RHDV2 with an RGD motif in the VP60 sequence were obtained, which could potentially be used to deliver cargo to eukaryotic cells. Virus-like particles based on the VP60 proteins of EBHSV and RHDV with a three-lysine substitution in the S or P2 domains were also obtained. Potential exists for VLPs of EBHSV and RHDV2 as vaccine candidates.

Introduction: The article presents a rapid and simple analytical procedure for determination of four sulfonamides (sulfadiazine, sulfamerazine, sulfamethazine and sulfamethoxazole), trimethoprim, tylosin and amoxicillin in animal medicated feed.

Material and methods: Eighteen medicated feed samples were analysed for active substances. The analytical protocol used a mixture of acetonitrile and 0.05 M phosphoric buffer, pH 4.5 for the extraction of seven antibacterial substances. After extraction, the samples were diluted in Milli-Q water and analysed by liquid chromatography with mass spectrometry. The developed procedure was subjected to validation in terms of linearity, selectivity, limits of quantification and determination, repeatability, reproducibility and uncertainty.

Results: The validation of the method was carried out in accordance with the criteria set out in Commission Implementing Regulation (EU) 2021/808 and ICH guidelines. This method provided average recoveries of 90.8 to 104.5% with coefficients of variation for repeatability and reproducibility in the ranges of 3.2-6.9% and 5.2-8.3%, respectively for all analysed antibacterial substances. The limit of detection and limit of quantification for all seven analytes ranged from 5.4 mg/kg to 48.3 mg/kg and from 10.4 mg/kg to 119.3 mg/kg, respectively. The uncertainty of the method depending on the compound varied from 14.0% to 24.0%. The validated method was successfully applied to the 18 medicated feeds.

Conclusion: The developed method can be successfully used to routinely control the content and homogeneity of seven antibacterial substances in medicated feed.

Introduction: Haemosporidian parasites are prevalent worldwide and can cause economic losses in poultry production. These parasites are arousing interest in Thailand and are found in many avian species. There is insufficient information on the genetic diversity of these alveolates from the largest families - Plasmodidae, Haemoprotidae and Leucocytozoidae - specifically parasitising ducks, turkeys, and geese.

Material and methods: Blood samples from 116 backyard poultry (60 ducks, 36 turkeys and 20 geese) in northeastern Thailand were investigated for Plasmodium spp., Haemoproteus spp. and Leucocytozoon spp. infections using microscopic examination and molecular approaches.

Results: A total of 37/116 birds (31.9%) had confirmed Plasmodium infections. The prevalence was 69.4% (25/36) in turkeys, 18.3% (11/60) in ducks, and 5.0% (1/20) in geese. Of these 37 positives, 86.5% were Plasmodium sp., 10.8% were P. gallinaceum and 2.7% were P. juxtanucleare. Sequence analysis based on the cytochrome b gene identified seven lineages, of which two were new lineages in backyard poultry.

Conclusion: This is the first report on the prevalence of haemosporidian parasites in backyard poultry in northeastern Thailand. The results provide important data for better understanding the molecular epidemiology of haemosporidian parasites infection in poultry in this region, which will be helpful in controlling these blood parasites.

Introduction: The broiler chicken digestive tract microbiome maintains the bird's immunity. Its composition has been shown to be important not only for the immune system but also for the gastrointestinal function and productivity of broiler chickens. If the microbiome is populated by supplementation with Lactobacillus, Pediococcus and Saccharomyces spp. - microorganisms with probiotic properties and alternatives to antibiotics - the immune system is stimulated. The use of probiotic supplements in the broiler production cycle can boost bird immunity and prevent adenovirus infection. The resilience of broiler chickens in different feeding schemes including supplementation with these microorganisms was assessed.

Material and methods: Four groups of Ross 308 chickens vaccinated on the standard scheme were investigated over 42 days. Group P received probiotics, prebiotics and vitamins; group AO received antibiotics; group P&AO received probiotics, prebiotics, vitamins and antibiotics; and the control group C received none of these. The birds' immunocompetence against common viral poultry pathogens and their immune response to an experimental challenge with a field strain of infectious bronchitis was evaluated by ELISA and production parameters were recorded.

Results: Mortality was only observed in the control group and was 10%. All birds from the P, P&AO and AO groups responded to the challenge as would be expected of appropriately immunised chickens.

Conclusion: The obtained results indicated that supplementation with synbiotic products and vitamins can enhance broiler chicken immunity and result in better production parameters.

Introduction: Determination of morphological and biochemical blood indices facilitates assessment of the health and welfare of horses, their nutrient demand, the effects of training already undertaken, and the horses' suitability for exercise. Identification of the season-dependent components and the effects of sex and exercise on changes in frequently referenced haematological and biochemical parameters was the main goal of the current study.

Material and methods: The blood morphology of 21 healthy adult Shetland ponies (11 mares and 10 stallions) aged 6.5 ± 1.4 years from the central Pomeranian region in Poland was analysed. Blood samples were taken once per season for one year.

Results: No statistically significant season-dependent differences were found in the blood morphology parameters in either mares or stallions before or after exercise. Beta-coefficient results revealed the strength and type of the relationship of red blood cell distribution width (RDW) and granulocyte count (GRA) with the season, of red blood cell count (RBC), haematocrit, mean corpuscular volume and mean platelet volume with the sex, and of RDW, white blood cell count, GRA and RBC with the exercise factor. Biomarkers demonstrating the relationship between aerobic and anaerobic levels of energy metabolism in the blood did not show any sex dependency in regression analysis.

Conclusion: The sex-independence of energy metabolism biomarkers may indicate the universality of these parameters. Both seasonality itself and its combination with the exercise factor took part in the formation of effective adaptive reactions for maintenance of morphological blood indices in the ponies during exercise.

Introduction: Ixodes ricinus ticks are an important vector and reservoir of pathogenic microorganisms causing dangerous infectious diseases in humans and animals. The presence of ticks in urban greenery is a particularly important public health concern due to the potential for humans and companion animals to be exposed to tick-borne diseases there. The study assessed the prevalence of Borrelia burgdorferi and Anaplasma phagocytophilum infection in I. ricinus ticks feeding on dogs.

Material and methods: The study consisted in analyses of I. ricinus ticks collected in 2018-2020 from owned and stray dogs in the north-eastern part of Lubelskie province (eastern Poland). An AmpliSens PCR kit was used for qualitative detection and differentiation of tick-borne infections.

Results: Infections of B. burgdorferi and A. phagocytophilum were detected in 10.9% and 12.9% of the examined ticks, respectively. One tick (0.7%) was co-infected by both pathogens. Infection with B. burgdorferi was significantly more highly prevalent in ticks collected from the owned dogs than from the strays (18.7% and 2.8%, respectively), whereas the prevalence of A. phagocytophilum was similar in both groups (12.0% and 13.9%, respectively).

Conclusion: The co-infection observed in the study suggests the possibility of simultaneous infection by both pathogens from a single tick bite. The presence of pathogens in ticks collected from dogs is a factor in assessing infection risk not only to companion animals but also to their owners, who are in close contact with their dogs and visit the same green areas recreationally.