Journal of Veterinary Research最新文献

Introduction: Chlamydia felis is the main chlamydial pathogen of cats and is associated with conjunctivitis and respiratory disease. This study aimed to estimate the prevalence of Chlamydiaceae and Chlamydia felis, to explore risk factors and predictors (age, sex, breed, origin and ocular signs) for infection using logistic regression, and to appraise genetic diversity via ompA sequencing and phylogenetic analysis.

Material and methods: Conjunctival swabs from 156 cats were examined using real-time PCR assays for Chlamydiaceae and C. felis. Logistic regression and Kaplan-Meier analysis evaluated risk factors, and partial ompA sequences were phylogenetically analysed.

Results: Chlamydiaceae DNA was detected in 7.7% (12/156) of cats and was identified as C. felis. Infections were mostly unilateral. Threshold cycle values varied widely, suggesting heterogeneous bacterial loads. Younger age was a significant risk factor, and the probability of infection decreased steadily with age. Ocular signs strongly predicted infection. British Shorthair/Longhair cats had more than threefold higher odds of infection than European Shorthair cats. Phylogenetic analysis of ompA showed very high genome conservation (99.7-100%), which was consistent with global data.

Conclusion: This first molecular study of C. felis in Poland in ten years demonstrates that infection mainly affects young, purebred cats with apparent conjunctivitis. The genetic stability of ompA supports the concept of a globally homogeneous C. felis population.

Introduction: To monitor the occurrence of antibiotics in feed, a two-step control strategy is often adopted of screening by microbiological inhibition followed by confirmation by chromatographic techniques. This study is devoted to the development of a reliable method for simultaneous determination of lincomycin, spiramycin, tylosin and tiamulin in animal feed using liquid chromatography coupled to mass spectrometry after a microbial assay.

Material and methods: The analytes were extracted from feed using a methanol:water mixture, and solid-phase extraction was employed for the isolation of the antibiotics. The determination of the presence of lincomycin, spiramycin, tylosin and tiamulin was carried out using high-performance liquid chromatography with mass spectrometry.

Results: The method was validated according to EU requirements. The decision limit and detection capability were 0.213-0.318 and 0.259-0.535 mg kg^-1, respectively, and the limits of detection and quantification were 0.029-0.151 and 0.069-0.223 mg kg^-1, respectively, depending on the analyte. Recoveries were satisfactory (86.6-105.1%), repeatability ranged from 2.6 to 18.3% and reproducibility from 6.2 to 11.7%.

Conclusion: The proposed method is reliable and applicable to identify four antibiotics for feed-safety control.

Introduction: Small ruminant lentivirus (SRLV) infections occur worldwide in goats and sheep and have negative impact on the production and welfare of animals. During recent years, many studies have focused on the host factors that determine the resistance of individual animals to SRLV infection; consideration of such factors would be an alternative to current control programmes based on culling seropositive animals. The aim of this study was to analyse the relationship between the expression of two previously selected goat genes, TMEM154 encoding transmembrane protein 154 and PARP14 encoding poly ADP-ribose polymerase 14, and the kinetics of SRLV replication in primary skin cells of goats. Potential role of these genes as host factors determining susceptibility to SRLV infection was investigated.

Material and methods: Primary fibroblast cultures obtained from the skin of goats with high SRLV proviral DNA load (HPL), low proviral load (LPL) or free of infection were inoculated with the A5 SRLV subtype circulating in the flock. The course of infection was observed based on cytopathic changes in cell cultures and the presence of SRLV A5 RNA, of which the level was monitored using a quantitative reverse-transcription PCR. The relative expression of the selected host genes following SRLV infection was analysed.

Results: The kinetics of SRLV replication differed, and distinctly higher numbers of SRLV particles were detected in cells derived from the HPL animal. The expression profiles of TMEM154 and PARP14 after in vitro SRLV infection also differed in skin cells derived from HPL from the profiles in LPL-animal cells.

Conclusion: The observed relationship between expression of TMEM154 and PARP14 and cell permissiveness after SRLV infection suggest their involvement in the infection process, but their utility as susceptibility factors still needs to be verified.

Introduction: Progesterone, a steroidal female sex hormone, can be used for anabolic purposes in cattle. Physiological levels of progesterone in animals are highly variable, and systematic studies of them in various matrices are limited. The purpose of the present study was to apply a developed and validated method routinely used for the determination of the natural hormones 17β-oestradiol and 17β-testosterone in serum to estimate natural cattle progesterone levels. The analytes were taken from serum samples collected from cattle as part of the Polish National Residue Control Plan.

Material and methods: A total of 1,537 bovine serum samples were analysed: 895 from females and 642 from males. Progesterone was extracted from serum with a mixture of tert-butyl methyl ether and petroleum ether, the extract was derivatised and the analyte was determined by gas chromatography coupled with mass spectrometry.

Results: The basic validation parameters specified for the method, namely repeatability, reproducibility and apparent recovery, indicated it to be useful for the intended purpose. The natural presence of progesterone was detected in 679 samples from females and in 375 samples from males. Progesterone in females was measured in the range of 0.001-496.059 μg L^-1 (in 61% of samples it was below 1 μg L^-1 and in 32% it was in the range of 1-7 μg L^-1, which are the physiological ranges of phases of the reproductive cycle) and progesterone in males was assayed in the range of 0.001-31.792 μg L^-1.

Conclusion: The results obtained may serve as a statistical basis for further research.

Introduction: Whole dead animals, parts of dead animals, products of animal origin or other products derived from animals that are not intended for human consumption are animal by-products, and legislation imposes restrictions on the use of those which may pose a risk to the food and feed chain. High-risk products should only be used outside the feed chain. Unsafe by-products are distinguished from safe ones, parcel by parcel, and those with the highest harm potential are permanently marked during processing with glycerol triheptanoate (GTH) to prevent their entry into the feed chain. The legislated minimum content of this marker must be 250 mg/kg of fat. This research is on the development and validation of methods using gas chromatography with flame ionisation or with mass spectrometry for GTH detection, and also comprises a report of compliance with the GTH content threshold among samples of animal by-products.

Material and methods: Between 2010 and 2024, 2,303 samples of meat and bone meal, rendering fat, processed animal protein, soil improvers, antioxidants, feed materials and mixtures, dog chews, feathers, bird balls and unknown material of animal origin were tested. Gas chromatography was used with either flame ionisation detection or mass spectrometry.

Results: Samples that did not meet the requirements under applicable law accounted for approximately 10.5% (240 samples). The highest percentage of non-compliant samples was recorded in the processed animal proteins group (20.7%). Incorrectly marked meat and bone meal and rendered fat accounted for 8% and 12% of their groups, respectively.

Conclusion: Nearly 90% of the samples tested were correctly marked with GTH as required or free of it, which may indicate progress in developing effective marking technology at processing plants.

Introduction: Gastrointestinal mycobacteriosis in horses is difficult to diagnose because of the pathogen's intracellular nature and the non-specific clinical symptoms. Effective accurate diagnosis facilitates prognosis and treatment. Current diagnostic procedures and methods of collecting material do not permit definitive antemortem diagnosis. However, culturing, acid-fast bacilli staining, histopathology, PCR and immunological marker evaluation may prove useful.

Material and methods: Three horses were admitted to a clinic for intensive care and a final diagnosis. Physical examination and additional tests were performed. Unfavourable prognoses and lack of treatment response prompted euthanasia decisions. Necropsy was performed, as were histological, microbiological and molecular investigations.

Results: The clinical condition of the animals deteriorated despite therapy. Two horses were euthanised when they did not respond to treatment and had poor prognoses. Intestinal mycobacteriosis caused by Mycobacterium avium subsp. hominissuis was diagnosed postmortem using laboratory investigations. One horse's diagnosis was established antemortem by cytological and microbiological examination of biopsy material from an abdominocentesis, and this animal was also euthanised because of its poor prognosis.

Conclusion: Mycobacteriosis should be considered in the differential diagnosis of chronic debilitating equine diarrhoea in addition to rhodococcosis, lawsoniosis, salmonellosis, gastric ulcers and food intolerance. Peritoneal fluid obtained by abdominocentesis proved to be an effective diagnostic method for microbiological and molecular identification of Mycobacterium avium subsp. hominissuis in horses with suspected enteric mycobacteriosis and concomitant ascites.

Introduction: Soil quality plays a crucial role for farm animals, particularly those raised under free-range or organic conditions. Substances contaminating soil with a significant impact on food of animal origin are persistent organic pollutants (POPs). Recently, polybrominated diphenyl ethers (PBDEs) were included in this group. Novel brominated flame retardants (nBFRs) may also be included soon because they behave similarly in the environment. The aim of the study was to develop and validate a multicomponent method for determining 10 PBDE congeners and 8 compounds classified as nBFRs in soil.

Material and methods: Three soil samples were taken from potentially contaminated sites and three from theoretically uncontaminated sites. A high-resolution gas chromatography coupled with high-resolution mass spectrometry method was adapted.

Results: The method demonstrated high sensitivity, precision and repeatability. The validated procedure enables quantification of $\sum \text{PBDEs}$ in the range of 0.16-1700 ng·g^-1 dry weight (d.w.) and $\sum \text{nBFRs}$ in the range of 0.072-1130 ng·g^-1 d.w. The optimised extraction and clean-up steps addressed the physicochemical diversity of the analytes and ensured reliable separation from co-contaminants. The levels of PBDEs in contaminated samples ranged from 0.23 to 485.7 ng·g^-1 d.w., while nBFRs were detected at significantly lower levels (0.11-0.81 ng·g^-1 d.w.).

Conclusion: Given the absence of regulatory limits for BFRs in food and feed, and their documented presence in agricultural products, the developed method provides a valuable tool for environmental monitoring and risk assessment related to soil contamination and its potential impact on food safety.

Introduction: This study investigates the correlation between intestinal flora and body condition score (BCS) in beef cattle, focusing on the impact of maternal body condition on gut microbiota and immune function in both cows and their offspring.

Material and methods: Faecal and blood samples were collected at various stages before and after parturition from Hereford beef cattle categorised into normal, higher and high BCS groups. Microbial DNA was extracted and analysed using 16S rRNA gene sequencing to assess microbial diversity and community structure.

Results: The research indicated that while maternal BCS had minimal impact on the gut microbiota of cows before and after parturition, significant differences were observed in the microbial composition of calf gut microbiota, particularly those of calves born to cows with higher BCS. Calves from high-BCS cows exhibited increased levels of Proteobacteria, a potential marker for dysbiosis. Immune function analysis revealed higher levels of interleukin 6 and tumour necrosis factor α in both cows and calves from higher-BCS groups, suggesting a link between maternal obesity and offspring health risks.

Conclusion: The findings point to the importance of managing body condition in pregnant cows to optimise calf health and reduce disease risks and to the linked role of gut microbiota.

Introduction: This study focused on the seasonal activity and species diversity of Culicoides biting midges collected from 11 locations along the western border of Poland and major livestock transit routes, and included screening for bluetongue virus (BTV) RNA.

Material and methods: The sampling was conducted between September and November 2024. Collected biting midges were counted and identified to the species level. The gonotrophic forms of the females were also determined. Pools of insects were tested for the presence of BTV genetic material using a reverse-transcription quantitative real-time PCR.

Results: A total of 13,022 individuals were identified. The results revealed spatial and temporal variation in midge abundance, likely influenced by local environmental conditions. A sharp decline in activity was observed after week 44, coinciding with decreasing ambient temperatures The widespread presence of Culicoides obsoletus / scoticus complex, recognised vectors of BTV, was confirmed along with high abundance of C. punctatus, a species considered a potential vector. All gonotrophic forms were identified, and 57.3% of females had taken a blood meal, indicating active reproduction and frequent host-animal contact throughout the sampling period. Pools of blood-fed, parous and gravid females were tested for BTV RNA, but all samples returned negative results.

Conclusion: Although no evidence of active BTV circulation was found, the presence of competent vectors and favourable autumn conditions highlights the potential risk of transmission. These findings underscore the need for continued entomological and virological surveillance to support early detection and control of BTV.

Introduction: Intestinal ischaemia-reperfusion (IR) injury has detrimental effects on both local and distant organs. Serious oxidative damage is caused by reperfusion, and betanin, known for its antioxidant properties, may reduce it. The aim of the present study was to test the hypothesis that betanin administration prior to intestinal IR may be protective of the lung parenchyma against damage inflicted by intestinal IR.

Material and methods: Forty-nine specific pathogen-free Charles River Wistar albino rats were divided into a sham group (without IR), an IR group (60 min of small-intestine ischaemia with 1, 4 and 24 h of reperfusion - group A and three subgroups) and a betanin-pre-treated IR group (intraperitoneal betanin at 50 mg/kg bw, administration 30 min before ischaemia followed by 1, 4 and 24 h of reperfusion - group B and three subgroups). Lung biopsies were screened for histopathological changes and immunohistochemical expression of anti-cyclooxygenase-2 (COX-2) and anti-proliferating cell nuclear antigen (PCNA).

Results: Pre-treatment with betanin significantly reduced cellular COX-2 expression during the early and late reperfusion periods (respective P-values <0.05 and <0.001) compared to the untreated group. Expression of PCNA was significantly upregulated in both injured groups comparted to the sham group. In betanin-pre-treated rats less than half the PCNA expression noted in the untreated rats was present in the late reperfusion period (group A at 24 h vs group B at 24 h; P-value < 0.001).

Conclusion: Betanin pre-treatment prior to intestinal IR is indicated to serve as a protective agent against the lung injury mediated by the intestinal injury.