Journal of Veterinary Research最新文献

Introduction: Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDFs) and polychlorinated biphenyls (PCBs) are a group of undesirable chemical substances classified as persistent organic pollutants (POPs). They enter the bodies of humans and animals mainly through the digestive tract. Therefore, the safety of the food chain with specific regard to keeping out these POPs depends heavily upon their elimination from animal feed. The aim of this study was to determine trends in PCDD/PCDF/PCB concentrations in three feed matrices over a six-year period.

Material and methods: Altogether, 360 feed samples were analysed using the isotope-dilution technique with high resolution gas chromatography coupled with high resolution mass spectrometry. Analysis of the variability of PCDD/PCDF, dioxin-like-PCB and non-dioxin-like-PCB concentrations by Mann-Kendall test and regression analysis for mean and median values was performed for the three most common feed categories (plant materials, fishmeal and feed mixtures).

Results: For two of the three types of feed materials analysed, changes in trends in the concentrations of the tested compounds over time were observed.

Conclusion: Considering the very limited amount of feed material analysis data on which to assess trends in dioxin concentrations, it is necessary to continue research on a wider group of feed types.

Introduction: Bovine leukaemia virus (BLV) is the aetiological agent of enzootic bovine leukosis. The aim of the study was to ascertain the ability of qPCR to detect proviral BLV DNA in various tissues from slaughtered cattle when BLV was suspected but serological testing was not possible.

Material and methods: Three types of tissues were collected during sanitary slaughtering of 22 cattle naturally infected with BLV: spleen, lymph node and muscle. The proviral load (PVL) was estimated in this tissue by a real-time quantitative PCR (qPCR) for BLV based on the pol gene. To measure provirus copy number per 10⁶ cells, the bovine histone H3 family 3A gene was also amplified by qPCR.

Results: The PVL was the highest in the spleen and ranged there from 1 to 59,188 copies/10⁶ cells, with four cases in which no proviral DNA was detected. In the lymph nodes the PVL ranged from 2 to 6,888 copies/10⁶ cells, with seven cases in which no copies were detected. The lowest PVL was recorded in DNA from muscle samples and ranged from 1 to 119 copies/10⁶ cells; no BLV was detected in 6 out of 22 samples.

Conclusion: The BLV qPCR is a suitable tool for the detection of proviral BLV DNA in various tissues when infection is suspected and no blood or other fluids are available for serological examination.

Introduction: Mitochondria are the primary sites for adenosine triphosphate production through oxidative phosphorylation, thus supporting the high metabolic demands of avian physiology. By administering prebiotics in ovo, the aim was to analyse how an early host-supporting strategy can modulate mitochondrial activity and affect the physicochemical composition of the pectoral muscles of chickens.

Material and methods: Three hundred incubated Ross 308 broiler eggs were injected: 60 with 0.2 mL of 0.2 mmol/L physiological saline (control group), and 60 each with 0.5 mg of xylotriose (XOS3 group), xylotetraose (XOS4 group), mannotriose (MOS3 group) or mannotetraose (MOS4 group) carried in 0.2 mL of physiological saline. On day 42 after hatching, the liver and pectoral muscle were collected from eight individuals from each group after sacrifice, and the muscle was evaluated physicochemically. Relative mitochondrial DNA (mtDNA) copy numbers were analysed in a real-time quantitative PCR (qPCR). Gene expression was determined by a reverse-transcription qPCR (RT-qPCR) for a mitochondrial gene panel.

Results: The experimental factor was not shown to affect pectoral muscle weight. Water loss was significantly greater in the XOS4 group's muscles. The overall mtDNA copy number was stable in both tissues. The XOS3 and MOS4 groups' gene expression was significantly changed in pectoral muscle. Contrastingly, the XOS4 and MOS3 groups' gene expression was more altered in the liver. Statistically significantly different expression was detected of the CS, EPX, CYCS, TFAM and NRF1 genes in pectoral muscles and of all tested genes in livers.

Conclusion: The potential of in ovo prebiotic administration is indicated as a strategic approach to optimise mitochondrial function, ultimately contributing to better growth rates and enhanced health in broiler chickens.

Introduction: Electrophoretic analytical techniques provide extremely important information about an animal's clinical condition. They are recommended in every case, including in screening tests of animals showing no concerning clinical symptoms. Such tests can detect subclinical conditions, such as inflammation, antigen stimulation or certain forms of cancer. The aim of the study was to determine the suitability of native serum protein electrophoresis and the comet assay for assessing the health status of cats.

Material and methods: Electrophoresis was performed on serum samples from 125 cats. On sera with abnormalities in electropherograms (25 individuals), the following additional analyses were performed: haematological analysis, microscopic examination of a blood smear, plate tests detecting antibodies against feline infectious peritonitis (FIP) and feline immunodeficiency virus (FIV), a plate test detecting feline leukaemia virus (FeLV) surface antigen and a comet assay in peripheral blood lymphocytes.

Results: Native protein electrophoresis enabled the identification of latent disease conditions in individuals assessed as good for overall condition on the basis of clinical examination. Some cats thus assessed had an abnormal electropherogram and were carriers of FIV, FeLV or FIP. In addition, the comet assay identified increased instability in the genetic material of cats with electropherogram abnormalities.

Conclusion: Electrophoretic techniques can be successfully used as a tools for identifying latent conditions and evaluating the overall health status of cats.

Introduction: The Silesian horse is a heavy warmblood breed developed in Polish Silesia through the covering of local mares by East Frisian and Oldenburg stallions. Because of its historical significance and genetic heritage, the breed is part of a conservation programme in Poland. One of the genetic disorders of concern in warmblood horses is fragile foal syndrome (FFS), an autosomal recessive disease caused by a mutation in the PLOD1 gene (c.2032G>A). Affected foals either perish in late pregnancy or are born with severe connective tissue abnormalities, leading to early death. As carriers do not exhibit symptoms, genetic testing is crucial for responsible breeding. This study aimed to assess the prevalence of the PLOD1 mutation in the Silesian horse population.

Material and methods: Samples of DNA from 284 breeding horses were analysed using PCR and restriction-fragment length polymorphism and validated by Sanger sequencing.

Results: The detected carrier frequency was 14.6%, an increase over previously reported carriage for this breed. Compared to other warmblood breeds, the carrier frequency in Silesian horses was higher than in Swedish Warmbloods, similar to the frequency in Hanoverians (14%) and also aligned with that in Oldenburg horses, from which Silesians historically derive.

Conclusion: The results highlight the need for continued genetic monitoring and informed breeding strategies to prevent the spread of FFS in the Silesian horse population.

Introduction: The virulence of Yersinia ruckeri, the causative agent of enteric redmouth disease in salmonids, is influenced by multiple factors, including flagellar gene expression. This study investigates the role of fliC gene expression in the pathogenicity of Y. ruckeri and its impact on the immune response of infected rainbow trout (Oncorhynchus mykiss).

Material and methods: Using two virulent strains differing in fliC expression, clinical symptoms, mortality rates and key immune parameters were evaluated. Ninety farmed rainbow trout with average body weight of 110.5 ± 24.1 g and average length of 20.7 ± 1.9 cm were used. Allocation was made of 10 fish each to a control group, a low-dose group challenged with one strain, a high-dose group challenged with that strain, and low- and high-dose groups challenged with the second strain, and each challenge group was duplicated.

Results: Fish infected with the fliC-repressed strain exhibited more severe symptoms, higher mortality rates and a weaker immune response regardless of infectious dose compared to those infected with the fliC-expressing strain. The lack of an active fliC gene was associated with a lower gammaglobulin level, decreased respiratory burst and suppressed T-cell proliferation. However, increased potential killing activity was noted for that strain.

Conclusion: These findings clearly demonstrate the dual role of the fliC gene in the pathogenicity of Y. ruckeri and host immune modulation in rainbow trout.

Introduction: Plant extracts have been noted to be effective against multiple bacterial and viral pathogens. The aim of the study was to determine the effect of a preparation based on nanoencapsulated thymol, carvacrol and cinnamaldehyde administered in the feed to farrowing sows on piglet production parameters.

Material and methods: The farrowing group unit had a stocking density of 1,100 pens, divided into groups of 25 stalls. The experiment was carried out in a group of 168 sows. The animals were selected and placed in the farrowing house in a randomised procedure. The animals were divided into two equal groups (84 animals in each), a control group and an experimental group. Appropriate biosecurity rules were applied and adhered to for each stage of production.

Results: The results showed positive effects of the supplement in feed in terms of average birth weight of litters and of piglets and number of piglet days fed by the sow. The experimental group of farrowing sows showed more effective feed consumption, better condition of the sows during weaning of the piglets, more even litters in terms of health and a significantly lower number of piglet deaths.

Conclusion: The use of the preparation positively influenced the number of piglets sold, with 88.5% reaching the market in the experimental group compared to 82.6% in the control group. In addition, fewer abortions and less lameness were observed in the experimental group than in the control group. The piglets born of control group sows performed worse economically than piglets born of experimental group sows, requiring feeding or being sold underweight.

Introduction: Bovine respiratory disease (BRD) complex is a leading cause of economic losses in the beef and dairy cattle industries. Mannheimia haemolytica is recognised as the primary pathogen associated with this disease. While antibiotics and vaccines are widely used against it, antimicrobial resistance and limited vaccine efficacy remain obstacles. Mannheimia haemolytica leukotoxin A (LktA) has been identified as a promising candidate for subunit vaccine development against BRD. However, the low expression and biological instability of the full-length LktA complicate its production. This study evaluated the immunogenic potential of the truncated LktA protein for subunit vaccine development.

Material and methods: Truncated proteins of LktA N-terminal (nLktA) and C-terminal (cLktA) were expressed in E. coli which were small enough for stable expression yet large enough to function as effective immunogens. The immunogenicity of the recombinant truncated LktA proteins was evaluated in mouse and goat models against a phosphate-buffered saline (PBS) negative-control group. Recombinant cLktA was emulsified with oil adjuvant and used to immunise mice and goats.

Results: The cLktA group had significantly higher antibody levels at four weeks post-immunisation (wpi) than the PBS group. In goats, cLktA elicited high antibody responses up to six wpi. A single administration of cLktA conferred 80% and 100% survival against a M. haemolytica challenge.

Conclusion: These findings show the C-terminal region of Mannheimia haemolytica LktA to be a highly immunogenic and protective antigen and suggest its potential as a candidate for subunit vaccine development.

Introduction: The prevalence of potentially pathogenic microorganisms in different foods is widely researched. The aim of this study was to investigate the prevalence and antimicrobial resistance of selected Enterobacterales species isolated from retail food of animal origin in Poland.

Material and methods: Cold cuts, cold-smoked fish and cheeses making 194 samples were tested with the ISO horizontal method for the detection of Enterobacteriaceae, and then Enterobacterales isolates were identified using matrix-assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI-TOF). The isolates' antimicrobial susceptibility was determined using the minimal inhibitory concentration method.

Results: Enterobacterales were detected in 159 (82.0%) samples, from which 226 bacterial isolates were recovered. Six bacterial species accounted for 65.9% of Enterobacterales isolates: Escherichia coli (n = 41), Enterobacter cloacae (n = 26), Hafnia alvei (n = 25), Citrobacter spp. (n = 20), Serratia liquefaciens (n = 20) and Klebsiella oxytoca (n = 17). The isolated E. coli strains showed low resistance to seven antimicrobials. E. cloacae isolates were mostly resistant to ampicillin (76.9%) and azithromycin (38.5%), S. liquefaciens to colistin (100%) and H. alvei strains to colistin (96.0%) and ampicillin (60.0%). The majority of K. oxytoca isolates (70.6%) were resistant to ampicillin, whereas only five Citrobacter isolates were. Twenty of the total pool of isolates (8.8%) were defined as multidrug resistant.

Conclusion: Retail food of animal origin can be contaminated with various species of Enterobacterales, including microorganisms pathogenic to humans as well as others resistant to commonly used antimicrobials.

Introduction: The aim of the study was to evaluate the effects of dietary supplementation with dried black chokeberry pomace (Aronia melanocarpa) on metabolic and antioxidant parameters in high-yielding dairy goats.

Material and methods: Twenty-seven Polish White Improved goats in mid-lactation were divided into three groups: a control group and two experimental groups receiving chokeberry pomace at 15 g/kg (A1) and 30 g/kg (A2) of dry matter in the feed. Biochemical, enzymatic, mineral, and oxidative stress parameters were analysed.

Results: Supplementation, particularly in group A2, improved the lipid profile by reducing low-density lipoprotein and triglycerides and increasing high-density lipoprotein levels. It also enhanced antioxidant capacity (higher glutathione and 2,2-diphenyl-1-picrylhydrazyl values) and positively influenced liver and lysosomal enzyme activity. Changes in creatinine, cholinesterase and creatine kinase levels were observed, along with correlations between calcium and metabolic markers.

Conclusion: These findings suggest that chokeberry pomace may serve as a valuable feed additive in the nutrition of high-yielding dairy goats, promoting their metabolic health and potentially enhancing milk quality.