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A Comparative Approach on the Prophylactic Impact of Fermented Beverages on Acute Ulcerative Colitis
Dr. Erol, Prof. Özmen,

Acute ulcerative colitis is an inflammatory disease of the colon that is becoming increasingly prevalent. Yet, a growing body of evidence supports the efficacy of dietary interventions in preventing acute ulcerative colitis. Fermented beverages have been the focus of research in humans and animals for several years due to their potential to influence overall health functions with an emphasis on gut health. This research comprehensively explores the preventive effect of three fermented beverages (water kefir, dairy kefir, and kombucha) on acute ulcerative colitis in a CD-1 mouse model. Histopathological evaluation of the colon samples indicated that consumption of kombucha led to increased alleviation of the gross and histopathological lesions. Oral administration of kombucha positively affected overall intestinal microecological homeostasis by decreasing the coliform counts in this group contrasting the water and milk kefir groups. Moreover, physicochemical evaluation of the fermented beverages was conducted covering key parameters such as pH, acidity, total solids, radical scavenging activity and total phenolic content. Kombucha had the highest radical scavenging activity (85.61), total phenolic content (5.04 mg GAE/ mL), and total solids (0.70%), but the lowest pH (3.1) values. The findings from this research offer valuable insights into the distinct contribution of different fermented beverages on prevention of acute ulcerative colitis. Kombucha unravels promising natural prevention approach for acute colitis, opening new perspectives for future research.



The effect of Silymarin on diabetes mellitus-induced male rats reproductive impairment: Evidences for role of heat shock proteins 70 and 90
Assistant professor Hejazi,

Male fertility is adversely influenced by diabetes. Beneficial effects of antioxidant bioflavonoids in improving fertility have been reported. This study was conducted to evaluate the effects of silymarin on diabetes mellitus-induced male reproductive impairment of rats through investigation of its role on Hsp70 and Hsp90. To follow-up the current study, 18 mature male Wistar rats were divided into control (Con), experimental diabetes type 1 (T1D-sole)-induced and silymarin (SMN, 120 mg/kg, orally)-treated T1D-induced groups. The testicular total antioxidant capacity (TAC) and malondialdehyde (MDA) were evaluated. Tubular differentiation index (TDI), repopulation index (RI), spermiogenesis index (SPI) and the Johnson score were investigated. DNA Ladder test used to evaluate the testicular DNA fragmentation and RNA damage was investigated by fluorescent staining. Immunohistochemical and RT-PCR analyses were performed for Hsp70 and Hsp90. Oral administration of SMN significantly (P<0.05) increased TAC ratio and decreased MDA content of testicles compared with T1D-sole group. The results showed that T1D increased the percentage of seminiferous tubules with negative TDI, RI and SPI, and reduced Johnson score compared to Con group (P<0.05), but the treatment with SMN ameliorated the T1D-induced damages on TDI, RI, SPI and Johnson score (P<0.05) compared to T1D group (P<0.05). Staining intensities and the number of Hsp70+ and Hsp90+ cells were significantly higher in Con group compared to the T1D-sole animals (P<0.05), but rats treated with SMN showed increased numbers of Hsp70+ and Hsp90+ cells/mm2 of tissue compared to T1D-sole group (P<0.05). The diabetes caused DNA fragmentation and RNA damage, but silymarin decreased its negative effects. SMN ameliorates the T1D-suppressed spermatogenesis by up-regulating testicular antioxidant status and Hsp70 as well as Hsp90 expressions in testicular tissue, and consequently can be considered as an alternative complementary medication in male patients with T1D.



Innervation of the female internal genital organs in 12-week-old porcine foetuses.
PhD, DVM Bossowska, DVM, Ph.D. Franke-Radowiecka, dr Demus,

The study for the first time aimed to investigate the innervation of the internal genital organs in 12-week-old female pig foetuses using single and double-labelling immunofluorescence methods. Immunostaining for protein gene product 9.5 (PGP, general neural marker) revealed that the most of PGP-positive nerve fibres were observed in the mesenchyme of the uterovaginal canal height. Numerous nerve fibres were observed in the uterine segment, less in the tubal segment of PD, and they usually occurred at the edge of the mesenchyme. A low number of fibres were visible in the developing ovary cortex and medulla. Many fibres expressed dopamine β-hydroxylase (DβH) and/or vesicular acetylcholine transporter (VAChT) in the studied period. Most DβH-positive nerve fibres were observed in all segments of PD. Many nerve endings containing VAChT were mainly visible in the uterovaginal canal of PD. DβH/VAChT-positive nerve fibres were observed in the mesenchyme of all sections of the PD, but they were most common in the uterovaginal canal and the uterine segment of PD. In the ovary, nerves were mainly DβH-positive and single nerve fibres containing VAChT. Few DβH/VAChT-positive nerve fibres were observed in the ovary.



Virus neutralization test for confirmation of ELISA-positive SARS-CoV-2 antibodies in dogs
Ph.D. Vračar, Ph.D. Kozoderović, Ph.D. Vesna, Ph.D. Petrović, Ph.D. Spasojević Kosić, M.sc. Vujin, Ph.D. Lalošević, Ph.D. Knežević,

Constant antigenic changes, new variants and easy transmission of SARS-CoV-2 virus should acquire greater zoonotic attention and need to remain alert. In this retrospective study the aim was to analyze seropositivity to SARS-CoV-2 in dogs by commercial ELISA. The Virus neutralization test (VNT) was modified for the purpose of confirmation of SARS-CoV-2 antibodies in ELISA-positive dog sera. The sera were collected from 204 dogs from different veterinary clinics across Vojvodina Province, Serbia, during COVID-19 pandemic. For the screening of antibodies a commercial double multi-species antigen ELISA was used, followed by the VNT modified with SARS-CoV-2 as a confirmatory test. VNT was modified as “one step” test using local isolate of SARS-CoV-2 and the results were checked by cytopathic effect in cell culture on the 96-well microtiter plate. Obtained data have shown that 9 out of 204 dogs were positive by ELISA (4,4%), while 2 (0,97%) sera were doubtful. VNT confirmed 9 positive dogs, but 2 doubtful samples were negative, exhibiting the seroconversion to SARS-CoV-2 in 4,4% dogs from Vojvodina region during pandemic of COVID-19. VNT with SARS-CoV-2 helped to elucidate ELISA ambiguous results. The occurrence of antibodies to SARS-CoV-2 in dogs in this study during COVID-19 pandemic suggested the possibility of viral transmission to dogs, implicating the potential for zoonotic transmission. This was the first research on seroconversion to SARS-CoV-2 in dogs from the Province of Vojvodina, the northernmost part of Serbia.



Effect of commercial prescription diets containing prebiotics on clinical sign and fecal miocrobiome in dogs with intestinal disease
PhD Mori, Miss Koyama,

Diet has emerged as a key modulator of the gut microbiota, offering a potential strategy for disease prevention and management. This study investigated the effects of the Prescription Diet Gastrointestinal Biome (GB) on 7 healthy dogs and 16 dogs with chronic gastrointestinal diseases (GI dogs). Our investigation monitored changes in body weight and the Canine Inflammatory Bowel Disease Activity Index (CIBDAI) in 16 GI dogs fed a GB diet. Additionally, we assessed the gut microbiota using 16S rRNA sequencing pre (GI dogs) and post (healthy dogs and GI dogs) administration of GB diet. In dogs with GI, a significant improvement in the severity of CIBDAI was observed post-feeding with the GB diet compared to the period pre-feeding, without any changes in body weight. Primary changes in the gut microbiome were marked by significant differences between healthy and GI dogs. However, post-feeding the GB diet in GI dogs, there was an increase in Turicibacter and a decrease in Escherichia-Shigella linked with gastrointestinal inflammation. In conclusion, the GB diet appears to positively influence the gut microbiota and clinical outcomes in dogs with GI. Future studies should explore these relationships by focusing on the long-term effects of diet on the gut health and disease management.



Cardiovascular problems in rabbits in reference to hypothyroidism – a four-year retrospective study
prof dr hab Adaszek, dr Skrzypczak, dr Staniec, PH.D Mazurek, dr Ziółkiewski,

The effects of T4 are mainly manifested by positive ino- and chronotropism. The syndrome accompanying hypothyroidism in rabbits (impaired myocardial contractility and reduced ejection capacity) is caused by a deficiency of thyroid hormones - especially T4. The study group consisted of a total of 41 animals: 15 males and 26 females, ranging in age from 2 months to 8 years. with echocardiogram showing reduced fractional shortening (<30%), with normal results of heamatological and biochemical tests. Blood was collected in order to measure T4 activity. Echocardiographic examinations were performed with two-dimensional (2D) imaging, M-mode measurements and the pulsed/colour-labelled Doppler technique. Statistical analysis was performed using Statistica 13.0. Correlations were determined: between serum thyroxine concentration and the value of the fraction of shortening in the groups: young animals (up to 5 years of age) and older animals, females and males, and sterilised and non-sterilised animals. Statistical analysis showed a positive correlation between T4 levels in the blood of the test animals and myocardial fractional shortening in the pre-treatment period. A positive correlation was also shown after dividing the patients into 2 groups based on their age (below 5 years vs. 5 years and over), sex (male and female rabbits) and fact of sterilization (yes/no). Our study unequivocally confirmed a positive correlation between the decreased serum T4 concentration and reduced fractional shortening, indicating decreased cardiac systolic function in hypothyroid rabbits.



In vitro antibacterial and antibiofilm effects of mupirocin spray against Staphylococcus pseudintermedius
Professor Bae, MS Lee,

Mupirocin is an effective antibiotic for infectious skin diseases. However, mupirocin is formulated as an ointment and is difficult to apply in canine systemic pyoderma. Therefore, many clinicians reformulate mupirocin off-label ointment into a spray. This study aimed to evaluate the antibacterial and antibiofilm effects of different concentrations of mupirocin spray (2%, 1%, and 0.5%) on Staphylococcus pseudintermedius over 21 days. Mupirocin spray was prepared by mixing mupirocin ointment and distilled water. The antibacterial effects were evaluated by measuring the optical density using broth microdilution assay and by live/dead staining. The antibiofilm activity of mupirocin spray was measured using a crystal violet staining method. All concentrations of mupirocin spray inhibited the growth of S. pseudintermedius. Mupirocin spray also inhibited biofilm formation of each isolate, although the degree of inhibition was influenced by mupirocin concentration. The antibacterial and antibiofilm effects of mupirocin spray were maintained for 21 days. The 2% and 1% mupirocin sprays exhibited significantly better antibacterial and antibiofilm efficacy than the 0.5% mupirocin spray. Thus, 1–2% mupirocin spray may be effective for clinical use. Mupirocin spray is convenient and effective for the treatment of canine systemic pyoderma caused by S. pseudintermedius infection.



Effect of pre-freezing on motility, viability and abnormality of Nile tilapia fish Oreochromis niloticus sperm post cryopreservation
Ph.D Muchlisin, B.Sc Hasibuan, Ph.D Maulida, Ph.D Eriani, Prof. Dr. Fadli, Ph.D Muhammadar, M.Sc Handayani, Prof. Dr. Kocabas, Ph.D Kocabas, Ph.D Fadli,

Nile tilapia Oreochromis niloticus is a popular freshwater fish that has been extensively and intensively cultured worldwide. However, cryopreservation of its sperm especially pre-freezing procedure, has not been properly developed. Therefore, the study aimed to determine the best pre-freezing procedure for cryopreservation of Nile tilapia Oreochromis niloticus. The completely randomized design with five treatments and four replications were employed in this study. The tested treatments were T1= 4 oC → 0 oC → -4 oC → -10 oC → -79 oC → -196 oC, T2= 4 oC→ 0 oC → -4 oC → -10 oC → -196 oC, T3= 4 oC → 0 oC → -4 oC → -196 oC, T4= 4 oC → 0 oC → -196 oC), and T5= 4 oC → -196 oC, with a 10 min equilibration at each respective temperature. Furthermore, sperm was cryopreserved for two weeks in liquid nitrogen (-179 oC). The results of the ANOVA test showed that pre-freezing had a significant effect on sperm motility, and viability (P<0.05), but had no considerable impact on sperm abnormality (P>0.05). Treatment T4 exhibited higher motility and viability, but these values were not significantly different from T3 and T5. Based on practical consideration, it was recommended to utilize the T5 pre-freezing procedures (4oC → -196oC) for cryopreservationof Nile tilapia sperm. Considering these results, Nile tilapia sperm can be directly cryopreserved into liquid nitrogen after equilibration at 4 oC for 10 min.



A TaqMan-based quantitative real-time polymerase chain reaction assay to detect the porcine circovirus-like virus
PhD Tu, ph,D Yu, phd Shao, phd Chen, master Zhang, master Cheng, phd Liu, phd Wang, PhD Song, PhD Qi,

The aim of this study was to develop a rapid, sensitive and highly specific TaqMan real-time polymerase chain reaction PCR (qPCR) assay for Porcine circovirus-like virus (PCLV). The primers and probe were designed based on the conserved regions of the PCLV ORF4 gene. The assay has a good detection performance (y = -3.3257x + 41.482, R2 = 0.9905), with a limit of detection of 10 copies, which was 100 times more sensitive than conventional PCR (cPCR). No cross-reactivity was observed with other common viruses. The intra- and inter-assay coefficients of variation were less than 1.25%. 36 fecal samples were analyzed by this method, detecting a positivity rate of 8.33% (3/36) that was higher than the cPCR detected. In summary, the established assay for PCLV detection has high specificity, sensitivity, and reproducibility and can be used as a tool for clinical diagnosis and epidemiological investigation.



Non-invasive methods for diagnosing pregnancy in cows and their real value
Engineer Wozniak, Profesor Jaśkowski, Student Kaźmierczak,

Proper management of cattle reproduction has a major impact on the efficiency and profitability of dairy production. Ultrasound examination and transrectal palpation or the pregnancy-associated glycoprotein (PAG) test are currently the most commonly used methods for pregnancy diagnosis. However, alternative methods to those mentioned above are constantly being sought in order to minimise stress during the examination, the cost of veterinary services and to reduce the rate of errors in pregnancy diagnosis. Non-invasive methods of pregnancy diagnosis in cows are being improved, which include the barium chloride test, sulphuric acid, seed germination test, measurement of progesterone, interferon-tau, PAG, early pregnancy factor (EPF), oestrone sulphate, thermography and electrocardiography. Over the past few decades, these methods have been extensively described. Some of these tests require blood, milk or urine for the diagnosis of pregnancy, while others require prolonged contact with the animal in order to take the appropriate measurements. Despite their advantages in terms of simplicity and lower cost compared with traditional methods of pregnancy diagnosis, they are sometimes problematic because of the difficulty of collecting material for testing. They allow the determination of a pregnancy without determining its age or pathology on the part of the development of the foetus and the reproductive system. They are also generally characterised by lower accuracy, sensitivity and specificity, which can have a negative impact on reproductive management and translate into the economics of dairy production. In the context of the above information, it appears that non-invasive methods of pregnancy diagnosis need to be further improved to minimise or eliminate the disadvantages cited.



Histopathology of the Haplorchis taichui infection in the freshwater fish, Tigris kingfish, and Tigris barb (Cypriniformes: Cyprinidae) from the Iran
DVM;Ph,D Golchin Manshadi,

Flukes can cause severe and lethal diseases in various animals, including fish. Both adult and larval stages of flukes are found in fish. Haplorchiasis is an infection of fish gills by heterophyid trematodes such as Haplorchis taichui. To detect this parasite, the gills of 30 Tigris kingfish and Tigris barb collected from the Shapour River in Kazerun, Fars province were found to be parasitized with metacercarial cysts of a heterophyid trematode identified as H. taichui. Histopathological examination of the infected fish gills revealed cartilage proliferation, severe hyperplasia, fusion, S-forming, shortening and thickening, distortion, and displacement of affected secondary gill filaments leading to deformities of the filament structure, clubbing, telangiectasis, and hyperemia. Although the gill damage was evident and potentially life-threatening for the cyprinid fish, the examined fish showed no clinical signs. This .finding indicates that H. taichui is pathogenic; therefore, prevention of infection and treatment should be a priority.



the cellular distribution of some intermediate filaments in the rat mammary gland during pregnancy, lactation and involution
Ph.D. Bayram, Prof Sağsöz, Prof Topaloğlu,

Intermediate filaments (IFs) play a major role in determining and maintaining cell shape and anchoring intracellular organelles in place, in the tissues and organs of several species, starting from the early stages of development. This study was aimed at the immunohistochemical investigation of the presence, cellular localization and temporal distribution of the intermediate filaments keratin 8 (CK8), keratin 18 (CK18), keratin 19 (CK19), vimentin, desmin and laminin, all of which contribute to the formation of the cytoskeleton, in the rat mammary gland during pregnancy, lactation and involution. It was determined that CK8 showed moderate immunoreactions in the alveolar and ductal epithelia, connective tissue and vascular endothelium of the rat mammary gland throughout pregnancy. On the 7th day of pregnancy, CK18 expression was absent in the alveolar and ductal epithelia, but was observed weakly in some connective tissue cells. Throughout pregnancy, lactation and involution, the alveolar and ductal epithelia of the rat mammary gland were determined to be negative for CK19. Desmin expression predominated in the mammary myoepithelium and vasculature throughout all three of the investigated periods. While vimentin was not expressed in any of the mammary tissue components during pregnancy and lactation, its moderate expression was observed in the alveolar and ductal epithelia during involution. The involution period was also characterized by the vimentin negativity of the myoepithelium, stroma, fat cells and blood vessels of the mammary gland. Throughout all three periods, laminin expression was strong in the alveolar and ductal epithelia, stromal and myoepithelial cells, and blood vessels, and did not vary in strength between the investigated periods. These findings demonstrated that intermediate filaments showed cell- and tissue-specific expression patterns in the rat mammary gland under the effects of pregnancy, lactation and involution.



Effects of caponization and age on the histology, lipid localization and fibre diameter in muscles of Rhode Island Red cockerels
Prof. Gesek, PhD Daria, DVM Michalska,

Poultry scientists are constantly studying different breeds of cockerels that would be suitable for capon meat production. Capon meat, although not yet very popular, is characterized by exceptional taste qualities that could appeal to many customers. Obtaining the appropriate palatability, structure and tenderness of capon meat is possible thanks to the reduction in androgen levels because of the castration of roosters. Surgical or chemical castration affects the metabolism of fats, thus increasing their accumulation in the abdominal cavity, subcutaneous tissue or muscles. The main aim of our research was histological evaluation and analysis of the concentration and distribution of adipose tissue in muscles in Rhode Island Red cockerels and capons. In addition, we analysed the diameter of the pectoral muscle fibre. The experiment was performed on 200 Rhode Island Red cockerels; the testes were removed at 8 week of age. At 12, 16, 20, 24 and 28 weeks of age, 6 cockerels and 6 capons were slaughtered, and samples from the pectoral and thigh muscles were evaluated. Differences in the accumulation of adipose tissue with muscular atrophy (p<0.05) were observed in thigh muscles, with higher numbers in capons than in cockerels. All examined locations in the pectoral and thigh muscles of capons (around the blood vessels, in the perimysium, in the endomysium, and in the sarcoplasm) showed much higher concentrations of lipids compared to the levels in cockerels. The diameters of the pectoral muscle fibres were different (p<0.05) at 12 and 16 weeks of age, and the diameters of the giant fibres were different (p<0.05) at 12 and 20 weeks of age, with higher values in cockerels. The high concentration of lipids in the skeletal muscles of Rhode Island Red capons is impressive. These dual-purpose cockerel breeds can be a source of high-quality meat.



Melatonin prevents nicotine-induced hepatotoxicity by modulating apoptosis and histopathological changes in rats
phd Aşır, Asst. Prof. ŞENGÜL, Asst. Prof. İÇEN TAŞKIN, Asst. Prof. ERASLAN ŞAKAR, Dr. PEKTANÇ ŞENGÜL,

Nicotine, the main toxic component of tobacco, causes directly or indirectly adverse effects on the liver metabolism. Melatonin, secreted by the pineal gland, has anti-apoptotic activity as well as antioxidant activity. In this study, it was aimed to reveal the antiapoptotic effects of melatonin in rats with experimentally induced chronic liver damage with nicotine. In this study, 32 male Wistar albino rats were divided into four groups: control, melatonin, nicotine and nicotine+melatonin. During the experiment, nicotine (1 mg/kg) and melatonin (10 mg/kg) were administered at a dose intraperitoneally for 56 days. At the end of the experiment, the liver tissues were taken for histopathological, immunohistochemical and molecular analysis. The administration of melatonin was determined to partially alleviate histopathological changes in the liver tissue induced by nicotine, such as hepatocyte degeneration, vascular dilatation and congestion, and leukocyte infiltration. It was observed that there was a significant decrease in Bax expression levels and a significant increase in Bcl-2 expression levels in the nicotine+melatonin group when compared to the injury group. On the other hand, it was determined that melatonin administration reduced the Bax/Bcl-2 ratio, which was significantly higher in the nicotine group compared to the other groups, to level close to the control group. Additionally, as a result of immunohistochemical evaluation, it was observed that decreased Bax expression and increased Bcl-2 expression in hepatocytes in the nicotine+melatonin group were at a level close to the control group. Our results revealed that melatonin is a hepatoprotective and effective antioxidant by suppressing cell apoptosis and increasing the rate of healing after damage at both the immunohistochemical and molecular levels.



Insight to the carriage of antimicrobial resistance genes in Escherichia coli of bovine origin
Assoc. prof., DVM., PhD. Zigo, Professor OZBEY , Dr. Tanriverdi, prof. Otlu, Dr. Acik, Dr. Kalin,

The present study aimed to search for the presence of the plasmid-mediated colistin resistance (mcr-1 to -9) in 106 Escherichia coli (E. coli) isolates from a total of 240 fresh fecal samples collected from 12 private cattle farms in Bingol province of East Türkiye from November 2021 to January 2022. In those colistin-resistant E. coli mcr-1 to -9, the major carbapenemase (blaOXA-48, blaNDM-1, blaIMP, blaVIM, and blaKPC), β-lactamase (blaTEM-1, blaCTX-M and blaSHV-1) and OXA-48 like β- lactamase (blaOXA-162, blaOXA-163, blaOXA-181, blaOXA-204 and blaOXA-232) resistance genes were searched by multiplex polymerase chain reaction (PCR) method and Next-generation sequencing (NGS) - PCR Amplicons with Nanopore Technology. Only the mcr-4 gene was found in one isolate and the remaining genes (mcr-1-9) were not shown in all E. coli isolates from cattle. Minimal inhibitory concentration (MIC) to colistin was detected in mcr-4 positive E. coli isolates by broth microdilution. We have performed the antimicrobial susceptibilities of mcr-4 positive E. coli isolates assessed by the Kirby-Bauer disk diffusion method. E. coli isolate was detected as negative for carbapenem and OXA-48 like β-lactamase resistance genes and positive for β-lactamase. In addition, E. coli isolates carrying mcr-4 were more resistant to colistin. Antimicrobial susceptibility testing by the disk diffusion assay represented that all 106 E. coli isolates (100%) were detected as sensitive to AMK and 105 E. coli isolates (99.1%) exhibited sensitivity to imipenem, meropenem, and doripenem and 1 E. coli isolate (0.9%) intermediate resistance to imipenem, meropenem and doripenem. It was observed that all strains (100%) were resistant to cefotaxime. E. coli isolates are resistant to ampicillin (95.3%), amoxicillin/clavulanic acid (95.3%), cefepime (14.2%), cefixime (19.8%), cephalexin (74.5%), gentamicin (42.5%), kanamycin (37.7%), streptomycin (69.8%), tetracycline (80.2%), ciprofloxacin (60.4%), norfloxacin (13.2%), trimethoprim/ sulfamethoxazole (68.9%) and chloramphenicol (59.4%). When we investigated the sequence in the Blast database, the genome of the E. coli isolate indicated high similarity with the mcr-4 sequences. To our knowledge, this is the first report searching on the mcr-4 gene in E. coli identified from cattle in Türkiye. Our results highlighted that cattle might be a potential risk in transmitting mcr genes.



An isothermal recombinase polymerase assay coupled with lateral flow dipstick for differentiation of Pseudorabies virus wild isolates and gE-deleted vaccine strains
PhD Ma, PhD Wang, PhD Wang, PhD Zhang, PhD Zhu,

Pseudorabies virus (PRV) is one of the most important infectious diseases which leads to significant economic losses in the global swine industry. The gE-deleted vaccine is widely used to prevent susceptible pigs from PRV infection. There is no report of the differentiation of PRV wild strain and vaccine strain by recombinase polymerase amplification (RPA) coupled with lateral flow dipstick (LFD) method. In the present study, the gD and gE gene-targeted primer-probe sets were designed respectively. The RPA-LFD assay could discriminate between PRV wild strain and vaccine strain. The RPA reaction conditions were also evaluated. The optimal reaction temperature and reaction time for the RPA-LFD assay were 37℃ and 20 min. The detection limit was 10 genome copies per reaction for PRV wild strain and gE-deleted vaccine strain, respectively. The assay did not have cross-reaction with other common swine viral pathogens. The effectiveness of the RPA-LFD assay for detecting the clinical samples was evaluated by testing 80 samples. The result of the assay was compared with that of the conventional PCR. The positive rate of PRV wild strain by the RPA-LFD assay was 20%, whereas the positive rate of PRV wild strain by the PCR assay was 18.8%. The assay provides a novel alternative for differentiation of PRV wild strain and vaccine strain.



Development of a capsid protein-based ELISA for the detection of PCV2 antibodies in swine serum
Ph.D. Wang,

Porcine circovirus type 2 (PCV2) is the major causative agent of postweaning multisystemic wasting syndrome which leads to significant economic losses in global swine industry. In China, there is a widespread dissemination of PCV2 infection in pig population. Serological diagnosis of the disease is considered as an effective control measure. Here, we developed a capsid protein-based enzyme-linked immunosorbent assay (Cap-ELISA) for the detection of PCV2 antibodies in swine serum using nuclear localization signal-truncated capsid protein produced in Escherichia coli. The Cap protein was expressed as water-soluble and purified through nickel-nitrilotriacetic acid (Ni-NTA) chromatography. After the optimization of the working conditions of Cap-ELISA by chessboard titrations, a total of 649 serum samples were tested by Cap-ELISA and a commercial ELISA kit. The diagnostic sensitivity (DSN), diagnostic specificity (DSP), and accuracy of Cap-ELISA were determined to be 96.7%, 94.1%, and 99.5%, respectively. Cross-reactivity analysis indicated that Cap-ELISA was PCV2-specific and possessed no cross-reactions with antibodies against other common swine pathogens including porcine circovirus type 1 (PCV1), porcine reproductive and respiratory syndrome virus (PRRSV), classical swine fever virus (CSFV), porcine parvovirus (PPV), foot and mouth disease virus (FMDV), porcine epidemic diarrhea virus (PEDV), and pseudorabies virus (PRV). Repeatability experiment showed that Cap-ELISA was highly repeatable with the intra- and inter-plate coefficients of variation less than 10%. Hence, the Cap-ELISA has the potential for swine industry to monitor PCV2 epidemiology and evaluate PCV2 vaccine efficacy.



Pathogenicity and drug resistance characterization of S. agalactiae isolated from dairy cows
Ph.D Jiang, Ph.D Liu, Ph. D Liu, Ph. D Wang, Ph.D Li, B. D Tan,

Streptococcus agalactiae, commonly known as S. agalactiae, is a critical zoonotic pathogen that significantly reduces milk yield and product quality and poses a significant risk to public health. Although S. agalactiae is increasingly recognised as a principal agent causing milkborne infections, research dedicated to this pathogen in dairy cattle has been less extensive than that of other pathogens. This study aimed to examine the antibiotic resistance profiles of S. agalactiae derived from dairy cows and assess its pathogenicity using validated in vivo models. The findings contribute essential scientific insights into the realm of environmental antibiotic resistance research. The resistance of S. agalactiae isolates to drugs was assessed using the broth microdilution technique. Additionally, PCR analysis was used to identify six important virulence genes. The study revealed that S. agalactiae was fully susceptible to streptomycin, meropenem, ciprofloxacin, clindamycin, cefquinome, and cloxacillin in general laboratory settings and within milk samples. However, among the antibiotics tested, tetracycline exhibited the highest level of resistance, with rates reaching 70%. Penicillin showed a resistance level of 50%, followed by doxycycline at 30%. Additionally, the resistance rates for apramycin and cefoxitin were both 20%, whereas florfenicol resistance was observed at a rate of 10%. All isolates of S. agalactiae carried the cfb gene. However, it is noteworthy that only one isolate possessed this gene exclusively, while the other nine isolates shared a uniform set of four additional virulence genes. The study highlighted the significant impact of these virulence factors on the pathogenic behaviour of S. agalactiae from dairy sources. This was demonstrated by the high mortality rates observed in experimental infections using Galleria mellonella (G. mellonella) larvae and mouse models. These findings contribute to understanding the relationship between the pathogenic properties of S. agalactiae and the virulence genes it carries.