Veterinary Research Forum

Abstract This study evaluated the protective effects of intraperitoneal (IP) tannic acid (TA) against ischemia-reperfusion (IR) injury in a rat model of testicular torsion. Eighteen mature male Wistar rats were randomized into three groups, including sham (surgery without ischemia), IR (3 hr ischemia + 3 hr reperfusion), and IR + TA (50.00 mg kg^-1 TA; 100 µL intraperitoneally 30 min before reperfusion). Testicular tissues were sampled immediately after reperfusion for biochemical assays to measure malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GPx) levels. Epididymides were analyzed 60 days later for sperm count, motility, viability, morphology, and DNA integrity. The IR significantly elevated MDA and sperm DNA damage while reducing SOD, GPx, sperm parameters, testicular weight, and spermatogenesis. The TA administration reversed these changes and restored the parameters to levels close to those of the sham group. Overall, intraperitoneal TA mitigated IR-induced oxidative stress and preserved reproductive function, indicating its potential therapeutic value in testicular torsion.

Abstract Swine colibacillosis, caused by colonization of the piglet small intestine with enterotoxigenic strains of Escherichia coli, imposes a significant economic burden on the swine industry. Due to high mortality rates and the emergence of antimicrobial resistance, it is considered one of the major welfare concerns in the livestock industry. This study elucidated the genetic basis and expression patterns of key antibiotic resistance genes in porcine E. coli isolates with colibacillosis. Intestinal contents from five affected piglets were subjected to high-throughput sequencing, revealing 26 resistance genes across seven antibiotic classes. Four strains (428, 430, 432, 433) were further analyzed for mRNA expression levels of six resistance genes (blaTEM, tetA, tetB, tetM, qnrB, and qnrS) under exposure to ampicillin, tetracycline and ciprofloxacin at three concentrations (0.01, 0.001, 0.0001% w/v). Our findings revealed five distinct expression patterns: (1) dose dependent upregulation/downregulation, (2) inverse response to concentration changes, (3) maximal downregulation at intermediate dose, (4) minimal down-regulation at intermediate dose, and (5) sustained upregulation. Strain 428 uniformly followed pattern one for all resistance genes, in strain 430, tetB followed pattern three while blaTEM matched pattern one, strain 432 exhibited patterns two for all tetracycline- and β-lactam-resistance genes, and pattern four for qnrB; strain 433 showed patterns three for both fluoroquinolone-resistance genes, pattern four for tetB, and pattern five for blaTEM. These findings highlighted strain-specific and dose-dependent gene expression responses in swine colibacillosis. This work underscored the need for tailored antibiotic strategies, targeted interventions and well-validated monitoring frameworks for antibiotic resistance in veterinary.

Abstract Pasteurella multocida is a widespread zoonotic pathogen associated with severe hepatic inflammatory responses. Although traditional medicinal plants like Tribulus terrestris L. (TL) possess anti-inflammatory properties, their protective effects against P. multocida-induced liver injury remain insufficiently studied. This study established a P. multocida-induced liver injury model to evaluate the protective efficacy of TL extract. Thirty-two male Kunming mice were randomly assigned to four groups: control, model, penicillin-streptomycin, and TL extract. Interventions included daily intra-peritoneal injection of P. multocida (50.00 CFU mL^-1) followed by treatment with antibiotics or TL extract (1,000 mg kg^-1 daily) for 7 consecutive days. Therapeutic potential was evaluated using histopathological analyses (H&E and Masson's staining), RT-qPCR, western blot, immunohistochemistry, and immunofluorescence to assess inflammatory cytokines and NFκB pathway activation. TL extract significantly attenuated hepatic fibrosis and inflammatory cell infiltration. Following infection, NFκB pathway activation was indicated by up-regulated NFκB1 and down-regulated inhibitor of nuclear factor kappa B alpha (IκBα) expressions, alongside increased pro-inflammatory cytokines TNF-α and IL-1β. Treatment with antibiotics or TL reversed these changes. TL likely suppressed NFκB activation by down-regulating the tumor necrosis factor receptor superfamily member 1A (TNFRsf1a) receptor. Furthermore, decreased phosphorylation of IκBα and reduced TNF-α and IL-1β after treatment indicated effective inhibition of NFκB signaling and inflammation, effects comparable to antibiotic treatment. In conclusion, our research reveals that TL extract alleviates P. multocida-induced hepatic inflammation by inhibiting NFκB activation, highlighting its potential as a plant-derived therapeutic agent for bacterial liver injury.

Abstract The present study showed riociguat supplementation modulates in a Tris–egg yolk extender on post-thaw ram semen quality. Semen samples were collected from eight healthy, sexually mature Tuj rams (n = 48 ejaculates) during the breeding season and cryopreserved after supplementation with riociguat at concentrations of 0.00 (control), 0.50, 5.00, 50.00, and 250 µM. Post-thaw sperm quality was evaluated using computer-assisted sperm analysis for motility and kinematic parameters, alongside assessments of plasma and acrosomal membrane integrity, mitochondrial membrane potential, DNA integrity and oxidative stress markers including malondialdehyde and glutathione. Riociguat supplementation (5.00 - 250 µM) significantly modulated mitochondrial membrane potential and intracellular antioxidant capacity as evidenced by reduced malondialdehyde and increased glutathione levels. Moreover, all riociguat-treated groups exhibited significantly improved DNA integrity compared with the control. Moreover, acrosomal damage was declined at the highest concentrations (50.00 and 250 µM). These findings suggest that riociguat exerted a protective effect on acrosomal membranes during cryopreservation. In conclusion, riociguat modulated post-thaw ram sperm function in a dose-dependent manner, exerting both beneficial and detrimental effects depending on concentration. Although fertility outcomes were not assessed in the present study, the observed biochemical and functional changes provided preliminary evidence that riociguat might influence key pathways associated with sperm resilience to cryoinjury, thereby, justifying further investigations incorporating in vivo fertility and reproductive performance assessments.

Abstract An emerging global threat is the development of resistance to various antibiotic groups among pathogenic bacteria, including Pasteurella multocida. The excessive use of antibiotics and presence of antibiotic resistance carriers play a significant role in the development of multiple resistances to anti-microbial agents. Given the role and importance of plasmids in the development of antibiotic resistance, it is important to prevent the transfer, replication, and multiplication of plasmids by eliminating plasmids. In this study, the role of plasmids in the development and transmission of antibiotic resistance in P. multocida was investigated and evaluated. This study was performed on P. multocida isolates collected from apparently healthy and ailing animals (February to September 2014). Identification of P. multocida isolates was carried out using standard biochemical tests and kmt1 gene amplification. After initial tests and plasmid DNA extraction, five plasmid-containing isolates were selected for further work. To compare antibiotic resistance after plasmid removal, the disk diffusion method was used. Based on the results, it was determined that all plasmid-containing isolates that showed a high level of antibiotic resistance (especially with large plasmids) became sensitive to anti-microbial agents after plasmid removal. Therefore, according to the findings, the role and importance of plasmids in the development of antibiotic resistance in P. multocida was determined. It was also found in this study that the existence and persistence of plasmids by P. multocida bacteria was of great importance in the role of plasmids in the development of antibiotic resistance.

Abstract Aging markedly increases vulnerability to cardiovascular disorders, including acute coronary syndrome and coronary artery disease. Although melatonin (M) and nicotinamide mono-nucleotide (N) have each shown cardioprotective properties, their combined effects on ischemia-reperfusion (IR) injury in the aged heart remain unclear. This study investigated co-administration of M and N enhances cardiac functional recovery and reduces inflammatory responses following myocardial IR injury in aged rats. Forty adult male Wistar rats (n = 8/group) were randomly assigned to five groups: Sham, IR, M (IR + M), N (IR + N), and N + M (IR + N + M). Cardiac function was evaluated after IR by measuring coronary flow, heart rate, left ventricular end-diastolic pressure, and left ventricular developed pressure. Melatonin was administered at 50.00 µM in the reperfusion solution for 15 min after 30 min of ischemia, N was administered intraperitoneally at 100 mg kg-1 every other day for 28 days. Creatine kinase and inflammatory markers, including interleukin IL-1β, IL-6, tumor necrosis factor-alpha, and nuclear factor kappa B, were also assessed. IR significantly impaired coronary flow and heart rate, both of which were improved by M and N treatment. These agents also reduced left ventricular end-diastolic pressure and improved left ventricular developed pressure recovery, with the combined therapy producing the greatest effect. Likewise, creatine kinase and inflammatory marker levels were significantly elevated in the IR group but markedly reduced by treatment, especially by combined administration. These findings suggest that M and N exert additive cardioprotective effects against IR injury in aged rats.

Abstract The rise of antimicrobial resistance poses a severe global health challenge, with multidrug-resistant bacteria causing millions of deaths annually and diminishing the effectiveness of traditional antibiotics. Bacteriophage-derived endolysins, such as PVP-SE1gp146 from Salmonella phage PVP-SE1, emerge as promising alternatives due to their high specificity, low toxicity, and minimal resistance development. However, their activity against Gram-negative bacteria is limited by poor outer membrane (OM) penetration. This study investigates the structural and functional impacts of fusing the polycationic nonapeptide, PCNP to PVP-SE1gp146 to create engineered endolysin that enhance OM permeability while preserving enzymatic function. Using advanced computational tools including Phyre2, GalaxyWEB, and AlphaFold2, three-dimensional models of native and engineered endolysins were generated and validated with Verify3D. Sequence analysis via Basic Local Alignment Search Tool identified homologs, and structural superposition with template modelin-align (TM-align) confirmed high conservation (TM-score 0.921, Root Mean Square Deviation 1.84 Å) despite the PCNP insertion. Active sites were predicted using PrankWeb, and molecular docking with AutoDock assessed interactions with peptidoglycan components (e.g., N-acetylmuramic acid - N-acetylglucosamine dimer, tetramer). Results revealed superior binding affinities in the native endolysin (e.g., – 10.35 kcal mol^-1 for N-acetylmuramic acid -L-alanine) compared to the engineered variant (– 9.65 kcal mol^-1 for N-acetylmuramic acid - N-acetylglucosamine -L-alanine trimer), with positive energies for larger ligands indicating steric hindrance. This trade-off reduced affinity for improved OM penetration supports potential enhancement of OM penetration while preserving bactericidal function like Pseudomonas aeruginosa. The findings highlight the potential of rational engineering for superior antimicrobials, emphasizing the need for molecular dynamics simulations and experimental validation to optimize Artilysin^® design in combating antimicrobial resistance.

Abstract The thyroid gland is an integral part of the complex anatomy of the equine neck. Trans-cutaneous ultrasonography provides a non-invasive method for assessing the thyroid glands parenchyma and dimensions in horses. This study evaluated 30 clinically healthy Turkmen horses whose health status was confirmed through comprehensive physical examination, complete blood count, serum biochemical analysis, and thyroid hormone analysis. The horses were divided into two age groups: Group 1 under 36 months (three males and eight females), and Group 2: Thirty-six months and older (eight males and eleven females). Ultrasonographic assessment of the thyroid region was performed using a high-frequency linear transducer. Each thyroid lobe was systematically evaluated for its dimensions, volume, morphology, contour, parenchymal echogenicity and echotexture. Statistical analysis revealed no significant age-related differences in thyroid parameters; however, sex-based differences were observed: females had significantly greater thyroid lobe length and volume on both the left and right sides compared to males. Qualitative B-mode ultrasonography showed consistent morphological features; in the longitudinal view, all thyroid lobes exhibited a flattened, oval shape. On transverse images, most lobes (83.93%, n = 47) appeared elliptical, while the remaining lobes (16.07%, n = 9) were spherical. Irrespective of shape, all thyroid lobes demonstrated regular contour margins. Regarding echogenicity, most lobes were hyperechoic, with a few being isoechoic, relative to the sternocephalic muscle. Furthermore, all thyroid lobes exhibited homogeneous to mildly heterogeneous echotexture. This study establishes diagnostic baselines for thyroid evaluation in the Turkmen horse breed aiding in the detection and management of thyroid pathologies.

Abstract A 5-month-old male Himalayan cat presented with labored tachypnea and abnormal inspiratory sounds (stertor) in the upper airways. Chest and head radiography revealed amorphous interstitial and alveolar patterns in both lung fields and a soft tissue mass occupying the nasopharynx dorsal to the soft palate. The owner reported that the cat had continuously made sustained inspiratory efforts, which had become more severe on the day of visit. Based on these findings, we considered that the clinical signs were due to negative-pressure pulmonary edema (NPPE) caused by a nasopharyngeal polyp. The cat responded well to symptomatic treatments, including oxygen therapy and intravenous furosemide, and was discharged with surgical treatment planned at the secondary hospital. Although the cat had one recurrence of NPPE before the polyp was surgically removed, however, not suffered from NPPE after the polyp disappeared. The NPPE is a rare disease in cats, and its association with nasopharyngeal polyps has not been previously documented. Nasopharyngeal polyps located above the larynx can cause NPPE because mouth breathing is uncommon in cats. Veterinarians should consider NPPE in cats exhibiting inspiratory effort, particularly when chest radiographs show signs of pulmonary edema. Careful and detailed interviews with the owners/caregivers about respiratory patterns and nasopharyngeal examinations are essential.

Abstract Hydronephrosis is an uncommon condition in cats and dogs, characterized by progressive dilation of the renal pelvis and subsequent atrophy of the renal parenchyma. This report described an 8-year-old spayed female domestic longhair cat diagnosed with left-sided hydronephrosis and concurrent polycystic kidney disease after comprehensive clinical, laboratory and imaging evaluation. Because the contralateral kidney appeared functionally preserved, unilateral nephrectomy was selected as the most appropriate treatment option. During surgical manipulation, however, the affected kidney unexpectedly separated completely from its attachments before vascular ligation could be performed, without evidence of hemorrhage. The procedure was completed without complication and no intraoperative or postoperative adverse events were recorded. The patient recovered uneventfully and remained stable throughout the perioperative period. To the authors’ knowledge, this report represented the first documented case in veterinary literature regarding spontaneous renal autoavulsion occurring during nephrectomy. This unusual finding underscored the severe structural fragility that could result from chronic obstructive renal disease and advanced parenchymal destruction. In addition, it suggested that renal autoavulsion might represent a previously unrecognized end-stage manifestation of longstanding hydronephrosis, particularly when associated with concurrent renal pathology such as polycystic kidney disease. This report emphasized the importance of thorough preoperative assessment, careful surgical planning and awareness of potentially extreme anatomic alterations in chronically diseased kidneys.