Veterinary Research Forum

Abstract Porcine respiratory disease complex is a clinically lethal condition and is the leading cause of mortality in weaned piglets as well as growing and fattening pigs. Pasteurella multocida (Pm) and Streptococcus suis (SS) are common respiratory pathogens in porcine respiratory disease complex. This study combined the recombinase polymerase amplification (RPA) technique with the lateral flow dipstick (LFD) technique. The dual Basic-RPA detection method for Pm and SS and the dual RPA-LFD rapid visualization detection method for Pm and SS were constructed, respectively. The detection limit of RPA-LFD was 10^-6 ng μL^-1, which was higher than the detection limit of RPA at 10^-5 ng μL^-1 and much higher than the detection limit of polymerase chain reaction at 10^-4 ng μL^-1. There was no cross-reactivity with other pathogens which indicated that the method had good specificity and high sensitivity. The detection rate of RPA-LFD was much higher than that of conventional Polymerase chain reaction in 60 clinical samples collected in 2023 with suspected Pm and SS. This method could avoid the complicated temperature cycling instruments and does not require professional laboratory skills, which makes it suitable for on-site detection.

Abstract This study aimed to evaluate malondialdehyde (MDA) expressions using the immunohisto-chemical method in order to reveal the role of lipid peroxidation in the development and progression of hepatocellular carcinoma (HCC) induced by diethylnitrosamine (DEN) in male Wistar albino rats. Avidin-biotin-peroxidase method was used for immunohistochemical evaluation. Histopathological examinations revealed that DEN caused a mixed pattern (trabecular and acinar formations) of HCC in the majority of rats. The MDA positive stainings were significantly increased in rats in the HCC group compared to the healthy rats in the control group. In conclusion, this study data contain three important findings. The first one is that DEN triggers the formation of reactive oxygen species (ROS), excessively produced ROS cause oxidative stress, and as a result, oxidative stress strongly causes lipid peroxidation. Secondly, it is clear that there is an important relationship between oxidative stress-induced lipid peroxidation and HCC progression. At the same time, MDA is an useful biomarker in determining the prognosis of patients with HCC. The third and final finding is that intra-peritoneal DEN injection once a week for 20 weeks, but not in combination with other promoting chemical agents, appears to be very effective in inducing experimental HCC.

Abstract To improve the structure of the heart muscle after myocardial infarction, methods of regenerative medicine are used. One of the promising areas is the intra-myocardial administration of acellular allogeneic biomaterial (AB). The AB stimulates the regeneration of organs and tissues. But, the effect of AB on the myocardium after its fibrous ischemic degeneration has not been assessed. The aim of the study was to assess the morphological structure of the heart after cryodestruction in the late period and the use of AB. Chronic myocardial infarction was modeled in 80 male rats. To simulate chronic myocardial infarction and fibrosis formation, contact cryodestruction was performed. After 45 days, during repeated thoracotomy in the main group, AB suspension was injected into the area of the cryogenic myocardial scar. Six injections of 0.50 mg of dry substance were administered. In the control group, physiological solution was injected. After AB administration, following 7, 14, 30, and 45 days, the animals were withdrawn from the experiment, and the hearts were excised for histological and immunohistochemical studies. The AB underwent gradual phagocytosis by macrophages and gradually replaced by loose fibrous connective tissue with the presence of cardiac troponin I⁺ labeled muscle cells, which over time underwent hypertrophy. Cardiomyocytes were grouped in the AB implantation zone as separate clusters. The heart mass did not change in both experimental groups. The use of AB in the area of the formed cryogenic myocardial scar promoted the transformation of dense fibrous connective tissue into loose tissue and its replacement with cardiac muscle tissue.

Abstract Medical imaging methods (magnetic resonance imaging, computed tomography, X-ray, and ultrasound) are used to guide physicians when diagnosing diseases and planning their treatment. Thorax radiography is frequently preferred for the detection of diseases related to the respiratory system and the heart. When the thorax anatomy is known, this facilitates the detection of diseases in these regions. The vertebral heart score (VHS) is a parameter used for the detection of cardiac anomalies. In cases such as cardiomyopathy and chronic pneumonia, the heart silhouette changes and cardiac enlargement is ensued. Knowing the normal VHS parameter is important in the detection of anomalies. In the present study, 15 male and 30 female adult Awassi sheep were used. The thorax region was imaged with an X-ray device in the right lateral position. Each animal was measured for nine parameters in the region. In the measurements, the female and male VHS scores were found to be 9.77 ± 0.48 and 9.69 ± 0.52, respectively, using one method and 10.11 ± 1.64 and 9.96 ± 0.73, respectively, using the other method. No statistical difference was found between the two methods. The cardiodiaphragmatic contact parameter was observed to be statistically significant between males and females. No statistical difference was found in other parameters. Consequently, this study was carried out to determine the VHS values in Awassi sheep, and the thorax measurements were evaluated. This study is considered to contribute to veterinary surgeons and the field of veterinary surgery.

Abstract This study focuses on understanding how the sensitivity patterns of common probiotic Lactobacillus species differ between healthy and colibacillosis-diseased broiler chickens and explores any correlation between these patterns and avian pathogenic Escherichia coli (APEC). Ileum samples were collected from the healthy (n = 10) and colibacillosis-diseased (n = 10) broiler poultry farms. Lactobacillus and E. coli were identified and incidence rate of six probiotic Lactobacillus species (L. acidophilus, L. brevis, L. casei, L. plantrum, L. delbrueckii, and L. fermenti) was determined, and their susceptibility to different antibiotics (ampicillin, chloramphenicol, erythromycin, kanamycin, tetracycline, and vancomycin) was tested. A total of 120 Lactobacilli were examined. Certain Lactobacillus spp. from healthy birds (L. brevis) and those affected by colibacillosis (L. acidophilus) showed better sensitivity and lower multiple antibiotic resistance to chloramphenicol, erythromycin, and kanamycin. Statistical analysis revealed significant correlations between ampicillin and chloramphenicol, ampicillin and erythromycin, ampicillin and tetracycline, and ampicillin and vancomycin resistance. Also, a significant correlation was observed between erythromycin and tetracycline, and kanamycin and vancomycin. All APEC strains showed multiple antibiotic resistance. A strong positive correlation was found between resistant Lactobacillus spp. and APEC isolates from diseased birds, indicating co-occurrence of antibiotic resistance. The study suggests that antibiotic resistance in APEC and Lactobacillus species may spread through horizontal transfer, highlighting the need for improved anti-microbial management in poultry systems.

Abstract Diazinon (DZN) is a widely used organophosphate. We studied the effect of quercetin pegylated liposome (QPEGL) on acute low dose DZN-induced oxidative stress and behavioral disorders through monitoring brain serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) in mature male rats. Animals were treated in two control groups that received a single dose of normal saline and dimethyl sulfoxide, and four groups that received a single dose of DZN 10.00 mg kg^-1 (DZN), DZN 10.00 mg kg + quercetin 20.00 mg kg^-1, DZN 10.00 mg kg^-1 + PEGL 20.00 mg kg^-1, DZN 10.00 mg kg^-1 + QPEGL 20.00 mg kg^-1 (QPEGL), respectively. Performances of the rats were investigated by the open field and elevated plus maze tests. Twenty-four hr after the treatments, animals’ brains were harvested and frozen at – 80.00 ˚C. Brain tissues 5-HIAA level was determined by the enzyme-linked immunosorbent assay. Furthermore, malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GPx) levels were determined for oxidative stress analysis. The motor activity was significantly reduced in the DZN group compared to the control group following increased anxiety-like behavior and ameliorated by QPEGL. Moreover, 5-HIAA and MDA levels notably increased in the DZN group compared to the control group and significantly decreased in the QPEGL group compared to the DZN group. The SOD and GPx contents were not significantly changed in the DZN group compared to the control; although, these parameters improved after treatment with QPEGL. Acute low dose DZN exposure resulted in lipid peroxidation and elevated levels of the serotonin metabolite (5-HIAA), leading to neurobehavioral disorders, such as anxiety-like behavior and impaired motor activity, which were alleviated by QPEGL.

Abstract Several bacteria, such as Escherichia coli, Pseudomonas, and Staphylococcus are considered as indicators of anti-microbial resistance (AMR) in a wide range of hosts and environments, because they may transfer AMR genes to important pathogenic bacteria. Hedgehog is one of the most important wild species living in urban areas. So, this study aimed to determine AMR against β-lactams and prevalence of colicin genes among various phylotypes of E. coli isolates from hedgehogs in the Kerman, Iran. Totally, 105 E. coli isolates were obtained from 21 hedgehogs (five isolates from each hedgehog). Resistances to the ampicillin (79.10%), cefotaxime (66.70%), and amoxicillin-clavulanate (62.00%) were the most prevalent, and resistance against ceftiofur (39.10%), ceftazidime (39.10%), and ceftriaxone (34.30%) had the lowest prevalence rates. In phenotypic tests, 2.90% of the isolates were extended spectrum β-lactamase producers. The prevalence of β-lactam resistance genes was 26.60% for bla_TEM, 3.80% for bla_CTX-M, 8.50% for bla_SHV, and 1.90% for bla_CMY. The frequency of colicin genes, including E1, V, E2-E9, and Ia.Ib was 5.71, 4.76, 10.47, and 11.42%, respectively. All E. coli isolates were negative for 5.10.K, Y.U, and A.N.S4 genes. Phylogenetically, B1 (49.50%), A (40.90%), and D (5.70%) were identified among the isolates, and 3.80% remained unknown. Wildlife could be considered as a bio-marker to determine the environmental dissemination of AMR. Also, hedgehog may be an important reservoir of antibiotic-resistant and non-pathogenic E. coli strains in urban environments. This study highlights the necessity of E. coli surveillance among domestic and wild animals.

Abstract To date, routine diagnosis of canine heartworm disease relies on detecting Dirofilaria immitis antigens in blood or the microscopic examination of blood smears. However, each method has limitations, potentially leading to life-threatening situations for infected dogs. This study aimed to determine the prevalence of filarial infection, risk factors, and appropriate detection methods in practical clinics. A total of 113 dog blood samples from two provinces in Thailand (Chonburi = 73 and Nakhon Nayok = 40) were analyzed for D. immitis infection using buffy coat smears, commercial immunochromatographic tests (SNAP 4Dx Plus), and polymerase chain reaction. Overall prevalence was 51.53% (58/113) across all methods. The positivity rates were 15.38% (12/78) for buffy coat smears, 8.00% (4/50) for SNAP 4Dx Plus, and 45.43% (51/113) for polymerase chain reaction. All positives from the test kits correlated with other methods. A significantly high prevalence was observed in dogs under 2 years old. Accessibility to pet care services in urban areas appeared to have a protective effect. Positive commercial test results could confirm D. immitis infection. However, selecting more than one diagnostic technique in clinics, including morphological examination, immunochromatography, or molecular methods, is recommended for early and more accurate detection, along with the promotion of heartworm prevention strategies.