Enhanced atherosclerosis in apolipoprotein E knockout rabbits: role of apoB48-rich remnant lipoproteins.

Introduction: Apolipoprotein E (apoE) acts as a binding molecule for both the low-density lipoprotein receptor and the lipoprotein receptor-related protein and this function is essential for facilitating the hepatocyte uptake of lipoproteins containing apoB. The absence of apoE leads to increased atherogenicity in both humans and mice, although the precise molecular mechanisms remain incompletely understood. Objectives: This study aimed to investigate the susceptibility of apoE knockout (KO) rabbits, in comparison with wild-type (WT) rabbits, to diet-induced hyperlipidemia and atherosclerosis. Methods: ApoE KO rabbits and WT rabbits were fed a diet containing 0.3% cholesterol for 16 weeks. Plasma lipid levels, lipoproteins, and apolipoproteins were analyzed. Atherosclerosis was evaluated at the endpoint of experiments. In addition, we evaluated the oxidizability of those lipoproteins containing apoB to investigate the possible mechanisms of atherosclerosis. Results: Male apoE KO rabbits showed significantly elevated levels of total cholesterol and triglycerides compared to WT rabbits, while female apoE KO rabbits displayed similar high total cholesterol levels, albeit with significantly higher triglycerides levels than WT controls. Notably, both male (2.1-fold increase) and female (1.6-fold increase) apoE KO rabbits exhibited a significantly augmented aortic lesion area compared to WT controls. Pathological examination showed that the increased intimal lesions in apoE KO rabbits were featured by heightened infiltration of macrophages (2.7-fold increase) and smooth muscle cells (2.5-fold increase). Furthermore, coronary atherosclerotic lesions were also increased by 1.3-fold in apoE KO rabbits. Lipoprotein analysis revealed that apoB48-rich beta-very-low-density lipoproteins were notably abundant in apoE KO rabbits, suggesting that these remnant lipoproteins of intestinal origin serve as the primary atherogenic lipoproteins. Moreover, apoB48-rich remnant lipoproteins isolated from apoE KO rabbits exhibited heightened susceptibility to copper-induced oxidation. Conclusions: The findings indicate that apoB48-rich remnant lipoproteins, resulting from apoE deficiency, possess greater atherogenic potential than apoB100-rich remnant lipoproteins, regardless of plasma TC levels.

Evaluation of the Spatial Arrangement of Rabbit Hepatocytes Based on Voronoi Tessellation Following Exposure to Zinc Oxide Nanoparticles.

Background: Zinc oxide nanoparticles have been utilized in different fields over the last decades. These nanoparticles can pose significant risks to various organs such as the liver. This study aimed to evaluate the effects of zinc oxide nanoparticles on liver histology, serum biochemistry, and spatial arrangement of the hepatocytes in the female New Zealand white rabbit. Methods: The rabbits received 1, 5, and 10 mg/kg of the zinc oxide nanoparticles (ZnO NPs) intraperitoneally once every 3 days for 28 days. The serum levels of the aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and zinc were assessed 48 hr following the first administration. The histopathological changes and Voronoi tessellation were evaluated after the last administration. Results: Our findings showed that the ZnO NPs significantly increased the serum levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and zinc. The histopathological findings showed ballooning degeneration, and sinusoidal congestion in ZnO NPs administrated groups. The Voronoi tessellation diagrams also confirmed that ZnO NPs changed the regular spatial arrangement of hepatocytes to random and cluster patterns. Conclusion: In conclusion, the ZnO NPs alter the liver spatial arrangement and induce hepatic pathological changes that may affect liver function in rabbits.

Homocysteine contributes to atherogenic transformation of the aorta in rabbits in the absence of hypercholesterolemia.

Atherosclerosis, the leading cause of cardiovascular disease, cannot be sufficiently explained by established risk factors, including cholesterol. Elevated plasma homocysteine (Hcy) is an independent risk factor for atherosclerosis and is closely linked to cardiovascular mortality. However, its role in atherosclerosis has not been fully clarified yet. We have previously shown that rabbits fed a diet deficient in B vitamins and choline (VCDD), which are required for Hcy degradation, exhibit an accumulation of macrophages and lipids in the aorta, aortic stiffening and disorganization of aortic collagen in the absence of hypercholesterolemia, and an aggravation of atherosclerosis in its presence. In the current study, plasma Hcy levels were increased by intravenous injections of Hcy into balloon-injured rabbits fed VCDD (VCDD+Hcy) in the absence of hypercholesterolemia. While this treatment did not lead to thickening of aortic wall, intravenous injections of Hcy into rabbits fed VCDD led to massive accumulation of VLDL-triglycerides as well as significant impairment of vascular reactivity of the aorta compared to VCDD alone. In the aorta intravenous Hcy injections into VCDD-fed rabbits led to fragmentation of aortic elastin, accumulation of elastin-specific electron-dense inclusions, collagen disorganization, lipid degradation, and autophagolysosome formation. Furthermore, rabbits from the VCDD+Hcy group exhibited a massive decrease of total protein methylated arginine in blood cells and decreased creatine in blood cells, serum and liver compared to rabbits from the VCDD group. Altogether, we conclude that Hcy contributes to atherogenic transformation of the aorta not only in the presence but also in the absence of hypercholesterolemia.

Clinicopathologic findings and causes of mortality in 100 pet rabbits from the Canary Islands, Spain, 2011-2022.

The European domestic rabbit (Oryctolagus cuniculus domesticus) is commonly kept as a pet, with increasing popularity among pet owners. Despite the increasing body of information on lagomorph medicine and pathology, comprehensive published compilations of causes of mortality in pet rabbits are limited. We analyzed health disorders, pathology findings, and most probable causes of death in 100 pet rabbits submitted to the Anatomopathological Diagnostic Service of the Veterinary School of the University of Las Palmas de Gran Canaria, Canary Islands, Spain, from 2011 to 2022. We reviewed clinical data and gross and histopathologic findings to classify the various disorders into infectious (n = 39), noninfectious (n = 45), and idiopathic conditions (n = 16). Within infectious disease processes, Encephalitozoon cuniculi infection (n = 14) and rabbit hemorrhagic viral disease (n = 14) had the highest prevalence. Regarding the noninfectious conditions, perioperative mortality (n = 10), gastrointestinal syndrome (n = 7), and trauma (n = 6) were the most common clinicopathologic entities observed.

Endoparasites of rabbits and hares.

Nematode, cestode, protozoan, microsporidian, and pentastomid parasites affect domesticated and wild rabbits, hares, and jackrabbits of the genera Brachylagus, Lepus, Oryctolagus, Pentalagus, and Sylvilagus. Some endoparasite infections are of limited or no significance, whereas others have potentially profound consequences. Accurate identification of endoparasites of rabbits, hares, and jackrabbits is an important facet of the work of veterinary pathologists engaged in lagomorph pathology. Here I review endoparasites from the pathologist's perspective, focusing on pathogenesis, lesions, and implications of infection. Stomach nematodes Graphidium strigosum and Obeliscoides cuniculi are infrequently pathogenic but may cause gastritis and gastric mucosal thickening. Nematodes Passalurus ambiguus, Protostrongylus spp., Trichostrongylus spp., and Trichuris spp. are rarely associated with disease. Adult Capillaria hepatica (syn. Calodium hepaticum) nematodes and non-embryonated eggs cause granulomatous hepatitis in wild Oryctolagus cuniculus and Lepus europaeus, resulting in multifocal, off-white, hepatic lesions, which may be misdiagnosed as hepatic eimeriosis. When the rabbit is an intermediate host for carnivore cestodes, the space-occupying effects of Cysticercus pisiformis and Coenurus serialis may have pathologic consequences. Eimeria stiedai is a major cause of white-spotted liver in O. cuniculus, particularly in juveniles. Enteric coccidiosis is a noteworthy cause of unthriftiness in young animals, and frequently manifests as diarrhea with grossly appreciable multifocal off-white intestinal lesions. O. cuniculus is the natural host for the zoonotic microsporidian Encephalitozoon cuniculi. Infection may be acute and focused mainly on the kidneys, or it may follow a chronic disease course, frequently with neurologic lesions. A latent carrier status may also develop.

Development of a peptide-generated antibody to rabbit hemorrhagic disease virus 2 VP60 and its immunohistochemical application in natural cases.

Rabbit hemorrhagic disease virus 2 (RHDV2) has spread across the United States infecting and causing death in domestic and wild rabbits. Immunohistochemistry (IHC) would be a useful tool for the detection of RHDV2 antigen in tissues as it is inexpensive and readily achievable in most diagnostic laboratories. However, there is no readily available antibody for this purpose. To fill this void, we generated an RHDV2 capsid protein VP60-specific antibody in chicken eggs and validated the antibody using formalin-fixed tissues from 5 domestic rabbits naturally infected with RHDV2. Viral antigen was detected immunohistochemically in various tissues, most prominently in hepatocytes and macrophages in liver, and in macrophages in spleen and cecal lymphoid tissue. Intravascular mononuclear cells in lung and renal tubular and biliary epithelium also were immunolabeled. Both nuclear and cytoplasmic immunolabeling were observed. This peptide-generated antibody is a potentially useful tool as an adjunct to reverse-transcription PCR or in situ hybridization for detection of RHDV2 in tissues.

Repeated injections of vitamin E and Se improves testicular morphology, testosterone and in vitro and in vivo sperm fertility in subfertile rabbits.

Subfertility is a multifactorial disorder that affects the rabbit production industry. However, subfertility may be treated by using a simple intervention such as vitamin supplementation. Vitamin E and selenium (Se) are potent antioxidants that protect the male reproductive system. The aim of this study is to determine the effects of vitamin E and Se on testicular size, semen quality and freezability, antioxidant activity, testosterone levels, and fertility in subfertile rabbits. Twenty-one New Zealand rabbits were classified as subfertile rabbits based on their semen characteristics and fertility records. The rabbits were randomly allocated into 3 equal groups (G1: control; G2: injected with Vit E 100 IU/head + Se 0.1 mg/kg b.w.; G3: injected with Vit E 200 IU/head + Se 0.2 mg/kg b.w. once weekly for 8 weeks).Once weekly for 8 W, blood samples were collected to measure serum testosterone level and total antioxidant capacity (TAC), and semen samples were collected by artificial vagina to assess the quality of fresh and frozen semen. At the 8th week of the study, 150 multiparous does were artificially inseminated with fresh semen to assess the fertility of rabbits after treatment; 50 does for each group. At the end of the study, rabbits were slaughtered to assess testicular morphometry. Fresh and post-thaw semen quality parameters were significantly (p < 0.05) higher in G3in comparison with G2and G1, respectively. Also, testosterone level was significantly (p < 0.05) increased at the 2nd week in G3in comparison with other groups. Conception and kindling rates were significantly (p < 0.05) higher in does which were inseminated with semen fromG3. In conclusion, injection of vitamin E and selenium at a higher dose (G3) improved the testicular morphology, quality of fresh and post-thaw semen, and most importantly, the fertility of subfertile rabbits.

Screening of Organic Acid Type and Dosage in Drinking Water for Young Rabbits.

Organic acids (OAs) are employed in animal feed to regulate gastrointestinal disorders and diarrhoea thanks to their ability to modulate the gastrointestinal environment and their antimicrobial capacity. However, there is not enough evidence regarding the most adequate OA and its effectiveness in rabbit farming. Therefore, the aim of this study was to screen and evaluate the response of young rabbits to six OAs, administered via drinking water, at three different concentrations (pH levels). Organic acids (acetic, ACET; formic, FOR; propionic, PROP; lactic, LAC; citric, CIT; and butyric, BUT) were tested at three concentrations (pH 3, 4, and 5). A negative control (CON; non-acidified water) was also included. We used 240 weaned rabbits (28 days old) divided into 2 batches. In each batch, animals were randomly allocated to 1 of the 19 experimental treatments and were housed in group cages of 6 animals per cage, treatment, and batch. Among the 240 rabbits, an additional cage with 6 animals was included to determine the initial physiological state of the animals. All animals were fed with commercial pelleted feed throughout the whole experiment. The duration of the study was 7 days, until 35 days of age. At 31 and 35 days of age, in each batch, three animals per day and treatment were slaughtered. The pH of the digestive contents in the fundus, antrum, duodenum, jejunum, ileum, and cecum, as well as the gastric pepsin enzyme activity, was measured. Water and feed consumption per cage and individual body weight (BW) were recorded daily. The type and dosage of OAs affected water intake. ACET 3, PROP 3, and BUT 3 reduced water intake compared to CON, negatively impacting feed intake and weight gain. FOR and CIT acids led to the highest BW and weight gain at 35 days, compared to PROP, LAC, and BUT (p < 0.05); showing ACET intermediate values. While OAs had limited effects on gastric and small intestine pH, acidified water at pH 4 and 5 lowered ileum and caecum pH (p < 0.05) compared to pH 3. Acidified water at pH 4 showed the highest (p < 0.05) pepsin activity compared to pH 3 and pH 5. Considering the limited sample size and short-term assessment period of our screening test, the OAs with the highest potential for use in post-weaning rabbits were FOR, ACET, and CIT at pH 4. The selected combinations did not exhibit any early adverse effects in young rabbits. These results should be further confirmed in a broader population of animals. It would also be advisable to extend the application of OAs over longer periods to evaluate their effects throughout the entire growing period of rabbits.

Neurodegeneration in a domestic rabbit with severe malnourishment and low hepatic copper.

Copper is a trace element that plays an essential role in neurodevelopment and neurologic function. Acquired copper deficiency has a range of neurologic manifestations, with myelopathy being the most common association. We describe here the clinical, radiologic, histopathologic, and toxicologic findings of a rabbit with malnutrition, neurodegeneration, and suspected copper deficiency. A stray, adult female dwarf rabbit cross (Oryctolagus cuniculus) in poor body condition developed ataxia and pelvic limb weakness progressing to lateral recumbency and urine retention. The clinical findings suggested multifocal brainstem disease with right-sided central vestibular involvement; however, microscopic examination identified thoracic and lumbosacral spinal cord myelopathy. Differentials for the spinal cord changes included neurodegenerative disease, nutritional deficiency, neurotoxin, trauma to the lumbosacral region, and ischemia. Hepatic copper levels were suboptimal at 18 ppm dry weight (RI: 24-150 ppm dry weight). While speculative, copper-deficiency myelopathy is a treatable cause of non-compressive myelopathy that may occur in this species.

Diseases of domestic rabbits by purpose; a retrospective study of 2,583 cases received at 4 diagnostic laboratories in California, USA, 2013-2022.

Domestic rabbits (Oryctolagus cuniculus) are commonly kept as pets or bred for laboratory investigation, meat, fur production, or a combination of these purposes. We conducted a retrospective study to assess the prevalence of diseases in domestic rabbits according to purpose. We retrieved results of autopsies, biopsies, and cytologies from 2,583 cases received at 4 diagnostic laboratories in California from 2013-2022. Rabbits were classified as pets (2,241; 86.8%), laboratory animals (92; 3.6%), meat-production animals (60; 2.3%), or multipurpose animals (190; 7.4%). A final diagnosis was reached in 2,360 (91.4%) cases and was classified by system, etiology, and type of process. Pet rabbits had the highest median age (5.9 y; vs. 3 y, 0.67 y, and 0.25 y in meat, multipurpose, and laboratory rabbits, respectively), and most of the neoplasms were diagnosed in this group (872 of the total 896 neoplasms in the study; 97.3%), with tumors of the skin, female reproductive tract, and hematolymphoid system being the most common. Laboratory rabbits had a high prevalence of infectious enterotyphlocolitis (40 of 92; 43.4%), and ~45% of those cases were due to opportunistic colibacillosis. Infectious and parasitic pneumonias were common in meat rabbits (18 of 60; 30%); pneumonic pasteurellosis accounted for >60% of those cases. Infectious cholangiohepatitides were common in multipurpose rabbits (61 of 110; 55.5%), with rabbit hemorrhagic disease representing the most common etiology (82.4% of those cases). Our results demonstrate that purpose of use can predict prevalence of disease in rabbits submitted to diagnostic laboratories.

KCNQ1 suppression-replacement gene therapy in transgenic rabbits with type 1 long QT syndrome.

BACKGROUND AND AIMS: Type 1 long QT syndrome (LQT1) is caused by pathogenic variants in the KCNQ1-encoded Kv7.1 potassium channels, which pathologically prolong ventricular action potential duration (APD). Herein, the pathologic phenotype in transgenic LQT1 rabbits is rescued using a novel KCNQ1 suppression-replacement (SupRep) gene therapy. METHODS: KCNQ1-SupRep gene therapy was developed by combining into a single construct a KCNQ1 shRNA (suppression) and an shRNA-immune KCNQ1 cDNA (replacement), packaged into adeno-associated virus serotype 9, and delivered in vivo via an intra-aortic root injection (1E10 vg/kg). To ascertain the efficacy of SupRep, 12-lead electrocardiograms were assessed in adult LQT1 and wild-type (WT) rabbits and patch-clamp experiments were performed on isolated ventricular cardiomyocytes. RESULTS: KCNQ1-SupRep treatment of LQT1 rabbits resulted in significant shortening of the pathologically prolonged QT index (QTi) towards WT levels. Ventricular cardiomyocytes isolated from treated LQT1 rabbits demonstrated pronounced shortening of APD compared to LQT1 controls, leading to levels similar to WT (LQT1-UT vs. LQT1-SupRep, P < .0001, LQT1-SupRep vs. WT, P = ns). Under ß-adrenergic stimulation with isoproterenol, SupRep-treated rabbits demonstrated a WT-like physiological QTi and APD90 behaviour. CONCLUSIONS: This study provides the first animal-model, proof-of-concept gene therapy for correction of LQT1. In LQT1 rabbits, treatment with KCNQ1-SupRep gene therapy normalized the clinical QTi and cellular APD90 to near WT levels both at baseline and after isoproterenol. If similar QT/APD correction can be achieved with intravenous administration of KCNQ1-SupRep gene therapy in LQT1 rabbits, these encouraging data should compel continued development of this gene therapy for patients with LQT1.

Integrated analysis of intestinal microbial community and muscle transcriptome profile in rabbits.

Intestinal microbial community plays an important part in maintaining health and skeletal muscle development in livestock. This study is the first of its kind in the world. In order to better understand the relationship between gut microbiota and gene expression in skeletal muscle of rabbits, caecum contents and longissimus dorsi tissues of rabbits at 0 d (S1), 35 d (S2) and 70d (S3) were collected and subjected for 16S rRNA sequencing and transcriptome sequencing. Our results showed that, among three groups of rabbits, Firmicutes and Bacteroidetes were the dominant phyla at the phylum level, while Akmansia, Bacteroides and Ruminobacter were the dominant genera at the genus level, and the relative abundance of Akmansia and Bacteroides increased firstly and then decreased from 0 d to 70 d. By analyzing the transcriptome sequencing data, we identified 2866, 2446 and 4541 differentially expressed genes (DEGs) in S1 vs S2, S2 vs S3 and S1 vs S3 groups, respectively. Finally, we performed correlation analysis between gut microbiota and the expression levels of muscle development-related genes of rabbits at 0 d and 70 d. Compared with 0 day old rabbits, in 70 day old rabbits Acinetobacter and Cronbacter with decreased abundance, and Ruminococcaceae_UCG-014 and Ruminococcus_1 with increase abundance is beneficial to caecum health in rabbits. These results will lay a foundation for further re-searches about the relationship between caecum microflora and muscle development in rabbits.

Association of single nucleotide polymorphisms in Neuropeptide Y (NPY) and Phosphoglycerate Mutase 2 (PGAM2) genes with growth traits in rabbits.

Genetic improvement of local rabbit breeds using modern approaches such as marker-assisted selection requires accurate and precise information about marker‒trait associations in animals with different genetic backgrounds. Therefore, this study was designed to estimate the association between two mutations located in the Neuropeptide Y (NPY, g.1778G > C) and Phosphoglycerate Mutase 2 (PGAM2, c.195 C > T) genes in New Zealand White (NZW), Baladi (BR), and V-line rabbits. The first mutation was genotyped using high-resolution melting, and the second mutation was genotyped using the PCR-RFLP method. The results revealed significant associations between the NPY mutation and body weight at 10 (V-line) and 12 weeks of age (NZW, BR, and V-line), body weight gain (BWG) from 10 to 12 weeks of age (BR), BWG from 6 to 12 weeks of age (NZW, BR, and V-line), average daily gain (NZW, BR, and V-line, and BR), growth rate (GR) from 8 to10 weeks (V-line), 10 to 12 weeks (BR), and GR from 6 to 12 weeks of age (BR, and V-line). The PGAM2 mutation was associated with body weight at 10 (V-line) and 12 (NZW, and V-line) weeks of age, with significant positive additive effects at 12 weeks of age in all breeds, and was associated with BWG from 8 to 10 and 10 to 12 in BR, and BWG from 6 to 12 weeks of age (NZW, and BR), and average daily gain (NZW, and BR), and was associated with GR form 8 to 10 weeks (BR), from10 to 12 weeks (BR, and V-line) and from 6 to 12 weeks (BR). The results highlighted the importance of the two mutations in growth development, and the possibility of considering them as candidate genes for late growth in rabbits.

Genetic assessment of litter size, body weight, carcass traits and gene expression profiles in exotic and indigenous rabbit breeds: a study on New Zealand White, Californian, and Gabali rabbits in Egypt.

Rabbits are essential for commercial meat production due to their efficient growth and productivity, breeds like New Zealand White (NZW), Californian (CAL), and Gabali (GAB) rabbits offer unique genetic traits in litter, growth, and carcass traits. This study aimed to evaluate heritability (h2), genetic and phenotypic correlations (rg and rp) for litter size, body weight and carcass traits across California (CAL), New Zealand white (NZW) and Gabali (GA) rabbits. Along with exploring gene expression profiles of TBC1D1, NPY, AGRP, POMC, Leptin, GH, GHR, IGF-1, CAA, GPR, ACC, CPT1, FAS, and CART in the brain, liver, and meat tissues of different rabbit breeds. The breed genotype had a significant impact on litter size (LS), litter weight (LW), body weight at 12 weeks (BW12), and daily weight gain (DWG) traits. NZW rabbits displayed superior performance in terms of litter size and litter weight, while CAL rabbits recorded the highest values for BW12 and DWG. Heritability estimates (h2) were generally low for litter size (ranging from 0.05 to 0.12) and medium for body weight (ranging from 0.16 to 0.31). Both genetic (rg) and phenotypic (rp) correlations for litter size were positive and moderate (ranging from 0.08 to 0.48), while correlations for body weight ranged from 0.21 to 0.58. Additionally, CAL rabbits exhibited higher carcass traits compared to NZW and GA rabbits. In terms of breed-specific gene expression patterns, New Zealand White (NZW) rabbits displayed the highest expression levels of key genes related to energy metabolism (TBC1D1), appetite regulation (NPY, AGRP, POMC), nutrient transport (CAA), and G protein-coupled receptors (GPR) in both brain and liver tissues. Californian (CAL) rabbits exhibited superior gene expression of the ACC gene in brain tissue and GH, GHR, and IGF-1 genes in brain and meat tissues. Gabali (GAB) rabbits demonstrated the highest expression levels of TBC1D1, NPY, AGRP, GPR, and ACC genes in meat tissues. These breed-specific gene expression differences, combined with genetic evaluation efforts, have the potential to enhance reproductive and productive performance in rabbits, offering valuable insights for rabbit breeding programs and genetic selection.

Comparison of two haemostasis techniques on procedural duration, postoperative pain and gastrointestinal function in pet rabbits undergoing ovariohysterectomy.

Ovariohysterectomy is a common surgical procedure in pet rabbits and one of its potential complications is postoperative gastrointestinal stasis, possibly exacerbated by prolonged surgery time. The objective of this prospective clinical study was to compare two techniques for surgical haemostasis with respect to procedural duration, postoperative pain, and return of gastrointestinal function, in 22 female rabbits undergoing ovariohysterectomy. Rabbits were assigned to one of two groups: conventional vessel ligation (CVL) and haemostasis with a vessel sealing device (VSD). The outcome variables for comparison between the two groups, recorded at 60-, 120-, 180-, and 360-minutes post anaesthesia, were duration of anaesthesia and surgery, postoperative Rabbit Grimace Scale scores, and measured food intake and faecal output. The vessel sealing device caused no appreciable blood loss. The duration of both surgery and anaesthesia was shorter in group VSD (20 ± 4 and 31 ± 6 minutes, respectively) than in group CVL (43 ± 9 and 54 ± 9 minutes, respectively) (p < 0.001). There were no differences between groups in time elapsed from the end of anaesthesia to both first food intake and first defecation. In both groups, the score of the Rabbit Grimace Scale decreased over time with statistically significant differences between 60 minutes and all the subsequent time points (p < 0.001). Vessel sealing devices may be recommended over conventional haemostasis for rabbit ovariohysterectomy to decrease the duration of surgery and anaesthesia, with potential beneficial effects on sustainability and practice workflow.

Morphological and molecular characterization of Eimeria magna infecting local rabbit (Oryctolagus cuniculus) in Alkarg City, Saudi Arabia.

Coccidiosis is one of the most prevalent diseases found in local rabbits (Oryctolagus cuniculus), which is caused by the Eimeria. The study aimed to more reliably identify Eimeria species (Eimeria magna) infecting Local Rabbits in Alkarg City, Saudi Arabia, based the method on the molecular properties and morphological and molecular biological techniques. Sub-spheroidal oocysts measuring 21-27 × 12-16 (24 × 14.4) µm (20 n) and with a length/width (L/W) ratio of 0.9-1.1 (1.0) were identified by microscopic analysis of a fecal sample. Oocysts feature a bi-layered wall that is 1.0-1.2 (1.1) µm thick. About two-thirds of the wall's thickness is made up of a smooth outer layer. A polar granule is present, but neither a micropyle nor an oocyst residuum is present. The ovoidal sporozoites measure 15-18 × 8-11 (16.5 × 9.5) µm, have an L/W ratio of 1.6-1.8 (1.7), and take up around 21% of the oocyst's total surface. The mean size of the sub-Stieda body is 1.4 × 2.3 µm, while the average size of the Stieda body is 0.9 × 1.8 µm. The para-Stieda body is lacking. Sporocyst residuum appears membrane-bound and has an uneven form made up of several granules. With two refractile bodies below the striations and pronounced striations at the more pointed end, sporozoites are vermiform, measuring an average of 11.6 × 4.0 µm. The results of the sequencing for the 18S rDNA gene confirmed the species of Eimeria parasites found in the host (rabbits). The current parasite species is closely related to the previously described and deposited E. magna and deeply embedded in the genus Eimeria (family Eimeriidae). According to the findings, single oocyst molecular identification of Eimeria may be accomplished through consistent use of the morphological and molecular results. It is possible to draw the conclusion that the current research supplies relevant facts that help assess the potential infection and future control measures against rabbit coccidiosis to reduce the financial losses that can be incurred by the rabbit industry in Saudi Arabia.

Comparative analysis of two novel complete genomes of myxoma virus vaccine strains.

Myxoma virus (MYXV) is a double-stranded DNA-containing virus of the family Poxviridae, genus Leporipoxvirus. MYXV is an important model virus for evolutionary and immunological research and a promising oncolytic. In this study, we sequenced and analyzed two complete genomes of MYXV virus vaccine strains B-82 and Rabbivac-B, which are widely used for vaccine production in Russia. Here, we first show that MYXV vaccine strains B-82 and Rabbivac-B share a common origin with the American recombinant MYXV MAV vaccine strain. In addition, our data suggest that the MYXV B-82 and Rabbivac-B strains contain a number of genes at the 5' and 3' ends that are identical to the virulent MYXV Lausanne strain. Several unique genetic signatures were identified in the M013L, M017L, M023, and M121R genes, helping to achieve high genetic resolution between vaccine strains. Overall, these findings highlight the evolutionary flexibility of certain genes in the MYXV genome and provide insights into the molecular epidemiology of the virus and subsequent vaccine development.

Assessment of the feed additive consisting of Saccharomyces cerevisiae CNCM I-4407 (Actisaf® Sc 47) for rabbits for fattening and non-food producing rabbits for the renewal of its authorisation (S. I. Lesaffre).

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the assessment of the application for renewal of authorisation of a preparation of dried cells of Saccharomyces cerevisiae CNCM I-4407 (Actisaf® Sc 47) as a zootechnical additive for rabbits for fattening and non-food producing rabbits. The applicant provided evidence that the additive currently in the market complies with the existing terms of the authorisation. The Panel concluded that the additive remains safe for the target species, consumers and the environment. Regarding the safety for the user, the additive is not a skin or eye irritant. However, it should be considered as a potential skin and respiratory sensitiser, and any exposure through skin and respiratory tract is considered a risk. The present application for renewal of the authorisation did not include a proposal for amending or supplementing the conditions of the original authorisation that would have an impact on the efficacy of the additive. Therefore, there was no need for assessing the efficacy of the additive in the context of the renewal of the authorisation.

Neoplastic and non-neoplastic lesions in biopsy samples from pet rabbits in Hong Kong: a retrospective analysis, 2019-2022.

Rabbits are popular pets in the urban environment of Hong Kong, ranking third behind cats and dogs. Here we describe the frequency of neoplastic and non-neoplastic lesions in biopsies from pet rabbits submitted to the CityU Veterinary Diagnostic Laboratory between 2019 and 2022, comprising 247 tissue samples from 243 rabbits collected by veterinarians in 19 veterinary clinics. Among the 243 rabbits, there were 128 females (65 spayed), 114 males (54 castrated); sex information was not provided for 1 rabbit. The rabbit breeds included 45 Lionhead, 35 Dwarf, 14 Lop, 11 Dwarf Lop, 5 French Lop, 3 Angora, 2 Dutch, 2 Holland Lop, and 1 each of Netherland Dwarf, Velveteen, Mini Lop, and New Zealand White. The mean ages of rabbits with neoplastic and non-neoplastic lesions were 7.1 and 5.7 y, respectively. The most common neoplastic lesions were adenocarcinoma (26.4%), trichoblastoma (21.4%), sarcoma (9.4%), and thymoma (8.2%). The most common non-neoplastic lesion was uterine cystic endometrial hyperplasia (14.8%), followed by dermal abscess formation in the ventral abdomen or skin of the head (12.5%). Although a broad spectrum of other lesions was described, our findings in biopsies from pet rabbits in Hong Kong are consistent with those in other jurisdictions.