BMC Veterinary Research最新文献

Background: Myxomatous mitral valve disease is the most common cardiac disease among dogs. The mitral valve consists of valve leaflets, chordae tendineae and papillary muscles. Much attention has been given to lesions of the valve leaflets, but there is still a lack of information in the literature about the chordae. During myxomatous mitral valve disease, an episode of chordae rupture can occur. Predisposing factors for such an episode are known in human cardiology.

Materials and methods: The 54 mitral valves were prepared from the hearts of older dogs, from which the chordae tendineae were then isolated. The chordae tendineae were subjected to two tests: biomechanical and histopathological. The first consisted of a uniaxial tensile test to determine the mechanical strength values of chordae tendineae. The histopathological examination was based on a 4-point scale (0-3 scale), which assessed the extent of degenerative changes within chordae tendineae. The biomechanical and histopathological findings were correlated in the statistical analysis.

Results: Degenerated chordae tendineae tended to rupture more rapidly during the static stretching test as compared to healthy chordae. The more advanced the degenerative changes in the chordae tendineae, the more the biomechanical function was affected.

Conclusions: Degeneration affects the biomechanical properties of the mitral valve chordae tendineae in dogs, as confirmed by chordae tendineae stress studies.

Background: Challenges of limited supply and increasing prices of fishmeal have driven the aquaculture nutritionists to seek alternative sustainable protein rich ingredients to keep manufacturing aquafeeds in a maintainable and cost-effective way. Black soldier fly, Hermetia illucenslarvae meal represent great potential as a sustainable alternative to fishmeal in aquafeeds.

Methods: Three replacement diets for fishmeal were prepared at different levels of defatted black soldier fly (Hermetia illucens) meal (DBSFM): Diet 1 (0 g DBSFM /kg diet, control), 33% (DBSFM-33%, 66 g DBSFM /kg diet), and 100% (DBSFM-100%, 200 g DBSFM /kg diet) to investigate their effects on biochemical parameters, immuno-hematological responses, antioxidant activities, and inflammatory gene expression in Nile tilapia, Oreochromis niloticus, a total of 270 (40.0 ± 0.50 g) before and after challenge with Streptococcus iniae (S. iniae). The feeding trial lasted six weeks (pre-challenge) and two weeks (post-challenge).

Results: The results showed a significant improvement in white blood cell count (P < 0.01), lymphocyte count (P < 0.01), serum lysozyme activity (P < 0.001), and phagocytic activity (P < 0.001), mostly in the DBSFM-100% group following the pre-challenge phase compared to the control group. Post-challenge phase exhibited significant increases in blood indices in the DBSFM-treated groups compared to the control group. Following pre- and post-challenge periods, both DBSFM-supplemented groups experienced significant increases (P < 0.01, P < 0.001), in serum total protein levels. Albumin and globulin levels also experienced similar increases (P < 0.05, P < 0.01), but only post-challenge. Total antioxidant capacity exhibited a significant increase in both DBSFM-supplemented groups following the post-challenge, as did superoxide dismutase, catalase, and glutathione peroxidase in the liver and spleen. Conversely, levels of glucose, cortisol, and malondialdehyde followed the opposite trend. DBSFM-100% inclusion revealed significant (P < 0.05) up-regulation of interleukin 1β (IL-1β) in the pre-challenge phase compared to control, but no significance (P > 0.05) was seen for other genes. Anti-inflammatory-related genes transforming growth factor-β and interleukin-10 mRNA expression levels were up-regulated in DBSFM-supplemented groups compared to the control post-challenge, but the opposite was seen for IL-1β and tumor necrosis factor- α.

Conclusion: These findings suggest that Nile tilapia challenged with S. iniae may experience significant enhancements in hemato-immunological parameters, antioxidant capability, and anti-inflammatory gene expression when fish meal is replaced with DBSFM up to 100%.

Background: Bovine coronavirus (BCoV) is a causative agent of enteric and respiratory diseases in cattle and is responsible for severe economic losses. Recently, a novel BCoV variant with 12-nucleotide deletion or insertion in the hemagglutinin-esterase (HE) receptor-binding domain (RBD) has emerged. However, the biological consequences of these deletions/insertions and the prevalence of these variants remain unknown. Here, 47 diarrheal and 47 nasal swab samples were collected from five cattle farms in various Ningxia, China regions to detect and isolate BCoV.

Results: Eleven complete HE genes and eight complete S genes were amplified from 34 BCoV-positive samples using RT-PCR. Eight BCoV strains were successfully isolated using HRT-18 cells, and four underwent genome sequencing. Three HE genes contained a 12-nucleotide insertion in the RBD, and a single HE gene contained a novel 12-nucleotide deletion. Phylogenetic analysis of genomes revealed that these HE-deletion/insertion variants do not share a common most recent ancestor with those reported from the US. Molecular docking results showed that the insertion of four additional amino acids between F211 and L212 increased the affinity of HE protein to O-acetylated sialic acid, which may be favorable for virion-particle attachment. Growth kinetics suggest that the HE-deletion variant had a non-cytopathic effect and lower virus titer.

Conclusions: These findings suggest that BCoV HE deleted/inserted variants are prevalent in cattle and exhibit various biological characteristics. We should be alert to these HE-variants with insertions or deletions in the RBD, which may increase the possibility of interspecies transmission.

Background: The raccoon (Procyon lotor) is a potential carrier of a large number of zoonotic pathogens, and its population is increasing in urban areas in Europe. In the present study, we investigated two cases of fatal enteritis in raccoons in Germany. Parvoviruses are a common cause of enteritis in raccoons, however in these cases an additional infection with zoonotic Salmonella was found, which has not yet been described in other countries than the United States.

Case presentation: Two female raccoons, aged 14 and 18 weeks, were submitted for necropsy. Histopathology of the small intestine revealed crypt degeneration and necrosis, atrophy and fusion of villi, as well as numerous bacteria partially covered by fibrinous pseudomembranes. By microbiological culture of small intestinal samples Salmonella enterica subsp. enterica Serovar Kottbus and Salmonella enterica subsp. enterica Serovar Ferruch were isolated, respectively. In addition, carnivore protoparvovirus type 1 was identified in the small intestine of both animals.

Conclusions: The infection of raccoons with carnivore protoparvovirus type 1 results in immunosuppression, which facilitates the spread of other pathogens. Both isolated Salmonella serovars represent a significant zoonotic threat for humans being in contact with the raccoon. Furthermore, in raccoons with sudden death a double infection with carnivore protoparvovirus type 1 and Salmonella should be considered as an important differential diagnosis.

Background: Bats and rodents have been identified as reservoirs for several highly pathogenic and zoonotic viruses including henipaviruses, a genus within the Paramyxoviridae family. A number of studies have revealed the circulation of henipaviruses at the wildlife-human-livestock interface in Cameroon. In this study, we describe the molecular analysis as well as the development and evaluation of a Bead-based Multiplex Binding Assay (BMBA) using an in-house Indirect Enzyme Linked Immunosorbent Assay (ELISA) to confirm the detection of henipavirus infection in wildlife species.

Results: A total of 600 fruit bats and 600 rodents were sampled between March 2018 and June 2020. Samples were analyzed using a semi-nested RT-PCR assay followed by sequencing of the PCR fragments. Transudates (754) were screened for the presence of henipavirus-specific antibodies in a BMBA and confirmed by ELISA using Hendra virus (HeV), Nipah virus (NiV) and Ghana virus (GhV) glycoproteins expressed in Leishmania tarentolae, and commercially available HeV G and NiV G glycoproteins. Henipavirus-specific antibodies were detected in 19/531 (3.6%) bat transudates screened by BMBA and confirmed by ELISA. Seroprevalence rates in the Centre and North Regions were 12/291 (4.1%) and 7/240 (2.9%) respectively. All rodents and shrews were serologically negative. Henipavirus RNA sequences were not detected in any of the samples screened in this work.

Conclusion: This study provides further data supporting the circulation of Henipaviruses in fruit bats (Eidolon helvum) which are roosting and reproducing in proximity to human and livestock populations in the Centre and North Regions of Cameroon. This also establishes the first detection of Henipavirus specific antibodies in Eidolon helvum populations in the North Region of Cameroon.

Background: Toxocariasis is caused by infection with Toxocara canis and Toxocara cati, common nematodes of canids and felids, respectively. Humans become infected after the accidental ingestion of embryonated eggs of Toxocara from the soil or the consumption of raw and undercooked meat containing Toxocara larvae. The aim of this cross-sectional study was to identify ascarid nematodes isolated from jackals in Guilan and Mazandaran provinces, based on morphological and molecular approaches.

Methods: This cross-sectional study was conducted on 41 road-killed golden jackals collected from Guilan and Mazandaran provinces in northern Iran. At first, species identification was carried out based on morphological characterization. Genomic DNA was extracted from the isolates of Toxocara collected from jackals. PCR-RFLP of Ribosomal DNA regions (ITS) using RsaI endonuclease enzyme and PCR-sequencing were carried out to identify Toxocara species. The sequence data were aligned using Bioedit software and compared with published sequences in GenBank using the BLAST system. Phylogenetic analysis was performed using MEGA 5.0 software.

Results: Eleven out of 41 road-killed golden jackals (26.8%) were infected with Toxocara nematodes. All the isolates were confirmed as T. canis based on morphological and molecular methods. A pairwise comparison of the sequences did not show any differences in nucleotide sequences within T. canis isolates, and the sequences were identical and exhibited 100% homology.

Conclusions: Considering the almost high prevalence of T. canis in golden jackals and its critical role in human toxocariasis, the identification of parasite species by molecular methods can be used to plan prevention and control programs in human and animal communities. Since, the ITS sequences of T. canis isolated from jackals in Iran were utterly similar to the ITS sequences of T. canis isolated from other hosts from different areas of the world, it is hypothesized that the type of host and geographical region do not affect the genetic diversity of the ITS region sequences of T. canis.

The use of animal cadavers in initial and continuing veterinary education is widely accepted, but ethical considerations regarding how to obtain and use them are often lacking. It can be argued that the use of animal cadavers should be guided by principles similar to those regulating the collection of human cadavers for scientific purposes. In humans, the use of unclaimed cadavers from unknown provenance, cadavers from criminals or homeless people, or cadavers robbed from their grave no longer happens in most countries. Accordingly, body donation programs have been emphasized to be the sole acceptable source of cadavers for medical education. The purpose of this article is to argue that this should also be the case for domestic animals, contrary to the current practices of using unwanted animals or animals bred for this purpose. But having a body donation program is not enough to make it ethical: care should also be taken in order to include principles such as informed consent from the owners, the absence of commercial uses of the bodily remains and the respect for all parties involved in the process. Overall, the importance of maintaining respect towards the reception and use of a donated cadaver in all circumstances should be the ethical priority for students and practitioners. By applying such principles, we can better ensure that the use of animal cadavers in education and training is transparent, respectful and responsible.

Background: Over the last decades, climatic and environmental changes have led to an expanding seasonal activity pattern and increasing distribution of ticks across Europe. In particular, Dermacentor reticulatus is now commonly found on dogs in central Europe. The present study compared attachment sites between Ixodes spp. and Dermacentor reticulatus ticks collected by veterinarians from dogs and cats, and investigated risk factors associated with tick infestation intensity and engorgement duration.

Results: The dataset comprised 6,335 dogs harbouring 10,287 ticks (8,095 Ixodes ricinus, 1,860 D. reticulatus, 218 Ixodes hexagonus/Ixodes canisuga, 114 of other tick species) respectively 4,248 cats harbouring 8,005 ticks (7,344 I. ricinus, 56 D. reticulatus, 505 I. hexagonus/I. canisuga, 100 of other tick species). Differing sites of tick attachment were not only found between the different host and tick species, but also between the tick developmental stages. Regarding the risk of infestation with multiple ticks, dogs and cats living in rural areas harboured significantly more often multiple than single specimens. Further, a long coat in cats was associated with a higher probability of multiple infestation, while this was not observed in dogs. However, there was a tendency towards a potential influence of the density of the undercoat (p = 0.051). In dogs, a tall to very tall body size as well as folded ears increased the risk of multiple infestation, while in cats, increasing age and increasing body size were negatively associated with multiple infestations. Ticks with an engorgement duration of > 48 h were found significantly more often on senior dogs and cats than on younger individuals, as well as on working/utility dog breeds, while engorgement duration was negatively correlated with infestation intensity in dogs. In cats, female gender and a rural residence were significantly associated with longer attachment duration.

Conclusions: Individual as well as breed specific characteristics can lead to a higher tick infestation intensity or longer engorgement duration. The knowledge of tick attachment sites and specific risk factors can help to raise awareness among owners concerning the importance of tick control with licensed acaricides, as recommended e.g. by the European Scientific Counsel Companion Animal Parasites (ESCCAP), and may aid in early tick removal to decrease the risk of pathogen transmission to dogs and cats whose owners nonetheless refuse acaricidal drugs.

Background: To study the problem of male sterility of cattle-yak and improve the yak crossbreeding, this study obtained the testicular Sertoli cells of yak and cattle-yak and compared the differences in transcriptome levels between the two bovine species. The testicular tissues of 3 healthy male cattle-yaks and 3 F₁ generation male yaks were collected at the age of 24 months. The Sertoli cells were isolated after enzymatic digestion, differential adhesion and starvation treatment. DATA-4 and SOX9 immunofluorescence staining were used to identify the cell type. Sertoli cells were subjected to transcriptome sequencing, GO analysis, KEGG analysis and differentially expressed gene were validated by RT-qPCR and Western blotting.

Results: The study successfully isolated and purified Sertoli cells of yak and cattle-yak. The transcriptome sequencing data were compared, analyzed and annotated. Compared to yak Sertoli cells, 6592 differentially expressed genes were identified, with 3007 genes upregulated and 3585 genes downregulated in cattle-yak Sertoli cells. GO analysis suggested that the upregulated genes might be mainly involved in processes such as translation, peptide biosynthetic process, amide biosynthetic process, peptide metabolic process, ribosome, cytoplasmic part, structural constituent of ribosome, structural molecule activity, endomembrane system, protein kinase activity, and phosphotransferase activity. The downregulated genes appeared to be primarily involved in protein phosphorylation, phosphorylation, endomembrane system, protein kinase activity, and phosphotransferase activity. KEGG analysis compared differential genes across 316 pathways, with 8 pathways showing significant enrichment. The upregulated pathways were potentially enriched in cattle-yak Sertoli cells, including ribosome, thermogenesis, and oxidative phosphorylation, while the downregulated pathways seemed to be significantly enriched in adherens junction, mTOR signaling pathway, AMPK signaling pathway, FoxO signaling pathway, and focal adhesion. Compared with yak Sertoli cells, ISOC2, RPL27A and FISI were highly expressed in cattle-yak, as confirmed by RT-qPCR analysis. PDPN, SORBS2, TF, PLSCR1, TJP2, KIF2C, ITGA3, SMTNL2, DSP, ADGRG1, DDR1, GSK3A, RBBP6, ZC3H15 and Claudin 11 showed low expression levels in cattle-yak.

Conclusions: Compared with yak Sertoli cells, the expression of genes related to protein activation, cell function, and membranous organelle composition in cattle-yak Sertoli cells appeared to be abnormal. The potential defects in cattle-yak Sertoli cells may hinder the creation of a suitable environment for spermatogenesis, which could be one of the factors contributing to male cattle-yak sterility. Claudin-11 might be a potentially important gene for further research into cattle-yak male sterility.

Background: Telocytes (TCs) are small interstitial cells that extend into multiple bead-like protrusions called telopodes (TPs). TCs are widely found in many tissues and organs, form connections with almost all types of cardiomyocytes, and participate in regulating cardiac microenvironment homeostasis.

Methods: In this study, transmission electron microscopy combined with special staining techniques (Gomori's, Masson's trichrome, and toluidine blue staining) were used to analyse the ultrastructure, distribution, and cytochemical characteristics of TCs in yak hearts. Immunohistochemistry and immunofluorescence double staining techniques were combined to identify the immunophenotypic characteristics of TCs functional markers (CD34, CD117, PDGFR-α and α-SMA) and further reveal their potential functions.

Results: The results showed that the TCs in the aortic bulb of yak hearts had prominent nuclei, and thin, long TPs with abundant secretory vesicles. TCs in the myocardial tissue exhibited irregularly shaped nuclei, shorter TPs, and connections with myocardial fibres and adjacent capillaries, forming a complex TC network. Immunohistochemical results demonstrated the positive expression of functional markers CD34, CD117, α-SMA and PDGFR-α in both the aortic bulb and myocardium. Immunofluorescence double staining results indicated co-expression of CD34/CD117, CD34/α-SMA, and CD117/PDGFR-α in TCs.

Conclusion: This is the first study to report the presence of TCs in the aortic bulb and myocardium of yak hearts and that it may form TC networks that mainly participate in mechanical support and cell communication in the heart. The presence and distribution characteristics of TCs in the heart of yaks provide important clues for further research on the role of TC networks in the adaptability of plateau animals to the environment.