BMC Veterinary Research最新文献

Background: Brucellosis is listed as a priority disease in low-income countries like Guinea, facing challenges in logistics, equipment, competence, and cost limitations for diagnosis. Serological diagnosis is mainly performed by the Rose Bengal agglutination test (RBT) in the veterinary sector. We have compared its discriminative capacity with more sophisticated and expensive serological tests, such as multi-species or species-specific ELISA kits and Complement Fixation test (CFT).

Methodology/principal findings: A panel of 554 serum samples of pigs, goats, sheep, and cattle collected throughout Guinea from 2017 to 2019 where tested by RTB and ELISA tests in parallel at the Institut Pasteur de Guinée (Conakry) and the Brucellosis WOAH/EU Reference Laboratory of the French Agency for Food, Environmental and Occupational Health & Safety (Maisons-Alfort, France). ELISAs performed equally across laboratories (Kappa =0.867-0.958); RBT and ELISA showed 94-95% concordance. The CFT value of positive cattle samples also logically followed the RBT scores CONCLUSIONS/SIGNIFICANCE: In low-income countries like Guinea, the less expensive RBT can be regarded as a convenient routine Brucella diagnosis tool, assuming a solid experience of the operator following standard operating protocols and regular proficiency tests. As WOAH recommends confirmatory methods, the multispecies ELISA kit appears as a good candidate for conveniently trained and equipped laboratories.

Background: The virulence and replication of PRV are not only regulated by the virulence genes gE or gI, but also related to host circRNA, miRNA, and lncRNA. Circular RNAs (circRNAs) fulfill a diverse array of biological functions. However, the functions of circRNAs in PRV infections by attenuated and virulent strains are not yet fully elucidated. In this study, the circRNA expression profiles of the PRV virulent strain FA and attenuated strain FB were established and analyzed by high-throughput sequencing technology. A ceRNA network was established utilizing differentially expressed circRNAs (DE circRNAs), and their biological functions of these circRNAs were subsequently predicted.

Results: We found that 4 DE circRNAs (animalcirc_014421, animalcirc_004115, animalcirc_010807, and animalcirc_000091) in infections with PRV virulent and attenuated strains mediated the interactions among circRNAs, miRNAs, and mRNAs within the ceRNA network. The target genes of these DE circRNAs were associated with lysosome and apoptosis-related biological processes. Notably, target genes such as PiK3rl and Pou2f1 were enriched in the Herpes simplex virus 1 infection pathway. The findings indicate that these DE circRNAs could be crucial in the infection process of Herpesviruses.

Conclusions: circRNAs may contribute to the differences in virulence and replication between the PRV FA strain and attenuated FB strain through pathways such as apoptosis and lysosomal regulation. This research provides novel insights into the molecular mechanisms by which host circRNAs modulate the phenotypic disparities between PRV virulent and attenuated strains.

Background: Group housing systems during gestation and free-farrowing pens have recently been implemented in Thailand. This study aimed to investigate how different housing systems, sow parity number and season affect the following outcomes: the percentage of sows returning to oestrus after insemination, farrowing rate, litter traits, piglet preweaning mortality and the age at which sows are removed from the herd. The dataset included 61066 service records from 15666 Landrace × Yorkshire crossbred gilts and sows across three housing systems within a breeding herd. The service records were categorized based on housing systems into three groups: conventional crate (CC, n = 11020), pen gestation with temporary confinement for 35 days post-mating and 10 days post-farrowing (PC, n = 16689) and pen gestation with temporary confinement for 7 days post-mating and complete free-farrowing (PP, n = 33357). The parity numbers of sows were divided into four groups: 0 (n = 11300), 1 (n = 10203), 2 to 4 (n = 25447) and ≥ 5 (n = 14116). The seasons were classified according to farrowing months into three groups: hot (16 Feb to 15 Jun), rainy (15 Jun to 15 Oct) and cool (16 Oct to 15 Feb).

Results: Sows in the CC group had higher farrowing rates and lower remating rates compared with the PC and PP groups (P < 0.001). Litter size was larger in the PP group than in CC and PC groups (P < 0.001), whereas BW was higher in PC group than in PP group (P < 0.05). A significant housing × parity × season interaction influenced most fertility and litter traits, with PP sows showing reduced farrowing rates, increased remating rates and lower BW, particularly in gilts and primiparous sows during the hot and rainy seasons. Weaning performance (NW and WW) was highest in CC sows, especially in gilts across all seasons (P < 0.001). PWM was lower in CC group compared to PC and PP groups (P < 0.001) and influenced by a housing × season interaction (P < 0.001). Sow longevity differed among housing systems, with CC and PC sows remaining in the herd longer and having higher stayability than PP sows (P < 0.001).

Conclusion: Sows in group housing systems experienced lower farrowing rate and higher remating rate. Sows in group housing with free-farrowing system had higher litter size and higher piglet preweaning mortality rate compared to those in the conventional crate system. Sows in the conventional crate system and group housing with temporary confinement post-farrowing remained in the herds longer than sows in group-housed with complete free-farrowing. Hence, there is a need for interventions and husbandry management for balancing animal welfare with reproductive trade-offs in these alternative welfare-friendly systems.

Background: Real-time reverse transcription quantitative polymerase chain reaction (RT-qPCR) is a technique that allows for the semi-quantification of mRNA transcripts present within a tissue of interest. Differences in the relative abundance of mRNA between samples detected by RT-qPCR require normalization with a reference gene or genes whose transcript abundance is stable within the tissue of interest independent of experimental conditions. In the field of equine reproductive studies, ACTB, GAPDH and B2M genes are the most widely used as reference genes for the normalization of RT-qPCR results. However, recent studies have demonstrated that these genes may have drastically varied expression levels in different tissues and various physiological states. Therefore, the aim of this study was to examine different putative reference genes in equine corpus luteum samples in pregnant and non-pregnant, mid-diestrus, animals. The stability of genetic expression was evaluated via three stability software analyses (GeNorm, NormFinder and BestKeeper). We hypothesized that the commonly used reference genes (ACTB, GAPDH and B2M) would be the most stably expressed genes in equine corpus luteum samples in both pregnant and non-pregnant mares.

Results: COX4I1 and SRP14 were both found to be among the top three most stable genes of all samples for all methods, though the ranking of stability changed depending on the software used. When assessing the least stably expressed genes, the commonly used reference genes were frequently identified across the three software.

Conclusions: Commonly used reference genes (ACTB, GAPDH, B2M) for RT-qPCR normalization were amongst the least stably expressed genes in equine corpus luteum samples of pregnant and nonpregnant mares at days 11 and 13 of gestation. The most stably expressed putative reference genes using 3 different analysis modalities were SRP14, COX4I1, RPL13 and RPL4. Exploration of putative reference genes should be considered when investigating dynamic endocrine organs such as those used in reproductive studies.

Background: In vitro semen preservation is a crucial technique for conserving genetic material from male dogs. However, during the storage, oxidative damage can compromise key sperm structures, resulting in the decline of sperm viability, affecting their recognition of oocytes, and even causing sperm death. Therefore, the addition of exogenous antioxidants to alleviate the oxidative damage to sperm has become an important strategy to improve the effect of sperm storage in vitro. Astragalus polysaccharide (APS) is a kind of water soluble heteropolysaccharide with high-efficiency antioxidant activity, but its effect and mechanism in the preservation of canine semen remain to be studied. Thus, the present was designed to investigate the effects of APS on canine sperm after chilled storage, as well as its mechanism.

Results: It was observed that the supplementation of 0.50 mg/mL APS significantly improved sperm motility parameters, plasma membrane integrity, acrosome integrity, mitochondrial membrane potential, enhanced sperm antioxidant capacity, and promoted AMPK phosphorylation, while reduced the level of lipid peroxidation, after chilled storage. In addition, the effects of APS were partly counteracted when oxidative stressed sperm induced by H₂O₂ was incubated with 0.50 mg/mL APS and 40 µM Compound C (an AMPK inhibitor). These results suggest that APS protects canine sperm after chilled storage via promoting AMPK phosphorylation.

Conclusion: The supplementation of APS to the extender protects canine sperm after chilled storage via promoting AMPK phosphorylation for enhancing the antioxidant capacity of sperm. These findings provide novel insight into the mechanism of APS in protecting canine sperm after chilled storage, and reveal the feasibility of APS supplementation to sperm extender for canine sperm preservation.

Background: Posturographic balance assessments are increasingly used in veterinary medicine, yet potential learning effects during evaluation remain unstudied. This study investigated learning effects in static, slow-dynamic, and fast-dynamic posturography using a modified Posturomed platform in healthy dogs.

Material and methods: Healthy adult dogs (n = 20) were positioned longitudinally on a pressure sensitive modified balance platform (Posturomed-FDM-JS, Zebris, Isny, Germany). Five static, slow-dynamic and fast-dynamic posturographic trials were recorded (duration: 20s) and repeated three times over three weeks. Center of pressure (COP) parameters-COP-path-length (PL, mm), 95% COP-confidence-ellipse-area (CEA, mm²) and COP-average-velocity (AV, mm/sec) were analyzed over five steady-state 5-s intervals per trial. Data were analyzed using generalised linear or robust linear mixed-effects models with random effects on the individual dog; p-values were adjusted using the Tukey method for multiple comparisons.

Results: Under static conditions, none of the COP-parameters differed significantly across time points (all p-values > 0.448). Under slow-dynamic conditions, all COP-parameters decreased significantly between time points 1 and 2 (all p values < 0.0007) but remained stable thereafter (all p-values > 0.159). Under fast-dynamic conditions, all COP-parameters decreased significantly from time point to time point (all p-values < 0.034), except for CEA between time points 1 and 3 (p = 0.0759) and 2 and 3 (p = 0.999). Differences among trials occurred only at the first time point under dynamic conditions and were more pronounced under fast-dynamic conditions.

Conclusions: No learning effects were observed during static posturography in healthy adult dogs. However, training effects must be considered in both slow- and fast-dynamic posturography.

Background: Recurrent otitis (RO) is characterized by inflammatory or infectious processes in dogs with allergic skin diseases, accompanied by recurrent secondary bacterial and fungal infections. Dogs underwent a combined therapeutic approach for RO, assessing the effect of long-term management during the Stabilization Phase (SP) using a suspension containing ciprofloxacin, clotrimazole, and betamethasone, followed by management in the Proactive Phase (PP) with topical hydrocortisone aceponate (HCA) administration. A total of 45 dogs were evaluated, totaling 90 ears. All animals had a clinical history of bilateral RO with an erythematous-ceruminous clinical presentation, as indicated by the anamnesis, clinical, cytological, and otoscopic evaluations, with three or more relapse episodes of otitis per year.

Results: The SP management reduced bacterial infections and led to an increase in yeast occurrence. There was a decrease in severe otitis cases, while the incidence of moderate scores-Otitis Index Score-3 (OTIS-3) (3 and 4) increased, indicating the persistence of RO with significant changes. In the PP, the topical HCA solution demonstrated efficacy, showing a marked reduction in cytology and clinical assessment over 90 days, with no signs of recurrence or otitis persistence throughout the remaining period. The PP, using HCA, promoted improvement in cytological and clinical outcomes, with most dogs showing no recurrence of otitis.

Conclusions: The likely favorable safety profile of HCA, its local anti-inflammatory effects, and its ability to avoid systemic side effects make it a promising therapeutic option for the long-term management of RO in dogs.

Background: Ovine rotavirus infection is a major viral cause of acute diarrhea in lambs, primarily affecting those aged 1 to 7 days, and can lead to mortality in both goats and sheep. Effective serological detection is crucial for disease surveillance and control.

Methods: The VP6 gene of ovine rotavirus was cloned and expressed as a recombinant protein (rVP6) in Escherichia coli (E. coli) using the pET-30a (+) vector. An indirect ELISA (iELISA) was subsequently developed using this rVP6 protein as the coating antigen. The assay conditions were systematically optimized. The performance of the iELISA was validated by evaluating its sensitivity and specificity using a panel of reference serum samples (n = 122), and its results were compared with those of an indirect immunofluorescence assay (IFA). Assay precision was assessed by calculating intra-assay and inter-assay coefficients of variation (CV).

Results: The rVP6 protein was successfully expressed. The optimized iELISA, using 50 ng of antigen per well and a 1:50 serum dilution, demonstrated a sensitivity of 86.96% and a specificity of 97.98%. Comparison with IFA yielded a Kappa value of 0.864, indicating almost perfect agreement. The assay showed good repeatability (intra-assay CV = 3.4%) and reproducibility (inter-assay CV = 4.53%).

Conclusions: A sensitive, specific, and reproducible iELISA based on the rVP6 protein was successfully developed for detecting antibodies against ovine rotavirus. This assay provides a reliable and cost-effective tool suitable for large scale seroepidemiological surveillance of ovine rotavirus infection.

The burden of infectious diseases in animals, particularly in livestock, significantly impacts global food security and economic development. Despite advancements in diagnostic technologies, substantial gaps remain that hinder effective disease control and surveillance. This study presents a new methodology for identifying gaps in animal health diagnosis by integrating data from DISCONTOOLS, the Diagnostics for Animals' List of Animal Health Diagnostics, and the World Animal Health Information System. Our analysis highlights significant diagnostic needs, particularly for high-priority infectious diseases in livestock. The findings aim to guide research and development efforts to improve disease surveillance and control.