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This study investigated whether different pacing patterns during high-intensity exercise elicit distinct transcriptional responses in equine skeletal muscle. Eight Thoroughbred horses completed two treadmill exercise sessions in a randomized crossover design. In the positive-pacing condition, horses exercised at 110% maximal O2 uptake (V̇O2max) for 1 min followed by 90% V̇O2max for 1 min, whereas in the negative-pacing condition, the order was reversed. At 4 h after exercise, the positive-pacing protocol resulted in upregulation of 1989 genes and downregulation of 840 genes, whereas the negative-pacing protocol resulted in upregulation of 1710 genes and downregulation of 593 genes (false discovery rate <0.05; fold change ≥1.5). Despite these differences, most exercise-responsive genes and pathways related to hypoxia signaling, extracellular matrix remodeling, and metabolic regulation were shared between protocols. A direct comparison of gene expression between the two protocols identified four genes with higher expression after positive pacing, including RP1, MORN5, and two unannotated equine transcripts (ENSECAG00000060378 and ENSECAG00000057614), whereas five genes (OLFML2B, POSTN, ANGPTL1, MAP1A, and ZNF554) showed higher expression after negative pacing. These findings indicate that the skeletal muscle transcriptomic response to workload-matched high-intensity exercise is largely conserved between pacing strategies in Thoroughbred horses, with only limited pacing-dependent differences.
Microbial resilience is important to maintain a healthy gut environment in horses, especially after antibiotic administration, but the efficacies of post-antibiotic recovery strategies remain poorly characterized. We used microbial amplicon sequencing to compare spontaneous recovery, autologous fecal microbiota transplantation (FMT), and probiotic administration in 18 horses following antibiotic-induced dysbiosis. Clinically healthy horses received a combination of cephalothin and minocycline for 5 consecutive days before intervention. Fecal microbial recovery was longitudinally evaluated by using community-level dissimilarity metrics. Antibiotic treatment induced marked dysbiosis in all horses. Autologous FMT resulted in significantly faster recovery toward individual pre-treatment baselines compared with spontaneous recovery (significantly lower dissimilarity at day 3 post-treatment, P < 0.05), whereas the effects of probiotics were only evident in cumulative recovery metrics and not at specific time points. These findings indicate that autologous FMT has the potential to accelerate the recovery of the equine gut microbiota following antibiotic-induced dysbiosis.
Glanders is a contagious zoonotic disease caused by Burkholderia mallei that primarily affects horses, donkeys, and mules. It remains endemic in parts of Asia, Africa, the Middle East, and South America, where increasing case reports highlight the need for accessible diagnostic tools. Conventional diagnostic methods are limited by high costs and specialized laboratory requirements, whereas lateral flow assays (LFAs) offer practical, user-friendly, and rapid alternatives. In this study, we developed three LFAs targeting antibodies against the B. mallei antigens Hcp1, GroEL, and whole-cell lysate (WCL), previously identified as promising markers in indirect enzyme-linked immunosorbent assays. Recombinant streptococcal protein G served as the colloidal gold conjugate. Diagnostic performance was evaluated using glanders-positive (n = 31) and glanders-negative (n = 51) equine sera collected in Mongolia. Hcp1-LFA demonstrated 100% sensitivity and 100% specificity, while WCL-LFA achieved 100% sensitivity and 98.0% specificity. GroEL-LFA showed 100% sensitivity but lower specificity (90.2%). Hcp1- and WCL-LFA also exhibited high sensitivity in asymptomatic horses. No cross-reactivity was observed with sera from horses with other infections (n = 60) collected in Japan. All LFAs remained functional for at least 16 weeks at 37°C. These results indicate that Hcp1- and WCL-based LFAs provide accurate, rapid, and equipment-free detection of glanders. Their simplicity, stability, and affordability make them highly suitable for field diagnosis, especially in low-resource endemic settings. Nonetheless, further validation using larger and more diverse sample sets is required to confirm their broader applicability. IMPORTANCE:Glanders is a contagious disease affecting horses, donkeys, and mules that can have serious economic and animal health consequences. Current diagnostic tests are expensive, time-consuming, and require specialized equipment. The assays developed in this study are simple, rapid, and cost-effective, allowing veterinarians to quickly identify infected animals in the field. Early detection helps prevent the spread of the disease, safeguarding livestock, supporting animal health, and reducing economic losses in affected regions.
Pathological hoof-wall cavities unrelated to nailing (so called "Gidoh" in Japan) often occur in the feet of horses. In 2001, in facilities managed by the Japan Racing Association (JRA), Gidoh was found to occur most frequently in the toe of the fore-hoof, with no gender predilection, and was more prevalent in older horses. However, it remains unclear whether this trend has continued in recent years, which pathological type of Gidoh predominates, and whether there are differences in prevalence among seasons. Therefore, in spring (April) and autumn (October) of 2020, we surveyed all racehorses stabled at the JRA training centers (TCs) regarding age, gender, lesion location, disease type, lesion severity, and prevalence of Gidoh. We reaffirmed that this foot problem occurred most frequently in horses aged 6 years or older, with no gender predilection. It occurred preferentially in the toe of the fore-hoof. White-line-fissure-type Gidoh was predominant, and about 80% of cases were mild. The prevalence was significantly lower in October than in April (P=0.02). The recent trend in the prevalence of Gidoh at the JRA TCs was similar to that in the 2001 survey, suggesting that routine hoof management at the JRA facilities has been stable for the past 19 years. In addition, the new finding of a lack of a difference in prevalence between the two JRA TCs indicated that hoof-care techniques at the two TCs have become more closely aligned over the past 19 years.
Synephrine is a sympathomimetic alkaloid of regulatory interest in both horse racing and equestrian sports, where feed‑related exposure may lead to its detection in equine blood and urine. This study characterized plasma and urinary concentrations of synephrine in horses following controlled oral administration. Six Thoroughbred horses received single oral doses of 100 mg or 800 mg synephrine, and blood and urine samples were collected sequentially. Each sample was analyzed both before and after β‑glucuronidase hydrolysis, demonstrating that synephrine was present predominantly as conjugated metabolites in both plasma and urine, and that hydrolysis substantially increased measurable concentrations. Non‑compartmental analysis was used to determine selected pharmacokinetic parameters, including half‑life, Cmax, Tmax, and AUC. These pharmacokinetic results indicated that synephrine was rapidly absorbed, with dose‑related increases in both systemic and urinary exposure. The findings provide initial quantitative information on circulating and urinary synephrine following defined oral exposure in horses. The concentration ranges and detection patterns described here may assist in interpreting field detections and support future studies aimed at understanding exposure arising from feed‑borne sources.
