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Made available in DSpace on 2020-12-12T01:17:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01 Background and aims Fecal microbial transplantation (FMT), a treatment for certain gastrointestinal conditions associated with dysbiosis in people, is also empirically employed in horses with colitis. This study used microbiota high-throughput sequencing to compare the fecal microbial profile of healthy horses to that of geriatric microbial transplant recipients experiencing diarrhea and tested whether FMT restores microbiota diversity. Methods To evaluate the effect of environment and donor characteristics on the intestinal microbiota, fecal samples were collected per rectum from 15 healthy young-adult (2–12 years) and 15 geriatric (≥20 years) horses. Additionally, FMT was performed for 3 consecutive days in 5 geriatric horses with diarrhea using feces from the same healthy donor. Fecal samples were collected from both donor and recipient prior to each FMT and from recipients 24 hours following the last FMT. The profile of the fecal bacterial microbiota was compared using 16S amplicon sequencing. Results and conclusions In contrast to diet and farm location, age did not significantly affect the healthy equine fecal microbiota, indicating that both healthy geriatric and young-adult horses may serve as FMT donors. The fecal microbiota of horses with diarrhea was significantly more variable in terms of β-diversity than that of healthy horses. An inverse correlation between diarrhea score and relative abundance of Verrucomicrobia was identified in surviving FMT recipients. At study completion, the fecal microbiota of horses which responded to FMT had a higher α-diversity than prior to treatment and was phylogenetically more similar to that of the donor. Department of Clinical Sciences Cummings School of Veterinary Medicine Tufts University Department of Infectious Diseases and Global Health Cummings School of Veterinary Medicine Tufts University Faculdade de Medicina Veterinária Universidade Estadual Paulista (Unesp) Equine Field Service Auburn University Faculdade de Medicina Veterinária Universidade Estadual Paulista (Unesp)

OBJECTIVES To determine the impact of age on survival in horses with colitis and to elucidate whether a lower type-1/type-2 cytokine ratio or an exaggerated inflammatory state contribute to reduced survival in aged horses. DESIGN Part 1: Retrospective cohort analysis. Part 2: Analytic observational study. ANIMALS Part 1: One hundred twenty-four adult horses with colitis. Part 2: Twenty-nine adult horses with new diarrhea onset while hospitalized. MEASUREMENTS AND MAIN RESULTS Part 1: Patient signalment, select clinicopathological data, diagnoses, treatment, hospitalization length, and invoice were compared between survivors (n = 101) and nonsurvivors (n = 23). Only age and plasma transfusion retained statistical significance in the final multivariate outcome model, with 8.5 times lower odds of survival in transfused horses (95% confidence interval [CI], 2.6-27.2%). Additionally, the likelihood of nonsurvival increased by 11.8% (95% CI, 4-20.2%) for every year the horse aged (P = 0.002). Similarly, geriatric horses (≥20 years) were 15.2 times more likely to die than young-adults (2-12 years, P = 0.03), independent of financial investment, documented comorbidities, and duration of hospitalization. Part 2: Select cytokine analyses were performed on serum collected from hospitalized horses within 1 hour of diarrhea onset (T0) and 6 hours later. At T0, all recorded clinicopathological variables were comparable between geriatric and young-adult horses, suggesting a similar degree of systemic illness. The median concentration of type-2 cytokines interleukin-4 and interleukin-10, and type-1 cytokine interferon-γ did not differ between age groups. Inflammatory cytokines interleukin-6 and tumor necrosis factor-α were significantly higher in geriatric compared to young-adult horses at both sampling time points. CONCLUSIONS Outcome of colitis was less favorable in aging horses and patients receiving a plasma transfusion. Although an exaggerated inflammatory state, based on increased interleukin-6 and tumor necrosis factor-α concentrations, in geriatric horses may contribute to reduced survival, a lower type-1/type-2 cytokines ratio was not identified in our geriatric population.

An 18-year-old, grey, Thoroughbred Cross gelding was referred to the Cummings School of Veterinary Medicine at Tufts University following a 3-week history of low-grade fever of unknown origin, distal limb swelling, and weight loss. Clinical examination identified a few black, round, smooth nodules along the ventral aspect of the proximal tail. Transabdominal ultrasound showed a markedly enlarged heterogenous spleen, hyperechoic liver nodules, and evidence of peritonitis with fibrin deposition. A mature neutrophilia was noted on complete blood count with variable numbers of phagocytized granules within neutrophils. The granules did not stain with Perl's Prussian blue, and were intensely positive when stained with Fontana-Mason, consistent with melanin. On necropsy, the spleen occupied approximately one-third of the abdominal cavity and was diffusely firm with abundant black pigment on cut section. The medullary space of the 18th thoracic vertebra was also diffusely blackened. The splenic, mediastinal, and tracheobronchial lymph nodes were five times the normal size and diffusely pigmented. The final anatomic diagnosis was disseminated malignant melanoma with extensive splenic involvement and hemolymphatic and vascular neoplastic dissemination. To the authors' knowledge, this is the first full report to identify circulating neutrophils containing phagocytized melanin granules, which confirmed an antemortem diagnosis of disseminated melanoma.

The popularity of therapeutic riding is growing rapidly. With greater numbers of horses used in this field, it is becoming increasingly important to understand how this work impacts horse quality of life. Salivary cortisol concentrations and behavior scores are two measures of stress in horses, and the goal of this study was to test the hypothesis that horses used in therapeutic riding exercises have greater increases in cortisol concentrations during therapeutic riding, when compared to a traditional hunt seat lesson program or at rest. Salivary cortisol concentrations were measured in six adult horses on 3 days per week for a total of 6 weeks. Horses served as their own controls, and salivary cortisol concentrations were measured during therapeutic riding, traditional riding, and at rest, with samples collected at 0, 30, and 60 minutes. Delta cortisol concentrations were calculated by subtracting baseline cortisol concentrations from values obtained at 30 or 60 minutes. Delta salivary cortisol values were compared among different types of activity by the nonparametric Wilcoxon matched-pairs signed-rank test. No significant differences in delta cortisol values were detected between riding conditions. Delta salivary cortisol values at 30 minutes were 0.147, 0.0762, and −0.032 μg/dL for rest, traditional riding, and therapeutic riding conditions, respectively, and delta values at 60 minutes were −0.0177, −0.002, and −0.031 μg/dL, respectively. Behavior scores did not differ significantly between different riding conditions. Our hypothesis was not supported, and we conclude that therapeutic riding was not associated with increased stress in horses in this sample.