Effect of Sugar Beet Pulp on the Composition and Predicted Function of Equine Fecal Microbiota.

The purpose of this study is to determine the effect of the partial replacement of dietary hay with sugar beet pulp (SBP) on the composition and predicted function of the fecal microbiota of healthy adult horses. Fecal samples were collected daily for 12 days from six adult horses after removal from pasture, including a five-day acclimation period, and a seven-day period following the introduction of SBP into their diet, and compared to six untreated horses over a comparable period. Fecal DNA was subjected to 16S rRNA amplicon sequencing and a longitudinal analysis was performed comparing the composition and predicted function. While no significant treatment-associated changes in the richness, alpha diversity, or beta diversity were detected, random forest regression identified several high-importance taxonomic features associated with change over time in horses receiving SBP. A similar analysis of the predicted functional pathways identified several high-importance pathways, including those involved in the production of L-methionine and butyrate. These data suggest that feeding SBP to healthy adult horses acutely increases the relative abundance of several Gram-positive taxa, including Cellulosilyticum sp., Moryella sp., and Weissella sp., and mitigates the predicted functional changes associated with removal from pasture. Large-scale studies are needed to assess the protective effect of SBP on the incidence of the gastrointestinal conditions of horses.

Head and neck squamous cell carcinoma with heterotopic ossification, lymphovascular invasion, and nodal and pulmonary metastases in a 23-year-old Morgan gelding.

Primary squamous cell carcinoma of the head and neck occurs in the skin or squamous epithelial lining tissues of the oral cavity, pharynx, larynx, and sinonasal tract. Although it is a common tumor in horses, distant metastatic spread to the lung is rare. This report describes a case of metastatic pulmonary squamous cell carcinoma in a 23-year-old Morgan gelding. The clinical signs displayed by this gelding in some ways mimicked the typical presentation of equine multinodular pulmonary fibrosis or thoracic lymphoma. The postmortem diagnosis in this case was head and neck squamous cell carcinoma, but a primary site of origin could not be ascertained. Cancer-associated heterotopic ossification (HO) was also identified in this case; this is an exceedingly rare finding with equine pulmonary neoplasia. Key clinical message: Careful physical examination should be undertaken in all horses presenting with clinical signs of intrathoracic disease. Clinical and radiographic abnormalities in this case of pulmonary metastatic disease resembled some of those associated with interstitial pneumonia. Rarely encountered in domestic animal species, there has been only 1 previous report of HO in a case of oronasal carcinoma in a horse.

Carcinome épidermoïde de la tête et du cou avec ossification hétérotopique, envahissement lymphovasculaire et métastases ganglionnaires et pulmonaires chez un hongre Morgan de 23 ans. Le carcinome épidermoïde primitif de la tête et du cou survient dans la peau ou les tissus épithéliaux squameux de la cavité buccale, du pharynx, du larynx et du tractus naso-sinusien. Bien qu'il s'agisse d'une tumeur courante chez les chevaux, la propagation métastatique à distance au poumon est rare. Ce rapport décrit un cas de carcinome épidermoïde pulmonaire métastatique chez un hongre Morgan de 23 ans. Les signes cliniques présentés par ce hongre imitaient à certains égards la présentation typique de la fibrose pulmonaire multinodulaire équine ou du lymphome thoracique. Le diagnostic post-mortem dans ce cas était un carcinome épidermoïde de la tête et du cou, mais un site d'origine primaire n'a pas pu être déterminé. L'ossification hétérotopique associée au cancer (HO) a également été identifiée dans ce cas; il s'agit d'une découverte extrêmement rare avec la néoplasie pulmonaire équine.Message clinique clé :Un examen physique attentif doit être entrepris chez tous les chevaux présentant des signes cliniques de maladie intrathoracique. Les anomalies cliniques et radiographiques dans ce cas de maladie pulmonaire métastatique ressemblaient à certaines de celles associées à la pneumonie interstitielle. Rarement rencontré chez les espèces animales domestiques, il n'y a eu qu'un seul signalement antérieur d'HO dans un cas de carcinome oronasal chez un cheval.(Traduit par Dr Serge Messier).

Concurrent chronic lymphocytic leukemia and primary hyperparathyroidism in a mule.

A 26-year-old mule gelding was evaluated for chronic weight loss and decreased appetite. The mule had been losing weight and intermittently hypophagic for approximately 7 months. Laboratory analysis of whole blood and plasma identified severe total hypercalcemia, marked hypophosphatemia, markedly increased parathyroid hormone concentration, and marked lymphocytosis. A sestimibi scan intended to identify parathyroid gland tissue was nondiagnostic. Results of flow cytometry and PCR for antigen receptor rearrangement (PARR) were consistent with a B cell lymphoproliferative disorder, likely chronic lymphocytic leukemia (CLL). Although not previously described concurrently, these conditions may sometimes arise together, complicating definition of the underlying mechanism for weight loss and hypercalcemia in aged equids.

Pathology in Practice.

In collaboration with the American College of Veterinary Pathologists.

The Influence of Diet Change and Oral Metformin on Blood Glucose Regulation and the Fecal Microbiota of Healthy Horses.

Common treatments for Equine Metabolic Syndrome (EMS) and associated conditions include removal from pasture and adoption of an all-hay diet. Pharmacological treatments for EMS include metformin, a biguanide antihyperglycemic agent also administered to people to help improve glucose tolerance and insulin sensitivity. Both treatments may work, at least partially, through the gut microbiota, yet little is known regarding these effects in the equine host. To determine the influence on the fecal microbiota of this diet change and administration of metformin, six healthy horses were removed from pasture and switched to an all-hay diet, with four of those horses also receiving oral metformin for seven days. Control horses (n = 24) remaining on pasture and receiving no metformin were sampled at the beginning and end of one week. All samples were subjected to 16S rRNA sequencing, and horses undergoing the diet change were subjected to an oral sugar test twice, one week apart. Characteristic changes in the microbiota following diet change included the significant expansion of the phylum Kiritimatiellaeota. As Kiritimatiellaeota are related to Verrucomicrobia, found to expand in the microbiota of mice and humans in response to metformin, this taxon may represent the cognate microbes in equine hosts.

Exodontia associated bacteremia in horses characterized by next generation sequencing.

Bacteremia resulting from dental surgery is increasingly recognized as a health risk, especially in older and immunocompromised patients. Dentistry-associated bacteremia can lead to remote infections, as exemplified by valvular endocarditis. Emerging evidence points to a novel role played by oral cavity commensals in the pathogenesis of diabetes, respiratory disease, cardiovascular disease, and adverse pregnancy outcomes. Whether dental extraction, a commonly undertaken procedure in old horses, causes bacteremia has not been reported extensively. In a prospective clinical study using next generation sequencing (based on bacterial 16S rRNA), the circulating blood microbiome was characterized before and at 1 h following extraction of incisor, canine or cheek teeth from 29 adult horses with dental disease. 16S rRNA gene sequencing results from the blood microbiome were compared with those from gingival swab samples obtained prior to extraction at the location of the diseased tooth. Bacteremia associated with translocated gingival commensals was demonstrated in horses undergoing exodontia and was, in some cases, still evident one hour post-operatively.