Effects of age and diet on glucose and insulin dynamics in the horse

Background Equine endocrinopathic laminitis is common and can be associated with an underlying endocrinopathy, such as equine metabolic syndrome (EMS), pituitary pars intermedia dysfunction (PPID), pasture consumption, or any combination of these factors. Objectives The aim of the study was to improve the risk assessment capabilities of clinicians, and to inform management strategies, for acute endocrinopathic laminitis by prospectively examining the phenotypic, hormonal, and clinical characteristics of the disease in a large cohort. Animals Privately owned horses and ponies (n = 301) of any age, sex, or breed diagnosed with laminitis by a veterinarian. A history of laminitis was acceptable. Methods This was a prospective cohort study. Veterinarians provided information on each case via an online questionnaire after informed consent from the animal's owner, and all data were de‐identified before analysis. Serum insulin and plasma adrenocorticotrophic hormone concentrations were measured in each case. Results Most cases were recruited in spring (109/301; 36.2%). Concurrent EMS and PPID resulted in higher basal insulin concentrations (49 [21.5‐141]; P < .02) than if an animal had a single underlying cause for their laminitis. The insulin concentration was negatively correlated (r 2 = −0.38; P < .001) with the animal's height, being higher in ponies (33[10‐14]; P < .001) than horses (9.5 [3‐25.7]) and was positively correlated (r 2 = 0.12; P = .05) with their grade (severity) of laminitis. Conclusions and Clinical Importance Horses and ponies with concurrent endocrinopathies have more marked hyperinsulinemia. Higher basal insulin concentrations were associated with more severe lameness.

Section: Discussionmentioning

confidence: 69%

Section: Discussionmentioning

confidence: 74%

Phenotypic, hormonal, and clinical characteristics of equine endocrinopathic laminitis

Laat

Sillence

Reiche

2019

“…Additionally, certain predisposed breeds such as Shetland ponies, donkeys, and miniature horses are frequently not exercised as much as many other breeds as part of standard management. Studies have generally found insulin concentrations to be significantly higher in older versus younger horses and ponies . Circulating adiponectin concentrations are also lower in older animals compared to younger animals, consistent with an age association with ID .…”

Section: Epidemiologymentioning

confidence: 74%

ECEIM consensus statement on equine metabolic syndrome

Durham¹,

Frank

McGowan

et al. 2019

176

227

Equine metabolic syndrome (EMS) is a widely recognized collection of risk factors for endocrinopathic laminitis. The most important of these risk factors is insulin dysregulation (ID). Clinicians and horse owners must recognize the presence of these risk factors so that they can be targeted and controlled to reduce the risk of laminitis attacks. Diagnosis of EMS is based partly on the horse's history and clinical examination findings, and partly on laboratory testing. Several choices of test exist which examine different facets of ID and other related metabolic disturbances. EMS is controlled mainly by dietary strategies and exercise programs that aim to improve insulin regulation and decrease obesity where present. In some cases, pharmacologic aids might be useful. Management of an EMS case is a long‐term strategy requiring diligence and discipline by the horse's carer and support and guidance from their veterinarians.

“…However, the improved glucose response seems to indicate that the onset of hyperinsulinemia was not related to tissue resistance to insulin. Diet‐induced improvement in insulin sensitivity has been documented previously in horses and ponies fed starch‐rich, sugar‐rich, or both diets 9,24,25 . A previous study showed that horses and ponies consuming a ration containing a once daily glycemic load for 12 weeks had improved insulin sensitivity based on a frequently sampled intravenous glucose tolerance test (FSIGTT), despite induction of obesity 9 .…”

Section: Discussionmentioning

confidence: 87%

Effect of long‐term overfeeding of a high‐energy diet on glucose tolerance in Shetland pony mares

Fonseca

Gibson

Doorn

et al. 2020

Background: Overfeeding is associated with obesity and insulin dysregulation (ID), which are both risk factors for equine metabolic syndrome. How chronic overfeeding affects development of these factors is poorly understood.Objectives: To examine the influence of long-term high-energy diet provision on body condition and ID.Animals: Eleven Shetland pony mares. Methods:In a 3-phase study, the high-energy group (n = 7) was fed 200% of net energy (NE) requirements (hay; concentrate: 36% sugar and starch, 13% fat) for 24 weeks, followed by 17 weeks hay-only feeding before resuming the high-energy diet (n = 4) for an additional 29 weeks. Mares were weighed weekly. Oral glucose tolerance tests were performed 3 to 4 times per dietary period. Results were compared with those of a control group (phase 1, n = 4; phases 2 and 3, n = 6) that received 100% NE requirements, using a general linear mixed model with post hoc Bonferroni testing.Results: The mean body weight of the high-energy group increased by 27% per highenergy feeding period. During both feeding periods, area under the curve (AUC) for plasma glucose concentration decreased (P < .01), whereas AUC for plasma insulin concentration increased. Mean basal plasma glucose concentration and peak plasma insulin concentrations were higher (P < .05) in the high-energy group than in the control group.Conclusion and Clinical Importance: Feeding a high-energy diet to healthy nonobese Shetland pony mares led to more efficient glucose metabolism within 5 weeks, followed by significant hyperinsulinemia and obesity. Hyperinsulinemic status was