A high protein meal affects plasma insulin concentrations and amino acid metabolism in horses with equine metabolic syndrome.
Authors: Loos C M M, Dorsch S C, Elzinga S E, Brewster-Barnes T, Vanzant E S, Adams A A, Urschel K L
Journal: Veterinary journal (London, England : 1997)
Summary
# Editorial Summary Equine metabolic syndrome (EMS) is characterised by pathological insulin responses to dietary challenges, yet the specific effects of dietary protein on insulin secretion in affected horses remain poorly understood despite evidence that certain amino acids directly stimulate insulin release. Loos and colleagues compared insulin and amino acid kinetics in six EMS-affected horses and six healthy controls following a high protein meal (4 g/kg body mass of 31% crude protein pellet administered over 30 minutes), measuring plasma concentrations of glucose, insulin, amino acids and urea over four hours. Whilst glucose responses were comparable between groups, EMS horses mounted a ninefold greater insulin surge than controls (P=0.046), with elevated post-prandial concentrations of eight amino acids (histidine, citrulline, tyrosine, valine, methionine, isoleucine, leucine and ornithine; all P<0.05), suggesting these particular amino acids may act as insulinotropic triggers in metabolically dysregulated individuals. For practitioners managing EMS horses, these findings underscore the importance of quantifying dietary protein content and amino acid profiles as part of nutritional management strategies, since high protein meals appear to exacerbate the insulin dysregulation characteristic of the condition rather than providing a metabolically neutral feeding option.
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Practical Takeaways
- •High protein feeds may exacerbate insulin response in EMS horses and should be avoided or carefully monitored in affected animals
- •When managing insulin-dysregulated horses, evaluate total dietary protein content alongside traditional focus on non-structural carbohydrates
- •Amino acid composition of feed may play a previously underrecognized role in triggering hyperinsulinemic responses in metabolically compromised horses
Key Findings
- •Horses with EMS had a 9-fold greater insulinemic response to high protein meal compared with controls (P=0.046)
- •Post-prandial levels of histidine, citrulline, tyrosine, valine, methionine, isoleucine, leucine and ornithine were significantly higher in EMS horses (P<0.05)
- •Plasma glucose concentrations were not significantly different between EMS and control groups (P=0.2)
- •Dietary protein content should be considered in management of horses with insulin dysregulation