Glycaemic and insulinaemic responses to feeding hay with different non-structural carbohydrate content in control and polysaccharide storage myopathy-affected horses.
Authors: Borgia L, Valberg S, McCue M, Watts K, Pagan J
Journal: Journal of animal physiology and animal nutrition
Summary
# Editorial Summary This research examined how different hay types affect blood sugar and insulin responses in both healthy horses and those affected by polysaccharide storage myopathy (PSSM), with particular attention to non-structural carbohydrate (NSC) content. Five control Quarter Horses and seven PSSM-affected horses were fed three types of hay over a crossover trial: high-NSC hay (17%), medium-NSC hay (10%), and low-NSC hay (4%), with blood glucose and insulin measured at 30-minute intervals for five hours following feeding. Control horses showed dramatically elevated insulin responses to high-NSC hay (area under the curve of 6,891.7 versus 1,185.4 for low-NSC), whilst PSSM horses exhibited both higher glucose and insulin responses to high-NSC forage, though their absolute insulin elevations were paradoxically lower than control horses despite greater glycaemic spikes. The findings demonstrate that NSC content substantially influences postprandial insulin dynamics, with practical implications suggesting that feeding hay exceeding 17% NSC may trigger problematic insulin surges in PSSM-affected horses and warrant consideration in nutritional management protocols for this condition.
Read the full abstract on PubMed
Practical Takeaways
- •Select hay with low NSC content (≤4%) for PSSM horses, as high NSC hay (17%) triggers disproportionate glucose and insulin responses that may exacerbate the condition
- •Even in control horses, feeding high NSC hay (17%) produces substantially higher insulin demands; lower NSC forage is preferable for metabolic health
- •Test hay NSC content before feeding to horses with PSSM or metabolic concerns, as standard hay sampling can reveal NSC levels and guide dietary decisions
Key Findings
- •Control horses fed 17% NSC hay had insulin AUC of 6891.7 vs. 1185.4 for 4% NSC hay, demonstrating significant difference in insulin response based on hay NSC content
- •PSSM horses showed significantly higher glycaemic and insulinaemic responses to 17% NSC hay compared to 4% NSC hay
- •PSSM horses demonstrated lower magnitude of insulin response but higher glucose response compared to control horses when fed high NSC hay
- •High NSC hay (17%) produced elevated insulin levels that could be detrimental for PSSM-affected horses