N. Richards

Proc. Australasian Equine Sc. Symp., Vol 3, 2010 pp30

Equilize Horse Nutrition Pty Ltd, Newcastle, NSW

While obesity and inactivity are almost certainly implicated in insulin resistance, diet, and specifically the consumption of high non-structural carbohydrate (NSC) feeds appear to negatively impact a horse?s insulin sensitivity (Treiber et al 2005; Quinn et al 2008). Feeding a low NSC diet therefore seems to be a sensible recommendation for horse owners wishing to maintain long-term insulin sensitivity. The aim of the study was to add to the current data available to help identify the level of NSC least likely to impact post-feeding glucose and insulin responses in horses and therefore more likely to maintain long term insulin sensitivity. a a b c 15 20 25 30 35 40 Pasture Meal Sweetfeed Pellets Area Under the Glucose Curve

Four horses were fed four diets; 24 hour pasture access (Pasture) with 7% DM NSC; or 10 hours pasture access supplemented with either 1% bodyweight of copra meal (Meal) with 11% DM NSC; extruded and pelleted feed (Pellet) with 25.3% DM NSC; or sweetfeed (Sweetfeed) with 33.7% DM NSC. Supplementary feeds were divided and fed in 2 meals per day. Horses were adapted to diets for 4 days. On the morning of the 5th day, a pre-feeding blood sample was taken. Horses were fed and blood samples were collected over a 6 hour period for a total of 13 samples per horse including the pre-feeding sample. Blood was immediately centrifuged and the plasma frozen until analysis. All samples were analysed for plasma glucose and insulin. Results were statistically analysed using a restricted maximum likelihood (REML) procedure to assess the effects of diet, period, and time. Significance of terms was assessed using Wald chi-square and F tests.

Diet had a significant effect on the area under the glucose (P<0.007) and insulin (P<0.001) response curves. The copra meal diet at 11% NSC did not differ significantly from the 7% NSC pasture, suggesting that feeds with a dry matter NSC level of 11% or less may be useful as a supplementary energy source where maintaining insulin sensitivity is a priority.

References

Treiber, K.H. et al (2005). Journal of Animal Science 83, 2357?2364.

Quinn, W. et al (2008). Journal of Equine Veterinary Science 28, 728 ? 738.