1 Institute of Agricultural and Nutritional Sciences, Group Animal Nutrition, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
2 Chair for Nutritional Physiology and Animal Nutrition, Faculty of Agricultural and Environmental Sciences, University of Rostock, Rostock, Germany
3 Institute of Reproductive Biology; Leibniz Institute for Farm Animal Biology, Dummerstorf, Germany
4 Institute of Physiological Chemistry, Faculty of Veterinary Medicine, University of Leipzig, Leipzig, Germany
5 Department of Large Animal Medicine, Faculty of Veterinary Medicine, University of Leipzig, Leipzig, Germany
6 Institute of Agricultural and Nutritional Sciences, Biometrics and Informatics in Agriculture Group, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
Relevant literature indicate that more than 0.8 g starch/kg body weight from compounded feed composed of different starch sources induces disproportionate glycaemic and insulinaemic responses in horses.
It should be investigated whether crushed oats, barley and maize also cause a disproportionate increase in plasma glucose and insulin when fed as the only concentrate in quantities equal to and above 0.8 g starch/kg body weight.
Four mares received hay plus oats, barley and maize, respectively, in quantities equal to 0.8, 1.0 and 2.0 g starch/kg body weight. At the test days, chewing parameters were detected and blood sampled before and 30, 60, 90 and 120 min after the concentrate meal. Plasma glucose and insulin were measured and areas under the curve were calculated.
Maize was ingested particularly slowly (dry matter basis; P < 0.05), but glycaemic and insulinaemic responses were particularly low (starch basis; P < 0.05). In general, the glycaemic responses were highest with 1 g starch/kg body weight (P < 0.05). The quantity of starch had no effect on the insulinaemic response (P > 0.05). A defined increase in plasma glucose induced the highest insulinaemic response with oat grains.
Oats and barley are ingested faster and induce higher glycaemic and insulinaemic responses than maize. Until 120 min postprandial, elevated quantities of starch from these grains seem to induce no disproportionate or at least linear increase of plasma glucose and insulin. The insulinaemic response to a defined increase of plasma glucose is particularly pronounced with oats.
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