Glucose clearance in grazing mares is affected by diet, pregnancy, and lactation.
Abstract: The glucose tolerance test in the horse may be used to determine metabolic responses to diet, disease, or physiologic state. The objective of this study was to determine the effect of reproductive stage (gestation and lactation) and supplemental dietary energy source (sugar and starch [SS] or fiber and fat [FF]) on glucose metabolism in grazing mares using an oral glucose tolerance test. Twelve mares, six on each supplement, were examined on three occasions: one in the third trimester of pregnancy, the second in early lactation, and the third in late lactation. During each test, venous samples were taken at 30 and 1 min before, and 30, 60, 90, 120, 150, 180, 240, and 300 min after a nasogastric dose of glucose at 0.2 g/kg of BW. Plasma was assayed for glucose, insulin, and cortisol. Statistical analysis was a mixed model with repeated measures with horse, diet, and reproductive stage as fixed effects. The incremental glucose area under the curve (AUC) in response to oral glucose was lower in SS than in FF mares (P = 0.022). Mares tended to have a lower incremental glucose AUC in early lactation than in late gestation (P = 0.057), and insulin AUC was lower in early lactation than in late gestation (P = 0.002) and late lactation (P = 0.013). Glucose clearance was more rapid (P = 0.007) in SS than in FF mares. The glycemic response to the oral glucose tolerance test was consistent with adaptation to dietary sugar and starch as well as metabolic changes associated with pregnancy and lactation. Feeding twice-daily grain meals rich in SS influenced glucose metabolism in horses to an extent that the natural adaptation of glucose metabolism to pregnancy was moderated. Feeding a diet rich in FF more closely mimics the natural grazing state of pasture and allows for adaptation of glucose metabolism to pregnancy and lactation.
Publication Date: 2003-07-12 PubMed ID: 12854813DOI: 10.2527/2003.8171764xGoogle Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research article explores how the type of diet and reproductive stage (gestation and lactation) impact glucose metabolism in horses. It determines that feeding horses a grain-heavy diet can influence glucose metabolism so much so that it can moderate the natural adaptations associated with pregnancy.
Objective of the Study
- The objective of the study was to examine the influence of diet and reproductive stage – gestation and lactation – on glucose metabolism in grazing mares. The study specifically looked at two types of diets: one rich in sugar and starch (SS) and the other in fiber and fat (FF). These diets were analyzed using an oral glucose tolerance test.
Research Methodology
- The study was conducted with twelve mares divided into two groups of six each, each fed one of the two diets. These mares were studied at three different stages – during the third trimester of pregnancy, early lactation, and late lactation.
- For the glucose tolerance test, venous samples were collected at 30 and 1 minute before the test, and also at 30, 60, 90, 120, 150, 180, 240, and 300 minutes after a nasogastric dose of glucose at 0.2 g/kg of body weight. Plasma was checked for levels of glucose, insulin, and cortisol.
Findings of the Study
- The results demonstrated that mares on the SS diet had a lower incremental glucose area under the curve (AUC) than those on the FF diet.
- Furthermore, during the early lactation stage, mares tended to have a lower incremental glucose AUC than during late gestation.
- The insulin AUC was found to be lower in the early lactation stage than during both late gestation and late lactation. This suggests that glucose clearance was quicker in SS-fed mares than in FF-fed mares.
- The glycemic response to the oral glucose tolerance test demonstrated that dietary adaptation to sugar and starch moderated the natural adaptation of glucose metabolism to pregnancy.
Conclusion and Implications
- Feeding horses a grain-rich (SS) diet significantly influenced glucose metabolism to such an extent that it moderated the natural metabolic adaptations associated with pregnancy.
- On the other hand, a diet rich in FF, which closer mimics a natural grazing diet, better supported the metabolic changes associated with gestation and lactation. This suggests the possibility of improving the health of pregnant and lactating mares through dietary modifications.
Cite This Article
APA
Hoffman RM, Kronfeld DS, Cooper WL, Harris PA.
(2003).
Glucose clearance in grazing mares is affected by diet, pregnancy, and lactation.
J Anim Sci, 81(7), 1764-1771.
https://doi.org/10.2527/2003.8171764x Publication
Researcher Affiliations
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg 24061-0306, USA. Rhonda.Hoffman@vt.edu
MeSH Terms
- Adaptation, Physiological
- Animal Feed
- Animals
- Area Under Curve
- Blood Glucose / metabolism
- Diet / veterinary
- Dietary Carbohydrates / administration & dosage
- Dietary Carbohydrates / metabolism
- Dietary Fats / administration & dosage
- Dietary Fats / metabolism
- Dietary Fiber / administration & dosage
- Dietary Fiber / metabolism
- Female
- Glucose Tolerance Test / veterinary
- Horses / metabolism
- Horses / physiology
- Hydrocortisone / blood
- Insulin / blood
- Lactation / metabolism
- Pregnancy
Citations
This article has been cited 3 times.- Weinert-Nelson JR, Biddle AS, Sampath H, Williams CA. Fecal Microbiota, Forage Nutrients, and Metabolic Responses of Horses Grazing Warm- and Cool-Season Grass Pastures. Animals (Basel) 2023 Feb 22;13(5).
- Yang Y, Hu CJ, Zhao X, Xiao K, Deng M, Zhang L, Qiu X, Deng J, Yin Y, Tan C. Dietary energy sources during late gestation and lactation of sows: effects on performance, glucolipid metabolism, oxidative status of sows, and their offspring1. J Anim Sci 2019 Nov 4;97(11):4608-4618.
- Polakof S, Panserat S, Soengas JL, Moon TW. Glucose metabolism in fish: a review. J Comp Physiol B 2012 Dec;182(8):1015-45.
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