A forage-only diet alters the metabolic response of horses in training.
Abstract: Most athletic horses are fed a high-starch diet despite the risk of health problems. Replacing starch concentrate with high-energy forage would alleviate these health problems, but could result in a shift in major substrates for muscle energy supply from glucose to short-chain fatty acids (SCFA) due to more hindgut fermentation of fibre. Dietary fat inclusion has previously been shown to promote aerobic energy supply during exercise, but the contribution of SCFA to exercise metabolism has received little attention. This study compared metabolic response with exercise and lactate threshold (VLa4) in horses fed a forage-only diet (F) and a more traditional high-starch, low-energy forage diet (forage-concentrate diet - FC). The hypothesis was that diet F would increase plasma acetate concentration and increase VLa4 compared with diet FC. Six Standardbred geldings in race training were used in a 29-day change-over experiment. Plasma acetate, non-esterified fatty acids (NEFA), lactate, glucose and insulin concentrations and venous pH were measured in samples collected before, during and after a treadmill exercise test (ET, day 25) and muscle glycogen concentrations before and after ET. Plasma acetate concentration was higher before and after exercise in horses on diet F compared with diet FC, and there was a tendency (P = 0.09) for increased VLa4 on diet F. Venous pH and plasma glucose concentrations during exercise were higher in horses on diet F than diet FC, as was plasma NEFA on the day after ET. Plasma insulin and muscle glycogen concentrations were lower for diet F, but glycogen utilisation was similar for the two diets. The results show that a high-energy, forage-only diet alters the metabolic response to exercise and, with the exception of lowered glycogen stores, appears to have positive rather than negative effects on performance traits.
Publication Date: 2012-05-04 PubMed ID: 22717208DOI: 10.1017/S1751731112000948Google Scholar: Lookup
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- Comparative Study
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research article studies how a forage-only diet changes the metabolic reactions in training horses, compared to traditional high-starch, low-energy forage diets, to possibly reduce health issues related to high-starch foods.
Research Context and Purpose
- The article begins by noting that high-starch diets are common for athletic horses, despite potential health risks.
- This research aims to examine whether replacing starch concentrate with high-energy forage could reduce such risks.
- One concern with high-energy forage is a shift in the primary source of muscle energy from glucose to short-chain fatty acids (SCFA), due to increased hindgut fermentation of fiber.
- Though dietary fat has been shown to provide energy during exercise, the use of SCFA in exercise metabolism isn’t well-studied.
- This study examines the metabolic responses during exercise and lactate threshold in horses on a forage-only diet against those on a high-starch, low-energy forage diet.
Methodology
- Six standardbred male horses in training were put under a 29-day dietary experiment.
- The researchers analysed plasma acetate, non-esterified fatty acids (NEFA), lactate, glucose, insulin concentrations, and venous pH from samples collected before, during, and after a treadmill exercise test.
- The muscle glycogen concentrations were also measured before and after exercise.
Findings
- Results revealed that plasma acetate levels were higher both before and after exercise in horses on a forage-only diet.
- There was a tendency for increased lactate threshold with the forage diet, indicating potentially better performance and endurance.
- Venous pH and plasma glucose concentrations during exercise, as well as plasma NEFA levels the day after exercise, were higher in forage-fed horses.
- However, plasma insulin and muscle glycogen concentrations were lower with the forage diet, but the glycogen utilisation did not differ significantly between the two diets.
Conclusion
- The research concluded that a high-energy, forage-only diet changes the metabolic response during exercise and seems to bring more positive effects on performance, despite lowered glycogen stores.
Cite This Article
APA
Jansson A, Lindberg JE.
(2012).
A forage-only diet alters the metabolic response of horses in training.
Animal, 6(12), 1939-1946.
https://doi.org/10.1017/S1751731112000948 Publication
Researcher Affiliations
- Department of Animal Nutrition and Management, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden. Anna.Jansson@slu.se
MeSH Terms
- Acetates / blood
- Animal Nutritional Physiological Phenomena
- Animals
- Blood Chemical Analysis / veterinary
- Diet / veterinary
- Dietary Carbohydrates / administration & dosage
- Dietary Supplements / analysis
- Energy Intake
- Glycogen / metabolism
- Horses / blood
- Horses / metabolism
- Horses / physiology
- Lactates / blood
- Male
- Muscle, Skeletal / chemistry
- Muscle, Skeletal / metabolism
- Physical Conditioning, Animal
- Silage / analysis
- Starch / administration & dosage
- Sweden
Citations
This article has been cited 18 times.- Zicarelli F, Tudisco R, Lotito D, Musco N, Iommelli P, Ferrara M, Calabrò S, Infascelli F, Lombardi P. Forage:Concentrate Ratio Effects on In Vivo Digestibility and In Vitro Degradability of Horse's Diet. Animals (Basel) 2023 Aug 11;13(16).
- Ermers C, McGilchrist N, Fenner K, Wilson B, McGreevy P. The Fibre Requirements of Horses and the Consequences and Causes of Failure to Meet Them. Animals (Basel) 2023 Apr 20;13(8).
- Moore-Colyer M, Westacott A, Rousson L, Harris P, Daniels S. Where Are We Now? Feeds, Feeding Systems and Current Knowledge of UK Horse Owners When Feeding Haylage to Their Horses. Animals (Basel) 2023 Apr 7;13(8).
- Han L, Lan T, Lu Y, Zhou M, Li H, Lu H, Wang Q, Li X, Du S, Guan C, Zhang Y, Sahu SK, Qian P, Zhang S, Zhou H, Guo W, Chai H, Wang S, Liu Q, Liu H, Hou Z. Equus roundworms (Parascaris univalens) are undergoing rapid divergence while genes involved in metabolic as well as anthelminic resistance are under positive selection. BMC Genomics 2022 Jul 4;23(1):489.
- Raspa F, Vervuert I, Capucchio MT, Colombino E, Bergero D, Forte C, Greppi M, Cavallarin L, Giribaldi M, Antoniazzi S, Cavallini D, Valvassori E, Valle E. A high-starch vs. high-fibre diet: effects on the gut environment of the different intestinal compartments of the horse digestive tract. BMC Vet Res 2022 May 19;18(1):187.
- Gandarillas M, Keim JP, Gapp EM. Associative Effects between Forages and Concentrates on In Vitro Fermentation of Working Equine Diets. Animals (Basel) 2021 Jul 26;11(8).
- Jansson A, Gunnarsson VÞ, Ringmark S, Ragnarsson S, Söderroos D, Ásgeirsson E, Jóhannsdóttir TR, Liedberg C, Stefánsdóttir GJ. Increased body fat content in horses alters metabolic and physiological exercise response, decreases performance, and increases locomotion asymmetry. Physiol Rep 2021 Jun;9(11):e14824.
- Yngvesson J, Rey Torres JC, Lindholm J, Pättiniemi A, Andersson P, Sassner H. Health and Body Conditions of Riding School Horses Housed in Groups or Kept in Conventional Tie-Stall/Box Housing. Animals (Basel) 2019 Feb 26;9(3).
- Connysson M, Muhonen S, Jansson A. Road transport and diet affect metabolic response to exercise in horses. J Anim Sci 2017 Nov;95(11):4869-4879.
- Nilsson E, Moazzami AA, Lindberg JE, Jansson A. The metabolomic profile of a high starch versus no starch diet in athletic horses. Sci Rep 2025 Oct 13;15(1):35576.
- Connysson M, Jansson A. Starch Allowance and Muscle Enzyme Activity in Healthy Standardbred Trotters Trained by Professional Trainers. J Anim Physiol Anim Nutr (Berl) 2025 Sep;109(5):1130-1137.
- Souza LA, Hunka MM, Rezende Júnior SF, Silva CJFLD, Manso HECDCC, Simões J, Coelho CS, Fazio F, Aragona F, Manso Filho HC. Potential use of beet-pulp concentrate supplementation in athletic horse. Heliyon 2025 Jan 15;11(1):e40961.
- Vasseur M, Lepers R, Langevin N, Julliand S, Grimm P. Fibrolytic efficiency of the large intestine microbiota may benefit running speed in French trotters: A pilot study. Physiol Rep 2024 Nov;12(21):e70110.
- Lashkari S, Beblein C, Christensen JW, Jensen SK. The effect of the fat to starch ratio in young horses' diet on plasma metabolites, muscle endurance and fear responses. J Anim Physiol Anim Nutr (Berl) 2025 Jan;109(1):113-123.
- Kara K, Altınsoy A. Comparison of forages’ digestion levels for different in vitro digestion techniques in horses. Vet Med Sci 2024 Mar;10(2):e31373.
- Johansson L, Ringmark S, Bergquist J, Skiöldebrand E, Jansson A. A metabolomics perspective on 2 years of high-intensity training in horses. Sci Rep 2024 Jan 25;14(1):2139.
- Martin A, Lepers R, Vasseur M, Julliand S. Effect of high-starch or high-fibre diets on the energy metabolism and physical performance of horses during an 8-week training period. Front Physiol 2023;14:1213032.
- Plancade S, Clark A, Philippe C, Helbling JC, Moisan MP, Esquerré D, Le Moyec L, Robert C, Barrey E, Mach N. Unraveling the effects of the gut microbiota composition and function on horse endurance physiology. Sci Rep 2019 Jul 3;9(1):9620.
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