FREE SHIPPING over $40
OVER 9000 FIVE-STAR REVIEWS
5% OFF ALL SUBSCRIPTIONS
100% HAPPINESS GUARANTEE
Analyze Diet
0
Home / Equine Research Bank / J Anim Physiol Anim Nutr (Berl) / Starch Allowance and Muscle Enzyme Activity in Healthy Stand...
Journal of animal physiology and animal nutrition2025; doi: 10.1111/jpn.14127

Starch Allowance and Muscle Enzyme Activity in Healthy Standardbred Trotters Trained by Professional Trainers.

Abstract: It is generally accepted that plasma muscle enzyme activity of creatine kinase (CK) and aspartate aminotransferase (AST) may increase in racehorses after exercise and racing, indicating muscle fibre damage and/or increased leakage from muscle fibres. However, other studies suggest that starch intake might influence plasma muscle enzyme activity reported postexercise. This study aimed to evaluate the effect of different starch allowances on plasma muscle enzyme activity in Standardbred trotters in professional training. Seventy-six horses from five professional trainers were sampled pre- and postexercise. The trainers had different feeding strategies and fed various amounts of starch to their horses. Postexercise plasma AST activity was higher (p < 0.007) for the high (H) and medium (M) starch allowances (451-967 and 988-1429 g/day, respectively) than for horses with low starch allowances (L) (0-268 g/day) (H:8.1 ukat/L (SE 0.5); M: 8.4 ukat/L (SE 0.5); L: 5.8 ukat/L (SE 0.7) (p < 0.007)). Postexercise plasma CK activity was higher (p < 0.01) for the medium starch allowance group than for the high and low starch allowance groups (H:4.6 ukat/L (SE 0.3); M: 5.9 ukat/L (SE 0.4); L: 3.9 ukat/L (SE 0.4)). In conclusion, this study showed higher plasma muscle enzyme activity of AST and some elevations in CK activity in horses fed high-starch allowances compared to horses fed low allowances or no starch. In addition, muscle enzyme activity increased in response to the duration of high-intensity exercise. Management systems aiming for low levels of plasma muscle enzyme activity could accordingly offer diets with low starch (< 450 g/day) contents and perhaps training regimes with shorter durations of high-intensity exercise. However, the mechanisms behind and the elevations' biological importance, need further investigation.
© 2025 The Author(s). Journal of Animal Physiology and Animal Nutrition published by Wiley‐VCH GmbH.
Get Full Text
Publication Date: 2025-05-06 PubMed ID: 40329464DOI: 10.1111/jpn.14127Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
LinkedInCopy
  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The study investigates if the levels of starch in a horse’s diet are linked to changes in muscle enzyme levels after exercise. The research implied that horses fed higher amounts of starch had elevated muscle enzyme activity when compared to horses fed on low or no starch diets.

Objective of the Research

  • The main objective of the study is to understand the possible influence of differing starch allowances or intake on the activity of plasma muscle enzymes in professional training horses, specifically Standardbred trotters. The researchers aim to observe any correlation between muscle enzyme activity, inferred muscle damage and starch intake levels in the horses’ diet.

Research Design and Methods

  • 76 Standardbred trotters from five professional trainers were chosen for the trial. The trainers used varying feeding strategies and fed different quantities of starch to their horses.
  • Blood samples were taken from the horses before and after exercise activities. Analysis of these samples allowed the researchers to measure the activity levels of specific muscle enzymes: creatine kinase (CK) and aspartate aminotransferase (AST).
  • The horses were classified into three groups based on their starch intake: high (H), medium (M), and low (L). The measured enzyme activities were compared between these three groups.

Findings

  • Results revealed that post-exercise plasma AST activity was significantly higher for horses in the high and medium starch allowance groups than for horses in the low starch allowance group.
  • Post-exercise plasma CK activity was observed to be higher for the group on a medium starch diet compared to those on high and low starch diets.
  • Scientists interpreted these findings to suggest that diets with high amounts of starch might lead to elevated muscle enzyme activity, which implies muscle fibre damage or leakage from muscle fibres.

Implications and Future Work

  • The results suggest that horse trainers may need to consider diet adjustments to optimize muscle health, mainly reducing starch intake (<450g/day) and perhaps altering training regimes to include shorter periods of high-intensity exercise.
  • However, this study is a preliminary investigation, and further research is required to understand the mechanisms behind the observed phenomena and the biological significance of the elevation in muscle enzyme activity.

Cite This Article

APA
Connysson M, Jansson A. (2025). Starch Allowance and Muscle Enzyme Activity in Healthy Standardbred Trotters Trained by Professional Trainers. J Anim Physiol Anim Nutr (Berl). https://doi.org/10.1111/jpn.14127

Publication

Journal of animal physiology and animal nutrition
ISSN: 1439-0396
NlmUniqueID: 101126979
Country: Germany
Language: English

Researcher Affiliations

Connysson, Malin
  • Department of Animal Biosciences, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Jansson, Anna
  • Department of Animal Biosciences, Swedish University of Agricultural Sciences, Uppsala, Sweden.

Grant Funding

  • This study was supported by Swedish-Norwegian Foundation for Equine Research.

References

This article includes 54 references
  1. Baird MF, Graham SM, Baker JS, Bickerstaff GF. Creatine‐Kinase‐And Exercise‐Related Muscle Damage Implications for Muscle Performance and Recovery.. Journal of Nutrition and Metabolism 2012 1: e960363.
    doi: 10.1155/2012/960363google scholar: lookup
  2. Cardinet GH, Littrell JF, Freedland RA. Comparative Investigations of Serum Creatine Phosphokinase and Glutamic‐Oxaloacetic Transaminase Activities in Equine Paralytic Myoglobinuria.. Research in Veterinary Science 1967 8: 219–226.
    doi: 10.1016/s0034-5288(18)34639-3google scholar: lookup
  3. Connysson M, Essén-gustavsson B, Lindberg JE, Jansson A. Effects of Feed Deprivation on Standardbred Horses Fed a Forage‐Only Diet and a 50:50 Forage‐Oats Diet.. Equine Veterinary Journal 2010 42: 335–340.
    doi: 10.1111/j.2042-3306.2010.00174.xgoogle scholar: lookup
  4. Connysson M, Jansson A. Effect of Concentrate Feeding on Muscle Enzyme Activity in Plasma in Healthy Standardbred Trotters.. Comparative Exercise Physiology 2022 Vol. 18, 31.
  5. Connysson M, Muhonen S, Jansson A. Road Transport and Diet Affect Metabolic Response to Exercise in Horses.. Journal of Animal Science 2017 95: 4869–4879.
    doi: 10.2527/jas2017.1670google scholar: lookup
  6. Connysson M, Muhonen S, Lindberg JE. Effects on Exercise Response, Fluid and Acid‐Base Balance of Protein Intake From Forage‐Only Diets in Standardbred Horses.. Equine Veterinary Journal 2006 38: 648–653.
    doi: 10.1111/j.2042-3306.2006.tb05620.xgoogle scholar: lookup
  7. Connysson M, Rhodin M, Bergh A, Jansson A. Effects of Horse Housing on Musculoskeletal System Post‐Exercise Recovery.. Comparative Exercise Physiology 2021 17: 421–428.
    doi: 10.3920/cep200088google scholar: lookup
  8. Connysson M, Rhodin M, Jansson A. Effects of Horse Housing System on Energy Balance During Post‐Exercise Recovery.. Animals: An Open Access Journal From MDPI 2019 9: 976.
    doi: 10.3390/ani9110976google scholar: lookup
  9. Cymbaluk NF, Christensen DA. Nutrient Utilization of Pelleted and Unpelleted Forages by Ponies.. Canadian Journal of Animal Science 1986 66: 237–244.
  10. Duren SE, Pagan JD, Harris PA, Crandell KG. Time of Feeding and Fat Supplementation Affect Plasma Concentrations of Insulin and Metabolites During Exercise.. Equine Veterinary Journal 1999 31: 479–484.
    doi: 10.1111/j.2042-3306.1999.tb05269.xgoogle scholar: lookup
  11. European Union. Directive 2010/63/EU of the European Parliament and of the Council of 22 September 2010 on the Protection of Animals Used for Scientific Purposes.. 2010.
  12. Frauenfelder HC, Rossdale PD, Ricketts SW, Allen WR. Changes in Serum Muscle Enzyme Levels Associated With Training Schedules and Stage of the Oestrous Cycle in Thoroughbred Racehorses.. Equine Veterinary Journal 1986 18: 371–374.
    doi: 10.1111/j.2042-3306.1986.tb03657.xgoogle scholar: lookup
  13. Gillen A, Catherine Archer D. Epidemiology of Colic: Current Knowledge and Future Directions.. Veterinary Clinics of North America, Equine Practice 2023 39: 157–174.
    doi: 10.1016/j.cveq.2023.03.005google scholar: lookup
  14. Harris PA. The Equine Rhabdomyolysis Syndrome in the United Kingdom: Epidemiological and Clinical Descriptive Information.. British Veterinary Journal 1991 147: 373–384.
    doi: 10.1016/0007-1935(91)90011-bgoogle scholar: lookup
  15. Harris PA, Marlin DJ, Gray J. Plasma Aspartate Aminotransferase and Creatine Kinase Activities in Thoroughbred Racehorses in Relation to Age, Sex, Exercise and Training.. Veterinary Journal 1998 155: 295–304.
    doi: 10.1016/s1090-0233(05)80026-7google scholar: lookup
  16. Harris PA, Snow DH, Greet TRC, Rossdale PD. Some Factors Influencing Plasma AST/CK Activities in Thoroughbred Racehorses.. Equine Veterinary Journal 1990 22: 66–71.
    doi: 10.1111/j.2042-3306.1990.tb04738.xgoogle scholar: lookup
  17. Hodgson DH, McGowan CM, McKeever KH. The Athletic Horse 2nd ed.. 2014.
  18. Jansson A, Connysson M, Lindberg JE, Dahlborn K. Starch Rich Levels Increase Morning Cortisol Levels and Activity Heart Rate Responses.. 2018 9th European Workshop on Equine Nutrition, 16–18 June 2018, Uppsala Sweden.
  19. Jansson A, Harris PA. A Bibliometric Review on Nutrition of the Exercising Horse From 1970 to 2010.. Comparative Exercise Physiology 2013 9: 169–180.
    doi: 10.3920/cep13018google scholar: lookup
  20. Jansson A, Lindberg JE. A Forage‐Only Diet Alters the Metabolic Response of Horses In Training.. Animal 2012 6: 1939–1946.
    doi: 10.1017/s1751731112000948google scholar: lookup
  21. Jansson A, Sandin A, Lindberg J. Digestive and Metabolic Effects of Altering Feeding Frequency in Athletic Horses.. Equine and Comparative Exercise Physiology 2006 3: 83–91.
    doi: 10.1079/ecp200683google scholar: lookup
  22. Jensen RB, Austbø D, Blache D, Bach Knudsen KE, Tauson A-H. The Effect of Feeding Barley or Hay Alone or in Combination With Molassed Sugar Beet Pulp on the Metabolic Responses in Plasma and Caecum of Horses.. Animal Feed Science and Technology 2016 214: 53–65.
    doi: 10.1016/j.anifeedsci.2016.02.003google scholar: lookup
  23. Karlsson CP, Jansson A, Essén-gustavsson B, Lindberg J-E. Effect of Molassed Sugar Beet Pulp on Nutrient Utilisation and Metabolic Parameters During Exercise.. Equine Veterinary Journal 2002 34: 44–49.
    doi: 10.1111/j.2042-3306.2002.tb05390.xgoogle scholar: lookup
  24. Kristensen L, Buhl R, Nostell K. Acute Exercise Does Not Induce an Acute Phase Response (APR) in Standardbred Trotters.. Canadian Journal of Veterinary Research = Revue canadienne de recherche veterinaire 2014 78: 97–102.
  25. Lacombe VA, Hinchcliff KW, Kohn CW, Devor ST, Taylor LE. Effects of Feeding Meals With Various Soluble‐Carbohydrate Content on Muscle Glycogen Synthesis After Exercise in Horses.. American Journal of Veterinary Research 2004 65: 916–923.
    doi: 10.2460/ajvr.2004.65.916google scholar: lookup
  26. Lindholm A. Pathophysiology of Exercise Induced Diseases of the Musculoskeletal System of the Equine Athlete.. 1987 In Equine Exercise Physiology, edited by J. R. Gillespie and N. E. Robinson, 2, 711–727. ICEEP Publications.
  27. MacLeay JM, Sorum SA, Valberg SJ, Marsh WE, Sorum MD. Epidemiologic Analysis of Factors Influencing Exertional Rhabdomyolysis in Thoroughbreds.. American Journal of Veterinary Research 1999a 60: 1562–1566.
  28. MacLeay JM, Sorum SA, Valberg SJ, Marsh WE, Sorum MD. Epidemiologic Analysis of Factors Influencing Exertional Rhabdomyolysis in Thoroughbreds.. American Journal of Veterinary Research 1999b 60: 1562–1566.
  29. Marlin DJ, Harris RC, Harman JC, Snow DH. Influence of Post‐Exercise Activity on Rates of Muscle and Blood Lactate Disappearance in the Thoroughbred Horse.. 1987 In: J. R. Gillespie and N. E. Robinson (eds.) Equine Exercise Physiology. 2: 321–331.
  30. 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.. Frontiers in Physiology 2023 14: 1213032.
    doi: 10.3389/fphys.2023.1213032google scholar: lookup
  31. McGowan CM, Fordham T, Christley RM. Incidence and Risk Factors for Exertional Rhabdomyolysis in Thoroughbred Racehorses in the United Kingdom.. Veterinary Record 2002 151: 623–626.
    doi: 10.1136/vr.151.21.623google scholar: lookup
  32. McKenzie EC, Valberg SJ, Godden SM. Effect of Dietary Starch, Fat, and Bicarbonate Content on Exercise Responses and Serum Creatine Kinase Activity in Equine Recurrent Exertional Rhabdomyolysis.. Journal of Veterinary Internal Medicine 2003 17: 693–701.
    doi: 10.1111/j.1939-1676.2003.tb02502.xgoogle scholar: lookup
  33. Morawetz D, Blank C, Koller A, Arvandi M, Siebert U, Schobersberger W. Sex‐Related Differences After a Single Bout of Maximal Eccentric Exercise in Response to Acute Effects: A Systematic Review and Meta‐Analysis.. Journal of Strength and Conditioning Research 2020 34: 2697–2707.
    doi: 10.1519/jsc.0000000000002867google scholar: lookup
  34. Muhonen S, Lindberg JE, Bertilsson J, Jansson A. Effects on Fluid Balance, Digestion and Exercise Response in Standardbred Horses Fed Silage, Haylage and Hay.. Comparative Exercise Physiology 2008 5: 133–142.
    doi: 10.1017/s1478061509342334google scholar: lookup
  35. Pagan JD, Harris PA. The Effects of Timing and Amount of Forage and Grain on Exercise Response in Thoroughbred Horses.. Equine Veterinary Journal 1999 31: 451–457.
    doi: 10.1111/j.2042-3306.1999.tb05264.xgoogle scholar: lookup
  36. Peake JM, Neubauer O, Della Gatta PA, Nosaka K. Muscle Damage and Inflammation During Recovery From Exercise.. Journal of Applied Physiology 2017 122: 559–570.
    doi: 10.1152/japplphysiol.00971.2016google scholar: lookup
  37. Persson SGB, Funkquist P, Nyman G. Total Blood Volume in the Normally Performing Standardbred Trotter: Age and Sex Variations.. Journal of Veterinary Medicine Series A 1996 43: 57–64.
    doi: 10.1111/j.1439-0442.1996.tb00428.xgoogle scholar: lookup
  38. Pösö AR, Soveri T, Oksanen HE. The Effect of Exercise on Blood Parameters in Standardbred and Finnish‐Bred Horses.. Acta Veterinaria Scandinavica 1983 24: 170–184.
  39. Powers SK, Jackson MJ. Exercise‐Induced Oxidative Stress: Cellular Mechanisms and Impact on Muscle Force Production.. Physiological Reviews 2008 88: 1243–1276.
    doi: 10.1152/physrev.00031.2007google scholar: lookup
  40. Raspa F, Dinardo FR, Vervuert I. A Fibre‐ Vs. Cereal Grain‐Based Diet: Which Is Better for Horse Welfare? Effects on Intestinal Permeability, Muscle Characteristics and Oxidative Status in Horses Reared for Meat Production.. Journal of Animal Physiology and Animal Nutrition 2022 106: 313–326.
    doi: 10.1111/jpn.13643google scholar: lookup
  41. Ribeiro WP, Valberg SJ, Pagan JD, Gustavsson BE. The Effect of Varying Dietary Starch and Fat Content on Serum Creatine Kinase Activity and Substrate Availability in Equine Polysaccharide Storage Myopathy.. Journal of Veterinary Internal Medicine 2004 18: 887–894.
    doi: 10.1111/j.1939-1676.2004.tb02637.xgoogle scholar: lookup
  42. Ringmark S. A Forage‐Only Diet and Reduced High Intensity Training Distance in Standardbred Horses.. 2014 PhD Thesis, Swedish University of Agricultural Sciences.
  43. Saastamoinen M. Factors Affecting Growth and Development of Foals and Young Horses.. Acta Agriculturae Scandinavica 1990 40: 387–396.
    doi: 10.1080/00015129009438574google scholar: lookup
  44. Seabra JC, Dittrich JR, Vale MM. Factors Associated With the Development and Prevalence of Abnormal Behaviors in Horses: Systematic Review With Meta‐Analysis.. Journal of Equine Veterinary Science 2021 106: 103750.
    doi: 10.1016/j.jevs.2021.103750google scholar: lookup
  45. Siciliano PD, Lawrence LM, Danielsen K, Powell DM, Thompson KN. Effect of Conditioning and Exercise Type on Serum Creatine Kinase and Aspartate Aminotransferase Activity.. Equine Veterinary Journal 1995 27: 243–247.
    doi: 10.1111/j.2042-3306.1995.tb04929.xgoogle scholar: lookup
  46. Stallones L, McManus P, McGreevy P. Sustainability and the Thoroughbred Breeding and Racing Industries: An Enhanced One Welfare Perspective.. Animals: An Open Access Journal from MDPI 2023 13: 490.
    doi: 10.3390/ani13030490google scholar: lookup
  47. Swedish Constitution. The Anilmal Protection Act.. 1988 National Board of Agriculture.
  48. Swedish Constitution. Animal Protection Ordinance.. 2012 National Board of Agriculture.
  49. Valberg SJ. Sporadic and Recurrent Exertional Rhabdomyolysis.. Veterinary Clinics of North America, Equine Practice 2025 41: 111–124.
    doi: 10.1016/j.cveq.2024.11.003google scholar: lookup
  50. Valberg SJ, McCue ME, Mickelson JR. The Interplay of Genetics, Exercise, and Nutrition in Polysaccharide Storage Myopathy.. Journal of Equine Veterinary Science, Proceedings of the 2011 Equine Society Symposium 2011 31: 205–210.
    doi: 10.1016/j.jevs.2011.03.001google scholar: lookup
  51. Valberg SJ, Velez-Irizarry D, Williams ZJ. Enriched Pathways of Calcium Regulation, Cellular/Oxidative Stress, Inflammation, and Cell Proliferation Characterize Gluteal Muscle of Standardbred Horses Between Episodes of Recurrent Exertional Rhabdomyolysis.. Genes 2022 13: 1853.
    doi: 10.3390/genes13101853google scholar: lookup
  52. Valberg SJ, Velez-Irizarry D, Williams ZJ. Novel Expression of GLUT3, GLUT6 and GLUT10 in Equine Gluteal Muscle Following Glycogen‐Depleting Exercise: Impact of Dietary Starch and Fat.. Metabolites 2023 13: 718.
    doi: 10.3390/metabo13060718google scholar: lookup
  53. Vokes J, Lovett A, Sykes B. Equine Gastric Ulcer Syndrome: An Update on Current Knowledge.. Animals: An Open Access Journal From MDPI 2023 13: 1261.
    doi: 10.3390/ani13071261google scholar: lookup
  54. Williams CA, Kronfeld DS, Staniar WB, Harris PA. Plasma Glucose and Insulin Responses of Thoroughbred Mares Fed a Meal High in Starch and Sugar or Fat and Fiber.. Journal of Animal Science 2001 79: 2196–2201.
    doi: 10.2527/2001.7982196xgoogle scholar: lookup
Subscribe to our newsletter
Join 99,344 horse owners like you who receive our email updates on horse health and nutrition.