The effect of the fat to starch ratio in young horses' diet on plasma metabolites, muscle endurance and fear responses

• Published in: Journal of animal physiology and animal nutrition 2025-01, Vol.109 (1), p.113-123
• Main Authors: Lashkari, Saman, Beblein, Carina, Christensen, Janne W., Jensen, Søren K.
• Format: Article
• Language: English
• Subjects: Animal Feed - analysis; Animal Nutritional Physiological Phenomena; Animals; Blood; Blood levels; cortisol; Diet; Diet - veterinary; Dietary Carbohydrates - administration & dosage; Dietary Carbohydrates - pharmacology; Dietary Fats - administration & dosage; Dietary Fats - pharmacology; Esterification; Exercise; Factorial design; Fear; Glucose; High fat diet; Hindgut; Horses; Horses - blood; Horses - physiology; insulin; L-Lactate dehydrogenase; lactate; Lactate dehydrogenase; Low fat diet; Male; Metabolites; Muscle, Skeletal - physiology; Muscles; Muscular function; Original; Physical Conditioning, Animal - physiology; Physical Endurance - physiology; Physiological effects; Plasma; Starch; Starch - metabolism; Stereoisomerism; Stereoisomers; Tocopherol; Vitamin E; α‐tocopherol
• ISSN: 0931-2439; 1439-0396; 1439-0396
• DOI: 10.1111/jpn.14037

High‐starch diets may affect equine hindgut microbiota and increase blood glucose levels, which may cause unwanted physiological changes, but may also elicit behavioural changes such as increased fear reactions. The purpose of the current study was to feed a high starch (300) and low fat (43; HS_LF) or a low starch (60) and high fat (85; LS_HF, g/kg of DM) concentrate within the available commercial range and investigate how muscle endurance and fear reactions of horses respond to different diets. Twenty Danish Warmblood stallions (4 years) were randomly allocated to two treatments: LS_HF (n = 10) and HS_LF (n = 10) for 9 weeks. During the two last weeks, a single step exercise test was performed, and plasma metabolites and blood gases were measured before and after exercise in a 2 × 2 factorial design. The effect of two diets on fearfulness was tested by exposing the horses to novel objects test (T1 and T2). Plasma metabolites was not affected by diets. However, plasma level of glucose post‐exercise (4.9) was lower than pre‐exercise (5.6 mmol/L; p