Dietary control of exertional rhabdomyolysis in horses.
OBJECTIVE
To determine whether feeding a low-carbohydrate, high-fat diet would decrease severity of exercise-induced muscle injury in horses with exertional rhabdomyolysis.


METHODS
19 horses with a history of exertional rhabdomyolysis.


METHODS
Case series.


METHODS
Specimens of the semitendinosus or semimembranosus muscle were obtained for histologic examination, and serum creatine kinase (CK) and aspartate transaminase (AST) activities 4 hours after exercise were determined. Horses were then fed a low-carbohydrate, high-fat diet, and serum CK and AST activities 4 hours after exercise were reevaluated at approximately monthly intervals for 3 to 6 months.


RESULTS
Serum CK and AST activities 4 hours after exercise were high before any change in diet. All 19 horses had evidence of chronic myopathic change and abnormal glycogen accumulation in muscle biopsy specimens; 11 horses also had evidence of complex polysaccharide accumulation. Adaptation to diet change required approximately 3 to 6 months. Sixteen horses did not have any episodes of exertional rhabdomyolysis after 3 to 6 months of diet change, and 3 horses had mild episodes of exertional rhabdomyolysis following either a reduction in dietary fat intake or restriction in exercise. Postexercise serum CK and AST activities 3 to 6 months after the change in diet were significantly less than initial values.


CONCLUSIONS
Results indicated that exertional rhabdomyolysis may be a result of abnormal carbohydrate metabolism in some horses. Feeding a diet with low carbohydrate and high fat content may reduce severity of exercise-induced injury in some horses with exertional rhabdomyolysis.
Valentine
B A
BA
Department of Pathology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853-6401, USA.
Hintz
H F
HF
Freels
K M
KM
Reynolds
A J
AJ
Thompson
K N
KN
D000821:Animal Feed; D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood; D003402:Creatine Kinase / Q000097:blood; D004032:Diet / Q000662:veterinary; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D004041:Dietary Fats / Q000008:administration & dosage*; D005260:Female; D006003:Glycogen / Q000378:metabolism; D006734:Horse Diseases / Q000178:diet therapy* / Q000209:etiology / Q000517:prevention & control; D006736:Horses; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology; D010805:Physical Conditioning, Animal / Q000009:adverse effects*; D012206:Rhabdomyolysis / Q000178:diet therapy / Q000517:prevention & control / Q000662:veterinary*; D012643:Selenium / Q000008:administration & dosage; D014810:Vitamin E / Q000008:administration & dosage
D004040:Dietary Carbohydrates; D004041:Dietary Fats; D014810:Vitamin E; D006003:Glycogen; D001219:Aspartate Aminotransferases; D003402:Creatine Kinase; D012643:Selenium