Effect of dietary supplements containing antioxidants on attenuation of muscle damage in exercising sled dogs.
OBJECTIVE
To determine whether dietary antioxidants would attenuate exercise-induced increases in plasma creatine kinase (CK) activity in sled dogs.


METHODS
41 trained adult sled dogs.


METHODS
Dogs, randomly assigned to 2 groups, received the same base diet throughout the study. After 8 weeks on that diet, 1 group (21 dogs) received a daily supplement containing vitamins E (457 U) and C (706 mg) and beta-carotene (5.1 mg), and a control group (20 dogs) received a supplement containing minimal amounts of antioxidants. After 3 weeks, both groups performed identical endurance exercise on each of 3 days. Blood samples were collected before and 3 weeks after addition of supplements and after each day of exercise. Plasma was analyzed for vitamins E and C, retinol, uric acid, triglyceride, and cholesterol concentrations, total antioxidant status (TAS), and CK activity.


RESULTS
Feeding supplements containing antioxidants caused a significant increase in vitamin E concentration but did not change retinol or vitamin C concentrations orTAS. Exercise caused significantly higher CK activity, but did not cause a significant difference in CK activity between groups. Exercise was associated with significantly lower vitamin E, retinol, and cholesterol concentrations and TAS but significantly higher vitamin C, triglyceride, and uric acid concentrations in both groups.


CONCLUSIONS
Use of supplements containing the doses of antioxidants used here failed to attenuate exercise-induced increases in CK activity. Muscle damage in sled dogs, as measured by plasma CK activity, may be caused by a mechanism other than oxidant stress.
Piercy
R J
RJ
Department of Clinical Veterinary Sciences, College of Veterinary Medicine, The Ohio State University, Columbus 43210, USA.
Hinchcliff
K W
KW
DiSilvestro
R A
RA
Reinhart
G A
GA
Baskin
C R
CR
Hayek
M G
MG
Burr
J R
JR
Swenson
R A
RA
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000097:blood / Q000494:pharmacology; D001835:Body Weight / Q000187:drug effects; D002784:Cholesterol / Q000097:blood; D003402:Creatine Kinase / Q000097:blood; D019587:Dietary Supplements; D004285:Dogs / Q000502:physiology*; D006304:Health Status; D009132:Muscles / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D010805:Physical Conditioning, Animal; D014280:Triglycerides / Q000097:blood; D014527:Uric Acid / Q000097:blood; D014801:Vitamin A / Q000097:blood / Q000494:pharmacology; D014810:Vitamin E / Q000097:blood / Q000494:pharmacology
D000975:Antioxidants; D014280:Triglycerides; D014801:Vitamin A; D014810:Vitamin E; D014527:Uric Acid; D002784:Cholesterol; D003402:Creatine Kinase; D001205:Ascorbic Acid