Effect of exercise on development of capillary supply and oxidative capacity in skeletal muscle of horses.
OBJECTIVE
To determine whether postnatal development of oxidative capacity and capillary supply of skeletal muscle is affected by various movement regimens in horses.


METHODS
35 foals.


METHODS
Dutch Warmblood foals were allocated into 3 groups (box stall rest, box stall rest with training, and free pasture exercise). Training comprised an increasing number of gallop sprints from 1 week after birth to 22 weeks of age. From 22 to 48 weeks, the 3 groups were combined and allowed to exercise freely. Capillary supply (diffusion index [ie, area supplied by 1 capillary]), citrate synthase (CS) activity, and succinate dehydrogenase (SDH) activity were measured in biopsy specimens of deep gluteus medius muscle.


RESULTS
During the first 22 weeks, diffusion index increased in all 3 groups (the training and pasture groups had a smaller increase, compared with the box stall rest group), total SDH activity increased in the training and pasture groups and decreased in the box stall rest group, and CS activity decreased in all groups. The effect of the various movement regimens on the diffusion index remained after the groups were combined.


CONCLUSIONS
Withholding of exercise had a negative effect on the capillary supply (ie, diffusion index increased) that remained after box stall rest was discontinued and on oxidative capacity. Box stall rest with training prevented the negative effects and eventually had the same positive effect as pasture exercise.
Rietbroek
Nancy J
NJ
Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht University, 3508 TD Utrecht, The Netherlands.
Dingboom
Elizabeth G
EG
Schuurman
Simon O
SO
Hengeveld-van der Wiel
Ellen
E
Eizema
Karin
K
Everts
Maria E
ME
D000818:Animals; D000831:Animals, Newborn; D001706:Biopsy / Q000662:veterinary; D002196:Capillaries / Q000502:physiology; D002950:Citrate (si)-Synthase / Q000378:metabolism; D006736:Horses / Q000502:physiology*; D006799:Housing, Animal; D018485:Muscle Fibers, Skeletal / Q000201:enzymology / Q000502:physiology; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000201:enzymology / Q000378:metabolism*; D010805:Physical Conditioning, Animal / Q000502:physiology*; D011897:Random Allocation; D013385:Succinate Dehydrogenase / Q000378:metabolism
D013385:Succinate Dehydrogenase; D002950:Citrate (si)-Synthase