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Tying-up and Carbs vs. Fats
As I mentioned on my earlier posting, tying-up
syndrome (exertional rhabdomyolysis) is a complex metabolic disease which is
likely to have many pre-disposing factors, including various dietary
While there has been a great deal of research
during the last several years focusing on increasing the percentage of dietary
fat as a management tool, it's unlikely that this practice will prove to be the
only solution to a complicated issue. Again, improving the cell's ability
to access energy whether - fat derived or carbohydrate supplied - remains an
area which may eventually hold the key to the tying-up mystery.
Following is an abstract from recent research which
compares the effect of feeding fat vs. carbohydrate to horses with a
history of recurrent exertional rhabdomyolysis.
Food for thought.
Michael Van Noy, DVM
Equine Vet J Suppl 1999 Jul;30:458-62
Effect of diet on thoroughbred horses with
exertional rhabdomyolysis performing a standardised
MacLeay JM, Valberg SJ, Pagan JD, de laCorte F, Roberts J,
J, McGinnity J, Kaese H
Department of Clinical and Population Sciences, University
Minnesota, St. Paul 55108, USA.
Previous studies have associated recurrent exertional
(RER) with a diet high in soluble carbohydrate (CHO). The purpose
this study was to investigate the effect of 3 diets on clinical
metabolic parameters in 5 Thoroughbred horses with RER and 3
Thoroughbreds performing a standardised exercise test (SET). Two
were formulated to meet energy requirements for the amount of
being performed in the form of CHO or fat (21.4 Mcal DE/day). The
diet was formulated to provide 135% of the DE of the other 2 diets
the form of an excessive amount of carbohydrate (28.8 Mcal
Diets were fed in a crossover design for 3 week blocks and then
performed a near maximal SET. Changes in heart rate (HR),
lactate, plasma glucose, total plasma solids, packed cell volume
muscle lactate and muscle glycogen concentration were
immediately prior to, during, and 5 min after exercise. Serum
kinase (CK) activity was measured prior to and 4 h post SET. A
ANOVA was used to examine the effect of group and dietary
When dietary treatments were compared, horses fed the high-CHO diet
a mean pre-SET PCV and pre-SET HR that was higher than horses fed
fat diet (P = 0.06 and P = 0.07, respectively). Pre-SET heart rates
highest in RER horses consuming the high-CHO diet compared to RER
consuming the low-CHO and fat diets (P = 0.02). Horses with RER had 4
post SET CK activity greater than 400 u/l in 7/14 (50%)
compared to control horses which had CK activity greater than 400 u/l
2/7 (29%) measurements. This study did not demonstrate a
effect of diet on rhabdomyolysis, indicated by CK activity, or on
metabolic response to exercise. However, diet may have a calming
on Thoroughbred horses with RER as manifested by
pre-exercise heart rates and decreased pre-exercise PCV in horses
the fat diet.
Check it Out!
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