Tying-up and Carbs vs. Fats

["Joy VanNoy" <joy@auburnlabs.com>]

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 influences.

 

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

www.auburnlabs.com

 

   

 

 

 

 

Equine Vet J Suppl 1999 Jul;30:458-62

 

                 Effect of diet on thoroughbred horses with recurrent
                  exertional rhabdomyolysis performing a standardised exercise
                  test.

 

                  MacLeay JM, Valberg SJ, Pagan JD, de laCorte F, Roberts J, Billstrom
                   J, McGinnity J, Kaese H

 

                  Department of Clinical and Population Sciences, University of
                 Minnesota, St. Paul 55108, USA.

 

                 Previous studies have associated recurrent exertional rhabdomyolysis
                 (RER) with a diet high in soluble carbohydrate (CHO). The purpose of
                 this study was to investigate the effect of 3 diets on clinical and
                 metabolic parameters in 5 Thoroughbred horses with RER and 3 healthy
                 Thoroughbreds performing a standardised exercise test (SET). Two diets
                 were formulated to meet energy requirements for the amount of exercise
                 being performed in the form of CHO or fat (21.4 Mcal DE/day). The third
                 diet was formulated to provide 135% of the DE of the other 2 diets in
                 the form of an excessive amount of carbohydrate (28.8 Mcal DE/day).
                 Diets were fed in a crossover design for 3 week blocks and then horses
                 performed a near maximal SET. Changes in heart rate (HR), plasma
                 lactate, plasma glucose, total plasma solids, packed cell volume (PCV),
                 muscle lactate and muscle glycogen concentration were measured
                 immediately  prior to, during, and 5 min after exercise. Serum creatine
                 kinase (CK) activity was measured prior to and 4 h post SET. A 2-way
                 ANOVA was used to examine the effect of group and dietary treatment.
                 When dietary treatments were compared, horses fed the high-CHO diet had
                 a mean pre-SET PCV and pre-SET HR that was higher than horses fed the
                 fat diet (P = 0.06 and P = 0.07, respectively). Pre-SET heart rates were
                 highest in RER horses consuming the high-CHO diet compared to RER horses
                 consuming the low-CHO and fat diets (P = 0.02). Horses with RER had 4 h
                 post SET CK activity greater than 400 u/l in 7/14 (50%) measurements
                 compared to control horses which had CK activity greater than 400 u/l in
                 2/7 (29%) measurements. This study did not demonstrate a significant
                 effect of diet on rhabdomyolysis, indicated by CK activity, or on the
                 metabolic response to exercise. However, diet may have a calming effect
                 on Thoroughbred horses with RER as manifested by decreased          
                 pre-exercise heart rates and decreased pre-exercise PCV in horses fed
                 the fat diet.