Download Why Fat-Enhanced, Lower Starch Diets

Why Fat-Enhanced, Lower Starch Diets Help Maximize Athletic Performance:
Matching the Physiological Effects of Conditioning to the Diet
of the Elite Performance Horse.
Dr. Dan Burke
Kalmbach Feeds, Inc
Upper Sandusky, Ohio
Outline
A. Definition of Fitness
B. Types of Exercise
C. Changes in Nutrient Requirements
D. Physiological Changes Due to Training (Conditioning)
E. Impact of Calories Source on Performance
F. Nutritional Management of “Tying-Up” Syndromes
1. P.S.S.M .– polysaccharide storage myopathy
2. R.E.R. – recurrent exertional rhabdomyolysis
G. Electolytes
H. Summary
There are a number of ways to define physical fitness. Below are (3) possibilities:
A. PHYSICAL FITNESS
1)
2)
3)
Increased capacity to perform work while increasing the efficiency
that work is performed.
Smaller disturbance in homeostasis (i.e. heart rate, blood parameters)
during work.
Faster return to normal resting state after performing work.
A horse becomes more fit due to physical and biochemical changes elicited by exercise
over time. This paper will review some of these changes and how horse diets can
maximize the benefits of the biochemical responses to short and long-term exercise.
Proceedings of the Illinois State Veterinary Medical Association Winter Equine Meeting 2011
B. TYPES OF EXERCISE
There are two main types of exercise, with a great range in between. The first is maximal
exercise, which is; work of high-intensity for a short period of time, such as sprint racing.
The main substrate used to supply energy in maximal exercise is non-structural
carbohydrates (NSC = starch + sugar). The second type of exercise is submaximal
exercise, which is; work of low-intensity for a long period of time, such as endurance
racing. The main energy substrate for submaximal exercise is fat. Obviously, there a
many types of exercise that fit between maximal and submaximal, like; dressage,
jumping, longer races, etc.
C. CHANGES IN NUTRIENT REQUIREMENTS
In a fit horse, the preferred energy substrate is fat. The preferred energy substrate would
depend on how close to maximal or submaximal of the work performed. The energy
substrate preference changes as the horse becomes more fit, allowing a greater portion of
the exercise bout to utilize fat, sparing CHO and lessening the production of lactic acid,
the end-product of CHO metabolism in the muscle. The end-products of fat metabolism
are CO2 and water – Much less disturbing to acid/base balance.
NRC 2007 -TYPES OF EXERCISE
Exercise
Category
Mean Heart
Rate (bpm)
Description
Light
80
1-3 hours/week; 40% walk, 50% trot, 10% canter
Moderate
90
3-5 hours/week; 30% walk, 55% trot, 10% canter,
5% low jumping, cutting, other skill work
Heavy
110
4-5 hours/week; 20% walk, 50% trot, 15% canter,
15% gallop, jumping, other skill work
Very Heavy
110-150
Various; from 1 hour/week of speed work to 6-12
hours/week slow work
Types of Events
Recreational riding,
Beginning of training,
Show horses (occasional)
School horses,
Recreational riding,
Beginning of
training/breaking,
Show horses (frequent),
Polo, Ranch work
Ranch work, Polo,
Show horses (frequent,
strenuous events).
Low-medium level
eventing, Race training
(middle stages)
Racing, Endurance,
Elite 3-day eventing
The main nutrient that increases with increasing exercise is calories. With the exception
of electrolytes, primarily sodium and chloride, possibly potassium, the requirements for
all other nutrients are satisfied when the horse is fed to maintain desired body condition.
Proceedings of the Illinois State Veterinary Medical Association Winter Equine Meeting 2011
The chart above shows the percent increase over maintenance for critical nutrients
for the working horse. Maintenance level is the 100% line (red) and the Digestible energy
(D.E.) increase with very heavy work is represented by the yellow dashed line.
D. LONG-TERM RESPONSE TO EXERCISE
Over many weeks of training, more permanent changes in physical and biochemical
characteristics of the horse develop.
LONG-TERM RESPONSE OF BLOOD PARAMETERS TO EXERCISE

Increased packed cell volume (PCV) and increased blood volume.

Possible increase in peripheral O2 utilization.

Increased work capacity at lower blood lactic acid concentration.

Increased tolerance of lactic acid.

Increased free-fatty acid utilization (sparing glucose).
Proceedings of the Illinois State Veterinary Medical Association Winter Equine Meeting 2011
LONG-TERM RESPONSE OF MUSCLE PARAMETERS TO EXERCISE:

Increased resting glycogen concentration.

Increased concentration of many enzymes used in energy metabolism.

Increased mitochondrial density.

Increased proportion of Type IIA fibers in locomotor muscles (may depend on
age)

Increased capillary density.

Increased oxidative capacity (may depend on age).

Increased mobilization and utilization of free-fatty acids (especially in
submaximal exercise).

Increased submaximal work capacity.
E. IMPACT OF CALORIES SOURCE ON PERFORMANCE
Effect of High Starch/Sugar Content in Small Intestine:
Absorption of simple sugars from dietary NSC across the small intestinal wall
causes an increase in plasma glucose, which causes an increase in plasma insulin.
Also, there is a small population of microorganisms in horse’s stomach – rapid
breakdown of NSC will decrease pH and contribute to ulcers
The elevated insulin level results in:
 facilitation of glucose and amino acid absorption into cells

increase in glycolysis - end product is lactic acid

increased conversion of glucose to fat
 decrease in lipolysis - but, in fit horse fat is preferred energy
source

alters serotonin levels in brain potentially causing hyperactivity
and waste of energy that could be used for work
Proceedings of the Illinois State Veterinary Medical Association Winter Equine Meeting 2011
Effect of High Starch/Sugar Content in the Large Intestine:
At high feeding rates, by volume and/or concentration of NSC, excess starch/sugar
can bypass small intestine’s capacity to digest and absorb the NSC and it passes
into the cecum/colon, resulting in:

rapid fermentation by microbes (structural CHO slowly
fermented), producing large amounts of gas
 favorable environment for the production of Lactobacillus, which
produces lactate that is poorly absorbed across the cecum and
colon walls causing a reduction in pH.
 Effects of lower hindgut pH :

Grazing horses – normal pH = 6.4 – 6.7

Cecal pH of 6.0 ~ sub-clinical acidosis

pH < 6.0 associated with:
 osmotic diarrhea
 overgrowth of undesirable bacteria
 lysis of beneficial bacteria
 Risk of endotoxemia and laminitis
All resulting in some level of discomfort to the performing horse.
Summary of Physiological Changes due to Exercise
Natural response to training shifts from carbohydrate to fat as preferred energy source.
Thus:
 A higher portion of workout/race run uses fat.
 Increased glycogen stores in muscle.
 Increased time to production of lactic acid.
 Increased tolerance of lactic acid.
Proceedings of the Illinois State Veterinary Medical Association Winter Equine Meeting 2011
F. NUTRITIONAL MANAGEMENT OF “TYING-UP” SYNDROMES
1. Nutritional Suggestions For Equine Polysaccharide Storage Myopathy
(PSSM)
PSSM (polysaccharide storage myopathy; also called EPSM –equine
polysaccharide storage myopathy) is a metabolic disorder of skeletal muscle
characterized by increased glycogen content, increased glycogen-related enzymes and
abnormal amylase (the enzyme which digests starch)-resistant polysaccharide particles.
Glycogen is the storage form of carbohydrates in the muscle and is a major energy
source for muscle contractions in the normal horse. A PSSM horse cannot properly
metabolize glycogen, which results in the buildup of glycogen in the muscle. As a result,
the horse experiences muscle weakness and cramping. Outward clinical signs include
muscle stiffness and pain, shifting lameness and a “camped-out” stance. PSSM has been
documented in several horse breeds, and can be confirmed by biochemical analysis of a
muscle biopsy.
Two forms of PSSM are now recognized according to Dr. Stephanie Valberg of
the College of Veterinary Medicine, University of Minnesota. Dr. Valberg has done
controlled studies on horses with PSSM.
TYPE 1 – due to a mutation in the gene controlling glycogen breakdown. Type 1
PSSM has been identified in at least 20 different breeds and can be diagnosed with a
genetic test.
TYPE 2 – shown by excessive glycogen storage in the muscle but do not have
the genetic mutation. TYPE 2 PSSM accounts for an estimated 25% of PSSM cases in
Quarter Horse-related breeds and 80% of PSSM cases in many Warmblood breeds.


Non-Medical Treatment
General - Rest and turnout. Regular daily exercise.
Nutritional Management.
The suggested nutritional approach is to:
1. minimize the intake of SUGAR and STARCH (collectively termed as “NSC”
– non-structural carbohydrates) to less than 20% of the CALORIES in the
TOTAL diet, hay and concentrate combined. NOTE – this suggestion refers
to 20% of the CALORIES in the horse’s diet, not 20% of the feed. The
calculation is a bit more complicated than merely using a 20% NSC program.
Proceedings of the Illinois State Veterinary Medical Association Winter Equine Meeting 2011
2. Any additional calories required by the horse to maintain adequate body
condition (Body Condition Score 5; simply where the horse’s ribs can be
easily felt but not seen) should be supplied by FAT or highly digestible fiber.
a. There is an opinion out there that EPSM horses need 1 pound of fat per
day. There is no controlled studies to support this concept and can result
in extra weight gain on horses that are already overweight.
b. Dr. Valberg has suggested a management approach to afford the working
muscle fatty acids as a calories source without contributing to obesity by
adding extra fat to the diet. The suggestion is until horses are of
acceptable weight, fat metabolism can be enhanced by riding horses
after a 5-8 hour fast as a means to elevate plasma free fatty acids.
Waiting 5-8 hours after eating allows plasma insulin levels to return
to normal. Allowing fat to be utilized during exercise – remember one
of the actions of insulin is to inhibit lipolysis and free fatty acids in the
bloodstream.
c. For horses that are underweight, adding additional calories in the
form of fat (and digestible fiber) is appropriate, but it may not be
necessary to hit a target of 1 pound of fat….just supply the extra
calories at a level to attain or maintain a body condition score of 5, as
described above.
3. provide at least 1,000 IU of vitamin E per
4. provide 1-2 mg. of selenium per day.
IT IS EXTREMELY IMPORTANT TO ASSURE THE REQUIREMENTS FOR
“NON-CALORIE” NUTRIENTS, SUCH AS AMINO ACIDS, VITAMINS AND
MINERALS ARE STILL MET IN LOW-NSC/HIGH FAT DIETS FOR THE
PSSM HORSE!!!
To minimize the effects of PSSM, the energy for muscle function must come from
sources other than traditional high-starch grains and molasses. Calories can effectively be
supplied from fat highly digestible fiber sources.
Dietary fat can come from a number of sources, typically of vegetable origin, as
animal fats tend not to be palatable to horses. Soybean oil, linseed (flaxseed) oil, palm oil
and coconut oil are commonly used, though newer sources of omega-3 fatty acids such as
descented and flavored menhaden oil are becoming popular.
Highly digestible fiber can come from very soft, high-quality forage (that is low
in sugar and starch – typically under 15%), unmolassed beet pulp, soy hulls and
dehydrated alfalfa meal.
Proceedings of the Illinois State Veterinary Medical Association Winter Equine Meeting 2011
Dietary fat can come from a number of sources, typically of vegetable origin, as
animal fats tend not to be palatable to horses. Soybean oil, linseed (flaxseed) oil, palm oil
and coconut oil are commonly used, though newer sources of omega-3 fatty acids such as
descented and flavored menhaden oil are becoming popular.
In many cases, pasture should be minimized, if not eliminated, to control NSC
intake.
2.
NUTRITIONAL SUGGESTIONS FOR EXERTIONAL RHABDOMYOLYSIS
Sporadic exertional rhabdomyolysis can occur when a horse is:
 exercised beyond the horse’s current fitness level .
 fed full rations on their day off from training
 exposed to respiratory diseases
Recurrent exertional rhabdomyolysis (RER) is an inherited, intermittent, stressinduced defect in the regulation of muscle contraction.
Occurs in 5-10% of Thoroughbred race horses and less commonly in other disciplines.
RER is especially common in nervous fillies. Stress, diet, season, estrous cycle and
lameness also play a role in RER occurrence.
NUTRITIONAL MANAGEMENT
1. Decrease NSC intake – high NSC may increase nervousness in the horse,
exacerbating RER
a. reduce % NSC in concentrate (lower corn, molasses)
b. reduce AMOUNT of concentrate fed per day and per meal
2. Provide needed calories with fat and digestible fiber – following
recommendations for PSSM above will help with RER horses
3. Electrolyte supplementation may help
FATIGUE
Causes of fatigue are poorly understood and are very complex. A simple explanation is
that during maximal effort, fatigue is related to waste product accumulation, especially
lactic acid - end-product of CHO metabolism.
During submaximal exercise, fatigue appears to be related to substrate depletion, most
likely glucose or glycogen.
Proceedings of the Illinois State Veterinary Medical Association Winter Equine Meeting 2011
DELAYING FATIGUE
The physiological response to training helps to delay the onset of fatigue in many ways:
1)
Glycogen Loading:
Increases the muscle stores of glycogen. This can be accomplished by feeding a fatenhanced diet, as will be discussed later. Early efforts to glycogen load horses as is done
on humans were largely unsuccessful.
2)
Fiber-type Recruitment:
Spares glucose and glycogen. Research suggests that intermediate muscle fiber types are
recruited to become either Type I (slow twitch) fibers or Type IIA (fast-twitch oxidative)
fibers, which utilize fat as an energy substrate much better than Type IIB (fast-twitch,
glycolytic) fibers. This will reduce the production of lactic acid, as fat becomes the
preferred energy substrate. This recruitment may depend upon the age of the horse and
the type of conditioning (maximal or submaximal) used in the training program.
3)
Enhances Waste Product Removal:
The horse’s body appears to become much more efficient in clearing lactic acid from the
muscles and CO2 from the blood over time.
4)
Improves Waste Product Tolerance:
The horse can tolerate higher levels of lactic acid and CO2 as he becomes more fit. The
cumulative benefit of improved waste product removal and waste product tolerance is
important to delaying fatigue.
SUMMARY – How do we manage nutrition for the equine athlete?
 As a horse becomes more fit, the muscles prefer fat as the energy substrate
 Providing more fat (and digestible fiber) in the working horse’s diet can help
maximize his performance and minimize issues such as hyperactivity, ulcers
and tying-up.
 Supply up to 15-20% of needed calories with fat during training and events.
 Decrease starch in diet (less corn, molasses etc.). Increase digestible fiber in
diet (excellent quality grass hay, dried beet pulp).
 Control feed intake – feed more often during the day; make good grass hay
available at all times.
 Supply electrolytes when horse is sweating
 Use professionally designed diet.
Proceedings of the Illinois State Veterinary Medical Association Winter Equine Meeting 2011
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Proceedings of the Illinois State Veterinary Medical Association Winter Equine Meeting 2011
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Proceedings of the Illinois State Veterinary Medical Association Winter Equine Meeting 2011