FATS: More Than an Energy Supply

By Melyni Worth PhD. PAS.


In recent years there has been much talk about the usefulness of adding fat as an energy supply to the equine diet. This is quite logical; since fats contain 2.5 times as more energy per gram then carbohydrates do and are a useful way to increase the calorie content of feed. With the recognition of the various problems that horses get when they are fed too many carbs, supplying calories as fat is increasingly important. But there is ore to fats than just a calorie supply.

Some fats have a molecule, which is held by a double bond, and these are referred to as unsaturated fats. A fat molecule can have more than one double bond. When the chain has two or three double bonds the fat is called a polyunsaturated. The more double bonds the molecule has, the more useful it is to the body. Polyunsaturated fats make up a special subgroup called Essential Fatty Acids or (EFAs). Horses (and humans) being mammals, cannot synthesize EFAs; they must be supplied in the diet hence they are called 'Essential'.

The most important EFAs are called the Omega-3 and Omega-6 fatty acids (linolineic, arachidonic, and linoleic acids). They are found in certain plants and in cold-water fishes. Their availability in plant products and fish oils depends on the oils and fats not being processed by heat or by chemical means. Foods are processed, (called partial or complete hydrogenation), to increase shelf life and slow the rate of oxidation of the fat. As the fat is oxidized it becomes chemically altered, which we refer to as going rancid Most polyunsaturated fats are fragile and are easily damaged by exposure to heat, light and oxygen (air), the preservation process tends to destroy the unsaturated bonds, which means that the oil or fat no longer contains EFAs.

The body uses the EFAs to produce prostaglandins (PGs). These are a class of compound used extensively as chemical messengers within the body. The EFAs are put into one of three families, depending on the kind of prostaglandin that they can produce. The body needs all three types of EFAs to produce the various kinds of PGs it needs PG-1, PG-2 and PG-3.

PG-1s are produced from a family of EFAs found in the oils of safflower, corn, sunflower, peanut and evening primrose.

PG-2s are derived from fats found in animal products such as meat and dairy products, mollusks and shellfish.

PG-3s are derived from the Omega-3 and Omega-6 fatty acids found in highest concentrations in walnut, olive, canola, linseed (flaxseed), hemp and cold-water fish oils.
Prostaglandin, PG-2 is a compound important in development of pain signals and in signaling inflammatory responses. PGs 1 and 3 appear to have important roles in tissue repair, growth regulation, central nervous system activity, and the modulation of inflammation. Thus it is better to have more PG 1 & 3's around than PG2's.

The amount of each prostaglandin that is produced depends on the relative concentration of each family of EFA present in the diet. Partial or complete hydrogenation of the fats results in a higher level of production of prostaglandin-2. These higher levels of prostaglandin-2 may result in increased rates of degenerative diseases and an increased perception of pain. Increasing the levels of prostaglandin's 1 and 3 has, in human nutrition, been shown to decrease pain perception and to decrease the rate of degenerative disease development.

To increase the level of the Omega-3 and 6 fatty acids in the horse's diet the best way is to feed one of the plant sources. The highest level of Omega-3 fatty acid is found in flaxseed. One way to raise the relative levels in the diet is to feed flaxseed oil, this oils is fairly expensive. To ensure that there has been no loss of EFAs, it must be cold pressed, in a dark, oxygen free environment. EFAs degenerate quickly upon exposure to light and air. Flaxseed oil must be kept in dark, closed containers and refrigerated. While fresh canola oil has a reasonably high level of EFAs, commercially available canola oil is processed and the EFAs will have been lost.

Another method is to feed whole linseed or flaxseed. The flaxseed should ideally have the seed coat cracked open or ground in order to be digestible, but there is one great problem. The seed contains an enzyme called a cyanogenic glycoside within it, which, on exposure to air will start to produce cyanide. This toxicity is why in the old days linseed was always fed cooked, usually by boiling. Cooking would remove the problem of the cyanide-producing enzyme and also destroyed the EFAs. The cooked linseed was beneficial but not as beneficial as the freshly ground seed would be.

If seeds are cracked or ground the exposure to air starts cyanide production, unless the ground meal is treated in a way to stop the enzyme working. This usually done by heat-treating the ground meal. The heat treatment denatures the enzyme responsible.
In practical terms this means either buying whole flaxseed and keeping it in the barn together with a coffee or spice grinder, grinding enough each day for that day's feeding, and feeding it promptly or buying and feeding the whole un-ground flaxseed.

Another way is to buy the heat treated (stabilized) ground meal. The heat-treated meal does not keep as well as the whole flax, and there is a slight loss of the more delicate fatty acids with the heat treatment. Thus the buyer has to decide if the loss of EFA's with the heat treatment offsets the higher digestibility or not. The jury is still out so far. If you feed an extra 10-20% more of the whole seed (5 oz instead of 4 oz) then the loss of flax due to indigestibility can be off set.

The addition of 4-8 ounces of flaxseed to a horses diet every day will do a tremendous amount to improve skin and coat condition, hoof growth, rate of healing from injury, and especially arthritic conditions.

Another huge benefit from feeding flax is if you wet it just prior to feeding it goes to a slimy mess, which is an excellent lubricant, and horses love the taste. This can be very useful for horses prone to blockages.

All these benefits of flax seed applies to humans and dogs as well as horses. We all can benefit from increasing the amount of polyunsaturated fat in our diets, humans and animals.

For further information, contact DR Melyni Worth at melyni@ntelos.net or call 540-942-4500.

Dr. Melyni Worth Ph.D. - 2006 (c)

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