David Nash, author of several research papers including the book 'Drought Feeding and Management of Horses', and internationally recognised equine nutrition consultant, investigates rice bran oil - an emerging new energy source for horses.

In recent years there has been an increasing trend in performance horse nutrition to increase the amount of fat in a horse's diet. The herbivorous nature of the horse has meant that the source of supplemental fat is almost exclusively vegetable based oils. Vegetable oils are largely unsaturated fat sources and as such provide optimal absorption and utilization. Animal fat sources such as tallow and some fish oils are far less suitable for horses due to lower rates of absorption and utilization, not to mention palatability and stability.

One oil that has managed to command particular attention is rice bran oil. The interest in rice bran oil stems largely from the fact that it not only offers the high energy and omega essential fatty acids contained in other vegetable oils, but, is one of the few natural sources of gamma-oryzanol and ferulic acid.
Gamma-oryzanol is a rice bran oil derivative with two major active molecules, sterol and ferulic acid. Trials in the U.S., Japan and Australia have shown that gamma- oryzanol has positive effects on weight gain and performance, comparable to some anabolic steroids. Gamma-oryzanol also stimulates the body's endocrine system resulting in increased metabolism of fat and increased synthesis of protein, in turn leading to increased lean body mass.
"increased muscle to fat ratio"
Research has shown that horses supplemented with gamma-oryzanol had improved muscle to fat ratio, with better muscle definition in the rump, neck and over the withers. The horses supplemented with gamma-oryzanol also maintained appetite better than the control group.

Another study has shown gamma-oryzanol to reduce the risk of gastric ulcers caused by stress while at the same time maintaining gastrointestinal motility.
The gamma-oryzanol / ferulic acid molecule is a fat soluble material which means that like the fat soluble vitamins A, D, E & K, fat is required for it to be efficiently metabolised in the equine digestive tract. The gamma-oryzanol in rice bran oil is in its natural state and is therefore absorbed far more efficiently than powdered forms of gamma-oryzanol.
"rice bran oil contains tocotrienols (nature's most active antioxidants)"
Rice bran oil is also an abundant source of the primary antioxidants (Vitamin E) including alpha, beta, gamma and delta tocopherol isomers as well as the most active of all antioxidants - the tocotrienols.
The importance of the natural antioxidants in rice bran oil cannot be underestimated as they serve to deactivate certain molecules known as free radicals. Free radicals are the natural by-products of many oxidative metabolic processes within cells. In horses, free radicals usually come in the form of O2, the oxide molecule and if allowed to go unchecked can cause damage to cell walls, certain cell structures, and genetic material within the cells.
Hard working horses with high metabolic work rates produce large amounts of metabolic by-products, which include free radicals. The addition of antioxidants to the equine diet is of benefit in neutralizing free radicals and accordingly has a positive effect on muscle integrity, the immune system and indeed the general health of the horse. Antioxidants are of particular benefit and an aid to horses at risk of suffering from exertional rhabdomyolysis (tying-up) or other muscle related disorders.
"Cool, safe energy"

With the high calorie demands of elite performance horses, oils play an important role in maximizing feed efficiency due to their energy dense nature. Rice bran oil contains approximately 2.5 times more energy than most raw cereal grains. Rice bran oil is also almost entirely absorbed in the horses' small intestine resulting in a cool, non-heating form of energy that is safe to feed to all classes of horse. Being able to reduce the amount of grain required to meet a horses energy requirement by the addition of rice bran oil, reduces the 'sugar high' associated with high grain intake and subsequent behavioural problems.

The high concentration of 'cool' energy provided by rice bran oil also makes it ideal for horses undertaking sustained aerobic activity such as endurance. This is largely due to the fact that the horses' body is particularly efficient in metabolising fat aerobically at this level of exercise intensity, and as such, produces less lactic acid.

The presence of essential fatty acids in rice bran oil has been shown to promote the shine and overall quality of a horses coat and as such is desirable for horses competing in shows or being prepared for sales. Older horses too can benefit from rice bran oil as a cool energy source particularly as it is easily digested in the small intestine. Aged horses tend to have a diminished capacity to effectively digest and process more complex energy sources such as grain.

From a thermogenic (heat producing) point of view, the addition of rice bran oil will allow a horse to achieve its energy requirements with the production of less metabolic heat. This advantage is of particular benefit to horses in warmer climates, and of course during summer.

"Rice bran oil has more than 5 times more fat than rice bran"

It is important to note however that while rice bran oil boasts many advantages, such advantages do not necessarily extend to rice bran/pollard products. At the very least, rice bran (meal or pellets) would need to be fed at up to 5 times the level of pure rice bran oil to achieve similar fat intakes.

Nutritionists and veterinarians often recommend the addition of fat to the equine diet as an alternate energy source for horses that are affected by problems associated with high grain (starch) diets. Whilst rice bran/pollard is high in fat (18-20%), it also contains moderate levels of starch (20-30%). By contrast, rice bran oil contains no starch and therefore does not contribute additional levels of starch to the diet. It therefore follows that rice bran oil should be more beneficial to horses prone to tying up than rice bran or rice bran based products.

In summary trials and anecdotal evidence in the field certainly support the notion that rice bran oil does indeed provide unique benefits compared to those offered by conventional vegetable or commercially blended omega oils. The reported increase in lean muscle mass and coat conditioning together with high antioxidant levels indicate that the addition of rice bran oil to any horses diet may be a sound and desirable alternative to current methods of supplementing fats and oils.

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