Rice bran oil (RBO) is an increasingly popular fat supplement fed to horses for weight management, cool energy, and coat quality.

The oil is derived from the germ and bran of brown rice grains and contains essential fatty acids and antioxidants. [1][3][4][5] Rice bran oil is palatable and provides a dense source of calories for horses.

RBO is primarily composed of monounsaturated fatty acids and polyunsaturated fatty acids. [1] It contains 42.6% oleic acid (an omega-9 monounsaturated fatty acid) and 28% linoleic acid (an omega-6 polyunsaturated fatty acid). [1]

Continue reading to learn about the benefits of feeding rice bran oil to horses and some considerations when adding fat to your horse’s diet.

Rice Bran Products for Horses

Mainly produced in Japan, Thailand, India, China, and Vietnam, rice bran oil is primarily used in the food industry and for industrial applications. [1][2] RBO has a neutral flavor and high smoke point, which makes it ideal for high-temperature cooking.

The oil is harvested from the bran layer which between the outer hull and inner germ, which is rich in vitamins and other nutrients.

Compared to many other vegetable oils, rice bran oil contains a higher level of antioxidants, including vitamin E, gamma-oryzanol, and phytosterols. [1][6] These nutrients offer a range of health benefits.

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Rice Bran

The bran component of rice kernels is commonly used in horse feeds and retains naturally present fatty acids, so long as the oil is not extracted.

Rice bran contains up to 20% oil and must be heat- and pressure-stabilized before feeding to prevent rancidity and digestive issues.

Rice bran consists of 21% non-structural carbohydrates (primarily starch and sugars). For horses that need to avoid high-NSC diets, the oil is carbohydrate-free and may be a better alternative.

The bran can also be high in phosphorus and low in calcium, or high in both minerals. Calcium and phosphorus levels meet the individual requirement levels and fall within specific ratios to optimize support of metabolic processes.

Rice Bran Oil Extraction

RBO is typically extracted through a solvent extraction process. [1] It can also be cold-pressed to retain more natural flavors and nutrients.

After milling, RBO oil is prone to degrade when exposed to light and air. If the oil is not stabilized through a heat treatment process, it has a shorter shelf life.

Some rice bran oil products are stabilized immediately after production to reduce lipase activity. This is an enzyme that breaks down fatty acid components of the oil.

Rice bran oil is low in potassium, which makes it safe for horses with Hyperkalemic Periodic Paralysis Disease (HYPP).

Both rice bran and RBO contain a high amount of omega-6 fatty acids and a negligible amount of omega-3 fatty acids. [1] Equine diets containing these fat sources should be properly balanced to ensure horses are receiving enough omega-3 fatty acids.

Nutritional Profile

Digestible Energy

Rice bran oil provides approximately 9.5 megacalories (mcal) / kg of dry matter (DM).

A typical adult horse at maintenance requires 16.65 mcal of digestible energy per day.

Fatty Acid Composition

The fatty acid composition of RBO is: [1]

  • 44% monounsaturated fatty acids
  • 6% polyunsaturated fatty acids
  • 5% saturated fatty acids

Unsaturated fatty acids present in RBO include: [1]

  • Oleic acid: 42.6% (omega-9 monounsaturated fatty acid)
  • Linoleic acid: 28% (omega-6 polyunsaturated fatty acid)
  • Linolenic acid: 0.8% (omega-3 and omega-6 polyunsaturated fatty acids)

Of the linolenic acid component of RBO, 0.5% is omega-3 fatty acids, and 33.1% is omega-6 fatty acids. [1]

The overall ratio of omega-6 to omega-3 fatty acids in rice bran oil is approximately 56:1.

Omega-3 and omega-6 fatty acids are essential for equine health and must be provided by the diet as the body cannot make them. Omega-6 fatty acids are important as they support inflammatory processes that are beneficial for fighting off infections and supporting tissue repair.

However, diets containing excessive omega-6 fatty acids and insufficient omega-3s can promote inflammation.

Nutrients

RBO is high in vitamin E and contains both tocopherols and tocotrienol forms of the nutrient. [4][7]

Unrefined RBO is higher in vitamin E than refined oil and contains approximately 24 to 60 mg of tocopherols/100 g of oil and 71 to 75 mg of tocotrienols/100 g of oil. [8]

Gamma-oryzanol is a group of antioxidant plant chemicals (ferulic acid esters and phytosterols) present in rice bran oil at a level of approximately 1 to 2%. [4][7][9]

Rice bran oil contains approximately 1 to 2% naturally occurring phospholipids, including lecithin. [10] Phospholipids are fatlike, phosphorus-containing compounds that serve metabolic and structural functions in cells. [11]

Benefits of Rice Bran Oil for Horses

Research on the specific effects of feeding rice bran oil to horses is limited. However, several components of rice bran oil have been studied and shown to support health benefits.

There are also general benefits associated with feeding fat in the equine diet.

Source of Antioxidants

Antioxidants combat cell damage due to oxidation. This process occurs when oxygen atoms interact with other molecules and cause damage by stealing electrons from them.

Free radicals are produced in our bodies due to normal metabolic processes, stress, and environmental toxins. Antioxidants work to neutralize these harmful free radicals, protecting cells in the body.

Vitamin E:

Vitamin E refers to a group of fat-soluble compounds, including tocopherols and tocotrienols, that serve as powerful antioxidants in the body.

Tocopherols and tocotrienols donate electrons to unstable atoms (free radicals) that can damage cells and help prevent cellular damage and premature aging.

Some of the key benefits of vitamin E for horses include:

  • Reduces muscle soreness and stiffness which helps sustain high levels of activity.
  • Helps muscles recover after exercise which can support athletic performance. [12]
  • Lowers the risk of chronic tying up (exertional rhadomyolysis).
  • Boosts the immune response and enhances the capacity of immune cells to kill bacteria. This helps horses recover from illness more quickly. [13]
  • Improves insulin sensitivity.
  • Enhances antioxidant defenses to help minimize stress and health issues related to travel and competition. [14]
  • Guards against the development of neurological disorders, such as equine motor neuron disease (EMND) and equine degenerative myeloencephalopathy (EDM) from developing. [15]
  • May lower oxidative stress in horses with polysaccharide storage myopathy (PSSM)/equine polysaccharide storage myopathy (EPSM).

Gamma-oryzanol:

Human research shows multiple health benefits of gamma-oryzanol, including antioxidant and anti-inflammatory effects. It has also been studied for anticancer, antidiabetic, and cholesterol-lowering effects. [9][16]

In horses, gamma-oryzanol is purported to have an anabolic effect on muscle growth. It is also purported to enhance athletic performance by reducing fatigue and decreasing lactate accumulation in tissues. [9][17][18][19][20]

Gamma-oryzanol is widely available in equine supplements for exercising horses.

Supports Gut Health

Rice bran oil also contains lecithin, which has been shown to support gastrointestinal health and intestinal barrier function in horses. Research shows a combination of lecithin and pectin supports gastric health. [21][22]

The amount of lecithin in rice bran oil is too small to produce the same results seen in research studies, but there could be some gut protective effects conferred by the lecithin content.

Source of Cool Calories

Rice bran oil is a cool energy source that can increase the calories in your horse’s diet without causing excitability or hot behaviour.

Fat is metabolized efficiently and digested slower than carbohydrates, making it an ideal feed to support exercise endurance and recovery. [23]

Unlike grains and starch-based feeds, which can cause hindgut issues, fat does not contribute to a risk of