Royal Canin Nutritional Information

Royal Canin Nutritional Information

The Collie (and the German Shepherd) may suffer primary disorders of lipoprotein metabolism, leading to hypercholesterolemia. The disease may lead to corneal lipidosis where the cholesterol and phospholipid vacuoles are present in the superficial stroma of the cornea. (© Renner).

Key Points to Remember:

In the Nutritional Management of Hyperlipidemia

• Achieve weight loss in the dog if the body condition demands it. There is a correlation between obesity and the plasma indicators of hyperlipidemia (lipoproteins, leptin, insulin and ghrelin) (Jeusette et al., 2005).
• Give the dog a low-fat diet: < 25 g/1000 kcal, or less than 9% fat in a 3500 kcal/kg diet. Controlling the energy ingested is the best way of controlling hyperlipidemia in obese dogs.
• During the low fat diet, simply controlling the hyperlipidemia is not enough. It may be necessary to prescribe a fish oil supplement(220 mg/kg) to provide EPA and DHA (long-chain omega 3 fatty acids), which have a lipopenic action.
• High levels of poly-unsaturated omega-3 fatty acids may increase the risk of oxidation of lipid membranes. The administration of biological antioxidants (e.g. vitamin E, vitamin C and beta-carotene) may be necessary to prevent oxidative reactions.
• Supplementation with fermentable fiber in association with a low-calorie diet may help to regress corneal lipidosis. In practice, this supplementation can be achieved by the inclusion of 1 - 2% fructo-oligosaccharides (FOS) or the gradual addition of guar gum in the same proportions (Jeusette et al., 2004). Interestingly, the effect of the FOS on hypercholesterolemia is in consistent.
• The patient should be re-evaluated every month for the first three months. Once the hyperlipidemia has been controlled re-evaluation every six months will be sufficient.

Focus on: Long-chain Omega 3 Fatty Acids (EPA-DHA)

Omega 3 fatty acids constitute a spe-cific family within polyunsaturated fatty acids (PUFA). Their precursor is alpha linolenic acid (C18:3, n-3), the chemical structure of which distinguishes it from linoleic acid (C18:2, n-6), which is the precursor of the omega 6 family of fatty acids. Both are essential fatty acids in dogs, because the dog lacks the appropriate enzymes to synthesize them hence, the dog depends on adequate dietary intake to meet its needs.

Figure 10. Linoleic acid:c18:2(n-6); omega 6fatty acid precursor and alpha linolenic acid:c18:3(n-3); omega 3 fatty acid precursor.  

The synthesis of long-chain fatty acids is due to the action of hepatic enzymes (desaturases and elongases), which attach to the carbon atoms and the unsaturated double bonds. These are the same enzymes that act in the synthesis of omega 3 and omega 6, which is the reason for competition between the two families.

Sources of Omega 3 Fatty Acids

Fish oils (especially fish from cold water, like salmon, mackerel, halibut and herring) may contain more than 30% EPA-DHA. They are by far, the most abundant sources. Marine PUFA are synthesized in the chloroplasts of phytoplankton or microalgae consumed by fish. Higher in the food chain, some fish incorporate omega 3 PUFA and transform them into fatty acids with 20 - 22 carbon atoms. EPA and DHA are especially concentrated in the fat tissue of fish.

Some vegetable oils contain a significant quantity of alpha linolenic acid, which is an EPA-DHA precursor. These include soybean oil and especially linseed oil. The efficiency of transformation to long-chain fatty acids is strongly dependent on the animal's age and health, and on the general dietary context. Fish oil is the best available source of EPA-DHA fatty acids.

Figure 11. Hepatic synthesis of long-chain omega 3 and omega 6 fatty acids from their respective precursors.