Fat, or lipids, are one of the three macronutrients of an animal’s diet, providing an energy rich fuel source and supplying building blocks for the formation of tissues in the body.

Triglycerides are the most important type of fat in the diet, consisting of a glycerol molecule attached to three fatty acids (FA).

Triglycerides are categorized according to the fatty acids they contain. Fatty acids are classified as saturated, unsaturated, or polyunsaturated according to their structure. All fatty acids share some common functions, including provision of energy, increased palatability, absorption of fat-soluble vitamins, and incorporation into cellular membranes. There are additional functions that are unique to mono- and polyunsaturated fatty acids that are beneficial to dogs and cats.

Essential Fatty Acids

There are two specific types of polyunsaturated fatty acids (PUFAs) that are considered essential. Omega-3 fatty acids and omega-6 fatty acids are named according to where the first carbon double bond is located within the carbon chain. These fatty acids have important roles in cell membrane structure, neurologic development, immune function, and managing inflammation.

Function of Lipids






Digestion of Fat

The digestion of fat is much more complex than digestion of carbohydrates and proteins. Both bile and pancreatic juices are excreted into the small intestine and work together for fat digestion. First, bile salts break the big fat droplets into smaller ones, in the same way dish detergent breaks up grease. This makes it easier for pancreatic enzymes (lipases) to digest the fat molecules. In the final stage, fatty acids are absorbed into the circulation where they are either stored or used by the body for normal biologic functions.

1. National Research Council (NRC). 2006. Nutrient Requirements of Dogs and Cats. The National Academies Press, Washington, DC, USA. Blood et al 2007

2. Case LP et al. 2011. Canine and Feline Clinical Nutrition; a resource for companion animal professionals. Mosby. London.
3. Alberts B et al. 2002. Molecular Biology of the Cell. 4th edition. New York: Garland Science. The Lipid Bilayer. Available from: http://www.ncbi.nlm.nih.gov/books/NBK26871/
4. Prottey C. 1976. Essential fatty acids and the skin. Br J Dermatol, 94: 579–587







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