Omega 3 fatty acids, found most commonly in fish oil supplements, decrease inflammation throughout the body and decrease risk for many diseases. In general, pet food does not contain enough of these vital nutrients for optimal health, so a supplement is needed unless your pet is eating a prescription diet that contains extra. We recommend fish oil supplementation for all adult and senior pets. Puppies and kittens require extra omega 3 fatty acids for the development of their brains and immune systems. Some high quality over-the-counter pet foods contain extra fish oil. Note that many pet foods contain flax seed with label claims that this provides extra OM3 fatty acids. Dogs and cats do not make the enzyme that digests flax seed, however, so flax is basically useless for pets.
For more information on fish oil, watch this video or follow these links.
Fatty Acid Supplementation in Cats
Annual 2018 Nutrition and Longevity