I found this in another forum, I thought it was interesting enough to share with you guys. 
For those of you still sitting on the fence regarding fatty acids and adding them to your pets diet, here is a good article. My boys get a Derm cap every day >>>>
Essential Fatty Acids and their derivatives serve a number of major vital functions in the body. They are required for the transport and metabolism of both cholesterol and triglycerides. They are required for normal brain development and brain function. They are required in visual function (retina), brain and nerve function (synapses), and adrenal function. They are required in the structure of the membranes that surround each cell in our body. They stimulate metabolism, increase metabolic rate, increase oxygen uptake, and increase energy production. They slow down growth of cancer cells.
EPA (from fish oil) also converts to series 3 prostaglandins, which have many benefits. They regulate inflammatory responses (Skin and Joint). They regulate immune function, which can help in fighting disease more effectively. They regulate platelet stickiness. They regulate arterial muscle tone, which involves blood pressure regulation.
The lack of Omega 3 and the excessive amount of Omega 6 in the modern diet ultimately create degenerative conditions. The store-bought processed foods still do not supply an adequate amount of Omega 3 to properly balance the ratio. Many nutritional supplements are still promoting and loading up the Omega 6 (LA) fatty acids -exacerbating an already severely imbalanced and unhealthy situation. The best solution to insure our pet's health is to provide a high quality Omega 3 Fish oil supplement along with a premium diet.
"Active EFAs can go straight to work in your dogs body, whereas inactive EFAs are unable to carry out their vital roles without first being converted by your dog to the active form. This conversion can only be carried out by enzymes, which your dog may or may not produce. If your dog does not produce those enzymes for any reason, those inactive essential fatty acids are not able to carry out many of their vital functions. This will lead to ill health.
Supplements which contain the activated omega 6 EFAs for dogs include Evening Primrose oil, Borage oil and Black Currant oil. Supplements which contain inactive omega 6 EFAs include vegetable oils such as safflower oil, sunflower oil and corn oil.
Supplements which contain the activated omega 3 EFAs include Cod Liver oil and Fish body oils such as Salmon oil. Supplements which contain the inactive omega 3 EFAs include flaxseed oil and hemp seed oil.
Why would these critical activating enzymes be missing?
The critical enzyme that converts inactive essential fatty acids into active essential fatty acids can be missing for one of several reasons. The first is heredity. The other more important reasons for the loss of this enzyme include aging, viral infections, any chronic disease state and a diet rich in trans fatty acids. Prevention is achieved by removing processed pet foods from our dogs’ lives and switching our dogs to their evolutionary diet together with appropriate fatty acid supplementation as and when required.
A diet that lacks sufficient omega 6 EFAs will cause skin problems, reproductive problems and growth problems. This situation can be counteracted by the addition of 'activated' omega 6 EFAs to the diet. A diet that lacks sufficient omega 3's is the number one fatty acid associated problem caused by modern processed pet foods. This lack of the omega 3’s allows the omega 6’s (if they are present in sufficient quantities) to produce the whole range of problems caused by an excess of the omega 6’s. In addition the lack of the omega 3’s can be a potent cause of infertility in our breeding stock together with growth problems in young pups and kittens, and most importantly, problems with the development of the nervous system. This can result in early deterioration of vision and hearing, learning difficulties in puppies and kittens and behavioral problems in our pets that can continue throughout life." Dr. Billinghurst's BARF World
"Fatty acids are essential components of cell membranes and are an integral component of the intercellular barrier in the stratum corneum. This barrier is formed by extrusion of lamellar granules containing phospholipids, glycosphingolipids, and free sterols that are produced by keratinocytes. Essential fatty acids cannot be synthesized and, therefore, must be supplied in the diet. Animals are unable to change one series of fatty acids to another, eg, omega-3 to omega-6. Dermatologic signs of fatty acid deficiency include a thin and discolored haircoat, scaly skin, sebaceous gland hypertrophy with hyperkeratosis of the sebaceous ducts and increased sebum viscosity, increased epidermal turnover rate, weak cutaneous capillaries, and decreased wound healing.
The essential fatty acids most important for homeostasis of the skin in dogs and cats are linoleic acid and linolenic acid. Arachidonic acid is also an essential fatty acid in cats. Dihomo-γ-linolenic acid (DGLA) and eicosapentaenoic acid can be synthesized from linoleic acid and linolenic acid, respectively. The skin is deficient in desaturase enzymes that insert double bonds into the fatty-acid chain; therefore, continual transport of unsaturated fatty acids from the liver to the skin is required for epidermal turnover. Because linoleic, γ-linolenic, and DGLA accumulate in the skin but cannot be converted to arachidonic acid at that site, these fatty acids compete with arachidonic acid for cyclooxygenase and lipoxygenase enzymes, which decreases production of inflammatory prostaglandins. Metabolites of DGLA (prostaglandin E1 and 15-hydroxy-8,11,13-eicosatetraenoic acid) and of eicosapentaenoic acid (leukotriene B5 and 15-hydroxyeicosapentaenoic acid) have anti-inflammatory and immunomodulatory effects.
In dogs with seborrhea, levels of linoleic acid in the skin are abnormally low, even though levels in the serum are normal. Oleic acid is believed to be substituted in skin when there is a relative deficiency of linoleic acid. Sunflower oil and safflower oil are good sources of linoleic acid and may be given at 1.5 mL/kg/day and 0.5 mL/kg/day, respectively. Concentrated fatty-acid supplements that contain eicosapentaenoic acid, γ-linolenic acid, decahexanoic acid, safflower oil, glycerin, and vitamin E have been effective in treatment of some seborrheic dogs.
Fatty acids are also beneficial in treatment of atopic disease. Atopic dogs have abnormal lipid absorption and metabolism. Although the benefits of fatty acids are clear, which combination of fatty acids is most effective and the most effective dose are not. Lack of response to one product does not preclude a favorable response to another product. Dosages several times those on the label may be required to control allergic pruritis. There are few side effects; however, pancreatitis has been rarely reported. Large doses may also cause weight gain or diarrhea." The Merck Veterinary Manual