Changes

#'''Skin and Hair Coat:''' Epidermal keratinocytes secrete the LA-enriched phospholipid, ceramide, in both dogs and cats. Ceramide functions to enhance cell cohesion and create an effective water barrier<ref name="Elias"/>. Increased intake of LA above the minimal requirement may improve skin and coat health in dogs and cats<ref name="Rees"/><ref name="Codner"/>.  

#'''Skin and Hair Coat:''' Epidermal keratinocytes secrete the LA-enriched phospholipid, ceramide, in both dogs and cats. Ceramide functions to enhance cell cohesion and create an effective water barrier<ref name="Elias"/>. Increased intake of LA above the minimal requirement may improve skin and coat health in dogs and cats<ref name="Rees"/><ref name="Codner"/>.  

#'''Inflammation:''' Arachidonic acid comprises approximately 20-25% of the fatty acids within the cellular membrane and acts as a substrate for cyclooxygenase (COX) and lipoxygenase (LOX) enzymes to form the inflammatory [[Nutrition Glossary#Eicosanoids|eicosanoids]] series-2 prostaglandins (prostaglandins, prostycyclins and thromboxanes) and series-4 leukotrienes<ref name="NRC"/>.  

#'''Inflammation:''' Arachidonic acid comprises approximately 20-25% of the fatty acids within the cellular membrane and acts as a substrate for cyclooxygenase (COX) and lipoxygenase (LOX) enzymes to form the inflammatory [[Nutrition Glossary#Eicosanoids|eicosanoids]] series-2 prostaglandins (prostaglandins, prostycyclins and thromboxanes) and series-4 leukotrienes<ref name="NRC"/>.  

#'''Reproduction:''' Queens fed AA deficient diets with adequate levels of LA are unable to support normal pregnancy and foetal development<ref name="MacDonald">MacDonald ML, et al. Effects of linoleate and arachidonate deficiency on reproduction and spermatogenesis in the cat. J Nutr 1984;114:719-726.</ref>, while no impact on male fertility and spermatogenesis is seen.

#'''Reproduction:''' Queens fed AA deficient diets with adequate levels of LA are unable to support normal pregnancy and foetal development<ref name="MacDonald">MacDonald ML, et al. Effects of linoleate and arachidonate deficiency on reproduction and spermatogenesis in the cat. J Nutr 1984;114:719-726.</ref>, while no impact on male fertility and [[Spermatogenesis and Spermiation - Anatomy & Physiology|spermatogenesis]] is seen.

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[[File:Omega 6.jpg|thumb|400px|center|Role of omega-6 fatty acids in the body<br>© Diffomédia/Masure]]

[[File:Omega 6.jpg|thumb|400px|center|Role of omega-6 fatty acids in the body<br>© Diffomédia/Masure]]

==Consequences of Omega-6 Fatty Acid Deficiency==

==Consequences of Omega-6 Fatty Acid Deficiency==

#'''Growth''': Kittens fed LA deficient diets fail to grow normally and develop course dull hair coats<ref name="Sinclair"/><ref name="Rivers"/>. Puppies fed a LA deficient diet developed coarse, dry hair coats with skin flaking after 2 months<ref>Weise HF, et al. Influence of High and Low Caloric Intakes on Fat Deficiency of Dogs. J Nutr 1962;76:71-81.</ref>.

#'''Growth''': Kittens fed LA deficient diets fail to grow normally and develop course dull hair coats<ref name="Sinclair"/><ref name="Rivers"/>. Puppies fed a LA deficient diet developed coarse, dry hair coats with skin flaking after 2 months<ref>Weise HF, et al. Influence of High and Low Caloric Intakes on Fat Deficiency of Dogs. J Nutr 1962;76:71-81.</ref>.

#'''Maintenance''': When fed a LA deficient diet, increased endogenous production of oleic acid (18:1n-9) occurs<ref>Spector AA. Lipid metabolism: essential fatty acids. In Biochemical and Physiologic Principles of Human Nutrition. First edition. 2000 Philadelphia, PA: WB Sunders p373. </ref>. Oleic acid is incorporated into ceramide in place of the missing LA, but is less effective at maintaining cell cohesion. Thickening of the epidermis and cellular swelling occur, and the thickened more loosely packed keratinocytes slough readily resulting in the clinical appearance of scaling<ref>Hansen AE, et al. Sequence of histological change in skin of dogs in relation to dietary fat. J Nutr 1954;52:541-554.</ref>. The greasy, flaky skin is prone to secondary infection and pyoderma occurs commonly with LA deficiencies<ref name="Codner"/><ref>Hansen AE, et al. Susceptibility to infection manifested by dog on low fat diet. Fed Proc 1948;7:289.</ref>. Interdigital exudation and [[Otitis Externa - Cat and Dog|otitis externa]] are also sequelae of LA deficiencies in dogs<ref>Hansen AE and Weise HF. Fat in the diet and relation to nutrition of the dog. I. Characteristic appearance and gross changes of animals fed diets with and without fat. Tex Rep Biol Med 1951;9:491-515. </ref>. There are no clinical signs reported with AA deficiency in adult, non-reproductive cats.

#'''Maintenance''': When fed a LA deficient diet, increased endogenous production of oleic acid (18:1n-9) occurs<ref>Spector AA. Lipid metabolism: essential fatty acids. In Biochemical and Physiologic Principles of Human Nutrition. First edition. 2000 Philadelphia, PA: WB Sunders p373. </ref>. Oleic acid is incorporated into ceramide in place of the missing LA, but is less effective at maintaining cell cohesion. Thickening of the epidermis and cellular swelling occur, and the thickened more loosely packed keratinocytes slough readily resulting in the clinical appearance of scaling<ref>Hansen AE, et al. Sequence of histological change in skin of dogs in relation to dietary fat. J Nutr 1954;52:541-554.</ref>. The greasy, flaky skin is prone to secondary infection and [[Superficial Pyoderma|pyoderma]] occurs commonly with LA deficiencies<ref name="Codner"/><ref>Hansen AE, et al. Susceptibility to infection manifested by dog on low fat diet. Fed Proc 1948;7:289.</ref>. Interdigital exudation and [[Otitis Externa - Cat and Dog|otitis externa]] are also sequelae of LA deficiencies in dogs<ref>Hansen AE and Weise HF. Fat in the diet and relation to nutrition of the dog. I. Characteristic appearance and gross changes of animals fed diets with and without fat. Tex Rep Biol Med 1951;9:491-515. </ref>. There are no clinical signs reported with AA deficiency in adult, non-reproductive cats.

#'''Reproduction''': Linoleic acid deficiency does not appear to impact reproduction in dogs and cats, but AA deficiency in queens does not support normal pregnancy or foetal development<ref name="MacDonald"/>. Queens fed AA deficient diets from weaning will have normal heat cycles and may have a single litters of kittens, but are unable to support further pregnancies.

#'''Reproduction''': Linoleic acid deficiency does not appear to impact reproduction in dogs and cats, but AA deficiency in queens does not support normal pregnancy or foetal development<ref name="MacDonald"/>. Queens fed AA deficient diets from weaning will have normal heat cycles and may have a single litters of kittens, but are unable to support further pregnancies.

[[Category:Fatty Acids]]

[[Category:Fatty Acids]]

[[Category:To Do - Nutrition]]

[[Category:To Do - Nutrition]]

[[Category:To Do - Nutrition GGP]]

[[Category:To Do - Nutrition preMars]]