NUTRITION
homeostasis , gastric acid secretion , regulation of body temperature , blood clotting , The Omega-3 fatty acids , EPA and DHA , modulate eicosanoid synthesis as they compete with arachidonic acid for the cyclo-oxygenase and 5-lipo-oxygenase enzymes involved in the arachidonic acid cascade leading to the production of less inflammatory 3-series eicosanoids . Oxidative stress and inflammation can thus be altered by dietary factors in various species .
Dogs easily convert linoleic acid ( LA ) into arachidonic acid ( AA ) and related pro-inflammatory eicosanoids . The conversion of α-LA to EPA and less inflammatory eicosanoids occurs at a lower rate . Conversion of α-LA to DHA is even lower . One source estimates that less than 10 percent of ALA becomes EPA and DHA .
The metabolism of LA and α-LA depends on the same enzyme systems and is thus competitive . Thus to avoid excessive omega-6 ( LA , AA ) metabolites , the inclusion of Omega-3 fatty acids ( α-LA , EPA , DHA ) to balance dietary Omega-6 fatty acids is recommended .
Increasing the amount of Omega-3 fatty acids in the skin and other tissues leads to decreased production and activity of the proinflammatory eicosanoids from Omega-6 fatty acids and increased synthesis of the less-inflammatory metabolites . However , the limited ability of adult animals to convert α-LA to long chain PUFA ’ s for incorporation into cell membranes suggests that this Omega-3 fatty acid has less value as a supplement for affecting the production of inflammatory mediators than EPA and DHA .
Long-chain Omega 3 fatty acids are probably “ conditionally essential ” nutrients given the low conversion rates of α-LA to EPA and DHA . Thus long chain Omega-3 fatty acids are considered conditionally essential for growth , development , metabolic balance , inflammatory response and possibly healthy ageing .
The ideal ratio of Omega-3 to Omega-6 fatty acids in carnivore diets remains unclear . Feral dogs and other wild canids are likely to obtain both α-LA and DHA from the tissues of herbivorous mammalian prey and birds , which more readily convert dietary Omega-3 precursors in plants to the longer chain Omega-3 fatty acids .
DHA is well conserved in tissues and adult dogs at maintenance may not require long chain fatty acids as the small amounts converted from α-LA may be sufficient , however , inclusion in the diet is still recommended due to individual variations in synthesis . Given that the “ typical Western diet ” exhibits an unhealthful high Omega-6 and low Omega 3 ratio , augmentation of Omega-3 seems advisable . Further , food grown today contains less Omega-3 and more Omega-6 fatty acids than in the past . Shifting the diet to weight Omega-3 more heavily may counter the development of a range of inflammation-based illnesses , including arthritis , heart disease , and cancer .
Role of long-chain Omega-3 Fatty Acids in dogs Cognition and healthy aging Antioxidant enriched diets containing a small amount of DHA have been found to be potentially beneficial in dogs .
In addition , a few reports have found associations between DHA and seizure treatment and possible aggression in dogs .
Development of puppies Puppies appear to synthesize DHA from α-LA in early life when still suckling , but lose this ability after weaning . Recent studies have shown that even prior to weaning , the efficiency of conversion os very low , so very large doses of α-LA are necessary to see a significant increase in tissue DHA levels . Puppies with proper Omega -3 supplementation before and after weaning , had better visual and cognitive function than those without , which were , however , still considered normal .
Skin conditions : Canine Atopic Dermatitis ( CAD ) Omega-3 fatty acids favor the production of less inflammatory eicosanoids as well as stabilize the epidermal lipid barrier . PUFAs are insufficient as a sole therapy for canine atopic dermatitis . Lower omega 6:3 ratios are more effective . A recent publication used a supplement with a ratio of Omega 3:6 of 1:3.75 to evaluate its cyclosporine sparing effects and found that the dose of Atopica ® could decrease from 4.1 mg to 2.6mg / kg and the median pruritis score decreased significantly in the patients receiving supplementation . ( Müller MR et al Vet Journal 2016 ( 210 ) 77-81 )
Hyperlipidaemia Management of primary hyperlipidemia is achieved by ultra-low fat diets with or without the administration of lipid-lowering drugs such as Omega-3 fatty acids , fibrates , niacin and statins . Synthesis of triglycerides and VLDL in the liver is decreased by Omega-3 acids .
Congestive heart failure Omega-3 fatty acids are known to decrease the production of inflammatory cytokines , TNF and IL-1 , which are elevated in CHF . Fish oil supplementation reduces cachexia and increases appetite is some dogs with CHF .
Osteoarthritis Arachidonic acid ( AA ) forms the pro-inflammatory series -2 eicosanoids , whereas EPA is converted to the less inflammatory series-3 eicosanoids . By altering the amounts of Omega-3 and Omega- 6 in the diets production of less inflammatory eicosanoids is favored . GLA is an Omega-6 fatty acid which also converts into less inflammatory eicosanoids , however , Omega-3 fatty acids seem to provide superior results .
Oncology EPA and DHA can have a profoundly suppressing effect on cancer cachexia .
Kidney failure : Remnant kidney studies in dogs have reported that long chain Omega- 3-fatty acid supplementation reduces inflammation , lowers systemic arterial pressures , alters plasma lipid concentrations , and preserves renal function .
Key : LA – linoleic acid GLA / γ-LA – gamma linoleic acid DHA - docosapentaenoic acid
ALA / α-LA – alpha linoleic acid EPA - eicosapentaenoic acid AA – arachidonic acid
REFERENCE : Bauer , John E , 2016 The essential nature of dietary omega-3 fatty acids in dogs . Journal of the American Veterinary Medical Association 249:1267 vet360
Issue 02 | APRIL 2017 | 34