Fatty Acid Analysis and Stability of Selected Edible Oils Used in Homemade Pet Diets

Abstract

Background: Edible oils often are included in recipes for home-prepared pet diets to supply essential fatty acids, but there may be discrepancies between database values and oil profiles. Furthermore, storage time and conditions influence quality. Hypothesis/Objectives: Determine the fatty acid profiles of commonly used oils and characterize fatty acid oxidation under recommended storage conditions. Samples: Fourteen products were purchased and stored according to label instructions, representing 2 brands each of walnut, corn, canola, and flaxseed oils, and 3 each of safflower and sunflower oils. Methods: Samples were collected at baseline and at 6 and 12 months and stored at −80°C until analysis. Aliquots were analyzed for fatty acid profile at baseline and 12 months, and at all 3 timepoints for free fatty acidity, peroxide value, and induction time. Results: Linoleic acid concentrations exceeded the United States Department of Agriculture (USDA) Food and Nutrient Database for Dietary Studies (FNDDS) values except for 2/3 sunflower and 1/3 safflower oil samples. Peroxide value was static for 3/14 products and significantly increased at 6 or 12 months for 11/14 products. Induction time was static for 2/14 products and significantly decreased at 6 or 12 months for 12/14 products. Conclusions and Clinical Importance: Sunflower and safflower oils are not reliable sources of linoleic acid. Cold storage appeared to better maintain oil quality. Oils for home-prepared pet foods should be carefully selected to ensure nutritional adequacy and refrigerated to maintain quality, especially those high in polyunsaturated fatty acids, high omega-6:omega-3 ratios, or both.