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

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.