Changes in the Fatty Acid Composition and Antioxidant Properties in Mono-Protein Commercial Dry Dog Foods During Storage

Dogs are the most popular companion animals in Europe, with an estimated population of 106 million in households. Commercial dry dog foods are formulated to meet specific nutritional requirements and ensure safety during storage, often through the addition of preservatives to extend shelf life. This pilot study investigated the antioxidant properties and changes in the fatty acid composition during storage in six mono-protein (containing only one source of animal protein) dry dog foods. These findings might contribute to a better understanding of the long-term nutritional stability of commercial dry dog foods and their potential implications for canine health. Changes in chemical composition, fatty acid profile, and antioxidant properties were analyzed immediately after opening the packages and after 3 and 6 months of storage. Significant alterations (<i>p</i> ≤ 0.05) were observed in nutrient content, particularly crude fat level (decrease from 18.37 g/100 g DM to 16.87 g/100 g DM after 6 months), as well as saturated and unsaturated fatty acids. Antioxidant properties, assessed via DPPH, FRAP, and ABTS, fluctuated over the storage period. Principal component analysis identified distinct patterns in nutrient and antioxidant profiles, highlighting the impact of storage duration and initial food composition on the stability of nutritional and antioxidant properties. The research demonstrates that the quality of commercial dry dog foods, particularly regarding oxidative stability and antioxidant properties, is subject to change over time after opening. The chemical composition of the foods was influenced by storage duration, with significant decreases in crude fat and variations in fatty acid profiles.