# Lipid Fraction Properties of Homemade Raw Cat Foods and Selected Commercial Cat Foods
## 1 Introduction  
Most cat owners feed their pets with commercial cat food because it is convenient and economical; however, over the last decade, the use of alternative diets, such as BARF (bone and raw food/biologically appropriate raw food), other raw meat-based diets, home-cooked diets and whole prey model diets have become more popular [1, 2, 3]. These raw food diets are often used by owners who have concerns about the wholesomeness and nutritional value of the ingredients used in commercial pet food. However, formulating a complete and balanced pet food needs knowledge about the nutritional requirements of cats. In the literature, it is hard to find studies in which the nutrient composition of raw meat-based foods was examined by analytical techniques. It was only found that [PERSON] et al. [4, 5] and [PERSON] et al. [6] examined the chemical composition of several raw meat-based diets for cats as well as the digestibility of these foods in cats and kittens. Most publications related to raw meat-based food for cats usually only present theoretical considerations on the impact of this type of food on the health of cats, along with its advantages and disadvantages [2, 7, 8, 9, 10]. [PERSON] et al. [10] performed computerized assessments of several types of homemade cat recipes, including some raw recipes, using the balancing software (_Balance IT_) available online. Laboratory analysis could confirm the correctness of the computerized assessment, but unfortunately, they were not performed. To the best of our knowledge, this is the first study dealing with the experimental research of the self-prepared cat food lipid fraction. The software used to compose thediets was _BARFny kalkulator_--a nutrition-balancing software, similar to the _Balance IT_ used by [PERSON] et al. [10]. Fat typically provides most of the energy, increases the palatability of food [11; 12], is a carrier of fat-soluble vitamins and is a source of essential fatty acids (EFA) for cats, which are recognized as obligate carnivores. The EFA for cats are linoleic (LA), alpha-linolenic (ALA) and arachidonic (AA) acids. The conditionally EFA are eicosapentaenoic (EPA) and docosahexaenoicenoic (DHA) acids. They are responsible, among others, for skin and coat condition, kidney function and reproduction [13; 14; 15]. Triacylglycerlycerols (TAG) are the predominant component of most dietary fats and oils. Identification and quantitative analysis of the composition of TAG is the first step in evaluating the quality of fats when considering their nutritional effects [16]. The distribution of FA in TAG molecules is particularly important in the process of their digestion and absorption in the gastrointestinal tract. The rate of hydrolysis at the _sn_-2 position of TAG is very slow and the FA in the _sn_-2 position remain intact as 2-monoacylglycerols during digestion and absorption. FA located in the _sn_-1 and _sn_-3 positions are preferentially hydrolyzed, leaving a 2-monoacylglycerolscerol [17]. Free FA are long chain saturated if released; they form acid-calcium soaps that are insoluble in aqueous media at the pH of the intestine, which causes impaired absorption of both SFA and calcium [17; 18]. Calcium loss can affect Ca:P ratio in the diet, which can be associated with kidney damage in cats [19; 20]. One of the most important parameters in the characterization of fats and oils is oxidative stability. Lipid oxidation is a major challenge to pet food preservation [21]. It determines the final quality and nutritional properties of the food product because it is the main reaction responsible for their degradation [22]. In food chemistry, pressurized differential scanning calorimetry (PDSC) is a convenient, reproducible and fast method used to determine the oxidative stability of fats and oils [23; 24]. Moreover, it is a nonchemical method without the time-consuming processing of test samples and it requires a small amount of sample (a few milligrams) for analysis [25; 26].