## 1 Introduction  
Due to the close connection between the diet and human health, improving the quality of food is a research focus of many scientists. Good nutritional habits have a positive effect on human health, they allow to limit the incidence of most metabolic diseases. Unfortunately, the diet structure of most consumers does not meet the recommendations of dieticians and doctors. An estimated one-third of cancers are associated with diet [1]. Meat and meat products are the basic components of the human diet. Pork meat and its products provide 10-20% of energy in the diet, and despite the prevailing opinion about its adverse impact on human health (high content of fat and cholesterol, an inappropriate ratio between SFA and UFA) the consumption of this type of meat continues to grow. Therefore, it is advisable to look for possibilities to, e.g., changes in the proportion of fatty acids in tissue [2]. Health-related modifications consist of increasing the content of nutritionally desirable ingredients and reducing those that can have a negative impact on human health. The content of nutrients in adipose tissue and meat of the slaughter animals is conditioned by many factors, such as species, breed, age, sex, diet or husbandry conditions. It is possible to produce animal raw materials with a composition appropriate to current nutritional recommendations because the nutritional, health-related, sensory value of raw materials of animal origin can be shaped along the nutritional, pharmacological and/or genetic path. Experiments have demonstrated that pigs quickly and easily react to established breeding criteria. Nutrition is one of the most effective factors affecting the quality of pork meat and fat. Through the appropriately composed fodder (share of protein and metabolic energy, feed additives) and the right way of feeding, one can model the composition of fatty acids, the amount of cholesterol, vitamins and minerals in the raw pork. In recent years, research into the possibility of obtaining high nutritional value of pork has been intensified by modifying the feed, e.g., replacing some of the metabolic energy in fodder with unsaturated fatty acids, necessary for the prevention of cardiovascular diseases [3; 4; 5]. Fatty acids as a feed additive fulfill many functions. Among other functions, they increase the productivity of pigs, improve the use of fodder, affect the condition of animals and increase the nutritional value of the feed [6]. The addition of fat to fodder raises its cost, but the expenses incurred are balanced by its lower consumption, larger daily increments and shorter fatening times [2]. Through the targeted supplementation of feed compound with adjuncts rich in polyene fatty acids, it is possible to obtain a meat and fat raw material with the characteristics of functional foods. Polyunsaturated fatty acids--in particular from the n-3 family, ALA, DHA, EPA--can be classified as nutraceuticalals, i.e., biologically active substances with demonstrated pro-health effects. Hence, by enriching raw material with them, both meat and fat can be used in the prevention of cardiovascular diseases [7; 8; 9]. Vegetable oils are a good source of n-3 acids. When used as a component of monogastric animal diets, they increase the content of these acids in pork, with a decrease in saturated acid content. Studies carried out in recent years [10; 11; 12] confirm the possibility of modifying pig meat by using in fattening maize grains, rapeseed, linseed, sunflower or soybean oil. The application of the aforementioned feed additives resulted in a significant increase in PUFA content, particularly of the n-3 family. The ratio of acids in the n-6 and n-3 families also changes. Reducing the proportion between these acid has been confirmed to have health-promoting effects. However, the high degree of non-saturation of the raw material reduces the resistance of the tissue to the oxidation process.