## 1 Introduction  
Nutrition is one of the most important factors influencing the fat content and composition of fatty acids in meat. Fatty acids from the diet are originally absorbed from the intestine and are then introduced into the tissues. Polyunsaturated fatty acids (PUFA) cannot be synthesized _in situ_; therefore, their concentration in tissues quickly responds to changes in PUFA content in the diet. Saturated (SFA) and monounsaturated fatty acids (MUFA) are synthesized _de novo_, and their concentration is less susceptible to the influence of feeding type [1, 2, 3]. As pigs grow, fat is synthesized sequentially, initially in the subcutaneous fat tissues, then in the intermuscular fat tissues, and finally in the intramuscular fat tissues. The casing of the carcass is subcutaneous fat that constitutes 65% of the total carcass fat tissue, followed by intermuscular fat (30%) and internal fat (about 5%) [4]. The fatty acid composition is the main factor taken into account when determining the nutritional value of meat. The composition of fatty acids affects the quality of meat, especially tissue elasticity, freshness, and taste [5]. Fatty acids are characterized by very different melting points,so any changes in the composition of fatty acids can influence the firmness and softness of the fat in the meat. These changes occur mainly in subcutaneous and intramuscular fat, but also can take place in intermuscular fat [6; 7]. The composition of fatty acids can be changed during animal breeding by introducing appropriate changes in the diet. As consequences of diet modifications, it is possible to reduce the share of SFA and increase the share of PUFA, e.g., long-chain n-3 fatty acids with a positive impact on the nutritional value of meat [7; 8; 9]. It was shown that the addition of oleic acid belonging to MUFA to the diet reduced the level of cholesterol in human blood plasma [10]. The level of n-3 PUFA can be increased by enriching feed with linseed. It was proven, that the use of feed with the addition of linseed led to an increase in the content of n-3 fatty acids in pork fat [11]. [PERSON] et al. [12] found that the addition of 4% and 8% of linseed to the diet of fattening pigs changed the composition of fatty acids, and caused an increase in the content of \(\alpha\)-linolenic acid. It was confirmed that sunflower oil can also be added to feed to improve the fatty acid profiles of fat. [PERSON] et al. [13] reported a positive effect of 5% sunflower oil supplementation on fatty acid profiles of pork fat by increasing the content of PUFA and reducing the content of saturated and monoenoic fatty acids. [PERSON] et al. [14] used a 5% addition of olive oil and linseed oil to feed to enrich the diet of pigs. There was a significant increase in the content of \(\alpha\)-linolenic acid in the fat of pigs fed linseed oil. [PERSON] et al. [15] examined the effect of feed with the addition of CLA diene on the fatty acid profile of bacon fat. They found that with the increased concentration of CLA in the diet, the content of MUFA decreased and the content of PUFA increased [15; 16]. [PERSON] et al. [17] also conducted studies on the incorporation of CLA in pig diets and confirmed that supplementation with CLA can positively affect the nutritional value of pork without changing its taste. Pork fat presence in products such as sausages and hams is considered to be beneficial as it ensures the right flavor and consistency. Pork fat is characterized by an unfavorable ratio of fatty acids from the \(n\)-6 to \(n\)-3 families, which significantly exceeds the recommended ratio of 4:1 [18]. Feed modifications can be useful in improving the fatty acid profile and quality of pork fat. Supplementation of the diet with properly selected oils makes it possible to reduce the content of SFA in favor of a greater share of MUFA and PUFA. Correct feeding management can be an effective way to improve pork quality by increasing the intramuscular fat content and improving the pork amino acid and fatty acid profiles in finishing pigs [19; 20; 21].