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Fatty acid (FA) content in the carcass is influenced by their intake with diet and synthesis and metabolism in animal tissues and organs. Diet supplementation with fat is commonly used in pig nutrition. This causes changes in lipogenic activity of tissues/organs and results in higher fatness of carcass or muscles. The aim of the study was to determine the influence of different FA sources (linseed oil - PUFA n-6 and n-3, rapeseed oil - MUFA, tallow - SFA and fish oil - PUFA n-3) on content of single FA and activity of the selected enzymes (Δ9- and Δ4-desaturases, and elongase) in liver and subcutaneous fat, as main sites of synthesis and metabolism of FA. The obtained results may correct the values of nutritive requirements for pigs and improve the quality and health-promoting properties of pork. Four iso-energetic and iso-protein diets with different ratio of PUFA/SFA and C 18:2 n-6/C 18:3 n-3 obtained by changing part of the diet energy with plant oils (linseed or rapeseed), tallow or fish oil, were given to pigs from 60 to 105 kg body weight (BW). Pigs were slaughtered at 105 kg BW. The content of FA in the liver and subcutaneous fat per 100 g tissue and the activity (index) of Δ4- and Δ9-desaturase and elongase were determined. It was assumed that replacing part of energy of the diet with energy from different FA of dietary oils will differ activity of enzymes in the investigated tissues and allow to determine in which the metabolism is more intense.
Replacement of the part of the energy diets with energy from SFA, MUFA and PUFA, improved those feeds in the quantity/quality of these FA and increased their proportional content, however, more in the subcutaneous fat than in the liver. Kind of diet had no influence on weight and fat content of the investigated tissues (P > 0.05). Irrespective of the applied diet, a lower activity of Δ9-desaturase but higher activity of Δ4-desaturase and index of elongation were detected in the liver rather than in the subcutaneous fat (P < 0.05).
Results showed that they yield of elongation of the carbon chain of FA and transformation of long-chain FA is higher in the liver, however stronger transformations of SFA and MUFA take place in the subcutaneous fat.
G Skiba, E Poawska, S Raj, D Weremko, M Czauderna and M Wojtasik, 2011. The influence of dietary fatty acids on their metabolism in liver and subcutaneous fat in growing pigs. Journal of Animal and Feed Sciences, 20: 379-388.
