The influence of dietary linseed on alpha-linolenic acid and its longer-chain n-3 metabolites content in pork and back fat/Utjecaj hranidbe lanom na sadrzaj alfa-linolenske kiseline i njenih dugolancanih n-3 metabolita u svinjskom mesu i lednoj slanini

The aim of this study was to examine the influence of dietary linseed on fatty acid profile and lipid oxidation in pig muscle (m. longissimus dorsi) and back fat. Sixty PIC fatteners were equally allotted to dietary treatments at an initial live weight of about 27 kg and fed for 90 days with a control or a linseed diet (3% linseed, 105 mg/ kg of a-tocopheryl acetate). Growth performance, carcass traits and meat quality were not affected by feeding linseed to any significant extent. No differences were found in the proportion of saturated, monounsaturated and polyunsaturated fatty acids of muscle or back fat between diets. However, both muscle and back fat from the linseed diet had a significantly higher n-3 and polyunsaturated fatty acid proportion (%), including C18:3n-3, C20:5n-3 and C22:6n-3, and a lower n-6/n-3 ratio compared with the control diet (4.3 vs.1.3, 1.9 vs. 0.44, 0.76 vs. 0.14, 0.17 vs. 0.12, and 4.6 vs. 17.4 ratio in muscle, and 5.3 vs.1.2, 4.3 vs. 0.87, 0.07 vs. 0.02, 0.04 vs. 0.02, and 2.8 vs. 15.8 ratio in back fat, respectively). Lipid oxidation, measured as 2-thiobarbituric acid-reactive substances, was similar in muscle when feeding both diets after cold storage up to 6 days, but more developed in back fat when feeding the linseed diet after 3 days of cold storage. This study confirmed that continuous feeding of pigs with a relatively low level of linseed can produce a pork meat enhanced with both C18:3n-3 and pre-formed C20-22n-3, and with nutritionally optimized n-6/n-3 ratios, without adverse effects on fatteners' performances, carcass traits and meat quality. Key words: pork, back fat, n-3 fatty acids, lipid oxidation, linseed Cilj rada bio je istraziti utjecaj dodatka lana u hranidbi svinja na sastav masnih kiselina i oksidaciju lipida u mesu (m. longissimus dorsi) i lednoj slanini. Sezdeset PIC nazimica i muskih kastrata pocetne mase oko 27 kg ravnomjerno je bilo podijeljeno u dvije skupine i hranjeno tijekom tova (90 dana) uobicajenom krmnom smjesom ili krmnom smjesom s 3% sjemena lana i 105 mg/kg [alpha]-tokoferol acetata. Hranidba lanom nije znacajnije utjecala na dnevni prirast, svojstva trupa i kakvocu mesa tovljenika. Izmecu skupina nisu postojale znacajnije razlike u sastavu zasi?enih, jednostruko nezasicenih ili visestruko nezasicenih masnih kiselina mesa ili ledne slanine. Medutim, pri hranidbi lanom u odnosu na uobicajenu hranidbu utvrden je znacajno visi udio (%) n-3 masnih kiselina, ukljucujuci C18:3n-3, C20:5n-3 i C