The influence of dietary linseed on alpha-linolenic acid and its longer-chain n-3 metabolites content in pork and back fatms.

This work aimed to study 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 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 α-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 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.