Comparison Between Two Different Levels of Replacement of Free-range Rearing by an Oleic Acid and α-tocopherol Enriched Diet on the Quality of Fresh Meat from Iberian X Duroc (50%) Pigs.

The aim of this work was to study the effect of two types of pig feeding systems (known as recebo) on fatty acid composition, tocopherols contents and susceptibility to lipid oxidation in muscle. A total of 26 lberian × Duroc (50%) barrows were divided into two groups (named as short replacement (SR) and long replacement (LR) groups) according to length of replacement of Free-range rearing (based on acorn and pasture) by an oleic acid and α-tocopherol (200 mg/kg) enriched concentrate feed (SR group: 67 days in free-range rearing and finished during 20 days with concentrate diet; LR: 55 days in Free-range rearing. finished 50 days with concentrate). No differences were found in chemical composition and colour of Gluteo biceps muscle between the two management systems, except for α-tocopherol content, which showed higher content (p < 0.001) in LR pigs than in SR pigs. The fatty acid composition of subcutaneous fat was slightly affected by feeding system. Total intramuscular and neutral lipids from Gluteo biceps muscle presented a higher proportion of C18:1 n - 9 (p < 0.05) in SR than in LR pigs; however, no differences were found in total saturated (SFA), monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA). Composition of polar Lipids revealed a higher proportion of MUFA and lower of total n - 3 fatty acids in LR than in SR pigs. Feeding regime significantly affected susceptibility of muscle to iron-ascorbate-induced peroxidation. Muscles from pigs reared on SR system showing higher levels (P<0.05) of MDA after 50 and 100 min of incubation. These results indicate that the content of oleic acid and α-tocopherol in muscle depends on the levels of both provided by dietary means, more than the practised handling. [ABSTRACT FROM AUTHOR]