Effect of rearing system on muscle lipids of gilts and castrated male pigs

The objective of this study was to investigate the polar and neutral lipid fatty acid composition of pig muscle as influenced by rearing conditions an d sex. A total of 120 Hampshire crossbreeds were divided in two groups, one reared free-range in a strip grazing fashion and one reared indoors in a l arge pen (120 m(2)). Free-range rearing produced a more unsaturated fatty a cid composition (M. biceps femoris) in the neutral lipids, although the eff ect was small. In the polar lipids the effect of rearing condition was sex dependent. In the muscle of free-range gilts, there: was a higher level of C18:2 n-6, compared with indoor gilts, indoor castrates, and free-range cas trates. Moreover, muscle of gilts irrespective of rearing condition, had a higher level of the C greater than or equal to 20 polyunsaturated fatty aci ds in the polar lipids (16.75 and 14.60, respectively). Thus, we suggest th at the difference between castrates and gilts with respect to fatty acid co mposition in the polar lipids, might be affected by rearing condition. (C) 2001 Published by Elsevier Science Ltd.