Age-related changes in intramuscular and subcutaneous fat content and fatty acid composition in growing pigs using longitudinal data

The evolution of intramuscular fat (IMF) and subcutaneous backfat (SB) content and fatty acid composition with age was investigated. A repeated sampling scheme (n = 517) for longissimus dorsi (LM) and SB specimens was performed from 160 to 220 days on 216 purebred Duroc barrows. IMF content increased linearly with age at a rate of 0.05%/day, with major compositional changes occurring in C18:1 and C18.2, which increased and decreased by around 4%, respectively. Backfat thickness increase rate declined with age, showing similar compositional changes to IMF but halved in magnitude. Fat content itself also influenced fat composition. At a fixed age, both saturated (SFA) (C16:0) and monounsaturated (MUFA) (C18:1) increased with IMF but only SFA (C16:0 and C18:0) with SB. Aging mostly affected MUFA while fatness SFA. A delay in age at slaughter will enhance IMF and C18:1 in relation to overall fatness but at expense of decreasing body and loin growth rate.