Modulation of Pork Fatty Acid Composition Through the Inclusion of Stearic Acid and Palm Oil in Growing–Finishing Pigs Diet

This study aims to evaluate the effect of stearic acid (SA) and palm oil (PO) on growth performance, carcass characteristics, and fatty acid composition in pork of growing-finishing pigs. A total of 150 pigs were assigned to three dietary treatments for 12 weeks: control (CON; basal diet), SA (CON + 0.50% SA), and PO (CON + 2% PO), with 10 replicates of 5 pigs/pen. Growth performance, backfat thickness, carcass weight, and meat quality were not significantly influenced by dietary treatments (<i>p</i> > 0.05). However, fatty acid (FA) analysis revealed that pigs fed the SA diet led to a consistent increase in SA (C18:0) content across pork belly fat, belly lean, and loin lean tissues (<i>p</i> < 0.05), resulting in significantly higher total saturated fatty acid levels and lower total unsaturated fatty acid concentrations. In contrast, the PO group showed increased monounsaturated fatty acids (MUFA), particularly oleic acid (C18:1c), and improved the MUFA/SFA ratio (<i>p</i> < 0.05) in all samples. Although polyunsaturated fatty acid (PUFA) content and the ω-6:ω-3 ratio were not significantly affected by treatments (<i>p</i> > 0.05), the PUFA/SFA ratio tended to be higher in the PO group, especially in pork loin lean (<i>p</i> = 0.085). The iodine value was significantly reduced in the SA group across all tissue types, confirming a more saturated lipid profile (<i>p</i> < 0.05). In summary, the SA and PO treated groups had no impact on growth performance or meat quality traits, but they markedly altered the fatty acid composition of pork. SA promoted a firmer, more saturated fat profile, potentially beneficial for processing traits but less favorable nutritionally. Palm oil (PO), on the other hand, supported a more unsaturated fat profile with improved nutritional attributes. These findings provide practical insights into swine diet formulation aimed at optimizing pork quality based on specific processing or health-oriented goals.