Deposition of dietary fatty acids, de novo synthesis and anatomical partitioning of fatty acids in finishing pigs

Predicting aspects of pork quality becomes increasingly important from both a nutritional and technological point of view. The aim of the present study was to provide quantitative information on the relation between nutrient intake and whole-body fatty acid (FA) deposition. This information is essential to develop mechanistic models predicting the FA content of tissues. A serial slaughter study was carried out in which thirty pigs were slaughtered between 90 and 150 kg. The diet included 15 g/kg soyabean oil and contained 44 g/kg fat. Only 0.31 and 0.40 of the digested n-6 and n-3 FA were deposited, respectively. Approximately one-third of the n-3 supply that was deposited resulted from the conversion of 18 : 3 to other metabolites (i.e. EPA, docosapentaenoic acid and DHA). This proportion was affected by the pig genotype. De novo-synthesised FA represented 0.86 of the total non-essential FA deposition, and its average composition corresponded to 0.017, 0.286, 0.025, 0.217 and 0.454 for 14: 0 16: 0, 16: 1. 18: 0 and 18: 1, respectively. Although the average whole-body FA composition was relatively constant during the finishing period, this was not so for the tissues. In the carcass (without backfat), the content of 18: 1 increased during the finishing period, whereas that of 16 : 0 and 18 : 0 decreased. Backfat captured a proportionally greater fraction of 18 : 2 than did the carcass or the residual tissues. In contrast, a proportionally greater fraction of the dietary 18 : 3 supply was deposited in the carcass compared to other tissues.