A nutritional model of fatty acid composition in the growing-finishing pig

Abstract

A dynamic model was developed to study the effects of diet composition on lipid deposition and fatty acid (FA) composition in pigs. A basic model of protein and lipid deposition was used. Deposited lipids originate from dietary FA and de novo synthesized FA. It is hypothesised that 0.85 of absorbed FA are deposited as-is, and that the composition of de novo synthesized FA was constant throughout growth. Sensitivity analysis indicated that feed intake, efficacy of dietary FA storage and partitioning of de novo synthesized FA had a major impact on FA composition. Evaluation of the model indicated that predictions of protein, lipid, and backfat mass were insufficient, mainly due to the assumption of a constant ratio of lipid to protein mass in the basic growth model. Nevertheless, predictions of the FA composition of backfat and perinephric tissue were reasonable. Differences in FA composition between different tissues could only partly be explained by differences in tissue development. Development of this conceptually simple model was hampered by the limited availability of experimental data on the contribution of dietary lipids to purposes other than lipid deposition, the composition of de novo synthesized FA and the partitioning of FA between different depot sites.