Chemical Composition and Energy Value of Different Fat Sources for Growing Pigs

The chemical composition, digestibility and energy value of eight animal and vegetable fat batches was determined (animal fat, soya oil, palm oil, palm oil, palm oil mix and vegetable oil byproduct). To a basal diet, 5, 10, 15, 20, 25 or 30% dietary fat was added, and digestibility and balance experiments with each fat batch were carried out with three litters of six female pigs, weighing 50-75 kg. The digestibility was determined by multiple regression analysis. The content of HCl-extracted fat and the amount of gross energy was nearly equal for all the fat sources and as such not related to the variation in fatty acid composition or digestibility. Inclusion of soya oil, which is high in polyunsaturated fatty acids, enhanced protein digestibility, whereas inclusion of the other fat sources did not influence protein digestibility. A curvilinear function of fat digestibility (% of intake) to dietary fat concentration was found, thus reflecting the significance of the endogenous fat losses on the determined digestibility value. In contrast, the relationship of digested fat (g day