Digestibility and Energetic Utilization of Lipids by Pigs

205 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2008.Five experiments were conducted to investigate the digestibility and energetic utilization of lipids by pigs. In Exp. 1, the effect of the form of dietary fat (liquid or intact fat form) and the concentration of dietary NDF on ileal and total tract endogenous losses of fat (ELF), on true ileal (TID) and true total tract digestibility (TTTD) of fat by growing pigs were determined. Results showed the estimates of ELF were lower (P < 0.05) for liquid fat than for intact fat at the end of the ileum and over the entire intestinal tract. The TID (93.8%) and TTTD (94.2%) of liquid fat were greater (P < 0.05) than the TID (78.6%) and TTTD (84.1%) of intact fat. Increasing dietary NDF did not influence the TID and TTTD of fat. In Exp. 2, the operational NE requirement for maintenance (ONE m) for growing and finishing pigs was measured at 3 experimental locations. The experiment was conducted at the University of Illinois (UIUC), the University of Missouri (MO), and the Prairie Swine Centre (PSC). The ONEm was greater (P < 0.01) for finishing pigs (219, 123, and 270 kcal/kg BW0.6&middot;d-1 at UIUC, MO, and PSC) than for growing pigs (128, 115, and 78 kcal/kg BW0.6&middot;d -1 at UIUC, MO, and PSC). The ONEm differed (P &le; 0.05) among locations. The interaction between the stage of growth and location for ONEm was significant (P < 0.01). In Exp. 3, the effect of sources or levels of dietary lipids on the NE of diets and lipids fed to growing and finishing pigs was measured. Soybean oil (SBO) and choice white grease (CWG) were used. The NE of diets increased (linear, P < 0.01) with increasing level of SBO (2,032, 2,186, and 2,292 kcal/kg for diets containing 0, 5, or 10% SBO). The NE of the diet containing 10% CWG (2,431 kcal/kg) was greater ( P < 0.05) than the NE of the diet containing 10% SBO. The NE of SBO included at 5% (5,102 kcal/kg) was not different from the NE of SBO included at 10% (4,619 kcal/kg), but the NE of CWG (6,017 kcal/kg) was greater ( P < 0.05) than the NE of SBO. In Exp. 4, the effect of dietary lipids on the NE of corn in growing and finishing pigs was measured. The NE of corn in the diet containing supplemental lipids (2,053kcal/kg) was not different from the NE of corn in the diet containing no supplemental lipids (2,197 kcal/kg). The NE of corn was greater (P < 0.05) for finishing pigs (2,607 kcal/kg) than for growing pigs (1,643 kcal/kg). In Exp. 5, the objective for this study was to compare NE values for diets and ingredients measured in North America (NENA) and values predicted from the French (NEINRA), the Dutch (NECVB), and the Danish (PPE) energy systems. Values for NENA of most diets fed to growing pigs were lower (P < 0.05) than values predicted from NEINRA and NECVB. However, values for NENA of most diets fed to finishing pigs were more comparable with values predicted from NEINRA and NECVB. The measured NE NA values for all ingredients fed to growing pigs were also lower ( P < 0.05) than values predicted from NEINRA and NE CVB. For both growing and finishing pigs, the measured NENA values for SBO and CWG were lower (P < 0.01) than values predicted from NEINRA and NECVB. The values for NENA of SBO and CWG were also numerically lower than the PPE values of SBO and CWG. In conclusion, liquid fat induces a lower ELF and has a greater true digestibility than intact fat at the end of the ileum and over the entire intestinal tract. Experimental location interacts with stage of growth on ONEm, indicating that different values for ONEm should be used for calculating the NE of diets and ingredients measured at different stage of growth and experiment locations. The NE of lipids is not affected by the level of dietary lipids but the NE of lipid containing more saturated fatty acids may be greater than the NE of lipid containing less saturated fatty acids. The NE of corn is not influenced by the absence or presence of supplemental lipids in the diet. The NE of corn for finishing pigs is greater than for growing pigs. European energy systems better predict energy values for diets and ingredients fed to finishing pigs than those fed to growing pigs. European energy systems tend to predict greater energy values for lipids than measured energy values in North America.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD