Digestibility of energy and caloric value in nursery pigs fed commercially available lipids

Measures Matter—Determining the True Nutri-Physiological Value of Feed Ingredients for Swine

“…Fortunately, there continues to be considerable interest in developing and using robust equations to accurately estimate DE, ME, and NE content of lipids based on chemical composition ( Table 8 ). However, although several equations have been developed for swine, their accuracy in predicting in vivo determined DE content is generally poor [ 141 , 144 , 150 ]. Kerr et al [ 150 ] determined the DE content of five sources of distillers corn oil (DCO) containing 0.04% to 93.8% FFA, and compared these values with predicted DE content using equations by Wiseman et al [ 151 ], which included FFA content and UFA to saturated fatty acid (SFA) ratio as the main variables ( Table 9 ).…”

“…Furthermore, the Powles et al [ 129 ] equation underestimated the negative effect of FFA content and was not accurate for estimating DE content of more saturated lipid sources that had a high proportion of fatty acids with chain lengths less than 16 carbons. In a subsequent study, Kerr et al [ 144 ] determined the DE content of 10 different fats and oils for 19 kg pigs ( Table 11 ), and reported values ranging from 8071 kcal/kg (tallow) to 9979 kcal/kg (soybean oil). However, when using the Powles et al [ 129 ] prediction equation to estimate DE content based on chemical composition of these lipids, and comparing predicted values with in vivo determined values, DE content was underestimated by 243 kcal/kg (tallow) to 2276 kcal/kg (coconut oil), except for fish oil, which was overestimated by 289 kcal/kg ( Table 11 ).…”

“…However, when using the Powles et al [ 129 ] prediction equation to estimate DE content based on chemical composition of these lipids, and comparing predicted values with in vivo determined values, DE content was underestimated by 243 kcal/kg (tallow) to 2276 kcal/kg (coconut oil), except for fish oil, which was overestimated by 289 kcal/kg ( Table 11 ). When Kerr et al [ 144 ] used the Kellner and Patience [ 141 ] DE prediction equations in a similar comparison, predicted DE content was also underestimated (440 to 967 kcal/kg), but generally to a lesser extent than the corresponding DE estimates derived from the Powles et al [ 129 ] equations, while the DE content of tallow was overestimated by 393 kcal/kg.…”

“…Third, energy prediction equations derived from various lipids with diverse fatty acid profiles are assumed to provide reasonably accurate predictions when compared with energy values directly determined from in vivo experiments. However, results from Kellner and Patience [ 141 ] and Kerr et al [ 144 ] have shown that this often does not occur. There may be at least two explanations for this.…”

“…Although prediction equations may reasonably estimate DE, ME, or NE content of lipid sources in an experiment from which they were derived [ 141 ], they may not result in accurate predictions when applied to lipid sources and composition not included in the original data set [ 144 ]. In addition, most energy prediction equations have been derived without considering the extent of oxidation of the lipids evaluated.…”