Lipid digestibility and energy content of distillers' corn oil in swine and poultry

Two experiments were conducted to determine the DE and ME and apparent total tract digestibility of ether extract of 3 distillers’ corn oil (DCO; 4.9, 12.8, or 13.9% free fatty acids [FFA]) samplescompared with a sample of refined corn oil (CO; 0.04% FFA) and an industrially hydrolyzed high­FFA DCO (93.8% FFA) in young pigs and growing broilers. In Exp. 1, 54 barrows (initial age = 28 d) were fed a common diet for 7 d and then fed their allotted dietary treatment (either 100% basal diet or 1 of 5 test diets consisting of 90% basal diet plus 10% test lipid) for the next 7 d in group pens (9 pigs/pen). For the next 10 d, pigs were moved to individual metabolism crates for continued diet and crate adaptation and to a twice­daily feeding regimen. Pigs remained on their respective diets for a 4­d total fecal and urine collection period. For Exp. 2, 567 male broilers were obtained from a commercial hatchery (1 d of age) and reared in grower battery cages that contained 9 chicks per cage. Broilers were fed a common corn–soybean meal starter diet from placement until the beginning of the trial (19 d of age). Birds were then randomly assigned to 1 of 6 dietary treatments (94% basal diet plus 6% dextrose or 94% basal diet plus 6% test lipid substituted for dextrose) on d 19 and were allowed an 8­d dietary acclimation period followed by a 48­h energy balance assay. In Exp. 1, the DCO sample with 12.8% FFA contained the lowest (P < 0.05) DE (8,036 kcal/kg) content compared with the 0.04% refined CO sample and the 4.9 or 93.8% FFA DCO samples (8,814, 8,828, and 8,921 kcal/kg, respectively), with the DCO source containing 13.9% FFA having intermediate DE (8,465 kcal/kg) content. The ME content of these lipid sources also differed among treatments (P < 0.01), following trends similar to their DE values, with no differences noted for ME as a percentage of DE (P > 0.35) content among the lipids evaluated. In Exp. 2, lipids containing 0.04, 4.9, 12.8, and 13.9% FFA had similar nitrogen corrected apparent ME (AMEn) values (8,072, 7,936, 8,036, and 7,694 respectively), except for the industrially hydrolyzed DCO sample containing 93.8% FFA, which contained 6,276 kcal/kg (P < 0.01). Using published prediction equations, the predicted DE of these lipids for swine was 3.5% greater than the values determined in Exp. 1 for all lipid sources, except for the DCO sample containing 93.8% FFA, which the predicted DE was underestimated. Likewise, the predicted AMEn of these lipids for broilers was 7.4% greater than the determined AMEn (Exp. 2) for all lipid sources.