Determining the metabolizable energy (ME) content and nutrient digestibility of ultra-high protein, low oligosaccharide soybean meal for growing pigs

Soybean meal (SBM) is used as the primary protein source in swine diets and a novel variety with less antinutritional factors has been developed from Ultra-High Protein, Low-Oligosaccharide (UHP-LO) soybeans. The experimental objective was to determine nutrient digestibility, digestible energy (DE), and metabolizable energy (ME) content of diets containing either conventional soybean meal (SBM-CONV) or UHP-LO SBM fed to growing pigs. A total of 30 barrows were selected (body weight = 43.0 ± 1.5 kg) and randomly assigned to one of three dietary treatments: a corn control diet containing no SBM, a diet containing 28% SBM-CONV, or a diet containing 28% UHP-LO SBM. Pigs were housed individually in metabolism crates throughout the 10-d dietary adaptation period and 96-h total collection period of feces and urine. Pigs were limit-fed at 80% predicted ad-libitum intake in two equal meals daily. Feces and urine were collected for total energy balance with the marker-to-marker method using TiO2 and to calculate apparent total tract digestibility (ATTD) of nutrients. UHP-LO SBM increased ATTD of dry matter (DM) by 1.52% (P = 0.012) and gross energy by 1.04% (P < 0.001), but did not alter ATTD of crude protein (P ≥ 0.10) compared with SBM-CONV. The UHP-LO SBM diet had greater (P < 0.001) DE and ME (kcal/kg, DM basis) compared to the corn control diet and the SBM-CONV diet, indicating more bioavailable energy per unit of DM in UHP-LO. However, in comparison to the corn control diet, DE:ME decreased by 2.21% in the SBM-CONV diet and by 2.95% in the UHP-LO diet, indicating increased urinary energy losses with the high protein ingredient. On an individual ingredient basis, the calculated DE and ME of UHP-LO SBM were 3,723 and 3,507 kcal/kg, representing increases of 2.9% and 2.8% over SBM-CONV, respectively (P < 0.001). Overall, results indicate that dietary inclusion of UHP-LO provided increased energy utilization efficiency in growing pigs in the form of additional DE and ME compared to conventional SBM.