Influence of soybean meal characteristics and feed enzyme technologies on nutrient utilization in pigs

Abstract

Soybean meal (SBM) is a common protein source in swine diets; however, SBM quality may be compromised by pauses or interruptions in thermal processing. In chapter 1, the objectives of the two studies were to determine the effects of startup SBM on standardized ileal digestibility (SID) of amino acids (AA) in grow-finishing pigs and to evaluate the effects of increasing startup SBM inclusion in nursery pig diets on growth performance, fecal dry matter (DM), and apparent total tract digestibility (ATTD) of crude protein (CP). Additionally, SBM contains an array of antinutritional factors; however, trypsin inhibitors specifically interfere with the digestion of protein. While thermal processing is utilized to minimize the effects of trypsin inhibitors, under processing may fail to inactivate trypsin inhibitors, while over processing may inactivate trypsin inhibitors, it may also reduce the availability of amino acids. In chapter 2, the objective was to evaluate the effects of exogenous protease on the SID of CP and AA in SBM sourced with differing trypsin inhibitor concentrations. Collectively, these studies demonstrated that the effects of pauses or interruptions in thermal processing may reduce the protein quality when fed to pigs but may also have age-specific effects in the early nursery phases. Additionally, the effect of protease supplementation may improve AA digestibility regardless of trypsin inhibitor concentration. Building on these findings, the effects of chapter 3 were to compare the effects of carbohydrase supplementation on the ATTD of nutrients, apparent metabolizable energy, and nitrogen retention in grow-finishing pigs fed corn and SBM-based diets. However, exogenous carbohydrase supplementation targeting NSP did not result in improved energy or nitrogen utilization in grow-finishing pigs, but did result in improvements of the ATTD of Ca.