Properly-Processed ExPress® Soy Meal Maintains High Digestibility & Greater Metabolizable Energy
We invented the high shear dry extrusion process, and have sought to optimize it over the years through research – much of which has been detailed here on the blog. Previously, in a past blog I discussed the advantages of using this method and how to process dry extruded soybeans, but today I will discuss the benefits of processing ExPress® soybean meal compared to solvent extracted.
In the early 1990’s, Insta-Pro Intl released a horizontal, mechanical oil press to be used immediately after the extruder for crude oil isolation. Interestingly, this chemical-free extraction process produces oil with different, beneficial properties when compared to solvent-extracted soy oil.
The result of including the oil press after the extruder is that a unique soy meal is produced – one that has highly-digestible amino acids and a greater metabolizable energy content, due to a residual oil content in the meal of 6-8%, and also because the dry extrusion process liberates more available energy.
I recently sent some ExPress® soy meal to the laboratory for determination of amino acid digestibilities and metabolizable energy using broiler chickens. Nutritionists and formulators rely on these values when assembling diets. Values for samples of commodity, solvent-extracted soybean meal, which were also recently analyzed, are shown for comparison.
| Digestible AA supply and % digestibility | ExPress® soy meal | Solvent-extracted soybean meal |
| Digestible lysine | 2.54 (88.7%) | 2.68 (87.5%) |
| Digestible methionine | 0.54 (90.6%) | 0.62 (91.2%) |
| Digestible cysteine | 0.48 (83.4%) | 0.50 (77.8%) |
| Digestible threonine | 1.44 (87.9%) | 1.61 (85.9%) |
| Digestible tryptophan | 0.66 (97.1%) | 0.71 (96.1%) |
| True metabolizable energy, nitrogen corrected (kcal/kg DM) | 3385 | 2796 |
| Dry matter (%) | 96.6 | 89.1 |
Several things are apparent. Overall, ExPress® soy meal is more digestible than solvent-extracted soybean meal. However, it’s important to remember that this is only true when extrusion is conducted at the proper temperature. Quality controls, such as monitoring temperature during runs, are crucial, and allow ExPress® meal to stand out from other ingredients which are more variable (see figure 3).
The residual oil and processing benefits associated with ExPress® meal result in a higher metabolizable energy value – typically this means that an additional energy source, such as AV blends or spent oils, is not required.
I would be happy to discuss the use of properly-processed ExPress® soy meal in a variety of formulations. Please contact myself, Dr. Dave Albin, for more information.
