Antinutrients Part I: Soy Test Kit Detects Urease Activity in Extruded Soy Products

Soybeans contain several antinutritional factors (ANFs). Ureases are common ANFs found in many plants and grains, but are at high levels in soybeans as described by Takeuchi. Most concerning, urease and trypsin inhibitor (TI) interfere with protein digestion when fed to animals. A recent study examined the correlation between dietary antinutrients and nutrient digestibility. As the antinutrient levels increased, both poultry and pigs suffered reduced protein digestibility and reduced feed intake.

Measuring the urease index (UI) is useful to determine if the soymeal was heated enough to deactivate ANFs. Recently, Insta-Pro® launched the Soy Test Kit that measures residual urease in extruded soy products as a marker of TI activity, which lets you know if the thermal cook process was adequate during the production of extruded soy proteins. As such, urease pH rise < 0.05 is the recommended quality levels by Insta-Pro® International. However, UI measurement alone is not useful to determine if the heating process was excessive. If the thermal process is not well controlled, damage to the amino acids in the meal – lower amino acid digestibility in the animal – can occur.

TI activity, TIU/mg TIUa Lysine Digesibility
Mean Range
Raw Soybeans 91.30 70.5 – 112 36%
SBM – Commodity Hi-Proc 6.21 3.60 – 11.8 88%
ExPress® Soymealb 4.50 2.6 – 10.0 89%
TIUa = As published by Woyengo et al. 2017; Soymealb = Crowe et al. 2001; Parsons et al. 2016; Hi-Proc = Parsons et al. 2016

High-shear dry extrusion has been optimized to produce highly-digestible extruded soy ingredients. Insta-Pro provides a total system solution and nutritional advantages for quality soy meal. When the recommended extrusion parameters are implemented, the resulting products have low antinutrient content and superior digestibility compared to commodity soy products, as demonstrated above. Furthermore, low TI and urease levels correlate to improved amino acid along with energy digestibility.

In summary, testing your soybean meal for deactivation of ANFs is critically important, but only half the story.  You still need a process that maximizes amino acid digestibility.  You can get both from Insta-Pro. Consult with an Insta-Pro representative today to learn more about the Soy Test Kit and to learn more about the university proven results of ExPress® soybean meal.

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