Soybean contains various non-nutritive compounds such as inositol phosphates, saponins, protease inhibitors, isoflavones, lectins, oligosaccharides and tannins, which reduce its nutritional value and hinder or inhibit the uptake of nutrients, producing adverse physiological and biochemical effects in animals when reaching certain concentration in the gut of the animals.
Protease inhibitors block the catalytic activity of normal digestive enzymes, such as serine-proteases (trypsin and chymotrypsin) characteristic of the gastrointestinal tract of birds, by forming stable complexes. These protein inhibitors are generally called Trypsin Inhibitors (TI). High intake of these TI via the diet consequently causes pancreatic hypertrophy/hyperplasia as compensation of the organ to secret enough digestive enzymes in response to the higher demand. As a result of an increased loss of endogenous protease, the digestibility of feed proteins and amino acids (AA) in the intestinal tract is also decreased: it has been demonstrated that the more TI the soy source contains, the lower the apparent ileal amino acid digestibility (AIAAD). This affects the nitrogen balance and gut viscosity in the gut which leads to an increased intestinal inflammation and incidence of leaky gut, ultimately conducting to different digestive disorders such as subclinical necrotic enteritis. Therefore, if these TI are not handled accurately, growth and feed efficiency of the bird will be compromised . Therefore, TI analysis of any soybean source purchased can be considered as a reliable in vitro predictor of the in vivo efficacy of such soybean source.
Considering variable levels of TI can remain in SBM, despite heat treatment, applying an efficient nutritional tool to reduce any residual TI in the intestinal tract, can be a valuable strategy to consider. CIBENZA® EP150 (Novus Int., Inc.) is a unique feed additive preparation containing a serine endoprotease with spores of its producing organism B. licheniformis (EU identification number 4d12). In vitro research done by the University of Sidney in Australia proved, when incubating purified Bowman-Birk and Kunitz factors, the 2 most common trypsin inhibitors in soy, with CIBENZA® EP150 for 2 hours at 37°C, both were destroyed at a 1:1 substrate to enzyme ratio. Other soy allergenic proteins, such as glycinin and β-conglycinin, could also strongly be hydrolyzed following the use of this additive. An in-vivo study published recently showed that when feeding broilers a diet in which 25% of the SBM was replaced by full fat extracted soybean (FFESB) with high TI content, CIBENZA® EP150 significantly minimized the impact on pancreas weight and AIAAD, allowing to achieve similar results as a corn SBM diet without FFESB6 (Fig.3,4).