In vitro evaluation of nonstarch polysaccharide digestibility of feed ingredients by enzymes

Some of the commonly used feed ingredients for poultry (corn, sorghum, finger millet, deoiled ricebran, soybean meal, peanut meal, sunflower meal, and rapeseed meal) were screened for pentosans, cellulose, pectin, and total nonstarch polysaccharides. The ingredient in vitro digestibilities by enzymes were evaluated. Cereal samples screened contained mainly pentosans. Pectin content was rich in oilseed meals. Sunflower meal, soybean meal, deoiled rice bran, and a broiler starter diet were subjected to a two-stage in vitro digestion assay with three different enzyme mixtures viz., Enzyme-I (xylanase + cellulase from Trichoderma viridae), Enzyme-II (xylanase + cellulase + beta-glucanase from Huminicola insolens), and Enzyme-III (xylanase + cellulase + pectinase + beta-glucanase from Aspergillus aculeatus) by incubating 0.1 g of the sample with 3 mL of a pepsin-HCl mixture (2,000 U pepsin/mL of 0.1N HCl) for 45 min to simulate the peptic phase of bird digestion. A pancreatin-NaHCO3 mixture (2 mg pancreatin/mL of 1 M NaHCO3) was used for 2 h at 40 C to simulate the pancreatic phase. Digestibility was assessed by measuring the relative viscosity of the digesta supernatent and the total sugars released. Enzyme-I produced the least relative viscosity and highest total sugars in sunflower meal, deoiled rice bran, and broiler starter diet, whereas Enzyme-III was very effective in soybean meal subjected to in vitro digestion. The assay was a convenient and rapid method of screening for effective and stable enzymes.