胃蛋白酶-胰蛋白酶两步体外消化法评定豆粕粉碎粒度

Study on the Particle Sizes of Soybean Meals with Enzyme by a Pepsin-Trypsin in Two-Step Vitro Method

选用1.0、1.5、2.0、2.5和3.0 mm筛孔孔径的筛片粉碎得到粒度为432、505、637、717、805μm的豆粕,然后制成粉状配合饲料和颗粒饲料。对豆粕及不同粒度基础配制的粉状配合饲料和颗粒料分别进行胃蛋白酶-胰酶体外模拟酶解法测定消化率。试验结果表明:随着筛片孔径从1.0 mm扩大到3.0 mm,豆粕粉碎样品的粒度也从432μm增大到805μm,筛孔孔径与粒度间具有线性关系(P<0.01);选用浓度为70mg/mL胃蛋白酶和16 mg/mL胰蛋白酶进行体外模拟消化,随豆粕粒度的增加,豆粕、粉状配合饲料、颗粒料体外干物质(DM)、粗蛋白质(CP)消化率均随豆粕粉碎粒度的增加均呈现降低。豆粕和颗粒料的体外消化率随豆粕粉碎粒度减小呈线性提高(P<0.01),但粉状配合饲料消化率随豆粕粉碎粒度的变化未出现明显的线性规律(P=0.443、P=0.113)。505μm组和637μm组均可得到较高的消化率,但考虑到加工成本问题,637μm可作为豆粕在仔鸡颗粒料最适粉碎粒度,即2.0 mm为制作仔鸡颗粒料的粉碎机筛片最佳筛孔孔径。

A two - step enzymatic method of pepsin - trypsin was used to evaluate the particle sizes of feeds （ soybean meals that were ground to particle sizes of 432,505,637,717 or 805 μm with 1.0,1.5,2.0,2.5 or 3.0 mm screen;mash diets and pellted diets that was based on soybean meals）. Particle sizes of soybean meal increased from 432 μm to 805 μm linearly （P 〈 0.01 ） as sieve pore diameter changed from 1.0 mm to 3.0 mm. Pepsase with the concenteration of 70 mg/mL and trypsin with the concentration of 16 mg/mL were adopted for in vitro digestion. The dry matter （DM） ,crude protein （CP） digestibility of soybean meals, mash diets and pellted diets was increasing by particle sizes of soybean meals. The digestibility of group 505 μm as good as group 637 μm, but group 637 μm supported the lower energy cost. We concluded that 637 p,m was the most suitable grinding particle size of soybean meals, that was to say that grinding to pass through 2.0 - mm screen was the best choice for broiler pelleted diets.