本试验旨在探讨仿生消化过程中生长猪体内4种小肠消化酶以及胃期和小肠期消化时间对植物性饲料磷体外消化率的影响,为确定仿生消化法评定生长猪常用植物性饲料磷体外消化率时模拟小肠消化液的组成与最佳消化时间提供参考。试验在SDS-Ⅰ型单胃动物仿生消化系统中进行,以玉米、豆粕和麦麸为测试原料,分3个试验进行。试验1,设置5个处理,1个不添加小肠消化酶的处理(对照)和4个添加不同小肠消化酶的处理,分别添加胰蛋白酶、胰蛋白酶+糜蛋白酶、胰蛋白酶+糜蛋白酶+淀粉酶、胰蛋白酶+糜蛋白酶+淀粉酶+脂肪酶,胃期消化时间为1.25 h,小肠期消化时间为4.00 h;试验2,确定小肠消化液主要消化酶组成后,设置5个不同的胃期消化时间的处理,分别为0.50、0.75、1.00、1.25、1.50 h,各处理的对应小肠期消化时间均设置为4.00 h;试验3,确定胃期消化时间后,设置6个不同的小肠期消化时间的处理,分别为1.00、2.00、3.00、4.00、5.00、6.00 h。以上各处理均设3个重复,每个重复5根消化管,分别测定3种饲料原料的磷体外消化率。结果表明:1)胰蛋白酶、淀粉酶和脂肪酶均可显著提高玉米、豆粕和麦麸磷体外消化率(P<0.05),糜蛋白酶可显著提高豆粕和麦麸磷体外消化率(P<0.05),却显著降低了玉米磷体外消化率(P<0.05)。2)胃期消化时间由0.50 h增加到1.00 h,玉米和豆粕磷体外消化率均无显著性变化(P>0.05);1.25 h时玉米和豆粕磷体外消化率显著降低(P<0.05);消化时间由0.50 h增加到1.00 h,麦麸磷体外消化率显著升高(P<0.05),1.25 h时达到稳定。3)小肠期消化时间由1.00 h增加到6.00 h,玉米、豆粕和麦麸磷体外消化率均显著增加(P<0.05),并分别在3.00、4.00、5.00 h达到稳定。分析以上结果得出:1)可采用胰蛋白酶、糜蛋白酶、淀粉酶和脂肪酶模拟小肠液。2)确定胃期消化时间为1.00 h,小肠期消化时间为5.00 h。

This study was investigated to research the effects of four small intestinal digestive enzymes and the digestive time of gastric phase and small intestinal phase on in vitro digestibility of phosphorus in plant-origin feeds in order to provide a basis for simulative small intestine fluid composition and optimal digestive time. The experiment was carried out on SDS-Ⅰ bionic digestion system for monogastric animals, and corn, soybean meal and wheat bran were used as trial materials. Experiment 1 included one no-enzyme treatment (control) and four enzyme treatments, which were supplemented with trypsin, trypsin+chymotrypsin, trypsin+chymotrypsin+amylase and trypsin+chymotrypsin+amylase+lipase, respectively. The digestive time of gastric phase was 1.25 h, and the digestive time of small intestinal phase was 4.00 h. Experiment 2: after the small intestinal digestive enzymes were selected,five treatments were made by the digestive time of gastric phase including 0.50, 0.75, 1.00, 1.25 and 1.50 h, respectively, and the digestive time of small intestinal phase was 4.00 h in all of treatments. Experiment 3: after the digestive time of gastric phase was selected, six treatments were made by the digestive time of small intestinal phase including 1.00, 2.00, 3.00, 4.00, 5.00 and 6.00 h, respectively. Each treatment had 3 replicates, and each replicate had 5 digestive tubes. The results showed as follows: 1) trypsin, amylase and lipase could significantly increase the in vitro digestibility of phosphorus in corn, soybean meal and wheat bran (P<0.05). Chymotrypsin could significantly increase the in vitro digestibility of phosphorus in soybean meal and wheat bran (P<0.05), but it significantly decreased the in vitro digestibility of phosphorus in corn (P<0.05). 2) When the digestive time of gastric phase increased from 0.50 to 1.00 h, the in vitro digestibility of phosphorus in corn and soybean meal had no significant change (P>0.05). When the time was up to 1.25 h, the in vitro digestibility of phosphorus in corn and soybean meal was significantly decreased (P<0.05). When the digestive time of gastric phase increased from 0.50 to 1.00 h, the in vitro digestibility of phosphorus in wheat bran was significantly increased (P<0.05), and it had no significant change at 1.25 h (P>0.05). 3) When the digestive time of small intestinal phase increased from 1.00 to 6.00 h, the in vitro digestibility of phosphorus in corn, soybean meal and wheat bran was all significantly increased (P<0.05), and had no significant changes at 3.00, 4.00 and 5.00 h, respectively. It is concluded that 1) trypsin, chymotrypsin, amylase and lipase can be used for simulating small intestinal fluid; 2) the digestive time of gastric phase and small intestinal phase are determined for 1.00 and 5.00 h, respectively.