外源酶制剂对仔猪消化酶分泌影响的研究

Experiments were conducted to determine the effects of extragenous enzymes on the digestive system development and the endogenous digestive enzymes activities of piglets. A total of 421 piglets of Duroc × Yorkshire × Landrace from 42 litters were fed with corn-soybean diets or wheat-soybean diets. There were 3 treatments : ①supplementation of digestive enzymes (α-amylase 5500U/kg; acidic protease 25000U/kg); supplementation of polysaccharide enzymes (β-glucanase 5500U/kg, xylanase 20000U/kg, cellulase 2500U/kg); supplementation of complex enzymes (α-amylase 5500U/kg, acidic protease 25000U/kg, β-glucanaase 5500U/kg, xylanase 20000U/kg, cellulase 2500U/kg).Piglets were provided with starter diet at 5 days of age and weaned at 28 days of age. Three piglets from each treatments were slaughtered at the age of 28,42,56 days of age respectively. Digesta of duodenum, pre-duodenum, mid-duodenum, post-jejunum and ileum. Pancreas and intestinal mucousae samples were also collected to determine activities of endogenous enzymes. Vili from mid duodenum, jejunum were scanned by electric microscope .Weight of digestive organs, length of small intestine and pH value in different parts of gut were determined. Effects of extragenous enzymes on the development of gut, digesta pH value, vili structure of small intestine, growth performance of piglets, effects of extragenous digestive enzymes and polysaccharide enzymes on endogenous enzymes activities were also determined..Furthermore ,in order to explore the stability of enzymes under different condition, in vitro simulated gut was used to determine effects of pH value, temperature , Ca2+, Cu2+ concerntration and endogenous protease on activities of α-amylase, acidic protease, β-glucanase, xylanase, cellulase and glutinase..The results showed that:1 Averge daily gain and feed intake were increased and diahrrea was decreased during the period of pre-weaning and post-weaning.2 The relative weight of gastron was increased when extragenous digestive enzymes were added to both diets.3 Extragenous enzymes could strengthen development of pancreas,but not significantly (P>0.05). .4 Relative weight of liver, gall bladder, small intestine in terms of body weight was increased by supplementing extragenous enzymes,but small intestine weight in terms of intestine length was not increased by supplementing extragenous enzymes. 5 The configuration of duodenum vili underwent changes from low and flat to finger-like. Vili in jejunum was less damaged with age.Vili in mid-duodenum,mid-jejunum underwent changes from leaflet-like to columic, Suggesting that extragenous enzyme could strengthen the development of small intestine vili..Furthermore, the results indicated that: .1 Activities of pancreas amylase was increased while the effects in corn-soybean diets was better than in wheat-soybean diets. 2 The activities of pancreas amylase in pre-jejunum,mid-jejunumand post-jejunum seemed to increase at the age of 28 and 56 days , but not at 42 days of age. 3 Pancreas protease activity seemed to increase at the age of 28,42 and decrease at 56 days of age, but neither significantly. 4 Pancreas protease activity in pre-jejunum ,mid-jejunum and post-jejunum seemed to increase when extragenous enzymes were supplemented in wheat-soybean diet , but not significantly affected in corn-soybean diet. .5 Sucrase activity in small intestinal mucosae seemed to increase with the supplementation of extragenous enzymes, no obvious effects on lactase and maltase activities were obsevered . 6 Protease activity was increased at age of 42, 56 days, but there is no effect at 28 days of age . In vitro experiment results suggested: 1 the optium pH value and temperature for α-amylase were 6.0 and 40℃; acidic protease were 4.2 and 30-40℃; xylanase were 6.0 and 40℃ and β-glucase were 6.0 and 40℃. 2 There is no effect of Ca2+ concentrations (2.5-160mmd/L) on th

..................本项目研究饲用酶制剂添加于仔猪日粮对仔猪消化道的消化酶分泌的影响，研究外源性消化酶对仔猪消化酶是否有抑制作用，用聚糖酶对消化酶是否有促进作用以及断奶前后仔猪消化道的胃蛋白酶、胰糜蛋白酶、淀粉酶和脂酶的分泌规律，本实验的研究对了解仔猪的消化生理及饲用酶制剂的作用机理，正确使用不同的酶制剂，提高仔猪的消化性能有重要意义。..................................................................................