【摘要】 旨在研究纳米氧化铈对蛋鸡生产性能、营养物质消化率、消化酶活性及基因表达的影响,并初步探讨纳米氧化铈提高蛋鸡生产性能和营养物质消化率的作用机理。试验选择26周龄健康商品蛋鸡396只,随机分为4组,每组8个重复,每个重复12只鸡。以玉米-豆粕型日粮为基础日粮,在基础日粮中分别添加0、30、60、90mg·kg-1纳米氧化铈,试验期7周。试验结果表明:(1)日粮中添加纳米氧化铈对产蛋率、料蛋比无显著影响(P>0.05),对蛋重、采食量以及破蛋率有显著影响(P<0.05)。蛋重以30mg·kg-1组最高,破蛋率以60mg·kg-1组最低。纳米氧化铈对钙利用率有显著影响(P<0.05),对脂肪、蛋白质、能量、磷的利用率无显著影响(P>0.05)。(2)纳米氧化铈对肠道中胰脂肪酶活性无显著影响,对胰腺中胰脂肪酶活性有显著影响,以60mg·kg-1组最高(P<0.05);对肠道及胰腺中胰蛋白酶及胰淀粉酶活性有显著影响,均以30mg·kg-1组为最高。(3)不同水平的纳米氧化铈对消化酶基因mRNA表达水平有影响。30mg·kg-1组与对照组相比,极显著上调了胰蛋白酶Ⅱ基因mRNA水平(P<0.01),显著上调了胰淀粉酶和胰蛋白酶Ⅰ基因mRNA水平(P<0.05),60mg·kg-1组与对照组相比,显著上调了胰脂肪酶基因mRNA水平(P<0.05),但却极显著下调了胰蛋白酶Ⅱ基因mRNA水平(P<0.01),显著下调了胰淀粉酶基因mRNA水平(P<0.05)。90mg·kg-1组与对照组相比,极显著下调了胰蛋白酶Ⅱ基因mRNA表达水平(P<0.01),显著下调了胰淀粉酶基因mRNA表达水平(P<0.05)。日粮中添加纳米氧化铈对蛋鸡生产性能及消化酶活性和基因表达有一定的影响。30mg·kg-1组与对照组相比,显著上调了胰淀粉酶、胰蛋白酶Ⅰ基因、胰蛋白酶Ⅱ基因mRNA水平(P<0.05),从而显著提高了蛋重和钙表观消化率;60mg·kg-1组与对照组相比,显著上调了胰脂肪酶,显著下调了胰淀粉酶和胰蛋白酶ⅡmRNA水平(P<0.05),使胰淀粉酶活性、胰蛋白酶活性和破蛋率降低;90mg·kg-1组与对照组相比,极显著下调了胰淀粉酶基因和胰蛋白酶Ⅱ基因mRNA表达水平,使蛋重、日采食量、胰蛋白酶活性降低,破蛋率提高。综合评定,日粮中以添加30mg·kg-1纳米氧化铈效果较佳。更多还原

【Abstract】 To study the effect of nano-ceria on production performance,nutrient digestibility,digestive enzyme activities and digestive enzyme gene expression of laying hens,the experiment was designed to preliminarily discuss the mechanism of improving production performance and nutrient digestibility of the optimum addition of nano-ceria.396 26-week-old healthy commercial laying hens were selected and allotted randomly to four treatments,each treatment was represented by eight replicates of twelve each,and were fed the corn-soybean basal diet with 0,30,60,90mg·kg-1 nano-ceria,respectively.The test lasted for seven weeks.The result showed that:(1)The nano-ceria had no significant effect on laying rate and feed egg ratio(P>0.05),but had significant effect on average egg weight,feed intake and broken rate of eggs(P<0.05).30mg·kg-1group had higher egg weight than other groups,60mg·kg-1 group had lower broken rate of eggs than other groups.The nano-ceria had significant effect on calcium utilization ratio(P<0.05),but had no significant effect on the utilization rate of fat,crude protein,energy and phosphorus(P>0.05).(2)The nano-ceria had no significant effect on pancreatic lipase activities in intestinal(P>0.05),but had significant effect on pancreatic lipase activity in pancreas,the highest in 60mg·kg-1 group.The nano-ceria had significant effect on trysin and pancreatic amylase activity in intestinal and pancreas,the highest in 30mg·kg-1 group.(3)The nano-ceria supplementation had effect on mRNA level of digestive enzyme gene.Compared with the control group,30mg·kg-1 group up-regulated mRNA level of trypsinⅡ gene(P<0.01),pancreatic amylase gene and trypsinⅠgene(P<0.05),but the change of mRNA level of pancreatic lipase was not significant(P>0.05).Compared with the control group,60mg·kg-1 group up-regulated mRNA level of pancreatic lipase,but down-regulated mRNA level of trypsinⅡgene(P<0.01)and pancreatic amylase gene(P<0.05).Compared with the control group,90mg·kg-1 group downregulated mRNA level of trypsinⅡgene(P<0.01)and pancreatic amylase gene(P<0.05),but had no influence on mRNA level of pancreatic lipase gene(P>0.05).The result indicated that nano-ceria could improve production performance by improving digestive enzyme activities and nutrients apparent digestibility caused by activation of digestive enzyme system.Compared with the control group,30mg·kg-1 group up-regulated mRNA level of trypsinⅡgene,pancreatic amylase gene and trypsinⅠgene(P<0.05),and then improved the egg weight and calcium digestibility;Compared with the control group,60mg·kg-1 group up-regulated mRNA level of pancreatic lipase,down-regulated mRNA level of trypsinⅡgene and pancreatic amylase gene(P<0.05),the pancreatic amylase,trypsin activity and broken egg rate decreased;Compared with the control group,90mg·kg-1group down-regulated mRNA level of trypsinⅡgene and pancreatic amylase gene(P<0.05),so egg weight,feed intake and trypsin activity decreased,broken egg rate increased significantly.Comprehensive assessment,the diet with addition of 30mg·kg-1 nano-ceria was better.更多还原