【作者】 王杰；

【导师】 姜淑贞；

【作者基本信息】 山东农业大学 ， 畜牧（专业学位）， 2023， 硕士

【摘要】 饲料是畜牧业生产的物质基础,由于中国畜牧业的迅猛发展,玉米、豆粕等饲料原料的需求量急剧增加,然而,由于原料价格的不断上涨,饲料的成本就会急剧增加,小麦使用的比例以及其他原料的种类会越来越大,添加酶制剂就会成为一种必然的选择。复合酶制剂是以简单的一种或者以上酶为首要组份,与其他的酶制剂混合在一起,从而形成的含有多种酶的复合酶制剂。在家禽业,饲料添加剂应用普遍,尤其是酶制剂的使用。酶制剂能降低抗营养因子,提升饲料转化率和养分消化率,改善畜禽生产性能,促进动物新陈代谢,同时能减少排泄物的污染,有利于促进动物生长。本试验通过在小麦日粮中添加复合酶制剂,研究其对杂交肉鸡生产性能和肠道健康的影响。本试验选用体重基本一致、健康的1日龄杂交肉仔鸡共640只,随机分为4个处理,每个处理8个重复,每个重复20只肉仔鸡,采用2×2因子设计。试验1组杂交肉鸡饲喂18%小麦日粮(W18),试验2组在试验1组的基础上添加300 mg/kg的复合酶(W18CE),试验3组杂交肉鸡饲喂36%小麦日粮(W36),试验4组在试验3组的基础上添加300 mg/kg的复合酶(W36CE)。预试期7 d,正试期35 d。结果表明:(1)生产性能和养分利用率:与36%小麦日粮相比,18%小麦日粮降低了杂交肉鸡21～42 d和0～42 d的平均日采食量和料重比(P<0.05),提高了21～42 d和0～42 d的平均日增重(P<0.05),粗蛋白质、蛋氨酸和精氨酸和胱氨酸的表观代谢率显著降低(P<0.05),甘氨酸的表观代谢率显著升高(P<0.05)。与不加酶相比,添加复合酶显著降低21～42d和0～42 d杂交肉鸡的平均日采食量和料重比(P<0.05),显著提高蛋氨酸和甘氨酸的表观代谢率(P<0.05),提高胸腺指数(P<0.05)。(2)血清代谢产物和抗氧化:与36%小麦日粮相比,18%小麦日粮显著升高杂交肉鸡血清还原型谷胱甘肽含量(P<0.05),显著降低丙二醛含量(P<0.05)。与不加酶相比,添加复合酶能显著降低血清中的甘油三酯和尿素氮的含量(P<0.05),增加血清中葡萄糖含量(P<0.05),提高超氧化物歧化酶活性和还原型谷胱甘肽含量(P<0.05)。(3)肠道健康:与36%小麦日粮相比,18%小麦日粮能提高空肠超氧化物歧化酶活性(P<0.05),提高十二指肠绒腺比(P<0.05),降低十二指肠隐窝深度(P<0.05),显著提高空肠过氧化氢酶、谷胱甘肽过氧化物酶-1、核因子E2相关因子、闭锁蛋白、跨膜蛋白-2和跨膜蛋白-3基因的表达量(P<0.05),在属水平上提高球藻菌属(Sphaerochaeta)的丰度,降低拟普雷沃氏菌属(Alloprevotella)的丰度。与不加酶相比,添加复合酶后提高空肠超氧化物歧化酶活性和还原型谷胱甘肽含量(P<0.05),降低丙二醛含量(P<0.05),提高空肠麦芽糖酶和蔗糖酶活性(P<0.05),增加十二指肠和空肠的绒毛高度和绒腺比(P<0.05),超氧化物歧化酶-1、过氧化氢酶、谷胱甘肽过氧化物酶-1、核因子E2相关因子、闭锁蛋白、跨膜蛋白-2和跨膜蛋白-3的基因表达量显著提高(P<0.05),在属水平上降低拟普雷沃氏菌属(Alloprevotella)的丰度。小麦日粮添加复合酶后能够促进杂交肉鸡对营养物质的消化吸收,提高养分利用率以及肠道的抗氧化能力,并促进肠道健康,综合各个指标,本试验条件下在18%的小麦日粮中添加复合酶的作用效果较好。更多还原

【Abstract】 Feed is the material basis of animal husbandry production.With the rapid development of animal husbandry in China,the demand for corn,soybean meal and other feed materials have also greatly increased.However,due to the rise in the price of soybean meal,the feed cost rise significantly,the proportion of wheat used and the variety of other raw materials will become larger and larger,and adding enzyme preparation will become an inevitable choice.Complex enzyme preparations are containing multiple enzymes by mixing one or more simple enzymes as the primary component with other enzyme preparations.In poultry industry,feed additives are widely used,especially enzyme preparations.Enzyme preparation can reduce anti-nutrient factors,improve feed conversion rate and nutrient digestibility,improve the production performance of livestock and poultry,promote animal metabolism,and reduce the pollution of excrement,which is conducive to promoting animal growth.This experiment was conducted to study the effects of wheat diets supplemented with compound enzymes on performance and intestinal health of hybrid broilers.In this experiment,a total of 640 one-day-old hybrid broilers with basically the same weight and health were randomly divided into 4 treatments,with 8 replicates(20 birds per replicate/cage)in a 2 × 2 design.The treatments were as follows:(1)18% wheat diet(W18);(2)W18 + 300 mg/kg complex enzyme(W18CE);(3)36% wheat diet(W36);(4)W36 + 300mg/kg complex enzyme(W36CE).The pre-test period was 7 days,and the trial period was 35 days.The results showed that:(1)Production performance and nutrient utilization:Compared with W36,W18 reduced average daily feed intake and feed/gain(P < 0.05)at21-42 d and 0-42 d,increased the average daily gain at 21-42 d and 0-42 d(P < 0.05),the apparent metabolic rate of crude protein,Methionine,Arginine,and Cystine were significantly decreased(P < 0.05),the apparent metabolic rate of Glycine was significantly increased(P < 0.05).Compared with no enzyme in diet,adding complex enzyme significantly reduced the average daily feed intake and feed/gain at 21-42 d and 0-42 d,significantly increased the apparent metabolic rate of Methionine and Glycine(P < 0.05),meanwhile increased the thymus index(P < 0.05).(2)Serum metabolites and antioxidants: Compared with W36,W18 significantly increased the glutathione content in serum of hybrid broilers(P< 0.05)and significantly reduced the malondialdehyde content(P < 0.05).Compared with no enzyme in diet,adding complex enzyme significantly reduced the content of triacylglyceride and serum urea nitrogen in serum(P < 0.05),increased the content of glucose in serum(P <0.05),meanwhile increased the content of superoxide dismutase activity and glutathione content(P < 0.05).(3)Intestinal health: Compared with W36,W18 increased jejunal superoxide dismutase activity(P < 0.05),increased duodenal villus height/crypt depth(P <0.05),and reduced the crypt depth(P < 0.05),significantly increased the relative expression of Catalase,Glutathione peroxidase-1,Nuclear factor erythroid derived-2,Occludin,Claudin-2,and Claudin-3 in jejunum(P < 0.05).At the genus level,increased the abundance of Sphaerochaeta and reduced the abundance of Alloprevotella.Compared with no enzyme in diet,adding complex enzyme significantly increased the superoxide dismutase activity and glutathione content in the jejunum(P < 0.05),reduced the malondialdehyde content(P <0.05),improved the jejunal maltase and sucrase activities(P < 0.05),increased villus height and villus height/crypt depth in the duodenum and jejunum(P < 0.05).The relative expression of Superoxide dismutase-1,Catalase,Glutathione peroxidase-1,Nuclear factor erythroid derived-2,Occludin,Claudin-2,and Claudin-3 in jejunum were significantly increased(P < 0.05),but reduced the abundance of Alloprevotella at the genus level.Adding complex enzymes on the wheat diet could promote the digestion and absorption of nutrients,improve nutrient utilization rate and intestinal antioxidant capacity,and promote intestinal health of hybrid broilers.According to all the indexes,the effects of adding complex enzymes on 18% wheat diet was the better.更多还原