【作者】 王玉莲；

【导师】 袁宗辉；

【作者基本信息】 华中农业大学 ， 农产品加工与贮藏工程， 2006， 博士

【摘要】 喹噁啉类为化学合成的动物专用药物，具有良好的抗菌促生长作用，作为饲料添加剂广泛应用于畜禽饲料中。我国批准使用的有喹乙醇、喹烯酮、乙酰甲喹。近年来大量研究表明喹乙醇、乙酰甲喹及其代谢物具有较强的蓄积毒性和致突变性，在我国和其他国家被禁止或限制使用。喹赛多为喹噁啉类药物新品种，毒性极低，用药后在动物体内消除迅速、残留期短、无蓄积作用，具有较好的开发应用前景。现有研究显示喹赛多可促进鸡、鸭、羊和牛生长，提高饲料转化率，改善胴体品质。但喹赛多对猪的促生长作用及其作用机制仍不清楚。本项目研究了喹赛多对猪的促进猪生长效果，并从动物营养生理、代谢调控和肠道微生态等方面研究了喹赛多对营养物质消化吸收、肠道微生态、肠道物质代谢以及肠道组织结构的影响，探讨抗菌药物、肠道微生物、物质代谢和动物生长的关系，为喹赛多的合理应用提供科学依据。1．喹赛多促进猪生长和营养物质沉积利用100头健康长大去势公猪，35日龄断奶，体重为(9.9±1.4)kg，随机分为5组，每组5个重复，用于研究喹赛多对猪的生长性能和营养物质沉积利用的影响。对照组饲喂基础日粮(不添加任何抗菌药物)，喹乙醇组在基础日粮中添加50mg／kg喹乙醇，3个喹赛多组分别在基础日粮中添加25、50和100mg／kg喹赛多。试验猪饲喂基础日粮7d后进入正式试验。试验期130d。在试验0、40、68、95和130d，对猪个体空腹称重，记录采食量，计算日增重(ADG)和饲料转化率(FCR)。在试验40、68、95和130d随机抽取试验猪5头屠宰，测定胴体性状，取背最长肌、肝脏和左侧股骨，测定其化学组成。试验0～40d，25、50和100mg／kg喹赛多分别改善猪ADG 5.4％(P＞0.05)、9.9％(P＞0.05)和24.3％(P＜0.01)，提高FCR 10.4％(P＜0.05)、15.0％(P＜0.01)、15.8％(P＜0.01)。50、100mg／kg喹赛多组猪ADG和FCR均高于50mg／kg喹乙醇组，100mg／kg喹赛多组猪ADG显著高于喹乙醇组(P＜0.01)。试验41～68d，25、50和100mg／kg喹赛多提高ADG分别为4.4％～6.8％(P＞0.05)，FCR改善2.7％～5.9％(P＞0.05)。50、100mg／kg喹赛多组猪ADG高于50mg／kg喹乙醇组(P＞0.05)。试验69～95d，25、50和100mg／kg喹赛多提高ADG和FCR分别为4.7％(P＞0.05)、7.9％(P＞0.05)、9.2％(P＞0.05)和4.0％(P＞0.05)、8.1％(P＜0.01)、8.1％(P＜0.01)。喹赛多3个剂量组ADG和FCR均高于50mg／kg喹乙醇组，50和100mg／kg喹赛多组FCR显著高于喹乙醇组(P＜0.05)。试验96～130d，25、50和100mg／kg喹赛多组ADG分别提高2.9％～6.4％(P＞0.05)，FCR分别提高1.8％(P＞0.05)、3.9％(P＞0.05)和8.3％(P＜0.05)。喹赛多3个剂量组ADG和FCR均高于50mg／kg喹乙醇组，100mg／kg喹赛多组FCR显著高于50mg／kg喹乙醇组(P＜0.05)。可见，喹赛多对猪有较好的促生长作用，在猪日粮中的适宜添加量为50～100mg／kg，最佳添加时程为95d。d 95，喹赛多25、50和100mg／kg组猪屠宰率提高3.8％～3.3％(P＞0.05)，瘦肉率提高3.4％～8.6％，眼肌面积增加7.45～14.5％，胴体背膘厚降低7.7％～14.8％，与对照组差异不显著(P＞0.05)。喹赛多3个剂量组肥肉率降低12.4％～29.0％，100mg／kg喹赛多组猪肥肉率显著低于对照组(P＜0.01)。试验130d，喹赛多25、50和100mg／kg组猪屠宰率分别提高4.2％～5.2％，瘦肉率提高2.7％～3.1％(P＞0.05)，眼肌面积增加17.9％～31.4％(P＞0.05)，肥肉率降低7.7％～11.5％(P＞0.05)，背膘厚降低7.0％～17.8％(P＞0.05)。喹赛多各剂量组对猪胴体性状有较好的改善作用，改善程度均高于喹乙醇组。25、50和100mg／kg喹赛多组猪肌肉中维生素A含量分别提高为33.5％(P＜0.05)、60.2％(P＜0.01)和78.0％(P＜0.01)，肝脏中维生素A含量分别提高17.4％(P＞0.05)、20.1％(P＞0.05)和24.0％(P＜0.05)，肌肉中维生素E含量分别提高6.5％(P＞0.05)、9.2％(P＞0.05)和10.2％(P＞0.05)，肝脏中维生素E含量分别提高24.4％(P＜0.05)、26.3％(P＜0.05)和29.8％(P＜0.05)。喹赛多各剂量组肌肉和肝脏中维生素A和E含量均高于喹乙醇组。25～100mg／kg喹赛多可促进维生素A和E在猪肌肉和肝脏组织中的沉积。试验期间，喹赛多各剂量组猪肌肉钙、磷、镁、铁、铜、锌和锰含量均在正常生理范围内。25、50和100mg／kg喹赛多提高猪肌肉中铁含量，100mg／kg喹赛多组肌肉铁含量显著高于对照组(P＜0.01)。25、50和100mg／kg喹赛多显著提高40d肌肉中铜含量和68d肌肉中锌含量(P＜0.05)，对锰含量无显著影响(P＞0.05)。喹赛多各组肝脏钙(P＜0.05)和镁含量高于对照组，对磷无显著影响(P＜0.05)。喹赛多组猪肝脏铁、锌和锰均高于对照组，对肝脏中铜含量无显著影响。喹赛多显著提高骨骼钙含量(P＜0.05)，提高40d骨骼磷含量，提高40d和95d镁含量，骨骼铁、锌和锰均显著升高(P＜0.05)，但不影响骨骼铜的含量(P＞0.05)。可见，喹赛多可促进钙、镁、铁、锌在肌肉中的沉积，促进钙、镁、铁、锰在肝脏中的沉积，促进钙、镁、铁和锰在骨骼中的沉积，对磷和铜在肌肉、肝脏和骨骼中的沉积无显著影响。喹赛多对肌肉和肝脏中水分、蛋白质、脂肪和灰分含量无显著影响(P＞0.05)。随着年龄的增长，猪肌肉和肝脏中水分含量下降，蛋白质、脂肪和灰分含量逐渐增加。整个试验期，各试验组猪肌肉中氨基酸含量和组成无显著差异(P＞0.05)。喹赛多各剂量组对肌肉和肝脏中脂肪酸的组成无显著影响(P＞0.05)。2．喹赛多对猪营养物质消化率和肠道代谢影响80头长大去势公猪随机分为3组，35日龄断奶，体重(12.06±0.13)kg，每组5个重复，每个重复25头，用于研究喹赛多对猪营养物质消化率以及肠道微生物和肠道物质代谢的影响。对照组饲喂基础日粮，喹乙醇组在基础同粮添加喹乙醇100mg／kg，喹赛多组在基础同粮添加喹赛多100mg／kg。所有试验猪在进入正式试验前饲喂基础日粮7d。试验期4周。试验前和试验后每周对猪个体空腹称重，记录采食量，计算ADG和FCR。同时，每周从每组随机抽取试验猪5头屠宰，取十二指肠、空肠和回肠，测定肠道绒毛高度和隐窝深度。无菌取空肠和回肠内容物，分析其菌群组成，另取部分肠内容物测定pH值、水分、微生物酶活性和微生物代谢产物。试验后第4周，连续收集每组猪的粪便6d，测定饲料和粪便中各种营养物质的含量，计算养分的表观消化率。100mg／kg喹赛多组仔猪ADG和FCR分别提高为19.4％(P＜0.01)和20.1％(P＜0.01)。100mg／kg喹乙醇组仔猪ADG和FCR分别提高7.8％(P＜0.05)和9.2％(P＜0.05)。喹赛多组猪ADG和FCR显著高于喹乙醇组(P＜0.05)。消化试验表明，喹赛多显著提高猪对日粮中干物质、粗蛋白质、粗纤维、粗脂肪、无氮浸出物的表观消化率和表观消化能(P＜0.05)，日粮中氨基酸和钙、磷、铁、铜、锌、锰的表观消化率显著高于对照组和喹乙醇组(P＜0.05)，这表明喹赛多可促进同粮中氨基酸、脂肪、矿物质的消化和吸收。喹赛多增加空肠和回肠绒毛高度及绒毛与隐窝深度比值，显著降低空肠和回肠内细菌总数(P＜0.05)，抑制空肠和回肠大肠杆菌、肠球菌和酵母菌的生长，促进乳酸杆菌的增殖，降低空肠和回肠内偶氮还原酶、硝酸还原酶和脲酶的活性，减少肠道氨、乙酸、丁酸和总挥发性脂肪酸的产量。这说明喹赛多的促生长作用是由于抑制肠道微生物，减少肠道微生物的活动，降低肠道微生物酶的活性，抑制不利生长的代谢产物的产生，增加小肠绒毛表面积，促进营养物质的消化吸收和利用，促进动物生长。3．喹赛多对猪血清中营养物质的影响规律60头断奶长大仔猪，35日龄断奶，体重(9.9±1.4)kg，随机分为5组，公母各半。对照组饲喂基础日粮；喹乙醇组，在基础日粮添加喹乙醇50mg／kg；3个喹赛多组，分别在基础同粮添加喹赛多25、50和100mg／kg。进入正式试验前，所有试验猪用基础同粮饲喂7d。试验期16周。于试验第0wk、4wk、8wk、12wk和16wk前腔静脉采血，测定血清中氨基酸、脂肪酸、矿物质元素、维生素A和E的含量。试验0～4wk，25、50和100mg／kg喹赛多提高猪ADG 18.1％(P＜0.05)、33.3％(P＜0.01)和34.3％(P＜0.01)，提高FCR 7.9％、24.0％和34.3％。50、100mg／kg喹赛多组ADG和FCR均显著高于50mg／kg喹乙醇组(P＜0.05)。试验5～8wk，喹赛多3个剂量组ADG和FCR分别提高2.9％～7.7％(P＞0.05)和2.0％～7.2％，50和100mg／kg喹赛多组猪ADG和FCR均高于50mg／kg喹乙醇组。试验9～12wk，喹赛多组ADG提高4.2％～6.8％(P＞0.05)，FCR提高6.0％～8.2％；喹赛多组猪ADG和FCR均高于50mg／kg喹乙醇组。试验13～16wk，喹赛多组提高ADG为1.3％～2.4％(P＞0.05)，FCR提高0.5％～1.3％。全期(0～16wk)，喹赛多提高ADG分别为4.8％～7.9％(P＞0.05)，FCR提高3.9％～7.5％；喹赛多组猪ADG和FCR均高于25mg／kg喹乙醇组。这进一步证实了喹赛多对猪的促生长作用，连续饲喂喹赛多12周均有良好的促生长效果。喹赛多在猪的最佳添加量为50～100mg／kg，最佳添加时间为12wk。喹赛多提高血清多数游离脂肪酸和氨基酸的浓度，促进体内脂肪分解供能，抑制组织蛋白质的分解，促进蛋白质沉积。整个试验期间，25、50和i00mg／kg喹赛多提高血清中维生素A 12.3％～153.2％(P＜0.05)，维生素E提高20.4％～122.9％(P＜0.05)。喹赛多各剂量组猪血清中无机离子(钾、钠、钙、镁、磷、铁、铜、锌、锰)含量均在生理范围内。综上所述，喹赛多可促进猪生长，提高饲料转化率，改善胴体品质，促进蛋白质和维生素A、E的沉积。喹赛多抑制肠道大肠杆菌、肠球菌繁殖，促进乳酸杆菌的增殖，降低肠道微生物酶活性，增加小肠绒毛表面积，促进养分的消化和吸收，提高养分的表观消化率。喹赛多提高血清中多数必需氨基酸、维生素A和E、游离脂肪酸的含量。血清中氨基酸、维生素的含量与蛋白质、维生素的沉积呈正相关。血清中游离脂肪酸的含量与蛋白质沉积呈负相关。本论文系统研究喹赛多促进猪生长和提高饲料利用率，对营养物质消化率、血液及组织中营养物质成分的影响，阐明喹赛多对营养物质吸收、利用和沉积的作用，确定了喹赛多在猪的作用、最佳作用剂量和时程，为喹赛多的合理应用提供理论依据和技术方案；深入研究喹赛多对肠道微生物及其酶和代谢产物的影响，揭示肠道微生物、物质代谢、喹赛多促生长三者之间的关系，从肠道微生物学角度探讨喹赛多的促生长作用机理；全面研究喹赛多对猪血液和组织中氨基酸、脂肪酸、维生素、矿物质等各类营养物质消长规律的影响，对动物的营养物质代谢研究和饲料添加剂的研发具有参考价值。更多还原

【Abstract】 Quinoxalines were a group of synthetic antibacterial agents which were widely used as antibacterial growth promoters in animals. Olaquindox, Quinocetone and mequindox have been approved to use as feed additives in China. However, olaquindox and mequindox have been recently forbidden or limited to use because of their side effects, such as mutagenicity, photo-toxicity, accumulation toxicity, etc. Cyadox was a new compound of the quinoxaline-1, 4-dioxide family at the exploitation stage. The recent researches showed that cyadox can enhance the growth and FCR, improve carcass traits and meat quality in poultry, lambs and cattle with lower toxicity compared with olaquindox. Furthermore, cyadox had the advantages of quick absorption, rapid elimination, short-term residue in animal tissues and no accumulation toxicity. However, effects of cyadox on growth, absorption and retention of nutrients in swine were not clear. The research investigated the effects of cyadox on the growth performance, carcass traits and meat quality, absorption and retention of nutrients. At the meanwhile, the relationship of the growth promotion of cyadox with animal nutritional physiology, metabolic regulations, intestinal flora and its metabolites were elucidated.1. Cyadox promoted growth and deposition of nutrient in pigs In order to study the effects of cyadox on growth and retention of nutrients in pigs, one hundred Landrace×Large White crossbred barrows, weaned at 35 days of age, were randomly allotted to five treatments with five replicates. The treatments were: one control fed the basal diet without any antimicrobial, one group fed the diet containing 50 mg/kg olaquindox, and the other three groups fed the diets containing 25, 50 and 100 mg/kg cyadox, respectively. The animals at the start of the 7-day adaptation period were fed a basal diet containing no antibiotics. At the age of 42 d the piglets entered the experiment. The experiment period lasted 130 d in four phases (1, from d 0 to 40; 2, from d 41 to 68; 3, from d 69 to 95; 4, from d 96 to 130). Average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ratio (FCR) were determined in each phase. At the end of each phase, five pigs were slaughtered to determine cyadox effects on carcass traits and meat quality. Longissimus muscle, liver, left femur and left tibia were sampled to analyze their chemical composition.Three doses of cyadox (25, 50 and 100 mg/kg) improved ADG and FCR by 5.4% (P＞0.05) and 10.4% (P＜0.05), 9.9% (P＞0.05) and 15.0% (P＜0.01), 24.3% (P＜0.01) and 15.8% (P＜0.01) in phase 1. ADG and FCR for pigs fed cyadox at 100 mg/kg were higher (P＜0.01) than those for pigs supplemented with 50 mg/kg olaquindox. In phase 2, 25 to 100 mg/kg cyadox improved (P＞0.05) ADG and FCR by 4.4% to 6.8% and 2.7% to 5.9%. ADG for pigs fed at cyadox at 50 and 100 mg/kg were higher (P＞0.05) than those for pigs in olaquindox. In phase 3, 25, 50 and cyadox improved ADG by 4.7% to 9.2% (P＞0.05), improved FCR by 4.0% (P＞0.05), 8.1% (P＜0.01) and 8.1% (P＜0.01), respectively. In phase 4, 25 to 100 mg/kg cyadox improved ADG and FCR by 2.9% to 6.4%, 1.8% to 8.3%, respectively. ADG and FCR for pigs fed cyadox at 25, 50 and 100 mg/kg were higher than those for pigs supplemented with 50 mg/kg olaquindox in phases 3 and 4. The results indicated that the optimum effective dose of cyadox in pigs was 50 to 100 mg/kg, the optimum supplementation period for pigs was 95 days.On d 95, inclusion of cyadox at 25, 50 and 100 mg/kg improved dressing percentage by 3.3% to 3.8% (P＞0.05), increased lean percentage by 3.4% to 8.6% (P＞0.05), enhanced longissimus muscle area (LMA) by 7.4% to 14.5% (P＞0.05), while fat percentages and backfat thickness decreased by 12.4% to 29.0%, 7.7% to 14.8%, respectively. On d 130, dressing percentage, lean percentage and LMA for pigs fed diets containing 25, 50 and 100 mg/kg cyadox increased by 4.2% to 5.2%, 2.7% to 3.1%, 17.9% to 31.4%, respectively, while fat percentages and backfat thickness decreased by 7.7% to 11.5%, 7.0% to 17.8%. It is obvious that cyadox, especially at the dose of 50 and 100 mg/kg, improved carcass charateristics.Inclusion three different doses of cyadox did not affect contents of moisture, crude protein, fat and ash in porcine muscle and liver. However, moisture content in porcine muscle and liver decreased as age of pigs increased, meanwhile, contents of crude protein, fat and ash increased. Compared with control, cyadox did not affect concentration and composition of amino acid of porcine muscle, did not affect concentration and composition of fatty acid in porcine muscle and liver.The three doses of cyadox (25mg/kg, 50mg/kg, and 100mg/kg) increased the retinol content of the muscle by 33.5% (P＜0.05), 60.2% (P＜0.01) and 78.0% (P＜0.01), respectively, increased retinol content of the liver by 17.4% (P＞0.05), 20.1% (P＞0.05) and 24.0% (P＜0.05). Meanwhile, tocopherol content of the muscle and live was elevated by 6.5% (P＞0.05) and 24.4% (P＜0.05), 9.2% (P＞0.05) and 26.3% (P＜0.05), 10.2% (P＞0.05) and 29.8% (P＜0.05), respectively.The contents of calcium, magnesium, phosphorus, iron, copper, zinc and manganese in the muscle and liver ranged within the physiological limits. As for the muscle, the content of iron, the content of copper on d 40 and the content of zinc on d 68 increased, but the content of manganese was not affected. The contents of calcium (P＜0.05), magnesium (P＞0.05), iron (P＜0.05), copper (P＞0.05), zinc (P＞0.05) and manganese (P＜0.05) in the liver for pigs fed cyadox increased, but phosphorus was not affected. Cyadox significantly increased the contents calcium, iron, and manganese in the bone, did not affect the contents of copper. The content phosphorus in the bone on d 40, and the content of magnesium in the bone on d 40 and d 95 increased (P＜0.05).2. Effect of cyadox on nutrient digestibility and metabolism in the intestinal of pigsEighty Landrace×Large White crossbred barrows, weaned at 35 days of age, were randomly allotted three groups with five replicates to evaluate the effect of cyadox on nutrient digestibility, intestinal flora and nutrients metabolism. The three groups were randomly allotted to one of three diets: 1) control diet without any antimicrobial agents; 2) an olaquindox diet containing 100 mg/kg olaquindox; 3) a cyadox diet containing 100 mg/kg cyadox. The pigs were fed the control diet at the start of the 7-day adaptation. At the age of 42 d the pigs entered the experiment. The experiment period lasted four weeks. ADG and FCR were determined weekly. Five pigs per group were selected to slaughter each week to determine intestinal flora, metabolites (including pH value, moisture, microbial enzyme activity, ammonia and VFA) and small intestinal villus morphology. Faeces were collected during wk four of the experiment and used for determining nutrients digestibility.Cyadox at the dose of 100 mg/kg improved (P＜0.01) ADG by 19.4% and FCR by 20.1% while 100 mg/kg olaquindox did (P＜0.05) by 7.8% and 9.2%, respectively. ADG and FCR for pigs fed 100 mg/kg cyadox were higher (P＜0.05) than those for pigs fed 100 mg/kg olaquindox.As compared with control, the apparent digestibilities of dry matter, crude protein, ether extract, nitrogen-free extract, and digestible energy were significantly increased (P＜0.05) in the cyadox-fed pigs. The apparent digestibilities of amino acid, calcium, phosphorus, iron, copper, zinc and manganese in the cyadox-fed pigs were significantly higher (P＜0.05) than those in pigs fed control diet and olaquindox diet. It is suggested that the growth promoting effect of cyadox may be attributed to the improvement in the digestibility of dietary nutrients.Cyadox increased the height of villi in the duodenum and in the jejunum, and the ratio of villus height to its recess depth in the jejunum, whichindicated that cyadox enlarged the surface area of small intestinal villi to absorb nutrients.Cyadox significantly increased (P＜0.05) lactobacillus counts in the jejunum and ileum, but decreased coliform, enterococcus and yeast counts. Similarly, cyadox significantly reduced the activity of urease, nitrated reducase and azoreducase in the jejunum and ileum with decreasing the content of ammonia, acetate acid, butyric acid and total of VFA. The results showed that the growth promoting effect of cyadox may be attributed to intestinal bacterial suppression, reduction of microbial enzyme activity and microbial metabolites.3. Effect of cyadox on serum concentrations of nutrients in pigsIn order to study the effects of cyadox on serum concentration of nutrients in pigs, sixty Landrace×Large White crossbred barrows, weaned at 35 days of age, were randomly allotted to five treatments. The treatments included one control fed the basal diet without any antimicrobial, one group fed the diet containing 50 mg/kg olaquindox, and the other three groups fed the diets containing 25, 50 and 100 mg/kg cyadox, respectively. The animals at the start of the 7-day adaptation period were fed a basal diet containing no antibiotics. At the age of 42 d the piglets entered the experiment. The experiment period lasted sixteen weeks. Growth performance data and serum were collected every four weeks. Serum free amino acid, free fatty acid, retinol, tocopherol and mineral concentrations were determined.During the first four weeks, 25, 50 and 100 mg/kg cyadox improved ADG by 18.1% (P＜0.05), 33.3% (P＜0.01) and 34.3% (P＜0.01), increased FCR by 7.9%, 24.0% and 34.3%, respectively. Smilarly, ADG and FCR for pigs fed cyadox at 50 and 100 mg/kg were higher (P＜0.05) than those of pigs fed 50 mg/kg olaquindox. From weeks 5 to 8, 25 to 100 mg/kg cyadox improved (P＞0.05) ADG by 2.9% to 7.7%, and FCR by 2.0% to 7.1%. From weeks 9 to 12, 25 to 100 mg/kg cyadox improved (P＞0.05) ADG by 4.2% to 6.8%, and FCR by 6.0% to 8.2%. From weeks 13 to 16, 25 to 100 mg/kg cyadox improved (P＞0.05) ADG and FCR by 1.3% to 2.4%, and 0.5% to 1.3%. Over the entire experimental period, pigs given 50 and 100 mg/kg cyadox diets showed the greatest ADG and the best food efficiency among the five diets. The results indicated that the optimum effective dose of cyadox in pigs was 50 to 100 mg/kg, the optimum supplementation period for pigs was 12 weeks. Cyadox increased most of free fatty acids and amino acids in serum, whereas urea and ammonia decreased. These results showed that cyadox promoted the rate of muscle protein synthesis and retention of protein, increased utilization of protein and amino acid.In pig feds 25 to 100 mg/kg cyadox diets, the concentrations of serum retinol increased by 12.3% to 153.2% (P＜0.05) while serum tocopherol concentrations increased by 20.4% to 122.9% (P＜0.05). The contents of sodium, potassium, calcium, magnesium, phosphorus, iron, copper, zinc and manganese in the serum ranged within the physiological limits. Increases in the concentrations of serum potassium in olaquindox and three cyadox group were found only in week 12 and week 16.In conclusion, cyadox increased ADG and FCR, improved carcass characteristics, increased deposition of protein, retinol and tocopherol. Cyadox increased absorption and digestibility of nutrients, but suppressed intestinal bacterial, reduced activities of microbial enzymes and production of microbial metabolites, we systemically investigated the growth promoting of cyadox, and effects cyadox on the nutrients digestibility, nutrients concentrations in the porcine serum and tissues. The effect of cyadox on absorption, utilization and deposition of nutrients in pigs were elucidated. It was confirmed the optimum application dose and duration in swine. The results provided the scientific guidance and technical project for reasonable application of cyadox. Lucubrating of the effects of cyadox on intestinal flora, bacterial enzymes and its metabolites gave a comprehensive explanation for the relationship of growth promotion of cyadox with intestinal flora and nutrient metabolism. The effects of cyadox on the concentrations of amino acids, fatty acids vitamins and minerals in the blood and animal tissues were roundly evaluated.更多还原