【作者】 张凯；

【导师】 方热军；

【作者基本信息】 湖南农业大学 ， 动物营养与饲料科学， 2012， 硕士

【摘要】 本论文旨在研究玉米豆粕型基础日粮中添加不同水平乳铁蛋白对早期断奶仔猪的生产性能、营养物质表观消化率、血清生化指标、胃肠道消化酶、血清及粪便中金属元素含量影响,探讨乳铁蛋白在日粮中的最适添加水平,诠释乳铁蛋白调控仔猪生产性能的作用机理,为在养殖业上乳铁蛋白的应用提供更多的理论依据。选用96头21日龄健康的杜×长×大三元杂交断奶仔猪,采用单因素试验设计,随机分为4个处理,每个处理4个重复,每个重复6头仔猪,分别在基础饲粮中添加0、250、500和750mg/kg乳铁蛋白。正式期为21天。试验结果表明：(1)在基础日粮中添加乳铁蛋白能使仔猪的平均日增重显著提高(P<0.05),各试验组间差异显著(P<0.05)；日粮中添加乳铁蛋白有降低料肉比的趋势,但与对照组差异不显著(P>0.05),其中以500mg/kg添加组最低；乳铁蛋白添加组的腹泻率显著低于对照组(P<0.05),250mg/kg与500mg/kg添加组间差异不显著(P<0.05)。(2)乳铁蛋白有提高断奶仔猪干物质消化率的趋势(P>0.05),其中500mg/kg添加组最高,达到82.25%；与对照组相比,250mg/kg.750mg/kg组能显著提高粗灰分的消化率(P<0.05),500mg/kg添加组有提高的趋势(P>0.05)；仔猪对钙、磷的表观消化率没有随着乳铁蛋白量的添加而呈显著性变化(P>0.05);500mg/kg和750mg/kg添加组与对照组相比均能显著降低粪样中金属铁元素的含量(P<0.05),对粪样中的铜、锌、锰元素含量的降低影响不显著(P>0.05)。(3)与对照组相比,日粮中添加乳铁蛋白有提高胃蛋白酶活性的趋势,差异不显著(P>0.05),其中250mg/kg组酶活力达到94.53U,比对照组提高4.79%；但试验组十二指肠中胰淀粉酶和胰脂肪酶活力随着乳铁蛋白添加量的提高并没有表现出明显的变化趋势,说明乳铁蛋白对胰淀粉酶和胰脂肪酶活力影响不显著(P>0.05)。(4)750mg/kg乳铁蛋白组血清中尿素氮和总胆固醇的含量显著低于对照组(P<0.05),各添加组血清中总蛋白水平有提高的趋势(P>0.05)；各乳铁蛋白添加组均能显著的提高血清中Fe离子的含量(P<0.05),对血清中Cu、Zn的含量有提高的趋势(P>0.05),其中500mg/kg添加组的血清总铁结合力显著高于对照组；各添加组中血清谷丙转氨酶、谷草转氨酶、碱性磷酸酶、乳酸脱氢酶的活性与对照组差异不显著(P>0.05)；在血液抗氧化性指标方面,500mg/kg添加组血清中MDA含量、GSH-PX和SOD酶活力与对照组的差异显著(P<0.05)。综上所述,在断奶仔猪日粮中添加一定剂量(本试验中500mg/kg效果最佳)的乳铁蛋白能提高断奶仔猪的生产性能,降低腹泻率。乳铁蛋白通过促进机体对Fe的吸收和转运,改善肠道中微生态环境,从而加强对营养物质的吸收,并通过提高血清中Fe、Cu、Zn等微量元素的含量,提高机体的抗氧化性能,增强机体的免疫功能,并能相对的减少仔猪粪便中金属元素的含量。更多还原

【Abstract】 The experiment was conducted to investigate the effects of supplemental lactoferrin in weaned piglets basal diet on growth performance, apparent nutrient digestibility, serum biochemical indexes, gastrointestinal digestive enzyme, metal content of serum and excrement, to explore the optimum level of lactoferrin in the diet and determine the specific regulation of lactoferrin in piglets for providing new theoretical basis about the application of lactoferrin in the animal production industry.Ninety-six weaned piglets at21-day-old,three-line crossbred (Duroc X Landrace X Yorkshire) were assigned randomly to4treatments and each treatment had4replicates with6piglet per replicate. Each treatment was fed basal diet supplemented with0、250、500and750mg/kg lactoferrin respectively. Experimental period lasted for21days. The results showed:(1) Basal diets supplied with lactoferrin could significantly improve the daily gain (P<0.05), the difference between all the experimental groups was significant (P<0.05). Dietary adding lactoferrin had the trend of decreasing feed/gain ratio, compared with the control group had no significant difference (P>0.05) supplemented with500mg/kg lactoferrin was the best feed/gain ratio. Compared with the control group, dietary adding lactoferrin could significant reduce the diarrhea rate (P<0.05), and the difference between250mg/kg group and500mg/kg was significant (P<0.05)(2) Lactoferrin had the trend of increasing digestibility of dry matter in weaned piglets(P>0.05),and the adding group with500mg/kg lactoferrin was the best, reach to82.25%. Compared with the control group, supplemented with250mg/kg and750mg/kg lactoferrin could significantly increasing digestibility of crude ash (P<0.05), adding of500mg/kg only had the trend (P>0.05). The apparent digestibility of calcium, phosphorus had not significantly change with the adding amount of lactoferrin (P>0.05). Compared with the control group, supplemented with500mg/kg and750mg/kg lactoferrin could significantly reduce the content of Fe in the excrement (P<0.05), and had not significant difference in the reduce the content of metal Cu、Zn、Mn in the excrement (P>0.05)(3) Compared with the control group, dietary adding lactoferrin had the trend of decreasing the activity of pepsin (P>0.05), activity of pepsin of the250mg/kg supplemented group reach to94.53U/mg, increased by4.79%. Enzyme activity of pancreatic amylase and pancreatic lipase had not significant changes as the content of lacroferrin improved (P>0.05)(4) Compared with the control group, supplemented with750mg/kg could significantly reduce the content of serum urea nitrogen and total cholesterol (P<0.05),and had the trend of improve the total protein content (P>0.05).Each supplemented group could significantly improve the content of Fe in the serum (P<0.05),and had the increased trend to the content of Cu、Zn in the serum (P>0.05) supplemented with500mg/kg Lf group could significantly improve TIBC compared with the control group. Each supplemented group had no significant difference in ALT, AST, ALP and LDH in the serum (P>0.05). About the antioxidant indicators of blood, supplemented with500mg/kg Lf group was significant difference in the content of MDA, enzyme activity of GSH-PX and SOD compared with the control group.In summary, dietary adding certain dosage lactoferrin could improve growth performance, reduced the rate of diarrhea. By promoting the absorption and transport of Fe, the lactoferrin improved the micro-ecological environment in the intestinal tract, thereby enhancing the absorption of nutrients, and by increasing the Cu, Zn and other trace element content in serum to improve the antioxidation of body, so the immune function was enhanced, and the metal element content in the excrement of piglets can be reduced.更多还原