【作者】 李浩杰；

【导师】 林树茂； 刘燊； 张秋生；

【作者基本信息】 佛山科学技术学院 ， 养殖（专业学位）， 2019， 硕士

【摘要】 锌是动物机体必需微量元素。现代集约化饲养条件下,微量元素锌通常过量添加,吸收不了的锌通过粪便排出造成的环境污染,已引起了人们的广泛关注。因此,探讨新型锌源是微量元素营养的研究热点之一。试验一、本研究旨在探讨乳酸锌对黄羽肉鸡生长性能、血清生化指标、免疫性能、肠道形态和肝脏（MT）基因表达的影响。试验选用19日龄健康黄羽肉鸡2 250只（公）,按体重无差异原则随机分为5组,每组3个重复,每个重复150只。对照组饲喂玉米-豆粕型基础日粮,试验组在基础日粮的基础上添加40、60、80 mg Kg^-1乳酸锌及80 mg/kg硫酸锌。结果表明:（1）日粮锌处理对黄羽肉鸡的生长性能没有显著影响,无论锌来源和剂量如何。（2）60 mg/kg锌可显著提高38日龄鸡血清总蛋白和白蛋白水平,表明鸡的蛋白质代谢明显改善。（3）60 mg/kg锌处理显著提高了62日龄鸡的血清谷胱甘肽过氧化物酶水平,表明它们具有较强的抗氧化能力。（4）60 mg/kg的锌可显著上调肝脏MT m RNA的表达,这可能是由于高锌吸收所致。（5）40和60 mg/kg乳酸锌的饮食补充显著增加了绒毛高度,同时降低了隐窝深度,显示出黄羽肉鸡肠道形态的改善。小结,中大黄羽肉鸡日粮中乳酸锌的适宜添加量为60mg/kg。试验二、通过对黄羽肉鸡生长性能、肠道形态结构、血液指标、胫骨锌含量、锌表观代谢率及肝脏金属硫蛋白m RNA基因表达的测定,比较4种有机锌源在黄羽肉鸡中的作用效果,旨在为黄羽肉鸡锌添加剂在生产实践中的选择和应用提供依据。试验选用18日龄健康黄羽肉鸡1 080只（母）,按体重无差异原则随机分成6组,每组6个重复,每个重复30只。对照组饲喂基础日粮（不额外加锌）,试验组在基础日粮的基础上分别添加乳酸锌、硫酸锌、蛋氨酸锌、甘氨酸锌、蛋白锌（60 mg/kg,以锌计）。结果表明:（1）在玉米-豆粕型基础日粮中添加60 mg/kg甘氨酸锌、乳酸锌和蛋氨酸锌能使黄羽肉鸡获得更大的生长性能。（2）锌添加组提高了血清总蛋白、白蛋白的水平,且甘氨酸锌组显著高于对照组,59日龄时血清总蛋白乳酸锌组显著高于对照组。（3）甘氨酸锌、乳酸锌和蛋氨酸锌对谷胱甘肽过氧化物酶活性的影响优于其他锌源,且显著高于硫酸锌组和对照组。39日龄有机锌添加组血清丙二醛含量与硫酸锌组和对照组相比存在显著差异。（4）锌添加组有增加绒毛高度,减少隐窝深度的趋势;十二指肠绒毛隐窝比甘氨酸锌组显著高于对照组,空肠绒毛高度及绒毛隐窝比显著高于对照组,回肠甘氨酸锌和蛋氨酸锌组显著高于对照组显示有机锌的添加对肠道形态结构有一定影响。（5）此外,根据锌相关转运蛋白基因MT m RNA的表达,乳酸锌、蛋氨酸锌和甘氨酸锌对锌的吸收更为有效。（6）胫骨锌含量及锌表观代谢率乳酸锌、甘氨酸锌和蛋氨酸锌组均比硫酸锌及对照组显著提高。（7）日粮不同锌源对黄羽肉鸡锌表观代谢率的影响差异显著,乳酸锌、甘氨酸锌和蛋氨酸锌显著高于硫酸锌组。小结,黄羽肉鸡的适宜日粮锌源为甘氨酸锌、乳酸锌及蛋氨酸锌。综上所述:乳酸锌的适宜添加量为60mg/kg。黄羽肉鸡的适宜日粮锌源为甘氨酸锌、乳酸锌及蛋氨酸锌。更多还原

【Abstract】 Zinc is an essential trace element in animal organisms.Under the condition of modern intensive feeding,the environmental pollution caused by the excessive addition of trace element zinc,which can not be absorbed by excrement,has aroused widespread concern.Therefore,exploring a new type of zinc source is one of the hot spots in the research of trace element nutrition.Experiment 1:The present study aimed to investigate the effects of zinc lactate on growth performance,serum biochemical indexes,immune,intestinal morphology and hepatic metallothionein（MT）gene expression in the yellow-feathered broilers.At 19days of age,2 250 yellow-feathered broilers were randomly allocated to 5 dietary groups with 3 replicates per group and 150 birds in each replicate.The control group of broilers was fed with basal diet,the treatment groups of broilers were fed with basal diets supplemented dietary supplementation of 40,60,80 mg Zn Kg^-1as reagent grade Zinc lactate groups,and 80 mg Zn Kg^-1from zinc sulfate group.As a result:（1）The dietary zinc treatments had no significant effect on the growth performance up to61 days of age,regardless of the zinc source and dosage.（2）Dietary supplementation of 60 mg/kg zinc lactate significantly increased the levels of the serum total protein and albumin at 44 days of age indicating an improved protein metabolism of birds as compared with both Zn SO₄ and control birds.（3）60 mg/kg zinc lactate supplementation significantly increased the serum GSH-Px levels at 62 days of age compared with the Zn SO₄ and the control groups,demonstrating an enhanced antioxidant ability of these birds.（4）In addition,60 mg/kg zinc lactate supplementation significantly up-regulated the hepatic expression of MT m RNA likely due to the higher zinc uptake.（5）Moreover,dietary supplementation of 40mg/kg zinc lactate significantly increased the villi height while decreased the crypt depth of ileum,exhibiting an improved intestinal morphology of the yellow-feathered broilers.The results showed that the optimal zinc level in yellow broiler chick was 60mg/kg.Experiment 2:The objective of this study was to evaluate the effects of different zinc sources on growth performance,intestinal morphology,serum biochemical indexes,carcass traits,tibia zinc content,zinc apparent metabolic rate and hepatic metallothionein（MT）gene expression in the slow-growing broilers（female）.The experiment was designed to compare the effects of four kinds of organic zinc on broiler chickens,to provide a scientific basis for the selection and application of broiler zinc additives.A total of 1 080 18-day-old healthy yellow-feathered broilers were randomly divided into 6 groups:basal diet+（zinc lactate,zinc sulfate,zinc methionine,zinc glycine,zinc methionine,zinc glycine,protein zinc 60 mg/kg）and basal diet group（excluding additional zinc sources）,with 6 replicates per group and30 birds in each replicate.As a result:（1）Adding 60 mg/kg Gly-Zn,zinc lactate and Gly-Zn to corn-soybean meal basal diet could increase the production performance of yellow feather broilers.（2）The level of serum TP,ALB was increased in zinc-supplemented group,and it was significantly higher in Gly-Zn group than that in control group;At the age of 59 days,the serum total protein of zinc lactate group was significantly higher than that of the control group.（3）The effects of Gly-Zn and zinc methionine on GSH-Px activity were better than those of other zinc sources,and significantly higher than that in zinc sulfate group and control group.There was a significant difference between the 39-day-old organic zinc addition group and zinc sulfate group and control group in serum MDA content.（4）Zinc addition group had the tendency of increasing villus height and decreasing recess depth.The ratio of duodenum villous crypt to zinc glycine group was significantly higher than that of control group.Zinc glycine and zinc methionine in the ileum were significantly higher than those in the control group,indicating that the addition of organic zinc had a certain effect on the intestinal morphology.（5）In addition,zinc lactate,Met-Zn and Gly-Zn were more effective in the absorption of zinc according to the expression of zinc-associated transporter MT.（6）Groups treated with Gly-Zn,zinc methionine and zinc lactate had higher tibia zinc content than groups with Zn SO₄ and control.（7）The effect of different dietary zinc sources on the apparent metabolic rate of zinc in yellow feather broilers was significant.Zinc lactate,glycine zinc and zinc methionine were significantly higher than those in zinc sulfate group.The results showed that the best dietary zinc source for yellow-feather broilers were zinc lactate,Met-Zn and Gly-Zn.In conclusion,the optimal zinc level in yellow broiler chick was 60mg/kg.The best dietary zinc sources for yellow feather broilers are glycine zinc,zinc lactate and zinc methionine.更多还原