日粮有机锌水平对产蛋后期蛋鸡生产性能、免疫功能和抗氧化指标的影响

Effects of Dietary Organic Zinc on Production Performance, Immune Function and Anti-oxidative Parameters of Laying Hens at the Late of Laying Cycle

试验旨在研究日粮有机锌水平对产蛋后期蛋鸡生产性能、免疫功能和抗氧化指标的影响。选取体重和产蛋率相近的57周龄海兰灰蛋鸡960只,随机分为4组,每组8个重复,每个重复30只。参照NRC(1994)蛋鸡饲养标准,结合海兰公司推荐日粮营养水平,设计玉米-豆粕型基础日粮(基础日粮锌水平35.08 mg/kg)。试验期16周,其中预试期2周(57～58周龄),各处理组均饲喂不补充锌的基础日粮;正试期14周(59～72周龄),对照组在基础日粮中添加80 mg/kg硫酸锌,试验组分别在基础日粮中添加20、40、80 mg/kg的羟基蛋氨酸螯合锌(MHA-Zn),常规饲养管理。结果表明:(1)锌源和添加水平对蛋鸡的产蛋率、平均蛋重、平均日采食量、料蛋比等产蛋性能指标没有显著影响(P>0.05),但添加40、80 mg/kg MHA-Zn显著降低蛋鸡破蛋率(P<0.05);(2)各处理组血清免疫球蛋白IgG和IgM水平,新城疫病毒抗体水平无显著差异(P>0.05),但添加40 mg/kg MHA-Zn显著提高蛋鸡H5亚型禽流感病毒抗体水平(P<0.05);(3)有机锌与无机锌相比,具有显著提高机体抗氧化能力的优势(P<0.05),主要表现为提高蛋鸡血清和肝脏中铜锌-超氧化物歧化酶(Cu/Zn-SOD)活性和总抗氧化能力(T-AOC),降低丙二醛(MDA)含量。综上所述,建议产蛋后期蛋鸡日粮中MHA-Zn添加水平为40 mg/kg。

This study was aimed to study the effects of methionine hydroxy analog chelate zinc （MHA-Zn） on production performance, immune function and anti-oxidative parameters of laying hens at the late of laying cycle. A total of 960 layers （Hy-line Grey, 57 weeks of age）were randomly assigned into 4 groups with 8 replicates per treatment. The experiment lasted for 16 weeks： During the first 2 weeks, birds were fed a basal diet without extra zinc （35.08 mg/kg Zn）, while during the ensuing 14 weeks, 4 levels of Zn （Inorganic Zn： 80 mg/kg; Organic Zn： 20, 40, 80 mg/kg）were added to diet, respectively. The results showed that neither Zn source nor level could influence laying rate, average egg weight, average daily intake, feed to egg ratio （P〉0.05）, while groups supplemented with 40 or 80 mg/kg MHA-Zn were significantly decreased broken egg rate （P〈0.05）. In addition, no remarkable difference was found in IgM, IgG and antibody level against Newcastle disease virus （P〉0,05）, while dietary 40 mg/kg MHA-Zn was dramatically increased antibody level against H5 subtype avian influence virus （P〈0.05）. Moreover, compared with inorganic zinc, MHA-Zn significantly promoted the anti-oxidative capacity （P〈0.05）, mainly by increasing the activity of Cu/Zn-SOD and T-AOC and decreasing MDA content in serum and liver. In conclusion, the optimal supplementation of MHA-Zn in diet of aged laying hen was 40 mg/kg.