肉仔鸡对不同铜源生物学效价的研究

STUDY ON THE UNAVAILABILITY OF DIFFERENT COPPER SOURCES FOR BROILERS

试验采用2×4因子的试验设计,通过屠宰试验结合代谢试验,研究肉仔鸡对不同铜源(硫酸铜、蛋氨酸铜、硬脂酸铜和天然饲料铜)的生物学效价及植酸对其影响。其中天然饲料铜主要指玉米和豆饼中的铜。试验用56日龄AA肉仔鸡16只,单笼个体饲养,每处理2个重复,采用强饲法,自由饮水。以淀粉—酪蛋白为主构成纯合型基础日粮。纯台型试验日粮的补铜水平与天然饲料的含铜量一致,为4.29mg/kg。外加植酸设两个水平:0％和1％。预试期3天,饲喂无铜纯合日粮,试验期3天,其中代谢试验期2天。结果表明:在本试验研究条件下,不同铜源对试鸡铜表观代谢率影响不显著;对肝脏铜浓度和红细胞铜—锌超氧化物歧化酶活性有极显著的影响(硫酸铜>蛋氨酸铜>天然饲料铜>硬脂酸铜)。日粮植酸水平对试鸡铜的表观代谢率、肝脏铜浓度及红细胞铜-锌超氧化物歧化酶活性的影响程度因铜源而异。就铜表观代谢率来说,硫酸铜组和蛋氨酸铜组因添加植酸降低量较大,硬脂酸铜次之,天然饲料铜则基本不受其影响。肝脏铜浓度和红细胞铜—锌超氧化物歧化酶活性受植酸的影晌表现出一致的趋势:硫酸铜和硬脂酸铜降低量大,蛋氨酸铜和天然饲料铜则受植酸影响较小。在本试验条件下。

16 fifty-six-day old Abro Acres broilers were used to evaluate the bioavailability of different copper sources and the effect of phytic acid on it.Broilers were allotted randomly to a 2×4 factorial design with two duplicates,and fed diets included a casein-corn starch basal purified diet supplemented with 4.29mg/kg Cu as CuSO4 5H2O,copper stearate [(C18H36O2)2Cu,SCu].copper methionine chelate [Cu(met)2]and the conventional diet based corn-soybean (this Cu source was named as nature Cu in this study,NCu).Levels of exogenous phytic acid were 0% and 1% as sodium phate at each Cu source.The Depletion-Repletion technique combined with balance experiment was used in this study.Apparent metabolizability of Cu(AMCu),liver Cu(LCu),erythrocyte copper-zinc superoxide dismu-tase(ECu-ZnSOD) were used as indexes to evaluate the bioavailability of different copper sources.Under the conditions of this study,AMCu was not affected by different Cu sources (P>0.05).but LCu and ECu-ZnSOD were influenced significantly.(P<0.01,CuSO4 5H2O>Cu(Met)2>NCu>SCu).AMCu,LCu and ECu-ZnSOD were decreased significantly by the addition of phytic acid into the diets supplemented CuSO4 5H2O FCu and Cu(Met)2 of Cu-deficient broilers,but were not be influenced by the addition of phytic acid into the diets supplemented NCu.Under different levels of phytic acid (0%,1%),relative to efficacy of the CuSO4 5H2O(100 assumed,the addition of phytic acid was 0%,1%),the bioavailabilities of Cu-SO4 5H2O,SCu,Cu(Met)2 and NCu were as follows :(1)Taking AMCu as index,100,34.93;91.39,53.32;86.39,41.39;97.29,86.44,respectively;(2)Taking LCu as index,100,57.59;69.19,51.19:73.21,73.24;69.45,81.74,respectively;(3)Taking ECu-ZnSOD as index,100,45.03;74.44,42.01;82.63,73.17;75.97,65.02,respectively;