饲粮锌对肉鸡生长性能、组织含锌酶活性以及金属硫蛋白含量的影响

选用720只1日龄商品代AA肉公鸡进行试验,研究饲粮中添加不同水平无机锌对肉仔鸡生长性能、肝脏铜锌超氧化物歧化酶(CuZnSOD)活性和肾脏金属硫蛋白(MT)含量的影响,以考核这些指标对评价肉仔鸡锌营养状况的意义。将肉鸡按平均体重随机分成8个处理组,分别饲喂不添加锌的玉米-豆粕型基础饲粮(对照组,含锌28.37mg/kg)和在对照组基础饲粮中以无机硫酸锌形式分别添加20、40、60、80、100、120mg/kg和140mg/kg锌的试验饲粮21d。结果表明:肉仔鸡的日增重、日采食量和肾脏MT含量均受到添加锌水平的显著影响(P<0.05),其中肾脏MT含量受锌水平影响极显著(P<0.01),而不同锌水平对肝脏CuZnSOD活性无显著影响(P>0.1)。这表明对于肉仔鸡,肾脏MT可能是评价机体锌营养状况的敏感指标。

Effect of Supplemental Zinc on Performance, Zn Metalloenzyme Activity and Metallothionein Concentration in Broilers

An experiment was conducted using a total of 720 one day-old Arbor Acres male broilers to study the effect of supplemental zinc (Zn) levels on performance, Zn metalloenzyme activity, and metallothionein (MT) concentration of the broilers. Birds were randomly allotted by body weight to one of eight treatments in a completely randomized design. They were fed either a Zn-unsupplemented corn-soybean meal basal diet or fed basal diets supplemented with 20, 40, 60, 80, 100, 120 or 140 mg/kg Zn as Zn sulfate (ZnSO4·7H2O) for a duration of 21 days. Results showed that weight gain and feed intake were increased with dietary Zn level increased (P < 0.05), and the maximum weight gain and feed intake were observed in the diet supplemented with 20 mg/kg Zn(48.37 mg/kg total dietary Zn). The supplemental Zn had no effect(P > 0.11) on Zn-containing superoxide dismutase (ZnCuSOD) activity in liver, while affected kidney MT concentration significantly(P < 0.05). The results from this study indicated that kidney MT concentration were a useful criterition for evaluating Zn status in broilers.