1～21日龄黄羽肉鸡锌需要量的研究

Zinc Requirement of Yellow Broilers Aged from One to Twenty-one Days

本研究旨在通过研究不同日粮锌(Zn)添加水平对黄羽肉鸡生长性能、抗氧化机能、免疫功能、组织Zn沉积等的影响,并对相对敏感指标进行非线性回归模型分析,以探讨1～21日龄黄羽肉鸡的Zn需要量。选用1日龄健康、发育良好的快大型岭南黄羽肉鸡公雏鸡1440只,根据体重随机分成6个处理,每个处理6个重复,每个重复40只鸡,处理1(空白对照组)为基础日粮,其中Zn水平为25mg/kg,处理2、3、4、5、6日粮分别在基础日粮中添加20、40、60、80、120mg/kgZn。结果表明,日粮中添加各Zn水平均显著提高了试鸡平均日增重(P<0.05),添加80、120mg/kgZn显著提高了平均日采食量(P<0.05),添加60mg/kgZn显著降低了料重比(P<0.05)。日粮中添加Zn显著提高了血清中谷胱甘肽(GSH)、Zn、金属硫蛋白(MT)含量和谷胱甘肽过氧化物酶(GSH-Px)、铜锌超氧化物歧化酶(CuZnSOD)、碱性磷酸酶(AKP)活性(P<0.05),并显著增加了胫骨中Zn含量和肝脏中MT含量(P<0.05),其中添加60mg/kgZn对改善血清AKP活性和胫骨Zn含量效果最佳。日粮中添加40mg/kgZn显著提高了脾脏指数(P<0.05),添加20～80mg/kgZn显著提高了胸腺指数和法氏囊指数(P<0.05)。试验结果提示,以平均日增重、血清AKP活性和胫骨Zn含量为衡量指标,并考虑基础日粮中Zn水平得出,1～21日龄阶段试鸡日粮Zn适宜水平均为85mg/kg,通过非线性回归模型估测得到的日粮Zn适宜水平分别为99、96和93mg/kg。

The experiment was conducted to investigate dietary zinc level on growth performance, antioxidant capacity, immune function and zinc deposition in yellow broilers aged from one to twenty-one days, and to estimate the optimal dietary zinc level for yellow broilers by NLIN. A total of 1 440 one-day-old male broilers were randomly assigned to six dietary treatments with six replicates of forty birds. The treatments received the same basal diet supplemented with 0, 20, 40, 60, 80 and 120 mg/kg zinc from zinc sulfate （ZnSO4 · H2O）, respectively. The feeding trial lasted for 21 days. The results showed that adding zinc significantly improved average daily gain of broilers （P〈0.05）, addition with 80, 120 mg/kg zinc significantly increased feed intake of broilers （P〈0.05）, and supplementation with 60 mg/kg zinc significantly decreased ratio of feed to gain of broilers （P〈0.05） ; zinc supplementation significantly increased the content of GSH, Zn and MT, as well as the activities of GSH-Px, CuZnSOD and AKP in serum （P〈0.05）, and significantly raised zinc content in tibia and MT content in liver （P〈0.05）, and addition with 60 mg/kg zinc showed the best result for AKP activity in serum and zinc content in tibia; supplementation with 40 mg/kg zinc significantly elevated spleen index （P〈0. 05）, and addition with 20 to 80 mg/kg zinc significantly improved thymus index and index of bursa of Fabricius of broilers （P〈0.05）. Based on the criteria including ADG, serum AKP activity and tibia zinc content, the estimated requirement of zinc was 85 mg/kg, but the optimal zinc levels estimated by NLIN were 99, 96, 93 mg/kg, respectively.