降低铜、锌含量添加植酸酶对育肥猪生长性能、养分表观消化率及血清生化指标的影响

本试验旨在探讨植酸水平较高饲料中育肥猪适宜的铜、锌添加水平。试验选取108头55 kg左右的苏姜猪，采用2×3因子设计将试验猪随机分为6组，每组3个重复，每个重复6头。将低、中、高剂量铜、锌与植酸酶添加、不添加组合成6种饲料，每组饲喂其中1种饲料。试验期42 d，测定试验期间育肥猪生长性能、养分表观消化率、血清生化指标及血清和掌骨铜、锌含量。结果显示，降低饲料中铜、锌含量并添加植酸酶未显著影响育肥猪生长性能（P>0.05）。将铜、锌水平从高剂量降低到中、低剂量极显著地提高了铜、锌的表观消化率（P<0.01），极显著降低了血清铜含量（P<0.01）；从高剂量降低到中剂量极显著降低了血清碱性磷酸酶活性（P<0.01）。添加植酸酶极显著提高了粗蛋白质表观消化率（P<0.01），显著提高了锌表观消化率和血清碱性磷酸酶活性（P<0.05）。铜、锌水平和添加植酸酶对血清和掌骨锌含量、血清铜蓝蛋白和乳酸脱氢酶活力均无显著影响（P>0.05）。综上所述，在较高植酸水平的饲料中将铜、锌含量降到中等水平可提高铜、锌表观消化率，而不影响生长性能。添加植酸酶有利于提高粗蛋白质、锌的表观消化率。因而建议育肥苏姜猪饲料中添加中剂量铜、锌（即25 mg/kg铜＋40 mg/kg锌）并添加植酸酶。

Effects of Decreasing Cu and Zn Contents and Supplementing with Phytase on Growth Performance,Nutrients Apparent Digestibility and Serum Biochemical Indexes of Finishing Pigs

This experiment was conducted to investigate suitable Cu and Zn contents for finishing pigs.One hundred and eight Su Jiang pigs with about 55 kg body weight were randomly divided into 6 groups with 3 replicates per group and 6 pigs per replicate by 2×3 factor design.The low-,medium-,and high-dose Cu and Zn combined with phytase addition and no addition were assigned to 6 diets,one for each group.The trial lasted for 42 d.The growth performance,nutrients apparent digestibility,serum biochemical indexes,and Cu and Zn contents in serum and metacarpals of finishing pigs were tested.The results showed that the growth performance of finishing pigs were not significantly affected by reducing Cu and Zn contents or supplementing with phytase (P>0.05).The apparent digestibility of Cu and Zn were extremely significantly increased (P<0.01) and the serum Cu content was extremely significantly decreased from high dose to medium dose or low dose (P<0.01).The activity of alkline phosphatase (AKP) in serum was extremely significantly decreased by decreasing the content of Cu and Zn from high to medium dose (P<0.01).The apparent digestibility of crude protein was extremely significantly increased (P<0.01),and the Zn apparent digestibility and AKP activity were significantly increased (P<0.05) by the addition of phytase.Zn content in serum and metacarpals,the activities of ceruloplasmin and lactate dehydrogenase (LDH) in serum were not significantly affected by the content of Cu and Zn and phytase addition (P>0.05).In conclusion,reducing Cu and Zn contents to medium level in high phytate diet could increase the apparent digestibility of Cu and Zn,but had no adverse impact on growth performance.Adding phytase in the diet could increase Zn and crude protein apparent digestibility.Therefore,moderate contents of Cu and Zn was 25 and 40 mg/kg,and phytase were recommended to add in diet of Su Jiang finishing pig.