不同水平铜源对奶牛生产性能、抗氧化能力和铜代谢的影响

Effects of different levels of copper sources on performance, antioxidant capacity and copper metabolism of dairy cows

关键词:  奶牛  铜源  生产性能  抗氧化能力  铜代谢

Key words:  dairy cows  copper source  performance  antioxidant capacity  copper metabolism

摘要:

为研究不同水平铜源对奶牛生产性能、抗氧化能力和铜代谢的影响，采用双因素试验设计，包括2种铜源(硫酸铜、赖氨酸铜和谷氨酸铜的1∶1络合物)，铜源的不同添加水平分别为0、3.5和7.0 mg/kg，2种铜源共用对照组，添加量均以铜元素计。选择80头胎次、泌乳天数和产奶量相近的健康荷斯坦奶牛，随机分为5组，每组16头，预试期2周，正试期12周。每2周测定干物质采食量(DMI)，每周测定产奶量和乳成分，每4周测定血清抗氧化指标，试验期最后3 d进行铜代谢试验。结果表明:铜水平为3.5和7.0 mg/kg组DMI和产奶量显著高于对照组(P<0.05)，铜水平为3.5和7.0 mg/kg组间 DMI和产奶量无显著差异(P>0.05)，2种铜源间DMI和产奶量无显著差异(P>0.05)；铜水平为3.5和7.0 mg/kg组乳脂率显著低于对照组(P<0.05)，不同水平铜源对乳蛋白率、乳糖率和总固形物无显著影响(P>0.05)；铜水平为3.5和7.0 mg/kg组铜蓝蛋白(CER)活性显著高于对照组(P<0.05)，铜水平为7.0 mg/kg组CER和超氧化物歧化酶(SOD)活性显著高于3.5 mg/kg组(P<0.05)，2种铜源间CER和SOD活性无显著差异(P>0.05)；铜水平为3.5和7.0 mg/kg组粪铜和铜沉积率显著高于对照组(P<0.05)，铜水平为7.0 mg/kg组粪铜和铜沉积率显著高于3.5 mg/kg组(P<0.05)，赖氨酸铜和谷氨酸铜的 1∶1 络合物组铜沉积率显著高于硫酸铜组(P<0.05)。综上所述，饲粮中添加铜可以提高奶牛产奶量和抗氧化能力，赖氨酸铜和谷氨酸铜的1∶1络合物相较于硫酸铜具有更高的铜沉积率，从生产性能和环境保护角度看，添加3.5 mg/kg的赖氨酸铜和谷氨酸铜的1∶1络合物效果最好。

Abstract:

The aim of the experiment was to study the effects of different levels of copper sources on performance, antioxidant capacity and copper metabolism of dairy cows. A two factor experimental design was used, including two copper sources(copper sulfate, 1∶1 complex of copper lysine and copper glutamic acid)and the different supplemental levels of copper sources were 0, 3. 5 and 7. 0 mg/kg, respectively. Two copper sources shared the control group, and the supplemental amount was based on copper element. 80 healthy Holstein cows with similar parity, lactation days and milk yield were randomly divided into 5 groups with 16 cows in each group. The pre-test period lasted for 2 weeks, and the trial period lasted for 12 weeks. DMI was measured every 2 weeks, milk yield and milk composition were measured weekly, serum antioxidant index were measured every 4 weeks, and copper metabolism test was conducted in the last 3 days of the trial period. The results showed that DMI and milk yield of 3. 5 and 7. 0 mg/kg copper groups were significantly higher than those in control group(P<0. 05). There was no significant difference in DMI and milk yield between 3. 5 and 7. 0 mg/kg copper groups(P>0. 05), and there was no significant difference in DMI and milk yield between two copper sources(P>0. 05); Milk fat rate in 3. 5 and 7. 0 mg/kg copper groups was significantly lower than that in control group(P<0. 05), and there was no significant effect of different levels of copper sources on milk protein rate, lactose rate and total solids(P>0. 05); CER activity in 3. 5 and 7. 0 mg/kg copper groups was significantly higher than that in control group(P<0. 05), CER and SOD activities in 7. 0 mg/kg copper group were significantly higher than those in 3. 5 mg/kg copper group, and there was no significant difference in CER and SOD activities between two copper sources(P>0. 05); Fecal copper and copper deposition rate in 3. 5 and 7. 0 mg/kg copper groups were significantly higher than those in control group(P<0. 05); Fecal copper and copper deposition rate in 7. 0 mg/kg copper group were significantly higher than those in 3. 5 mg/kg copper group(P<0. 05), and copper deposition rate in 1∶1 complex of copper lysine and copper glutamic acid group was significantly higher than that in copper sulfate group(P<0. 05). In conclusion, diet supplemented with copper can improve milk yield and antioxidant capacity of dairy cows. 1∶1 complex of copper lysine and copper glutamic acid has higher copper deposition rate than copper sulfate. From the perspective of performance and environmental protection, diet supplemented with 3. 5 mg/kg 1∶1 complex of copper lysine and copper glutamic acid has the best effect.