饲粮铜、锌含量及其互作效应对育成期水貂生长性能、营养物质表观消化率及铜、锌和氮代谢的影响

摘要

本试验旨在研究饲粮铜、锌含量及其互作效应对育成期水貂生长性能、营养物质表观消化率及铜、锌和氮代谢的影响。试验采用3×3完全随机试验设计,分别在基础饲粮(不添加铜、锌)基础上添加3个水平(0、15和30 mg/kg)的铜(以硫酸铜形式)和3个水平(0、150和300 mg/kg)的锌(以硫酸锌形式)。选用(60±3)日龄、体重相近的健康雄性水貂108只,随机分成9组,每组12个重复,每个重复1只。预试期为7 d,正试期为60 d。结果表明：1)饲粮铜含量对水貂平均日增重( P=0.069)和料重比( P=0.058)有影响趋势。以平均日增重为响应指标,通过二次响应面回归模型估测育成期水貂铜、锌适宜含量分别为51和117 mg/kg时,此时水貂可以获得最大平均日增重14.10 g。2)饲粮铜含量对水貂粗脂肪的表观消化率有显著影响( P=0.019),对铜的表观消化率有极显著影响(P=0.001)；饲粮锌含量对水貂粗脂肪和铜的表观消化率均没有显著影响( P>0.05)；饲粮铜、锌含量的互作效应对水貂粗脂肪的表观消化率没有显著影响(P>0.05),对铜的表观消化率有极显著影响(P=0.002)。3)饲粮铜含量对水貂铜的摄入量、粪铜和尿铜的排出量以及铜沉积量均有极显著影响( P=0.001)；饲粮铜、锌含量的互作效应对铜沉积量有显著影响( P=0.019),对粪铜的排出量有极显著影响( P=0.001)。饲粮锌含量对水貂锌的摄入量、粪锌和尿锌的排出量以及锌沉积量均有极显著影响( P=0.001)；饲粮铜、锌含量的互作效应对锌代谢指标没有显著影响( P>0.05)。饲粮铜、锌含量以及二者的互作效应对水貂氮代谢指标没有显著影响(P>0.05)。综合试验结果得出,饲粮中铜、锌含量分别为51、117 mg/kg时,育成期水貂可以获得最大平均日增重；饲粮中铜含量为39.83 mg/kg时,育成期水貂对粗脂肪的表观消化率较高,对锌的表观消化率和锌的代谢没有产生显著影响；饲粮锌铜比例大于40时,会降低育成期水貂铜的表观消化率和铜沉积量。%This experiment was conducted in a 3×3 factorial experiment based on a completely randomized de-sign to evaluate the effects of dietary copper ( Cu) and zinc ( Zn) contents and their interaction on growth per-formance, nutrient apparent digestibility and Cu, Zn and nitrogen metabolism of growing mink ( Mustela vi-son). One hundred and eight (60±3) days old male mink were randomly divided into 9 groups with 12 repli-cates each and 1 mink per replicate. The mink in those 9 groups were fed the basal diet ( without Cu and Zn supplementations) supplemented with Cu from copper sulfate ( CuSO4 ) and Zn from zinc sulfate ( ZnSO4 ) . The three Cu supplemental levels were 0, 15 and 30 mg/kg, respectively, while the three Zn supplemental levels were 0, 150 and 300 mg/kg, respectively. The pre-test period lasted for 7 days, and the trial period las-ted for 60 days. The results showed as follows: the average daily feed intake ( P=0.069) and average daily gain ( ADG, P=0.058) had a influenced trend by dietary Cu content. Based on the ADG, the optimal copper and zinc contents estimated by Box-Behnken regression model were 51 and 117 mg/kg, respectively. In this case, the ADG obtained the highest value which was 14.10 g. 2) The ether extract ( EE) apparent digestibility was significantly ( P=0.019) and Cu apparent digestibility ( P=0.001) were extremely significantly influenced by dietary Cu content, however, they were not significantly influenced by dietary Zn content ( P>0.05) . The interaction of Cu and Zn contents had no significant influence on EE apparent digestibility ( P>0.05) , but ex-tremely significantly influenced Cu apparent digestibility ( P=0.002) . Cu intake, fecal and urinary Cu excre-tion and Cu retention were extremely significantly influenced by dietary Cu content (P=0.001). The interac-tion of Cu and Zn contents had a significant influence on Cu retention ( P=0.019) , and had an extremely sig-nificant influence on fecal Cu excretion ( P=0.001) . Zn intake, fecal and urinary Zn excretion and Zn reten-tion were extremely significantly influenced by dietary Zn content (P=0.001). The interaction of Cu and Zn contents had no significant influence on Zn metabolism indices (P>0.05). The nitrogen metabolism indices were not significantly influenced by dietary Cu and Zn contents and their interaction ( P>0.05) . Comprehensive the results show that when the dietary Cu and Zn contents are 51 and 117 mg/kg, respectively, the growing mink has the highest ADG;when dietary Cu content is 39.83 mg/kg, growing mink has a higher EE apparent digestibility, which does not significantly influence Zn apparent digestibility and Zn metabolism; when Zn/Cu is more than 40, the Cu apparent digestibility and Cu retention are reduced.