日粮锌水平对生长肉兔生产性能、血清肝脏抗氧化酶活性和金属硫蛋白-1基因表达的影响

本文旨在探讨日粮不同锌添加水平和锌源对2～3月龄生长肉兔生产性能、血清肝脏抗氧化酶活性和金属硫蛋白-1(MT-1)基因表达的影响.选用2月龄新西兰肉兔70只,随机分为7个处理,对照组饲喂基础日粮,试验组在基础日粮中分别以硫酸锌和蛋氨酸锌形式添加40、80和120 mg/kg锌,预试期7 d,正试期23 d.结果表明:日粮锌添加水平对生长肉兔平均日增重(ADG)和料重比(F/G)无显著性影响(P>0.05),对平均日采食量(ADI)影响显著(P<0.05);不同锌水平对血清铜锌超氧化物歧化酶(CuZn-SoD)和谷胱甘肽过氧化物酶(GSH-Px)活性影响显著(P<0.05),对肝脏CuZn-SoD和GSH-Px活性影响极显著(P<0.01);随日粮锌水平的增加,肝脏、肾脏MT-1mRNA相对表达丰度呈先升高后降低趋势(P<0.01),80 mg/kg添加水平时2种锌源MT-1mRNA相对表达丰度均达到最高.MT-1mRNA相对表达丰度可以作为评价动物机体锌营养状况的敏感指标.

Effects of Dietary Zn Levels on the Production Performance, Antioxidase Activitv in Serum and Liver, and Metaliothionein (MT)-1 mRNA Expression of Growing Rabbits

To study the effects of dietary ZnSO4 and Zn-Met levels on production performance,CuZn-SOD in serum and liver,GSH-Px activities,MDA concentration and MT-1mRNA expression of 2 to 3-month-old New Zealand growing rabbits.In the experiment,1 basal diet and 6 trial diets(the basal diet with the supplementation of 40,80 and 120 mg/kg of ZnSO4 and Zn-Met,respectively) were prepared for the control and trial groups.Seventy two-month-old New Zealand rabbits were randomly allotted to seven treatments with ten rabbits for each.The trial lasted for 30 days,including 7 days for adaptation.The results showed that different Zn levels had no significant effects on the average daily gain(ADG) and the feed/gain ratio(F/G)(P>0.05),but significant effects on the average daily intake(ADI)(P<0.05);The dietary Zn level could significantly improve the CuZn-SOD and GSH-Px activities in serum(P<0.05),with extremely significant effect on the CuZn-SOD and GSH-Px activities in liver(P<0.01);With the increase of Zn level,the relative MT-1mRNA expression abundance in liver and kidney increased at the beginning and then decreased(P<0.01),reaching the highest when 80 mg/kg of either Zn source was supplemented;In conclusion,the MT-1 mRNA expression abundance in liver could be adopted to evaluate the zinc nutritional status in growing meat rabbits;The appropriate dietary Zn level for 2 to 3-month-old growing meat rabbits was 80 mg/kg,while Zn-Met was more effective than ZnSO4.