肌肉注射pCEP4-PTH基因质粒对饲喂低钙日粮蛋鸡的效应研究

为研究钙供给不足时肌肉注射鸡甲状旁腺素基因质粒(pCEP4-PTH质粒)对蛋鸡生产性能、蛋壳质量和激素水平的影响。选择150只56周龄新扬州产蛋鸡,随机分为3组(低钙组、质粒组和高钙组),各组5个重复,每重复10只。低钙组和质粒组均饲喂含钙2.5%的日粮,并在左腿肌肉部位分别以0、200μg剂量注射pCEP4-PTH表达质粒;高钙组饲喂含钙3.5%的日粮,注射0μg pCEP4-PTH质粒。预试期14 d,试验期28 d。结果显示,质粒组生产性能、蛋壳质量均优于低钙组,但差异不显著(P>0.05),与高钙组间也无显著差异(P>0.05);高钙组产蛋率、料蛋比、蛋比重、蛋壳强度、蛋壳比例均显著优于低钙组(P<0.05),采食量和蛋壳厚度差异不显著(P>0.05)。质粒组甲状旁腺素(PTH)水平显著高于高钙组(P<0.05),其他各组间差异不显著(P>0.05),各组CT、E2、BGP、IGF-1水平差异不显著(P>0.05)。试验表明,pCEP4-PTH质粒可减缓饲粮钙供给不足对蛋鸡生产性能和蛋壳质量造成的不利影响,且不影响其体内正常的骨代谢。

Effect of intramuscular plasmid of pCEP4-PTH gene on layers of low calcium diets

The present study was conducted to investigate the effect of intramuscular plasmid of pCEP4-PTH gene on the production performance,eggshell quality and hormone levels of layers under low calcium diets.One hundred fifty New Yangzhou chickens of 56-week-old laying hens were randomly divided into three treatments(low calcium treatment,plasmid treatment and high calcium treatment) with five replicates which had 10 birds each.The low calcium treatment and plasmid treatment were fed diet including 2.5% calcium,and injected 0 and 200 μg dose pCEP4-PTH plasmid into the muscle of left leg,respectively.In addition,high calcium treatment was fed diet of 3.5% calcium,injected 0 μg dose pCEP4-PTH plasmid.The whole experiment contained 14 days as fore trial period and 28 days as trial period.The result showed that,production performance and eggshell quality of plasmid treatment surpassed the low calcium treatment,but was not significant(P>0.05).While,laying rate,feed/egg ratio,egg proportion,eggshell strength and eggshell weight percentage in high calcium treatment obviously surpassed the low calcium treatment(P<0.05),but the difference of foraging and eggshell thickness was not remarkable(P>0.05).PTH level of plasmid treatment was higher than the high calcium treatment(P<0.05),other treatments was not different significantly(P>0.05),the difference of CT,E2,BGP and IGF-1 level in each treatment was also not significant(P>0.05).The experiment indicated that pCEP4-PTH plasmid might slow down the adverse effect of production performance and the eggshell quality,which was caused by low calcium,and without affecting the body normal bone metabolism.