【作者】 董海军；

【导师】 王康宁；

【作者基本信息】 四川农业大学 ， 动物营养与饲料科学， 2007， 硕士

【摘要】 本文考察了pGRF基因质粒对免疫应激断奶仔猪生产性能的影响,探讨了pGRF基因质粒缓解免疫应激引起的生长抑制作用及其可能的机理。选用日龄为35±2d、体重为7.86±0.59Kg未去势的DLY断奶仔猪18头,按体重相近、性别一致的原则配对,分为3个处理,即pGRF基因质粒组、pGRF基因质粒+LPS(脂多糖)组和LPS组,每个处理6个重复,每个重复1头猪。单笼饲养,日粮中不添加抗生素。试验猪自由采食与饮水,记录试验猪采食、增重以及腹泻发生情况,试验期为3周。饲养考查指标为采食量、日增重、料重比、腹泻频率。pGRF基因质粒和pGRF基因质粒+LPS组在实验的第1d注射1.0mg pGRF基因质粒/头,只注射一次,LPS组注射等量的生理盐水。在试验的第8、15d,pGRF基因质粒+LPS和LPS组按100μg/kgBW(体重)剂量颈部肌肉注射LPS,pGRF基因质粒组注射等量的生理盐水;注射LPS 2h后,采血,免疫比浊法测定外周血中的IgG浓度,采用酶联免疫吸附法(ELISA)测定外周血中IGF-Ⅰ、IL-1和IL-6。试验结果表明:1.pGRF基因质粒+LPS组生产性能显著优于LPS组(P＜0.05),而劣于pGRF基因质粒组(P＜0.01),全期日增重由高到低依次为394.47g/d、331.14g/d、297.94g/d;在全期料重比上,pGRF基因质粒+LPS与LPS组相比差异不显著(P＞0.05),但有下降趋势,且均显著高于pGRF基因质粒组(P＜0.05)。2.pGRF基因质粒+LPS组仔猪的腹泻率较LPS组下降了10.32%(P＜0.05),而显著高于pGRF基因质粒组(P＜0.05)。3.pGRF基因质粒+LPS组血清IGF-Ⅰ的浓度显著(P＜0.05)或极显著(P＜0.01)高于LPS组,而极显著低于pGRF基因质粒组(P＜0.01)。4.pGRF基因质粒+LPS组血清IgG的浓度显著高于LPS组(P＜0.05),而低于pGRF基因质粒组(P＞0.0(?))。pGRF基因质粒+LPS组血清IL-1的浓度显著(P＜0.05)或极显著(P＜0.01)低于LPS组,而显著(P＜0.05)或极显著(P＜0.01)高于pGRF基因质粒组;pGRF基因质粒+LPS组血清IL-6的浓度极显著低于LPS组(P＜0.01),而极显著高于pGRF基因质粒组(P＜0.01)。结论:pGRF基因质粒缓解了断奶仔猪因注射脂多糖引起的生长抑制,降低了血清IL-1和IL-6的水平,提高了血清IgG的浓度,提高了仔猪的抗病力,从而缓解了断奶仔猪的免疫应激;pGRF基因质粒缓解免疫应激的作用与其促进IGF-Ⅰ的分泌密切相关。更多还原

【Abstract】 The purpose of this study was toevaluate the effect of pGRF gene plasmid on the performance and immunological function of immune-challenged Weaned Piglets for 35±2d,and also the potential mechanism of these effects were discussed.Eighteen weaned DLY pigs with age of 35±2d and initial body weight(BW) 7.86±0.59kg were not castrated and randomly assigned to three treatments according to gender and BW by single factor design.The three treatments were pGRF gene plasmid group,pGRF gene plasmid plus lipopolysaccharide(LPS) group and LPS group.Each treatment had six replicates and one piglet in each replicate.Dietary treatmenf did not have additive antibiotics.During the three weeks’ experiment the piglets were allowed ad libitum to feed and water.Feed consumption,average daily gain(ADG),feed to gain ratio(F/G) and diarrhea frequency were investigated.On d 1 of the experiment,pGRF gene plasmid and pGRF gene plasmid plus LPS groups were only once injected 1.0mg pGRF gene plasmid per head and only one time,and LPS group were injected normal saline.On d 8 and 15,pGRF gene plasmid plus LPS and LPS groups were injected LPS according to 100μg per kilogram body weight,and pGRF gene plasmid group were injected normal saline.On 2 h after LPS challenge,blood samples were collected,In the peripheral blood serum,the levels of IgG were determined using immuno-turbidimetry method,and IGF-Ⅰ,IL-land IL-6 was determined by ELISA technique.The results were as follows:1.The piglets in the pGRF gene plasmid plus LPS group had a better growth performance than those in the LPS group(P＜0.05),and worse than those in the pGRF gene plasmid group(P＜0.01).The ADG of piglets in the pGRF gene plasmid,pGRF gene plasmid plus LPS and LPS groups were 394.47g/d,331.14g/d,297.94g/d respectively.The F/G of piglets in the pGRF gene plasmid plus LPS group was lower than that in the lipopolysaccharide group(P＞0.05),and higher than that in the pGRF gene plasmid group(P＜0.05).2.Compared with that in the LPS group,the diarrhea frequency in the pGRF gene plasmid plus LPS group was significantly decreased by 10.32%(P＜0.05),and higher than that in the pGRF gene plasmid group(P＜0.05).3.The serum IGF-1 level in the pGRF gene plasmid plus lipopolysaccharide group was higher(P＜0.05)or significantly higher(P＜0.01)than that in the lipopolysaccharide group,and significantly lower than that in the pGRF gene plasmid group(P＜0.01).4.The serum IgG level in the pGRF gene plasmid plus LPS group was higher than that in the LPS group(P＜0.05),and lower than that in the pGRF gene plasmid group(P＞0.05).The serum IL-1 level in the pGRF gene plasmid plus LPS group was lower(P＜0.05)or significantly lower(P＜0.01)than that in the LPS group,and higher(P＜0.05)or significantly higher(P＜0.01)than that in the pGRF gene plasmid group. The serum IL-6 level in the pGRF gene plasmid plus LPS group was significantly lower than that in the LPS group(P＜0.01),and significantly higher than that in the pGRF gene plasmid group(P＜0.01).In conclusion,Compared with those in the LPS group,in the pGRF gene plasmid plus LPS group,the levels of serum IL-1 and IL-6 were reduced,and the levels of serum IgG were increased.The statuses of immune challenge induced by LPS injection was improved.The characteristics of resisting diseases were increased.However,the characteristics of pGRF’s immunoregulation may closely related to its contribution to the secretion of growth hormone,IGF-Ⅰ.更多还原