猪瘟母源抗体衰减及保护水平分析

为分析仔猪体内猪瘟母源抗体的衰减规律及母源抗体保护水平，测定了断奶时母猪和仔猪抗体水平，并监测仔猪母源抗体水平至81日龄；分别对12头81日龄仔猪（来自5头母猪）和25头35日龄仔猪（来自5头母猪）进行了攻毒试验，并用RT—nPCR进行了跟踪检测，对7头攻毒耐过猪用兔体中和法测定了中和效价。结果表明，母猪抗体水平不均衡会导致仔猪群体母源抗体水平不均衡；仔猪群体抗体到60日龄时仍然有67％（12／18）的个体用ELISA检测阻断率在50％以上：81日龄攻毒组有3头（3／12）耐过，35日龄攻毒组能全部耐过（25／25），但有2头（2／25）在攻毒27d后仍然呈PCR阳性，此时中和抗体水平从低于1：4到1：16不等，推测中和抗体水平1：8～1：16是母源抗体保护的临界线。

Classical Swine Fever Maternal Antibodies Decreasing Patternand Threshold of the Protective Level Research

In order to analyse classical swine fever maternal antibodies decreasing pattern and threshold of the protective Level, antibody of sow and piglets were detected at weaning day, maternal antibodies of piglets were monitored until 81 days after birtth, moreover, 12 81-days piglets from 5 sows and 25 35-days piglets from another 5 sows were challenged by SM strain. and furthermore were monintored with RT nPCR, the antibody level of 7 piglets were detected with rabbit neutralization test. The results shows that, antibody of sow is correlative to that of piglets, antibody uniformity of sow lead to the uniformity of piglets, blocking rates is more than 50% in 72%(13/18) piglets at 60 days post birth. However, after challenging, 3(3/12) 81-days piglets could survived,but in 35 days piglets, all piglets(25/25) could survived, but RT-nPCR detection was positive from 2 piglet(2/25). the neutralization antibody titers were from < 1:4 to 1:16. the results indicated that 35 days maybe the threshold of preotective level.