高致病性猪繁殖与呼吸综合征(HP-PRRS)给我国养猪业造成了巨大的经济损失。为研究高致病性猪繁殖与呼吸综合征病毒(HP-PRRSV)感染后血清病毒载量和体重增长的变化规律,以大白猪和通城猪的高代横交群体中72头健康仔猪为研究对象进行HP-PRRSV人工感染 ,观察临床症状、在感染前和感染后第4、7、11、14、21、28、35 天空腹采血、称量体重,分离血清并检测其病毒载量。研究结果表明：在感染后第0-4天体重增长速度缓慢,第4-21天体重一直呈负增长、第7-11天体重减少量达最大值、第21-35天体重呈正增长且增长量逐渐增加；病毒载量在第0-4天升高,第4天达到峰值并持续到第7天,第7-35天病毒载量逐渐下降至6.62log10copies/mL；感染后第7天出现死亡,死亡个体主要集中在7-14天,在第10天出现死亡高峰,第19天后基本稳定,根据第14天存活与否,将试验猪分为抗病和易感两个组,抗病组的病毒载量在第4、7、11天均显著低于易感组的病毒载量(p<0.05),抗病组的体重增长量在第4-7、7-11、11-14天均显著高于易感组的体重增长量(p<0.05)。上述结果表明在感染过程中体重增长和病毒载量两个性状可作为预测PRRS抗病性的指示性状。
HP-PRRSV has caused great economic losses to pig industry in China. In order to study the changes of viremia in serum and body weight after HP-PRRSV infection,72 healthy piglets selected from a large white pigs and Tongcheng pigs crossed population were infected with HP-PRRSV. The clinical symptoms were observed,the blood samples were collected and weight was measured on 0 4, 7, 11, 14, 21, 28 and 35 day post infection(dpi),serum was separated and viremia was measured. The results showed that the growth rate of body weight was slow from 0 to 4dpi,the body weight increased negatively from 4 to 21dpi, the loss of weight reached the maximum from 7 to 11dpi,the body weight increased positively and the growth increased gradually 21 to 35dpi.Viremia increased from 0 to 4dpi, peaked on 4dpi and lasted until 7dpi ,viremia decreased to 6.62log10 copies/mL from 7dpi to 35dpi.Death occurred 7dpi, and the dead individuals were mainly concentrated on 7 to 14 dpi. The death peak appeared on the 10dpi, and the number of dead individual was basically stable 19dpi.According to the survival or not death on 14dpi, the pigs were divided into two groups: resistance and susceptibility,the viremia of resistance was significantly lower than susceptibility 4,7,11dpi(p<0.05),the weight gain of resistance was significantly higher than that of susceptibility at 4-7dpi,7-11dpi,11-14dpi(p< 0.05).The above results showed that the weight gain and viremia could be used as indicators to predict the resistance of PRRS.