HP-PRRSV人工感染后猪4种血液指标的变化规律及与病毒载量的关系

为研究高致病性猪繁殖与呼吸综合征病毒(highly pathogenic porcine reproductive and respiratory syndrome virus,HP-PRRSV)感染后猪血液指标的变化及与病毒载量的关系,以大白猪×通城猪高代横交群体为对象,选用72头平均11周龄的健康仔猪进行HP-PRRSV人工感染,在感染前和感染后第4、7、11、14、21、28天和第35天进行白细胞计数、淋巴细胞百分比、单核细胞计数、粒细胞百分比4种血常规指标的测定,并与病毒载量进行相关分析。结果显示:(1)感染与感染前相比,感染第4、7天的白细胞计数、淋巴细胞百分比、单核细胞计数均极显著降低,粒细胞百分比极显著升高;感染第11、14天的淋巴细胞百分比显著降低,粒细胞百分比显著升高,其他时间点均无显著变化。(2)抗病组和易感组的淋巴细胞百分比和粒细胞百分比在感染第7天存在显著差异,其中抗病组的淋巴细胞百分比显著高于易感组(P0.05),粒细胞百分比显著低于易感组(P0.05)。(3) 4种血液指标与病毒载量之间均存在中度相关(P0.01)。以上结果表明,血液指标可以考虑作为PRRS早期抗病性的指示性状。

Change of four hematological parameters and relationship with viremia after artificial infection with highly pathogenic porcine reproductive and respiratory syndrome virus

The highly pathogenic porcine reproductive and respiratory syndrome (PRRS) is the most important infectious disease of pigs. The host would respond to PRRSV by regulating different immune responses at different days post infection (DPI). The routine blood testing is the most intuitive way to detect changes of blood cell in the body. Therefore,it is necessary to detect and analyze hematological parameters for predicting the process of the disease. To investigate the changes of hematological parameters after infection with HR-PRRSV,72 Large White×Tongcheng advanced generation inter-cross piglets with an average age of 11 weeks,were used for the artificial HP-PRRSV infection experiment. The white blood cell (WBC) count,the lymphocyte percentage,the monocyte count and the granulocyte percentage were determined at 0,4,7,11,14,21,28,35 DPI,then association analysis of them with viremia were carried on. The results showed that when compared to 0 DPI,the WBC count,lymphocyte percentage and monocyte count were significantly reduced,and the granulocyte percentage was significantly increased at both 4 DPI and 7 DPI. The lymphocyte percentage was significantly reduced and the granulocyte percentage was significantly increased at both 11 DPI and 14 DPI,but there were no significant differences at the other DPI. Groups of piglets with PRRS-resistant and PRRS-susceptible were set on the basis of viremia and survive rate. It was showed that the lymphocyte and the granulocyte percentage were significantly different at 7 DPI between groups. The lymphocyte percentage of the PRRS-resistant group was significantly higher (P<0.05),and the granulocyte percentage was significantly lower (P<0.05) than the PRRS-susceptible group. For other DPI,as well as other hematological parameters,there were no significant differences. Furthermore,correlation analysis showed that the hematological parameters and viremia at all DPI in piglets were moderately correlated (P<0.01). The results demonstrated that the lymphocyte percentage and granulocyte percentage could be used as indicators of resistance to PRRS. Our current study provides basic data for further research on the changes of hematological parameters after PRRSV infection and relationship with viremia.