铅暴露对猪免疫功能影响

Effect of lead exposure on immune function in pigs

目的探讨饲料中添加不同剂量铅对猪免疫功能的影响。方法将24头14～17kg仔猪随机分为4组,用正常饲料和分别添加5,15,45mg/kg(分别为低、中、高剂量组,均按含铅量计)醋酸铅的饲料对其进行90d攻毒饲养试验。测定猪血液中白细胞数量(WBC)、血清中免疫球蛋白(IgM、IgG、IgA)、和补体(C3,C4)含量,并使用四甲基偶氮噻唑盐(MTT)法检测血液中T淋巴细胞活力。结果低剂量组T淋巴细胞活力降低29.3%,与对照组比较差异有统计学意义(P<0.05);中剂量组IgA含量下降0.12g/L,T淋巴细胞活力降低25.2%,与对照组比较差异均有统计学意义(P<0.05);高剂量组的白细胞(WBC).IgM、IgG、IgA、C3含量分别下降4.3×109,1.48,0.13,0.14,0.31g/L,T淋巴细胞活力下降37.4%,与对照组比较差异均有统计学意义(P<0.05)。结论饲料中含铅量达到5mg/kg时影响猪免疫功能,高于45mg/kg时可导致猪免疫力显著降低。

Objective To study the effect of lead exposure on immune function of pigs.Methods Twenty-four pigs were randomly divided into four groups and were fed for 90 days with normal feeds and feeds with lead content of 5 mg/kg（low dose）,15 mg/kg（medium dose）,45 mg/kg（high dose）,respectively.The number of white blood cell（WBC）and IgM,IgG IgA,C3,C4 level in serum were measured and T lymphocyte activity was determined by MTT method.Results T-lymphocyte activity in low-dose group decreased by 29.3% compared with the control group（P〈0.05）.The content of IgA and T-lymphocyte activity in the medium-dose group decreased by 0.12 g/L and 25.2%,respectively,compared with the control group（P〈0.05）.The content of WBC,IgM,IgG IgA and C3 in high dose group decreased by 4.3×10^9/L,1.48 g/L,0.13 g/L,0.14 g/L,0.31 g/L,respectively.While the T-lylnphocvte activity was 37.4%lower than that of the control group,and all the differenes compared with the control group were statistical significant（P〈0.05）.Conclusion The immunity of pigs could be affected by lead in feed when its content was up to 5 mg/kg,and could be signincantly dereased with the lead content above 45 mg/kg.