【摘要】 为了解基因Ⅶ型新城疫病毒（NDV）母源抗体对雏鸡的免疫保护作用,对雏鸡母源抗体水平与种母鸡免疫抗体间的相关性、雏鸡母源抗体衰减规律以及不同母源抗体水平对雏鸡的免疫保护效果进行了研究。结果显示:雏鸡母源抗体水平与相应种母鸡的抗体水平基本一致,虽然1日龄雏鸡平均抗体滴度较相应种母鸡抗体滴度约低1.3 log₂,但在其出生后最初几天内会稍有上升;雏鸡母源抗体半衰期为3.20 d;不同母源抗体水平雏鸡用基因Ⅶ型NDV强毒株攻毒后,死亡率与排毒率均随母源抗体滴度上升而呈下降趋势;母源抗体滴度达到7 log₂时即对雏鸡产生95%以上的保护率,但各攻毒组均存在不同程度的排毒现象,即使其抗体滴度高达11 log₂也不例外;母源抗体滴度为4 log₂和5 log₂的雏鸡可持续排毒至攻毒后27 d,个体排毒期为9²5 d,平均为15 d。更多还原

【Abstract】 To investigate the protective efficacy of maternal antibody against genotype Ⅶ Newcastle disease virus（NDV） in chicks, the correlation between chicks and their parents in antibody levels, the decay pattern of maternal antibody and protective efficacy of different maternal antibody titers were determined. The results showed antibody levels in chicks were generally the same as those in the parents; although the mean antibody titer in 1-day-old chicks was1.3 log₂ lower than that in their parents, it increased slightly in the first few days after birth of chicks. The half-life of maternal antibody was 3.20 days. The mortality rate and virus shedding rate of chicks challenged with virulent genotypeⅦ NDV decreased with the increase of maternal antibody titer. The protective rate of the maternal antibody was more than 95% when the titer reached 7 log₂. However, the chicks in all challenged groups shed virus in varying degrees even if the antibody titers reached 11 log₂. Moreover, the chicks with antibody titers of 4 log₂ and 5 log₂ could continuously shed virus until the 27 th day after challenge. The durations of virus shedding in individuals were 9 to 25 days with an average of about 15 days.更多还原