H_(5)、H_(7)亚型禽流感母源抗体对蛋雏鸡首免日龄的影响

Effect of maternal antibody of H_(5) and H_(7) subtype avian influenza on the age of first immunization of layer chick

为科学制定蛋种鸡禽流感的免疫程序,对父母代蛋种鸡以及蛋雏鸡出壳后第1、2、5、10、15、20、25、30 d进行禽流感母源抗体水平跟踪检测。结果表明,蛋雏鸡出壳24 h后母源抗体水平最高,效价均在7 log2以上,群体抗体合格率均在99%以上;鸡群H_(5)、H_(7)亚型禽流感母源抗体效价和群体抗体合格率在5日龄前维持高水平,之后随着日龄增加而逐渐下降;7日龄后呈直线下降趋势。蛋雏鸡临床判定认为禽流感母源抗体≥6 log2时可完全保护,4 log2时可获得大群保护。5日龄时禽流感H_(5)亚型Re-11株、Re-12株抗体水平在合格临界值(6 log2)以上;10日龄时在保护临界值(4 log2)以上,群体保护率仍在70%以上;禽流感H_(7)亚型抗体水平在10日龄后低于保护临界值,群体保护率不足60%,表明鸡群已经面临禽流感威胁。为避免母源抗体对疫苗免疫应答的干扰作用,建议该种鸡场雏鸡H5和H7亚型禽流感疫苗首免时间在7日龄。

In order to scientifically formulate avian influenza immunization programs for layer breeder,and test the parental generation layer breeder and layer chick at the 1,2,5,10,15,20,25 and 30 days,follow-up detection of maternal antibody levels of avian influenza.The results showed that level of maternal antibody was the highest in layer chick 24 hours after the hatching,average titer was above 7 log2,and the qualified rate of population antibody was above 99%,the titers of maternal antibody of H_(5) and H_(7) subtype of avian influenza and the qualified rate of population antibody in chicken maintained a high level before five days of age,and then gradually decreased with the increase of day age.After seven days of age,they showed a linear downward trend.Layer chicken were clinically judged that the maternal antibody of avian influenza can be completely protected when≥6 log2,and large groups can be protected when 4 log2.At the age of five days,the antibody levels of the avian influenza H_(5) subtype Re-11 and Re-12 strains were above the qualified threshold(6 log2),at the age of 10 days,they were above the protection threshold(4 log2),and the population protection rate was still 70%above.The level of avian influenza H_(7) subtype antibody was below protection threshold after 10 days of age,and the group protection rate was less than 60%,indicating that the chicken flock was faced the threat of avian influenza.In order to avoid the interference of maternal antibody on the immune response of the vaccine,it is recommended that the first immunization time for the H_(5) and H_(7) subtype avian influenza vaccine of the chickens in this breeder farm should be seven days of age.