- 期刊
雞傳染性華氏囊病移行抗體與保護力之關係
The Protection Conferred by Maternal Antibody Against Highly Virulent Infectious Bursal Disease Virus
摘要
調查彰化地區白色及有色肉種雞場各2場。此4場皆採行14日齡接種雞傳染，性華氏囊病（IBD）中間毒活毒疫苗，18週齡左右注射IBD油質死毒疫苗之免疫計畫。於種雞29-61週齡時取得種蛋，於本試驗室孵化後隔離飼養。來自各場雛雞分別於1-5週齡時，每場各取出5隻，以本省分離之高病原性IBD毒株攻毒。攻毒後觀察其死亡及發病情形，7天後剖檢測定華氏囊／體重比值。如雛雞在攻毒後未發病死亡，且華氏囊未發生萎縮者，即判定該雛雞為具抵抗力。結果發現移行抗體在雛雞於1-5週齡時之保護率分別為80-40％、60-20％、20-0％、20-0％、0％。就個別雞隻攻毒前移行抗體之中和價分析，中和價在16倍及以下者完全無保護力，在256倍及以上者有100％的保護率，至於中和價在128、64及32倍時之保護率分別為81％、47％及14％。
並列摘要
Four broiler breeder flocks employing the same vaccination program against infectious bursal disease (IBD) were investigated. Breeders were vaccinated with an intermediate type IBD live vaccine at 2 weeks of age and were boosted with an oil-based inactivated vaccine at 18-weeks-old. To evaluate the protection conferred by maternal antibodies (Mab), chicks hatched from eggs laid by these breeders at 29-61 weeks of age were challenged with a highly virulent IBD virus. The chicks surviving the challenge and showing no signs of bursal atrophy were regarded as protected. The results showed only 40-80%, 20-60%, 0-20%, 0-20%, and 0% of chicks were protected when they were challenged at 1-5 weeks old, respectively. Neutralizing MAb at the titre of 1:256 or higher could confer full protection against IBDV challenge, while all the chicks with the MAb of titer at 16 or lower were susceptible. The protection rate of the chicks with MAb titers at 128, 64, and 32 were 85%, 47% and 14%, respectively.