Twenty-seven 20-day-old PIC piglets were divided into control and experimental groups and were given an intramuscular injection of 3 mL sterilized normal saline and extracts of bursa of Fabricius(EBF) respectively.

• 27头20日龄PIC仔猪,分为试验组和对照组,分别颈部肌肉注射法氏囊提取物注射液和灭菌生理盐水,试验至出栏为止。