Proliferation index(PI)which indicates cell proliferation activity was 3 56,31 92 and 7 03 in thymus,bursa of Fabricius and spleen.

• S期细胞分别为 :2 77%25、30 52%25、4 67%25 ,表明细胞增殖活性的增殖指数 (PI)是 :3 56、31 92、7 0 3。