日粮锌水平对雏番鸭免疫器官中细胞凋亡及Fas表达的影响

Effects of Dietary Zinc Levels on the Cell Apoptosis and the Expression of Fas in the Immune Organ of Young Muscovy Duck

为了探讨微量元素锌对雏番鸭主要免疫器官中细胞凋亡及Fas表达的影响,选取135只1日龄体况一致的健康番鸭随机分成3组,A组为低锌组,B组为对照组,C组为高锌组,分别饲喂含锌20、40和200mg/kg的日粮,试验期45d,通过TUNEL法和免疫组织化学法观察15、30、45日龄3组雏番鸭胸腺、法氏囊和脾脏中细胞凋亡的变化规律及Fas的表达情况。结果表明,15d时,胸腺、法氏囊中细胞凋亡数,A组极显著高于B组(P<0.01),B组显著高于C组(P<0.05);脾脏中细胞凋亡数A组显著高于B组(P<0.05),B组极显著高于C组(P<0.01);30d时,胸腺、法氏囊、脾脏中细胞凋亡数A组仍最多,与B、C组差异极显著(P<0.01),胸腺、法氏囊中细胞凋亡数C组和B组差异不显著(P>0.05),脾脏中细胞凋亡数C组显著地低于B组(P<0.05);45d时,胸腺和法氏囊中细胞凋亡数C组均显著高于B组(P<0.05),而脾脏则仍表现为C组最少(P<0.01)。Fas的表达情况与细胞凋亡规律具有一致性,但略有不同,主要表现为Fas蛋白表达的变化早于细胞凋亡。提示,低锌能够诱导雏番鸭免疫器官细胞凋亡,试验早期高锌抑制细胞凋亡,但是较长时间的添加高锌反而会诱导免疫细胞凋亡。细胞凋亡的死亡因子Fas的表达情况进一步表明,日粮锌对雏番鸭主要免疫器官中细胞凋亡的影响是通过Fas/Fas-L途径来调控的。

In order to study the effects of dietary zinc levels on the cell apoptosis and the expression of Fas in the immune organ of young muscovy duck, one hundred and thirty-five 1-day-old ducks were randomly divided into three groups, which A was the low zinc group, 13 was the control group, C was the high zinc group. They were fed for 45 days with the diets of 20, 40 and 200 mg/kg zinc separately. By TUNEL and the immune tissues chemistry method, the cell apoptosis rule and the expression of Fas were observed in thymus, bursa of Fabricius and spleen of young muscovy ducks at the age of 15 d, 30 d and 45 d. The results showed that （1） at 15 d, the quantity of cell apoptosis in thymus, bursa of Fabricius of A group was significantly higher than that of group B （P〈0.01）, and which of group B was significantly higher than that of group C （P〈0.05）. The quantity of cell apoptosis in spleen of group A was significantly higher than that of group B （P〈0.05）, and which of group B was significantly higher than that of group C （P〈0.01）; （2） at 30 d, the quantity of cell apoptosis of group A still was the highest in three groups （P〈0.01）. There was no significant difference of group C and group B in the quantity of cell apoptosis in thymus, bursa of Fabricius （P〉0.05）. The quantity of cell apoptosis in spleen of group C was significantly lower than that of group B （P〈0.05）; （3） at 45 d, the quantity of the cell apoptosis in thymus and bursa of Fabricius of group C was higher than that of group B （P〈0.05）, but which in spleen of group C was still lowest （P〈0.01）. The change of Fas expression was consistent with the rule of cell apoptosis. But the time of change in Fas expression was earlier than that of cell apoptosis. In a word, the low zinc content diet could induce the apoptosis of immune cell in young muscovy duck. In the earlier experimental period, the higher zinc content diet could inhibit the cell apoptosis. But fed with the high zinc content diet for longer time, the cell apoptosis of the immune organ in ducks would induce instead. The expression of Fas as death gene of cell apoptosis showed farther that the effect of zinc in the diet on the cell apoptosis of the immune organ in young muscovy duck was regulated by the signal of Fas/Fas-L.