Niu Z Y, Liu F Z, Yan Q L, Li W C
College of Animal Science & Technology, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
Poult Sci. 2009 Oct;88(10):2101-7. doi: 10.3382/ps.2009-00220.
This experiment was undertaken to evaluate the effect of dietary vitamin E on growth performance and immune response of broilers under heat stress (HS). Birds raised in either a thermoneutral (23.9 degrees C constant) or HS (23.9 to 38 degrees C cycling) environment were fed a corn-soybean meal basal diet supplemented with vitamin E at 0, 100, or 200 mg/kg, respectively. Two hundred forty 1-d-old male broiler chicks were randomly assigned to 6 groups; each group had 4 replicates of 10 birds. Humoral immunity was assessed by i.v. injection of 7% SRBC followed by evaluation of serum for antibody titers in primary and secondary responses. Cell-mediated immunity was assessed by using a Sephadex stimulation method to recruit abdominal exudate cells (AEC) to evaluate macrophage phagocytic ability. Body weight and feed intake were not significantly influenced by dietary vitamin E (P>0.05), whereas feed conversion was significantly affected by vitamin E at 100 mg/kg (P<0.05). Heat stress significantly reduced BW, feed intake, and feed conversion (P<0.05). Numbers of AEC, percentage of macrophages in AEC, phagocytic macrophages, and internalized opsonized and unopsonized SRBC were increased by dietary vitamin E (P<0.05). Both primary and secondary antibody responses were significantly increased by dietary vitamin E when birds were exposed to HS (P<0.05). Lymphoid organ weights, antibody responses, incidence of macrophages in AEC, and phagocytic ability of macrophages were all significantly reduced under HS. These results indicated that HS severely reduced growth performance and immune response of broilers, whereas the immune response of broilers could be improved by dietary vitamin E supplementation under HS.
本试验旨在评估日粮维生素E对热应激（HS）条件下肉鸡生长性能和免疫反应的影响。将肉鸡饲养在中性温度（23.9℃恒温）或热应激（23.9至38℃循环）环境中，分别饲喂添加0、100或200mg/kg维生素E的玉米-豆粕基础日粮。240只1日龄雄性肉鸡雏随机分为6组；每组有4个重复，每个重复10只鸡。通过静脉注射7% SRBC评估体液免疫，随后评估血清中初次和二次反应的抗体滴度。通过使用葡聚糖刺激法募集腹腔渗出细胞（AEC）以评估巨噬细胞吞噬能力来评估细胞介导免疫。日粮维生素E对体重和采食量没有显著影响（P>0.05），而100mg/kg维生素E显著影响饲料转化率（P<0.05）。热应激显著降低了体重、采食量和饲料转化率（P<0.05）。日粮维生素E可增加AEC数量、AEC中巨噬细胞百分比、吞噬性巨噬细胞以及内化调理和未调理SRBC的数量（P<0.05）。当肉鸡暴露于热应激时，日粮维生素E显著增加了初次和二次抗体反应（P<0.05）。在热应激条件下，淋巴器官重量、抗体反应、AEC中巨噬细胞发生率和巨噬细胞吞噬能力均显著降低。这些结果表明，热应激严重降低了肉鸡的生长性能和免疫反应，而在热应激条件下日粮添加维生素E可改善肉鸡的免疫反应。
