本文旨在研究日循环高温对肉鸡淋巴细胞钙离子浓度、白介素-2（IL-2）水平、脾脏T淋巴细胞转化率以及细胞周期的影响。选择32日龄爱拔益加（AA）肉用公鸡150只，随机分为3个处理（适温组、配对组和高温组），每个处理5个重复，每个重复10只鸡。其中适温组昼夜维持恒温22 ℃，自由采食；配对组昼夜维持恒温22 ℃，按前1天高温组的采食量饲喂；高温组为27 ℃—35 ℃—27 ℃循环变化，自由采食；试验持续2周。结果显示，日循环高温可显著提高肉鸡的直肠温度、呼吸率和淋巴细胞内钙离子浓度（P<0.01）；日循环高温处理7 d时，可显著提高肉鸡血浆中皮质酮浓度和脾脏T淋巴细胞IL-2的分泌水平（P<0.05），显著降低肉鸡淋巴细胞伴刀豆球蛋白A诱导的T淋巴细胞转化率（P<0.01），日循环高温处理14 d时，各组间均无显著差异（P>0.05）；日循环高温处理14 d时，可使处于G1期的细胞比例显著升高（P<0.05），使S期的细胞比例显著下降（P<0.01），而对G2期的细胞比例无显著影响（P>0.05）。综合试验结果，日循环高温处理可使肉鸡淋巴细胞内钙离子浓度升高，同时提高细胞IL-2分泌水平；持续日变高温可抑制肉鸡的免疫功能，表现在抑制脾脏T淋巴细胞转化率以及降低细胞从G1期进入S期的比例等方面。

The experiment was conducted to investigate the effects of cyclic high temperature on Ca2+ concentration and interleukin-2 (IL-2) level in lymphocyte, and T lymphocyte transformation rate and cell cycle in spleen of broiler chickens. One hundred and fifty 32-day-old Arbor Acres male broilers were randomly allotted to 3 treatments (normal-temperature group, paired-feeding group and high-temperature group) with 5 replicates in each treatment and 10 birds in each replicate. The broilers in the normal-temperature group and paired-feeding group were housed in controlled environment chambers at 22 ℃. The broilers in the high-temperature group were housed in a controlled environment chamber with daily cyclic high temperature (27 ℃—35 ℃—27 ℃), and the experiment lasted for two weeks. In addition, the broilers in normal-temperature group and high-temperature group were fed ad libitum, but the broilers of paired-feeding group were matched the diet intake of broilers in high-temperature group at the previous day of the experiment. The results showed that cyclic high temperature stress significantly increased the rectal temperature, respiratory rate and ［Ca2+］i of lymphocyte of broilers (P<0.01); after 7-d cyclic high temperature, the corticosterone (CORT) level in plasma was significantly increased (P<0.05), and the secretion of interleukin-2 in splenic lymphocytes was significantly enhnced (P<0.05), and Con A-stimulated lymphocyte transformation rate was significantly suppressed (P<0.01), and after 14-d cyclic high temperature, there was no significant difference among groups (P>0.05); flow cytometric analysis of the cell cycle indicated that the 14-d high temperature stress significantly decreased the S phase proportion of lymphocyte (P<0.01) and increased the G1 phase proportion of lymphocyte (P<0.05), but there was no significant difference in the G2 phase proportion of lymphocyte (P>0.05). These results suggested that the cyclic high temperature stress increased the concentrations of Ca2+ and interleukin-2 in lymphocyte; long-term stress exposure had a negative effect on the immune function of broilers, such as the suppression of splenic T lymphocyte transformation rate and the transition of activate T cells from the G1 phase to the S phase.［Chinese Journal of Animal Nutrition, 2010，22（5）:1243-1250］