中文摘要：

动物的免疫系统是防御细菌、病毒等病原体侵害的重要途径,对其生存至关重要,而食物短缺是影响动物免疫的重要因素。前期研究发现,禁食3 d可抑制雌性长爪沙鼠T细胞介导的免疫功能,而禁食时长可能在影响动物免疫中起重要作用。为此,本实验主要测定不同的禁食时间如何影响雌性长爪沙鼠的免疫功能,该问题的解决有助于了解它们在野外面临食物短缺时的生存状况。将55只成年雌鼠随机分为8组,分别禁食1 d、2 d、3 d和自由取食,每种处理分别注射磷酸缓冲液和植物血凝素（PHA）。结果发现,随禁食时间的延长,PHA反应（指示T细胞介导的免疫功能）逐渐受到抑制,胸腺和脾脏逐渐萎缩,表明禁食时间对长爪沙鼠的免疫功能影响显著。同样,随饥饿时间增加,长爪沙鼠的体脂、血糖和血清瘦素水平逐渐下降,并且与PHA反应呈正相关,但白细胞总数和皮质酮水平不受禁食时间的影响。结果表明,禁食时间长短能显著影响雌性长爪沙鼠的免疫功能,随禁食时间的延长,长爪沙鼠T细胞介导的免疫功能逐渐受抑制,这可能与体脂和葡萄糖含量下降有关,血清瘦素逐渐降低也可能是其免疫受抑制的原因。

英文摘要：

The immune system protects animals from the effects of pathogens including bacteria and viruses,hence it plays an important role in their survival. However,immune function is affected greatly by food shortage. Our previous research showed that 3 days of fasting suppressed phytohaemagglutinin（PHA） response in female Mongolian gerbils（Meriones unguiculatus）. The duration of fasting might play a key role in influencing animals＇ immunity. In order to clarify this question,we investigated how different fasting durations would have effects on immunity in gerbils. Fifty-five adult female gerbils were randomly divided into 4 groups that,in turn,were subjected to 1 day,2 days,and 3 days of fasting or fed ad libitum,respectively. Half of each treatment group received phosphate buffered saline or PHA injection. We found that PHA response indicative of T-cell-mediated immunity was suppressed gradually with duration of fasting. Similarly,fasting led to spleen and thymus atrophy in gerbils. These results indicate that the duration of fasting had an important effect on immunity. Moreover,body fat mass,blood glucose and leptin levels decreased gradually with duration of starvation,which were all positively correlated with PHA response. However,white blood cells and corticosterone concentrations were not affected by fasting. Taken together,the duration of fasting had an important effect on immunity in gerbils. Suppression of T-cell-mediated immunity might be due to the gradual decrease of body fat mass,blood glucose and leptin levels with the time of fasting.