State Key Laboratory of Integrated Management for Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beichen West Road, Chaoyang, Beijing 100101, China.
J Comp Physiol B. 2013 May;183(4):511-23. doi: 10.1007/s00360-012-0726-z. Epub 2012 Dec 13.
The phenotypic plasticity of the digestive system may determine the diversity of animal diets and, thus, their niche width. This study examines the effects of seasonal fluctuations in food quality and temperature on the gut morphology and the activity of sucrase, maltase, and aminopeptidase-N in the small intestinal brush-border membrane of male Mongolian gerbils (Meriones unguiculatus). Based on the adaptive modulation hypothesis and the principle of optimal gut function design, we hypothesize that the gut size, tissue-specific activity, and total hydrolytic capacity of intestinal digestive enzyme are upregulated in winter and downregulated in summer in response to diet shifts and energy demand in free-living Mongolian gerbils. Various seasonal modulation patterns in digestive enzyme activity in different regions of the small intestines were observed. The results show that male gerbils have the longest and heaviest small intestines in winter. This mechanism may be adapted to increase their food intake during winter. Male gerbils also exhibit the highest tissue-specific and total sucrase, maltase, and aminopeptidase-N activity in winter and in spring. Seasonal modulations are more distinct in the jejunum than in the duodenum and the ileum of the small intestines. The digestive phenotypic flexibility of male gerbils effectively corresponded with seasonal diet shifts and temperature fluctuations.
消化系统的表型可塑性可能决定了动物饮食的多样性，从而决定了它们的生态位宽度。本研究考察了食物质量和温度的季节性波动对雄性蒙古沙鼠（Meriones unguiculatus）小肠刷状缘膜中蔗糖酶、麦芽糖酶和氨基肽酶-N 的肠道形态和活性的影响。基于适应调节假说和最佳肠道功能设计原理，我们假设肠道大小、组织特异性活性和肠道消化酶的总水解能力在冬季上调，在夏季下调，以响应自由生活的蒙古沙鼠的饮食变化和能量需求。在小肠的不同区域观察到了各种季节性的消化酶活性调节模式。结果表明，雄性沙鼠在冬季拥有最长和最重的小肠。这种机制可能适应于在冬季增加食物摄入。雄性沙鼠在冬季和春季也表现出最高的组织特异性和总蔗糖酶、麦芽糖酶和氨基肽酶-N 活性。与十二指肠和空肠相比，小肠的空肠季节性调节更为明显。雄性沙鼠的消化表型灵活性与季节性饮食变化和温度波动有效对应。
