野生小熊猫肠道微生物的季节性变化——食物组成、营养、叶围微生物的影响？

Animals can adapt to their unique diets through their own specific intestinal tract microbes. And they are strongly affected by feeding habits, food nutrition, intaked microorganisms and so on. During the long time, the red panda (Ailurus fulgens) in the order Carnivora have evolved to specialize on bamboo. Intestinal tract microbes play an important role in the adaptation of red pandas to bamboo with low nutrient and high fiber content. At present, however, researches about gut microbiome of red panda mainly focus on captive individuals, and there is fewer research on how wild red pandas adapt to bamboo foods through seasonal varying of intestinal tract microbes. Basing on field tracking, sample collection and indoor analyses in our project, and combining Next-generation sequencing technology, we will conduct a study in Megu Dafengding National Nature Reserve to (1) investigate the effects of food composition and nutrition on intestinal tract microbes of wild red panda, (2) uncover inner relationships between seasonal variations of bacterial microbes in red panda intestinal tract and bamboo phyllosphere microbes, and (3) demonstrate how the microbial diversity, community similarity, cellulose degradation functions of red panda’s intestinal microbial flora associated with combined influence of food composition, nutrition and bamboo phyllosphere microbes. Our findings could not are helpful to further reveal the evolutionary mechanism of red panda's adaptation to special bamboo food by intestinal tract microbes, but can supply guidelines to improve in-situ conservation for this rare animal.

动物可通过特有的肠道微生物适应其独特的食物，而肠道微生物受动物食性、食物营养及摄入微生物等因素的综合影响。食肉目小熊猫（Ailurus fulgens）在食性上已特化为以竹为生，肠道微生物在小熊猫适应营养含量低而纤维含量高的竹子食物上扮演着重要角色。然而，目前有关小熊猫肠道微生物的研究集中在圈养个体，野生小熊猫如何通过季节性肠道微生物变化以适应竹子食物的研究较为空缺。本项目拟在野外跟踪、样品收集和室内分析等基础上，结合高通量测序技术，探讨四川美姑大风顶国家级自然保护区内野生小熊猫食物组成和食物营养对肠道微生物的影响，揭示小熊猫肠道微生物的季节性变化与叶围微生物的内在联系，弄清食物组成、营养和叶围微生物对小熊猫肠道微生物多样性、群落相似性、纤维素降解功能等的综合作用。预期研究成果既有利于深入揭示小熊猫通过肠道微生物适应竹子这一特殊食物资源的进化机制，亦能为该物种的科学就地保护提供指导与参考。

动物可通过自身特有的肠道微生物以适应独特的食物来源。本项目通过收集小熊猫个体新鲜粪便样品、主食竹竹叶样品，运用高通量测序、宏基因组学和营养学等手段研究季节、食性、营养等对小熊猫肠道微生物的影响。结果发现，不同食性组成的肠道微生物形成不同的聚集分布，冬春季节肠道微生物多样性和丰富度高于其它季节；宏基因组学发现肠道微生物氨基酸转运代谢功能以及碳水化合物代谢功能占主导地位，CAZyme功能在不同季节间具有差异。而竹叶叶围微生物组成、丰富度和多样性受季节、竹种、海拔、营养等因素的强烈影响，部分微生物群落的丰度与竹子本身的长势相关。进一步的研究发现不同竹种其叶围细菌拥有不同的功能特征，季节和海拔的强烈影响现象表明了小熊猫栖息的山区冬季长期的低温可能会在冬春季形成更加多样化和复杂的叶围微生物群落，在食性变化的情况下进而形成复杂多样的肠道微生物群落。