穆棱林区野生东北马鹿种群冬季食物组成模式与植物代谢产物的关系

高纬度地带，在冬季食物资源有限的环境中，野生大型有蹄类动物满足营养需求的同时，需要对植物中次生代谢产物进行平衡，回避有害物质并选择对机体有益的成分，从而形成特定的食物组成模式。以东北马鹿（Cervus elaphus xanthopygus）为研究对象，于2020年11月，在黑龙江穆棱东北红豆杉国家级自然保护区境内，采集东北马鹿粪便和植物样本。通过粪便显微分析法确定保护区内马鹿冬季食物组成，采用k-means聚类分析揭示马鹿冬季食物组成模式。应用广泛靶向代谢组技术对部分植物中次生代谢产物的含量进行全覆盖定性和相对定量检测，将食物组成与次生代谢产物数据整合，进行曼特尔检验（Mantel test）分析，以探究植物次生代谢产物对马鹿种群内食物组成模式的影响。结果表明，林区内马鹿种群冬季共采食30种植物，其中木本植物占92.48%；且种群内分别呈现出以东北红豆杉（Taxus cuspidata），簇毛槭（Acer barbinerve），毛榛子（Corylus mandshurica）为主要食物的不同食物组成模式。广泛靶向代谢组技术共检测出638种次生代谢产物，有25种代谢物与马鹿采食频率显著相关，其中多数萜类物质抑制马鹿采食，而鞣质类物质对马鹿的采食选择有一定的正向作用；Mantel test结果显示，上述25种物质中黄酮、鞣质、萜类化合物相对含量与不同马鹿个体食物组成显著相关，说明这些代谢物相对含量和性质的差异会造成种群内不同个体食物组成的差异，是种群内形成不同食物组成模式的原因之一。从植物次生代谢产物角度揭示了该地区东北马鹿种群冬季食物组成模式呈现差异的可能因素，为进一步研究大型有蹄类营养策略和植物化学防御关系提供基础依据。

Relationship between winter food composition pattern of red deer (Cervus elaphus xanthopygus) and plant secondary metabolites in Muling, China

In environments with limited winter food resources and high latitudes, large wild ungulates must balance toxic and harmful secondary metabolites in plants, avoid harmful substances, and choose beneficial components to form a specific food composition pattern. As the subject of this study, red deer (Cervus elaphus xanthopygus) was was chosen. In this study, we collected fecal samples from wild red deer and their foraged plants by backtracking footprint chain and non-invasive sampling methods in the territory of Heilongjiang Muling Japanese Yew National Nature Reserve in November 2020. The winter food composition of red deer in the protected area was determined by fecal micro histological analysis, and the winter food composition pattern of red deer was uncovered through k-means cluster analysis. Contents of secondary metabolites of some plant species were detected qualitatively and quantitatively using a widely targeted metabolome technology, and statistical analysis was performed to investigate the effects of plant secondary metabolites on the food composition pattern of red deer population. Through the analysis of fecal residue, it was determined that the red deer population in the reserve fed on 30 plant species during the winter, among which woody plants accounted for 92.48%. Three different food composition patterns dominant by Taxus Cuspidata, Acer Barbinerve and Corylus mandshurica as the main food found. A total of 638 secondary metabolites were detected using widely targeted metabolome technology with broad targeting. 25 of them were significantly correlated with red deer feeding frequency. Most of terpenoids inhibited feeding of red deer, whereas tannins had a certain positive effect on feeding selection of red deer. The results of Mantel test revealed that the relative contents of some flavonoids, tannins and terpenoids in the 25 substances above were significantly correlated with the individual food composition of different red deer, to illustrate these metabolites relative content and nature of the differences will lead to different populations in different individual differences in food composition, population is in one of the reasons to form different patterns of the food composition. The flavonoids mainly affected the red deer population feeding on Taxus Cuspidata, while the tannins and terpenoids mainly affected the red deer population feeding on Corylus mandshurica and Acer Barbinerve. This study reveals the possible factors for the differences in winter food composition patterns of red deer populations in this region from the perspective of plant secondary metabolites, and provides a foundation for further research on the relationship between trophic strategies and chemical defense of large ungulates.