Mammalian faeces can be collected noninvasively during field research and provide valuable information on the ecology and evolution of the source individuals. Undigested food remains, genome/metagenome, steroid hormones, and stable isotopes obtained from faecal samples provide evidence on diet, host/symbiont genetics, and physiological status of the individuals. However, proteins in mammalian faeces have hardly been studied, which hinders the molecular investigations into the behaviour and physiology of the source individuals. Here, we apply mass spectrometry-based proteomics to faecal samples (n = 10), collected from infant, juvenile, and adult captive Japanese macaques (Macaca fuscata), to describe the proteomes of the source individual, of the food it consumed, and its intestinal microbes. The results show that faecal proteomics is a useful method to: (i) investigate dietary changes along with breastfeeding and weaning, (ii) reveal the taxonomic and histological origin of the food items consumed, and (iii) estimate physiological status inside intestinal tracts. These types of insights are difficult or impossible to obtain through other molecular approaches. Most mammalian species are facing extinction risk and there is an urgent need to obtain knowledge on their ecology and evolution for better conservation strategy. The faecal proteomics framework we present here is easily applicable to wild settings and other mammalian species, and provides direct evidence of their behaviour and physiology.

中文翻译：

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粪便蛋白质组学作为研究哺乳动物行为和生理学的新方法

可以在实地研究期间无创收集哺乳动物粪便，并提供有关源个体生态和进化的宝贵信息。未消化的食物残渣、基因组/宏基因组、类固醇激素和从粪便样本中获得的稳定同位素提供了关于饮食、宿主/共生体遗传学和个体生理状态的证据。然而，哺乳动物粪便中的蛋白质几乎没有研究，这阻碍了对来源个体行为和生理学的分子研究。在这里，我们将基于质谱的蛋白质组学应用于从婴儿、少年和成年圈养日本猕猴 ( Macaca fuscata ) 收集的粪便样本 ( n = 10))，描述来源个体的蛋白质组、它消耗的食物及其肠道微生物。结果表明，粪便蛋白质组学是一种有用的方法：(i) 研究随着母乳喂养和断奶的饮食变化，(ii) 揭示所消耗食物的分类和组织学起源，以及 (iii) 估计肠道内的生理状态。这些类型的见解很难或不可能通过其他分子方法获得。大多数哺乳动物物种面临灭绝风险，迫切需要了解其生态和进化知识，以制定更好的保护策略。我们在这里介绍的粪便蛋白质组学框架很容易适用于野生环境和其他哺乳动物物种，并提供了它们行为和生理学的直接证据。