Marín-García Pablo Jesús, Llobat Lola, Rouco Carlos, Aguayo-Adán Juan Antonio, Larsen Torben, Cambra-López María, Blas Enrique, Pascual Juan José
Department of Animal Production and Health, Veterinary Public Health and Food Science and Technology (PASAPTA), Facultad de Veterinaria, Universidad Cardenal Herrera-CEU, CEU Universities, 46113 Valencia, Spain.
Ecology Area, Faculty of Science, University of Cordoba, 14071 Cordoba, Spain.
Animals (Basel). 2022 Sep 28;12(19):2608. doi: 10.3390/ani12192608.
European wild rabbit (Oryctolagus cuniculus) populations have drastically reduced, and recently, rabbits have been classed as “endangered” by the IUCN. This animal plays an important ecological role in Mediterranean ecosystems and its introduction could significantly contribute to ecological restoration. Rabbits have high nutrient requirements that apparently cannot be covered in all ecosystems, and there are clues that nutrition can limit their abundance and density. On the other hand, some studies reflect the effects of food availability on the metabolomic status of other animal species, but there are no specific studies on this keystone species. The main aim of this work is to find biomarkers to assess the previous levels of ingestion of European rabbits (Oryctolagus cuniculus). To address this gap, gastric content and blood samples were collected from European rabbits (n = 99) in a Mediterranean area for the analysis of glucose, non-esterified fatty acids (NEFA), plasmatic urea nitrogen (PUN), albumin, glutamate and total protein metabolites. Depending on their previous feed intake (gastric content and the ratio between the gastric content and the weight of the animal), the animals were divided into two groups (lower and normal previous feed intake). Our work shows that the metabolomic profiles of the animals were affected. Levels of glucose (+82%; p = 0.0003), NEFA (−61%; p = 0.0040) and PUN (+139%; p < 0.001) were different in the animals with lower previous feed intake than the animals with normal previous feed intake. This work summarises that metabolic phenotype can be interesting when seeking to discover the limiting nutrients and food availability in diets that could affect the ecological fitness and conservation of European wild rabbits. It is important to mention that in this work, only the effects on six different metabolites have been analysed and more studies are necessary to complement the knowledge of possible metabolites that indicate the level of ingestion in this species and others. These (and new) biomarkers could be used as a tool to provide information about individual or population characteristics that other physiological parameters cannot detect, improving the conservation physiology field.
欧洲野兔（穴兔）的数量已大幅减少，最近，野兔被国际自然保护联盟列为“濒危”物种。这种动物在地中海生态系统中发挥着重要的生态作用，其引入对生态恢复具有重要意义。野兔对营养的需求很高，显然并非所有生态系统都能满足，有线索表明营养状况会限制其数量和密度。另一方面，一些研究反映了食物可利用性对其他动物物种代谢组状态的影响，但针对这种关键物种尚无具体研究。这项工作的主要目的是寻找生物标志物，以评估欧洲野兔（穴兔）先前的摄食水平。为填补这一空白，在地中海地区采集了99只欧洲野兔的胃内容物和血液样本，用于分析葡萄糖、非酯化脂肪酸（NEFA）、血浆尿素氮（PUN）、白蛋白、谷氨酸和总蛋白代谢物。根据它们先前的采食量（胃内容物以及胃内容物与动物体重的比值），将这些动物分为两组（先前采食量较低组和正常组）。我们的研究表明，动物的代谢组特征受到了影响。先前采食量较低的动物，其葡萄糖水平（升高82%；p = 0.0003）、NEFA水平（降低61%；p = 0.0040）和PUN水平（升高139%；p < 0.001）与先前采食量正常的动物不同。这项工作总结认为，在探寻可能影响欧洲野兔生态适应性和保护的饮食中限制营养物质和食物可利用性时，代谢表型可能具有重要意义。需要指出的是，在这项研究中，仅分析了六种不同代谢物的影响，还需要更多研究来补充对可能指示该物种及其他物种摄食水平的代谢物的认识。这些（以及新的）生物标志物可作为一种工具，提供其他生理参数无法检测到的个体或种群特征信息，从而推动保护生理学领域的发展。
