Navarro-Castilla Álvaro, Hernández M Carmen, Barja Isabel
Eco- and Ethophysiology Lab, Departamento de Biología, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
Centro de Investigación en Biodiversidad y Cambio Global (CIBC-UAM), Universidad Autónoma de Madrid, C. Darwin 2, 28049 Madrid, Spain.
Animals (Basel). 2023 Mar 28;13(7):1176. doi: 10.3390/ani13071176.
The analysis of carbon and nitrogen elemental (C, N) and isotopic compositions (δC, δN) in faeces are considered reliable methodologies for the study of diet in wildlife. Here, we tested the suitability of these techniques to detect variations in the amount of food intake. We captured wild wood mice ( with Sherman live traps where bait access was initially free, and later it was experimentally limited inside by four different devices to cause intended variations in the amount ingested. The total C and N (%) and stable δC and δN isotopic values were determined for the bait and in mice faecal samples. Faecal values were lower than bait ones except for N, likely due to animal matter ingested before capture. No significant differences in total C, N and δC were found due to individual traits. However, breeding males showed higher δN values than breeding females, probably due to differences in energy and protein demands between both sexes during the breeding season. Only δC detected food intake variations (≥2 g). Despite further research being needed, these results initially support the potential of δC to provide information on the amount ingested, thus being useful to complement trophic ecology studies.
粪便中碳、氮元素（C、N）及同位素组成（δC、δN）的分析被认为是研究野生动物饮食的可靠方法。在此，我们测试了这些技术在检测食物摄入量变化方面的适用性。我们用谢尔曼活饵诱捕器捕获野生林鼠，起初诱饵可自由获取，之后通过四种不同装置在实验中限制诱饵进入，以造成预期的摄入量变化。测定了诱饵以及小鼠粪便样本中的总碳和氮（%）以及稳定的δC和δN同位素值。除了氮，粪便中的值低于诱饵中的值，这可能是由于捕获前摄入的动物物质所致。未发现因个体特征导致的总碳、氮和δC的显著差异。然而，繁殖期雄性的δN值高于繁殖期雌性，这可能是由于繁殖季节两性在能量和蛋白质需求上存在差异。只有δC检测到了食物摄入量的变化（≥2克）。尽管还需要进一步研究，但这些结果初步支持了δC在提供摄入量信息方面的潜力，因此有助于补充营养生态学研究。
