Department of Biology, University of Western Ontario, 1151 Richmond St, London, ON, N6A 3K7, Canada.
Environment and Climate Change Canada, Saskatoon, SK, S7N 3H5, Canada.
Oecologia. 2021 Jan;195(1):37-49. doi: 10.1007/s00442-020-04827-1. Epub 2021 Jan 3.
Using measurements of naturally occurring stable isotopes in feathers to determine avian origin and migratory patterns is well established. However, isotopically determining nutritional origins of lipids, a major migratory fuel, has not been attempted. This study explores isotopic links between diet and stored lipids in captive white-throated sparrows (Zonotrichia albicollis) by providing isotopically distinct mixtures of carbohydrates/oils and drinking water and assessing the δC and δH values of stored lipid, breath CO (δC) and breath water vapour (δH). Stored lipid δC and δH values correlated with the isotopic values found in dietary carbohydrates/oils and drinking water treatments, respectively, indicating a clear traceable transfer of environmental dietary isotopic signals into body lipids. Dietary oils and carbohydrates contributed 80-82% of carbon and 44-46% of hydrogen, respectively, to stored lipids. Drinking water contributed 18-28% of hydrogen to stored lipids. Isotopic relationships were quantifiable using linear calibration algorithms which provide the basis for the construction of tissue isoscapes for migratory passerines. Breath CO δC values and breath water vapour δH values for fed and fasted birds reflected dietary sources. Breath CO δC values were higher for fasted birds than for fed birds by an average of 4.5‰ while breath water vapour δH values were lower for fasted birds by an average of 48.9‰. These results indicate that lipids and metabolites from their subsequent breakdown for fuel isotopically reflect dietary sources but complicate interpretation of such data, especially for wild migrating birds. Applications and limitations of these findings to the creation of "liposcapes" are examined.
利用羽毛中天然稳定同位素的测量来确定鸟类的起源和迁徙模式已经得到了很好的证实。然而，利用同位素来确定作为主要迁徙燃料的脂质的营养来源尚未尝试过。本研究通过提供同位素不同的碳水化合物/油脂和饮用水混合物，并评估储存脂质、呼吸 CO（δC）和呼吸水蒸气（δH）的 δC 和 δH 值，探索了圈养白喉雀（Zonotrichia albicollis）饮食和储存脂质之间的同位素联系。储存脂质的 δC 和 δH 值分别与饮食中碳水化合物/油脂和饮用水处理的同位素值相关，表明环境饮食同位素信号明显可追踪地转移到体脂中。饮食中的油脂和碳水化合物分别为储存脂质贡献了 80-82%的碳和 44-46%的氢。饮用水为储存脂质贡献了 18-28%的氢。同位素关系可以通过线性校准算法进行量化，为构建迁徙雀形目鸟类的组织同位素景观提供了基础。进食和禁食鸟类的呼吸 CO δC 值和呼吸水蒸气 δH 值反映了饮食来源。禁食鸟类的呼吸 CO δC 值比进食鸟类平均高出 4.5‰，而呼吸水蒸气 δH 值平均低 48.9‰。这些结果表明，用于燃料的脂质和代谢物的同位素反映了饮食来源，但使这些数据的解释复杂化，尤其是对于野生迁徙鸟类。本研究还探讨了这些发现对“脂质景观”创建的应用和限制。
