Jégo M, Lemaître J-F, Bourgoin G, Capron G, Warnant C, Klein F, Gilot-Fromont E, Gaillard J-M
Université de Lyon, Université Lyon 1, UMR CNRS 5558, Villeurbanne Cedex, France; Université de Lyon, VetAgroSup, Marcy-l'Étoile, France.
J Evol Biol. 2014 Dec;27(12):2745-52. doi: 10.1111/jeb.12535. Epub 2014 Nov 22.
Increasing evidence of senescence has been reported from long-term studies of wild populations. However, most studies have focused on life-history traits like survival, reproduction or body mass, generally from a single intensively monitored population. However, variation in the intensity of senescence across populations, and to a lesser extent between sexes, is still poorly understood. In addition, the pattern of age-specific changes in haematological parameters remains virtually unknown to date for any population of vertebrate living in the wild. Using repeated blood samples collected from known-aged (2-15 years of age) roe deer (Capreolus capreolus) from two populations facing highly different environmental conditions, we filled the gap. In particular, we investigated age-specific changes in haematocrit, albumin and creatinine. We reported clear evidence of senescence in all haematological parameters. Moreover, senescence patterns differed between sexes and populations. The rate of senescence was higher in males than in females for haematocrit with no site difference. On the other hand, the rate of senescence in creatinine was higher at Trois Fontaines than at Chizé with no sex difference. Our findings provide a first demonstration of age-specific declines in haematological parameters in wild populations of large herbivores and show that the process of senescence in vertebrates is not restricted to body mass or fitness components. We also demonstrate that the senescence pattern of haematological parameters is context dependent and varies both between sexes and according to environmental conditions.
长期对野生种群的研究报告了越来越多衰老的证据。然而，大多数研究集中在生存、繁殖或体重等生活史特征上，通常是针对单一的、受到密集监测的种群。然而，不同种群间衰老强度的差异，以及在较小程度上性别间衰老强度的差异，仍未得到很好的理解。此外，迄今为止，对于任何野生脊椎动物种群，血液学参数随年龄变化的模式实际上仍不清楚。我们利用从面临截然不同环境条件的两个种群中已知年龄（2至15岁）的狍（Capreolus capreolus）采集的重复血样填补了这一空白。具体而言，我们研究了血细胞比容、白蛋白和肌酐随年龄的变化。我们报告了所有血液学参数中明显的衰老证据。此外，衰老模式在性别和种群之间存在差异。血细胞比容方面，雄性的衰老速率高于雌性，且不存在种群差异。另一方面，肌酐的衰老速率在三河泉高于奇泽，且不存在性别差异。我们的研究结果首次证明了大型草食动物野生种群中血液学参数随年龄的下降，并表明脊椎动物的衰老过程不仅限于体重或健康组成部分。我们还证明了血液学参数的衰老模式取决于环境背景，且在性别之间以及根据环境条件而有所不同。
