Frigerio Didone, Ludwig Sonja C, Hemetsberger Josef, Kotrschal Kurt, Wascher Claudia A F
Core Facility Konrad Lorenz Forschungsstelle for Behaviour and Cognition, University of Vienna, Grünau im Almtal, Austria; Department of Behavioural Biology, University of Vienna, Vienna, Austria.
Core Facility Konrad Lorenz Forschungsstelle for Behaviour and Cognition, University of Vienna, Grünau im Almtal, Austria; Game & Wildlife Conservation Trust, The Coach House, Eggleston Hall, Barnard Castle, United Kingdom.
PeerJ. 2017 Jan 3;5:e2792. doi: 10.7717/peerj.2792. eCollection 2017.
Blood parameters such as haematocrit or leucocyte counts are indicators of immune status and health, which can be affected, in a complex way, by exogenous as well as endogenous factors. Additionally, social context is known to be among the most potent stressors in group living individuals, therefore potentially influencing haematological parameters. However, with few exceptions, this potential causal relationship received only moderate scientific attention.
In a free-living and individually marked population of the highly social and long-lived Greylag goose, , we relate variation in haematocrit (HCT), heterophils to lymphocytes ratio (H/L) and blood leucocyte counts to the following factors: intrinsic (sex, age, raising condition, i.e. goose- or hand-raised), social (pair-bond status, pair-bond duration and parental experience) and environmental (biologically relevant periods, ambient temperature) factors. Blood samples were collected repeatedly from a total of 105 focal birds during three biologically relevant seasons (winter flock, mating season, summer).
We found significant relationships between haematological parameters and social as well as environmental factors. During the mating season, unpaired individuals had higher HCT compared to paired and family individuals and this pattern reversed in fall. Similarly, H/L ratio was positively related to pair-bond status in a seasonally dependent way, with highest values during mating and successful pairs had higher H/L ratio than unsuccessful ones. Also, absolute number of leucocytes tended to vary depending on raising condition in a seasonally dependent way.
Haematology bears a great potential in ecological and behavioural studies on wild vertebrates. In sum, we found that HTC, H/L ratio and absolute number of leucocytes are modulated by social factors and conclude that they may be considered valid indicators of individual stress load.
血细胞比容或白细胞计数等血液参数是免疫状态和健康的指标，其会受到外源性和内源性因素的复杂影响。此外，社会环境是群居个体中最强大的应激源之一，因此可能影响血液学参数。然而，除了少数例外情况，这种潜在的因果关系仅受到适度的科学关注。
在高度群居且长寿的灰雁自由生活且个体有标记的种群中，我们将血细胞比容（HCT）、嗜异性粒细胞与淋巴细胞比率（H/L）以及血液白细胞计数的变化与以下因素相关联：内在因素（性别、年龄、饲养条件，即鹅饲养或人工饲养）、社会因素（配对状态、配对持续时间和育雏经验）和环境因素（生物学相关时期、环境温度）。在三个生物学相关季节（冬季鸟群、交配季节、夏季），从总共105只焦点鸟身上反复采集血样。
我们发现血液学参数与社会和环境因素之间存在显著关系。在交配季节，未配对个体的HCT高于配对个体和有家族成员的个体，而这种模式在秋季逆转。同样，H/L比率以季节依赖性方式与配对状态呈正相关，在交配期间值最高，成功配对的个体的H/L比率高于未成功配对的个体。此外，白细胞绝对数量倾向于根据饲养条件以季节依赖性方式变化。
血液学在野生脊椎动物的生态和行为研究中具有巨大潜力。总之，我们发现HTC、H/L比率和白细胞绝对数量受社会因素调节，并得出结论，它们可被视为个体应激负荷的有效指标。
