Hematological Condition Indexes in Greenfinches: Effects of Captivity and Diurnal Variation

Abstract

Ecophysiological research aiming at explaining the causes and consequences of variation in individual condition, health state, and allostasis is traditionally performed on captive animals under controlled laboratory conditions. The question about how captivity per se affects studied parameters is therefore of central importance for generalizing the information gained from such studies. We addressed this question by comparing various indexes of physiological condition of wintering greenfinches sampled in the wild and kept in captivity for different time periods. Bringing wild greenfinches into captivity did not result in systematic alteration in nine of 12 physiological parameters studied. Captive birds had consistently lower plasma carotenoid and uric acid levels than wild ones. Variation in differential leukocyte counts did not reveal any signs of elevated stress of birds kept in captivity. These results indicate that for a number of physiological parameters, information obtained from captive animals can be generalized to natural situations. Variance in traits most closely related to physical exercise capacity (body mass and hematocrit) were much lower in the wild than in captivity. These findings suggest that under harsh environmental conditions experienced by wild birds (i.e., predation threat, scarce resources), traits such as hematocrit and body mass are fine tuned by physiological trade-offs.

Does immune suppression during stress occur to promote physical performance?

“…immunopathology) on hosts (Graham et al, 2011). In the present study, we examined captivity effects on two innate immune measures: BKA (Millet et al, 2007) and oxidative burst (Sepp et al, 2010;Sild and Horak, 2010). Functionally, the former index is simple to interpret: a higher BKA is likely protective.…”

“…Inflammatory cells and processes seem particularly prone to perturbation in captivity (Buehler et al, 2008), although this observation has exceptions (Sepp et al, 2010). House sparrows appear prone to hyper-inflammation over long periods in captivity ( enhancements might be interpreted as protective, these elevations are more likely indicative of immune disregulation with subsequent, strong negative impacts (i.e.…”

Oxidative stress and information content of black and yellow plumage coloration: an experiment with greenfinches

“…Plasma TAC was measured from 5l plasma samples according to the method described by Erel (Erel, 2004) with minor modifications as described by Sepp et al (Sepp et al, 2010). The assay is based on the capacity of antioxidants in the solution to decolorize the ABTS + [2,2-azinobis(3-ethylbenzothiazoline-6-sulfonate)] according to their concentrations and antioxidant capacities.…”

On the methodological limitations of detecting oxidative stress: effects of paraquat on measures of oxidative status in greenfinches

“…Plasma TAC was measured from 5μl plasma samples according to a method described previously (Erel, 2004) with minor modifications (see Sepp et al, 2010). The assay is based on the capacity of antioxidants in the solution to decolorise ABTS + [2,2-azinobis(3-ethylbenzothiazoline-6-sulphonate)] according to their concentration and antioxidant capacity.…”

“…The assay is based on the capacity of antioxidants in the solution to decolorise ABTS + [2,2-azinobis(3-ethylbenzothiazoline-6-sulphonate)] according to their concentration and antioxidant capacity. The main contributors to TAC are plasma uric acid and free sulphydryl groups of proteins (Erel, 2004;Sepp et al, 2010). The results are quantified in mmoll -1 Trolox (watersoluble vitamin E analogue) equivalents.…”