Multiple Concurrent Stressors in Chicks.

McFARLANE, James M.; Curtis, S. E.; Šimon, Jan; Izquierdo, Òscar

doi:10.3382/ps.0680510

Cited by 38 publications

(15 citation statements)

References 32 publications

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“…For instance, newts injected with hydrocortisone did not exhibit altered N:L ratios until 3 days post-injection, whereas some frogs responded within 12-144 h of injection (Bennett and Harbottle, 1968). In addition, a study in poultry demonstrated prolonged elevation of H:L ratios even after corticosterone concentrations had returned to baseline levels (McFarlane et al, 1989), similar to our observations in hellbenders. Although N:L ratios are often used as an indicator of acute stress in individuals when it is difficult to obtain enough blood to analyze for corticosterone (Davis et al, 2008), N:L ratios may not be a good surrogate for detecting stress responses in hellbenders over short time scales (i.e.…”

Section: Relationship Between N:l and Corticosterone Responsessupporting

confidence: 75%

Evidence of ectoparasite-induced endocrine disruption in an imperiled giant salamander, the eastern hellbender (Cryptobranchus alleganiensis)

DuRant

Hopkins

Davis

et al. 2015

Journal of Experimental Biology

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Parasitic leeches and trypanosomes release chemical signals into their hosts to evade immuno-detection, but it is unknown whether these compounds manipulate host behavior or endocrine physiology. We determined whether parasitic infections with leeches and/ or trypanosomes affected the immune and stress response of an imperiled giant species of amphibian, the eastern hellbender (Cryptobranchus alleganiensis Daudin). We monitored corticosterone and white blood cell counts in response to restraint and injection with adrenocorticotropin hormone (ACTH) or saline for up to 50 h. The presence of leeches dampened hellbender corticosterone responses to restraint and reduced diel patterns of plasma corticosterone. Injection with ACTH restored the normal inter-renal responses of hellbenders, suggesting that leeches, possibly through neurotransmitters in leech saliva, cause down-regulation of corticosterone release at the level of the pituitary or hypothalamus. Infection with leeches also increased the relative abundance of eosinophils, white blood cells often recruited into circulation in response to parasitic infection. Lastly, neutrophil to lymphocyte (N:L) ratios increased in all animals after 24 h of capture and remained elevated for up to 50 h, but these temporal dynamics did not differ with parasite infection. Trypanosome infection did not affect any aspect of hellbender physiology that we measured. Our findings reveal a previously undocumented host-parasite dynamic. While the functional significance to the parasite is unclear, the physiological and behavioral implications for the host are great, given the important role of glucocorticoids in regulating physiology and behavior.

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Section: Relationship Between N:l and Corticosterone Responsessupporting

confidence: 75%

Evidence of ectoparasite-induced endocrine disruption in an imperiled giant salamander, the eastern hellbender (Cryptobranchus alleganiensis)

DuRant

Hopkins

Davis

et al. 2015

Journal of Experimental Biology

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“…These were subjected to statistical analyses. Results for all leukocyte traits except H/L (reported here) are reported elsewhere (McFarlane et al, 1989b). Statistical Analysis.…”

Section: Introduction Materials and Methodsmentioning

confidence: 99%

Multiple Concurrent Stressors in Chicks.

1989

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Effects of multiple concurrent stressors on female Hubbard x Hubbard chicks were studied in a 2(6)-factorial experiment that employed as stressor treatments aerial ammonia (A, 0 or 125 ppm), beak trimming [B, sham handled or beak trimmed/cauterized on trial Day 1 (posthatch Day 10)], coccidiosis (X, gavage with 0 or 6 x 10(5) sporulated Eimeria acervulina oocysts), intermittent electric shock (E, 0 or between 2.9 and 8.7 mA), environmental heat stress (H, air temperature 30.4 or 34.8 C), and continuous noise (N, 80 or 95 dB). Plasma corticosterone concentration on trial Day 7 was unaffected by any stressor or stressor combination, but the heterophil:lymphocyte ratio (H/L) was increased by A, E, and H. Also, the B x X interaction was significant for H/L. The H/L increased linearly from .53 to .86 as number of concurrent stressors increased from zero to six. These findings indicate that the chick's leukocyte changes in response to stress are less variable and more enduring than its corticosterone response, and H/L are sometimes a more reliable indicator of stress.

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“…Unlike the glucocorticoid response to stress, which starts within 2-5 min after a stress event (Romero and Reed 2005), changes in the leukocyte population in the peripheral blood are not evident until 1-2 h afterwards (e.g., Dhabhar et al 1995;Cirule et al 2012) and remain altered longer than plasma glucocorticoid levels (McFarlane et al 1989). However, the timing of these responses varies among taxa (Romero and Reed 2005;Davis et al 2008).…”

Section: Electronic Supplementary Materialsmentioning

confidence: 97%

Why fly the extra mile? Using stress biomarkers to assess wintering habitat quality in migratory shorebirds

et al. 2016

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Migratory birds make decisions about how far to travel based on cost-benefit trade-offs. However, in many cases the net effect of these trade-offs is unclear. We sought to address this question by measuring feather corticosterone (CORTf), leucocyte profile, avian malaria parasite prevalence and estimating fueling rates in three spatially segregated wintering populations of the migratory shorebird ruddy turnstone Arenaria interpres during their stay in the winter habitat. These birds fly from the high-Arctic breeding ground to Australia, but differ in that some decide to end their migration early (Broome, Western Australia), whereas others travel further to either South Australia or Tasmania. We hypothesized that the extra costs in birds migrating greater distances and overwintering in colder climates would be offset by benefits when reaching their destination. This would be evidenced by lower stress biomarkers in populations that travel further, owing to the expected benefits of greater resources and improved vitality. We show that avian malaria prevalence and physiological stress levels were lower in birds flying to South Australia and Tasmania than those overwintering in Broome. Furthermore, our modeling predicts that birds in the southernmost locations enjoy higher fueling rates. Our data are consistent with the interpretation that birds occupying more costly wintering locations in terms of higher migratory flight and thermoregulatory costs are compensated by better feeding conditions and lower blood parasite infections, which facilitates timely and speedy migration back to the breeding ground. These data contribute to our understanding of cost-benefit trade-offs in the decision making underlying migratory behaviour.

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Multiple Concurrent Stressors in Chicks.

Cited by 38 publications

References 32 publications

Evidence of ectoparasite-induced endocrine disruption in an imperiled giant salamander, the eastern hellbender (Cryptobranchus alleganiensis)

Evidence of ectoparasite-induced endocrine disruption in an imperiled giant salamander, the eastern hellbender (Cryptobranchus alleganiensis)

Multiple Concurrent Stressors in Chicks.

Why fly the extra mile? Using stress biomarkers to assess wintering habitat quality in migratory shorebirds

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