Evaluating the Stress Response as a Bioindicator of Sub-Lethal Effects of Crude Oil Exposure in Wild House Sparrows (Passer domesticus)

Abstract

Petroleum can disrupt endocrine function in humans and wildlife, and interacts in particularly complex ways with the hypothalamus-pituitary-adrenal (HPA) axis, responsible for the release of the stress hormones corticosterone and cortisol (hereafter CORT). Ingested petroleum can act in an additive fashion with other stressors to cause increased mortality, but it is not clear exactly why—does petroleum disrupt feedback mechanisms, stress hormone production, or both? This laboratory study aimed to quantify the effects of ingested Gulf of Mexico crude oil on the physiological stress response of house sparrows (Passer domesticus). We examined baseline and stress-induced CORT, negative feedback, and adrenal sensitivity in house sparrows given a 1% oil or control diet (n = 12 in each group). We found that four weeks on a 1% oil diet did not alter baseline CORT titers or efficacy of negative feedback, but significantly reduced sparrows' ability to secrete CORT in response to a standardized stressor and adrenocorticotropin hormone injection, suggesting that oil damages the steroid-synthesizing cells of the adrenal. In another group of animals on the same 1% oil (n = 9) or control diets (n = 8), we examined concentrations of eight different blood chemistry parameters, and CORT in feathers grown before and during the feeding experiments as other potential biomarkers of oil exposure. None of the blood chemistry parameters differed between birds on the oil and control diets after two or four weeks of feeding, nor did feather CORT differ between the two groups. Overall, this study suggests that the response of CORT to stressors, but not baseline HPA function, may be a particularly sensitive bioindicator of sub-lethal chronic effects of crude oil exposure.

Behavioral and physiological responses of a freshwater turtle to anthropogenic activity

“…As the urban and rural sites were ~32km apart on a similar stretch of the Mississippi River and exhibit virtually no genetic variation between one another (Starkey et al 2003), this similarity in CORT levels implies either that the urban population has habituated to the presence of humans, or that C. picta are not stressed by the presence of human regardless of whether they have been exposed to them previously. This finding is in contrast to previous studies of songbirds and snakes (Lattin et al 2014, Deviche et al 2014, Moore et al 2001. The results from these previous studies may differ from my own because C. picta are long-lived whereas most of the previously studied taxa are not.…”

Adrenal Gland and Lung Lesions in Gulf of Mexico Common Bottlenose Dolphins (Tursiops truncatus) Found Dead following the Deepwater Horizon Oil Spill

“…Naphthalene, a common PAH associated with crude oil, reduced plasma corticosterone in mallard ducks following ingestion of petroleum-contaminated food, and a similar acute decrease in cortisol was detected in exposed eels [ 46 , 47 ]. House sparrows exposed orally to 1% crude oil from the GoM exhibited decreases in cortisol in response to stressors or to adrenocorticotropin hormone injection [ 48 ].…”

Feather corticosterone content in predatory birds in relation to body condition and hepatic metal concentration

“…Feather CORT concentrations have also been shown to be related to problem solving and learning (Bókony et al, 2014), and to feather pigmentation (Fairhurst et al, 2014;Kennedy et al, 2013;Lendvai et al, 2013;Martínez-Padilla et al, 2013). However, as far as we are aware there have been only a few studies that report feather CORT concentration in relation to pollutant exposure (Cruz-Martinez et al, 2015;Harms et al, 2010;Lattin et al, 2014).…”