Abstract:

To fully assess the impacts of Deepwater Horizon (DWH) oil on the vertebrate stress response and the trajectory for recovery, our research integrated molecular, cellular, gland/organ and whole animal physiological and behavioral studies using a benthic marine teleost, the Gulf toadfish, a resident of the Gulf of Mexico. These studies evaluated multiple pathways (e.g., pituitary fatigue, reduced receptor sensitivity, disruption or overstimulation of cortisol biosynthesis) and the consequence of these changes at the whole animal level (e.g., changes in carbohydrate metabolism, immune capacity and responses to natural stresses such as predation and social interaction). In this series of experiments, fish plasma parameters such as cortisol, adrenocorticotropic hormone (ACTH) and glucose concentrations were evaluated during short-term exposures to DWH oil. Each exposure was followed by a complementary recovery period (i.e., no oil or PAH exposure) to assess the recovery trajectory. These experiments were completed at Rosenstiel School of Marine and Atmospheric Science (RSMAS), University of Miami, Marine Technology & Life Sciences Seawater Complex (MTLSS) Building, room 211 between January 2018 to December 2018.

Suggested Citation:

McDonald MD, Alloy MA, Cartolano MC, Plotnikova A, Sundaram R, Milton E. 2019. Acute exposure plasma parameters. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/n7-nn0x-2b64

Purpose:

These data were collected to determine if continuous exposure to low levels of DWH polycyclic aromatic hydrocarbons (PAHs) resulted in changes in blood cell levels, blood plasma stress hormone levels and blood plasma glucose concentrations.

Data Parameters and Units:

Replicate fish ID, plasma cortisol concentrations (ng/ml), plasma ACTH concentration (adrenocorticotropic hormone concentration, pg/ml), Plasma glucose concentration (mmol/L), total white blood cell counts (cells/ml), total red blood cell counts (cells/ml), differential white blood cell counts (cells/ml). The naming convention for replicate fish ID is where A = Treatment (X = Initial sample; C = control, 0.006 ug/L sum total PAH; L = low concentration exposure, 0.009 ug/L sum total PAH; M = medium concentration exposure, 0.06 ug/L sum total PAH; H = high concentration, 2.8 ug/L sum total PAH exposure); XXX = Fish number (1-152); B = Trial # (1 or 2); C = Fish state (Not stressed [NS] or Stressed [S]); D = Time sample taken in hours (h; either 4, 8, or 24) or days (d; either 3 or 7); Z = Period sample taken (either during Exposure [E] or during Recovery [R]). Please note - cross out = Fish died during the experiment; nd = data point not determined (oftentimes due to a bubble in the hemocytometer), not enough plasma for hormone assay, or issues with assay; and yellow highlight high values compared to typical.

Methods:

The oil used in this study was oil from extensively weathered surface slicks taken by the ship Juniper during the active phase of the Deepwater Horizon oil spill (Sample ID: OFS-20100719-Juniper-001:00979, 00919). Toadfish were exposed to 0.006 (control), 0.009 (low), 0.06 (medium) and 2.8 (high) ug/L sum 50 total PAH for 4, 8, 24 h, 3 days and 7 days and were then exposed to control water conditions for up to 4, 8, 24 h, 3 days and 7 days. Red blood cells and all white blood cells (leukocytes were not differentiated at this stage) were counted in triplicate (in the case of red blood cells) and quadruplicate (in the case of white blood cells) using a hemocytometer on 8 ul of whole blood that was incubated with 20% Natt and Herricks stain (Vetlab). Glucose was measured in plasma by a hexokinase total glucose kit (Sigma-Aldrich). Plasma cortisol was measured using a radio-immunoassay kit (MP Biomedicals). Plasma ACTH was measured using a radio-immunoassay kit (MP Biomedicals). Fish used in experiments were obtained by commercial shrimpers using trawl nets on the Atlantic coast of Florida (within Biscayne Bay) (Florida Fish and Wildlife Conservation Commission Special Activity License #SAL-16-0729-SR).

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