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Moss RA, Murphy KM, Gardner ST, Watkins MM, Finger JW, Kelley MD, Elsey RM, Warner DA, Mendonça MT. Exposure to ecologically relevant estrogen levels do not influence morphology or immune parameters in hatchling American alligators (Alligator mississippiensis). Comp Biochem Physiol C Toxicol Pharmacol 2024; 275:109767. [PMID: 37827394 DOI: 10.1016/j.cbpc.2023.109767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 09/26/2023] [Accepted: 10/08/2023] [Indexed: 10/14/2023]
Abstract
Human activity has increased concentrations of endocrine-disrupting contaminants (EDCs) in many ecological systems. Many EDCs are xenoestrogens, which imitate naturally derived estrogen like estradiol 17-β (E2). These pollutants can critically affect a broad range of biological functions, particularly in organisms inhabiting aquatic environments. E2 and associated receptors are involved in regulating innate immune responses, where documentation of exogenous E2 on immune parameters is important for understanding health consequences. In this study, we explore the impact of environmentally relevant concentrations of E2 on circulating glucocorticoid levels and several innate immune parameters in hatchling American alligators (Alligator mississippiensis). Twenty-three hatchling alligators were randomly placed in one of three groups that differed in dietary E2 concentration: control (no E2 exposure), low E2 (0.5 μg/kg E2), or high E2 (1 μg/kg E2) for 10 weeks. Following this period, several biomarkers were quantified to monitor the impact of E2: growth, change in body condition, white blood cell (WBC) counts, glucocorticoid levels, and general antibody response. Blood E2 concentrations were greater in individuals exposed to E2, but plasma corticosterone levels were reduced among the experimental groups. Morphology, growth, and immune parameters of E2 exposed animals did not differ from controls. These results suggest that acute exposure to increased environmental estrogen concentrations may alter plasma hormone concentrations but have little to no impact on immediate morphology or immune responses. Future studies may expand on this by monitoring biomarkers in wild populations across time, which will provide insight into how different ontogenetic stages are impacted by environmental contaminants.
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Affiliation(s)
- Regan A Moss
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, United States of America; Mailman School of Public Health, Columbia University, New York, NY 10027, United States of America
| | - Kaitlyn M Murphy
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, United States of America.
| | - Steven T Gardner
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, United States of America
| | - Madison M Watkins
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, United States of America
| | - John W Finger
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, United States of America; Department of Biological Sciences, University of Alabama, Tuscaloosa, AL 35487, United States of America
| | - Meghan D Kelley
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, United States of America; Department of Biological Sciences, University of Alabama, Tuscaloosa, AL 35487, United States of America
| | - Ruth M Elsey
- Louisiana Department of Wildlife and Fisheries, Grand Chenier, LA 70643, United States of America; 728 Saratoga Drive, Murfreesboro, TN 37130, United States of America
| | - Daniel A Warner
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, United States of America
| | - Mary T Mendonça
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, United States of America
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Murphy KM, Watkins MM, Finger JW, Kelley MD, Elsey RM, Warner DA, Mendonça MT. Xenobiotic estradiol-17ß alters gut microbiota of hatchling American alligators (Alligator mississippiensis). Environ Microbiol 2022; 24:6336-6347. [PMID: 36164972 DOI: 10.1111/1462-2920.16222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 09/23/2022] [Indexed: 01/12/2023]
Abstract
Environmental oestrogens pose serious concerns for ecosystems through their effects on organismal survival and physiology. The gut microbiome is highly vulnerable to environmental influence, yet the effects of oestrogens on gut homeostasis are unknown because they are poorly studied in wildlife populations. To determine the influence of environmental oestrogens (i.e., xenoestrogens) on the diversity and abundance of gut microbiota, we randomly assigned 23 hatchling American alligators (Alligator mississippiensis) to three ecologically relevant treatments (control, low, and high oestrogen concentrations) for 10 weeks. We predicted that xenoestrogen exposure would decrease microbial diversity and abundance within the digestive tract and that this effect would be dose-dependent. Microbial samples were collected following diet treatments and microbial diversity was determined using 16S rRNA gene-sequencing. Individuals in oestrogen-treatment groups had decreased microbial diversity, but a greater relative abundance of operational taxonomic units than those in the control group. In addition, this effect was dose-dependent; as individuals were exposed to more oestrogen, their microbiome became less diverse, less rich and less even. Findings from this study suggest that oestrogen contamination can influence wildlife populations at the internal microbial-level, which may lead to future deleterious health effects.
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Affiliation(s)
- Kaitlyn M Murphy
- Department of Biological Sciences, Auburn University, Auburn, Alabama, USA
| | - Madison M Watkins
- Department of Biological Sciences, Auburn University, Auburn, Alabama, USA
| | - John W Finger
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, Alabama, USA
| | - Meghan D Kelley
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, Alabama, USA
| | - Ruth M Elsey
- Louisiana Department of Wildlife and Fisheries, Grand Chenier, Baton Rouge, Louisiana, USA
| | - Daniel A Warner
- Department of Biological Sciences, Auburn University, Auburn, Alabama, USA
| | - Mary T Mendonça
- Department of Biological Sciences, Auburn University, Auburn, Alabama, USA
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3
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Romero-Calderón AG, Alvarez-Legorreta T, Rendón von Osten J, González-Jáuregui M, Cedeño-Vázquez JR. Stress responses in captive Crocodylus moreletii associated with metal exposure. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 308:119685. [PMID: 35764186 DOI: 10.1016/j.envpol.2022.119685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 06/22/2022] [Accepted: 06/23/2022] [Indexed: 06/15/2023]
Abstract
Environmental pollution by metals has repercussions on wildlife health. It is known that some metals can have an influence on the neuroendocrine stress response, and at the same time, metals have pro-oxidant effects that can overwhelm the antioxidant system and cause oxidative stress. This study evaluates the association of metals with neuroendocrine stress activity and biomarkers of oxidative stress in 42 captive female Morelet's crocodiles (Crocodylus moreletii). We measured five metals of ecotoxicological importance (Hg, Cd, Pb, Cu and Zn), and three biomarkers of the oxidative stress response in the liver: glutathione (GSH) and glutathione disulfide (GSSG) as markers for antioxidant system and thiobarbituric acid reactive substances (TBARS) for oxidative damage. We also measured one biomarker of the neuroendocrine response to stress: corticosterone (B) in blood plasma. The mean ± SD concentrations of metals in the liver expressed in μg/g (dw) were: Cd: 0.004 ± 0.003, Hg: 0.014 ± 0.019, Cu: 0.017 ± 0.013, Zn: 0.043 ± 0.035, Pb: 0.16 ± 0.256. The mean ± SD of GSH was 0.42 ± 0.35 nmol/mg protein, the mean ± SD of GSSG was 0.24 ± 0.20 nmol/mg protein, the mean ± SD concentrations of TBARS were 0.36 ± 0.21 nmol/mg protein, and the mean ± SD of B was 393.57 ± 405.14 pg/mL. Hg presented a significant negative relationship with corticosterone. Cd had a negative relationship with both GSH and GSSG; meanwhile, Zn showed a negative relationship with TBARS levels, could be a protective element against hepatic oxidative damage. Finally, B had negative relationship with oxidative damage. The connection found between Hg and the neuroendocrine stress response, as well as the correlations of Cd and Zn with oxidative damage and antioxidant activity should be studied further, given their toxicological importance and implications for the conservation of C. moreletii and other crocodilians.
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Affiliation(s)
- A G Romero-Calderón
- Department of Sustainability Sciences. El Colegio de la Frontera Sur (ECOSUR), Av. Centenario Km 5.5, 77014, Chetumal, Quintana Roo, Mexico.
| | - T Alvarez-Legorreta
- Department of Sustainability Sciences. El Colegio de la Frontera Sur (ECOSUR), Av. Centenario Km 5.5, 77014, Chetumal, Quintana Roo, Mexico.
| | - J Rendón von Osten
- Instituto de Ecología, Pesquería y Oceanografía del Golfo de México (EPOMEX), Campus VI, Av. Héroes de Nacozari 480, Universidad Autónoma de Campeche, 24070, Campeche, Mexico.
| | - M González-Jáuregui
- Centro de Estudios de Desarrollo Sustentable y Aprovechamiento de la Vida Silvestre (CEDESU), Av. Héroes de Nacozari 480, Universidad Autónoma de Campeche, 24070, Campeche, Mexico.
| | - J R Cedeño-Vázquez
- Department of Systematics and Aquatic Ecology. El Colegio de la Frontera Sur (ECOSUR), Av. Centenario Km 5.5, 77014, Chetumal, Quintana Roo, Mexico.
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Finger JW, Kelley MD, Zhang Y, Ka C, Hamilton MT, Elsey RM, Kavazis A, Mendonca MT. Relationships of Brain Glucocorticoid Receptors and Commonly Used Stress Parameters with Body Condition of Juvenile American Alligators (Alligator mississippiensis). SOUTH AMERICAN JOURNAL OF HERPETOLOGY 2022. [DOI: 10.2994/sajh-d-20-00008.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- John W. Finger
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Meghan D. Kelley
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Yufeng Zhang
- School of Health Studies, University of Memphis, Memphis, TN 38152, USA
| | - Cheikhouna Ka
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Matthew T. Hamilton
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN 47907, USA
| | - Ruth M. Elsey
- Louisiana Department of Wildlife and Fisheries, Rockefeller Wildlife Refuge, Grand Chenier, LA 70643, USA
| | - Andreas Kavazis
- School of Kinesiology, Auburn University, Auburn, AL 36849, USA
| | - Mary T. Mendonca
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
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Finger JW, Kelley M, Hamilton M, Zhang Y, Elsey R, Mendonca M, Kavazis AN. Changes in antioxidant enzyme levels following capture in juvenile American Alligators (Alligator mississippiensis) are tissue dependent. CAN J ZOOL 2022. [DOI: 10.1139/cjz-2021-0231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Many parameters used to investigate stress in vertebrates are temporally sensitive. The act of capture and sampling can influence them, hindering their functionality for evaluating the effects of stressors. Consequently, the investigation and subsequent incorporation of less time sensitive parameters are necessary to better evaluate stressors affecting vertebrates. In this study, we investigated how capture stress and handling associated with sampling influences antioxidant status in American Alligators (Alligator mississippiensis, Daudin, 1802; hereafter Alligator), long-lived, top-trophic carnivores found in the southeastern United States, by measuring levels of two antioxidant enzymes in destructive (brain and pancreas) and nondestructive (tail scutes) tissues: superoxide-dismutase-1 (SOD1) and glutathione peroxidase-1 (GPX1). Capture stress had no effect on pancreatic SOD1 and no effect on brain and pancreatic GPX1 (all p > 0.05). However, brain SOD1, scute SOD1, and scute GPX1 were all impacted by capture stress. These disparate results illustrate that the influence of capture stress on antioxidant enzymes in Alligators is tissue and marker dependent, necessitating further investigation. Our results provide a firm foundation to further investigate oxidative status in crocodilians.
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Affiliation(s)
- John W. Finger
- Auburn University, 1383, Department of Biological Sciences, Auburn, United States, 36849-5412
| | - Meghan Kelley
- Auburn University, 1383, Auburn, Alabama, United States
| | - Matthew Hamilton
- Purdue University, 311308, West Lafayette, Indiana, United States
| | - Yufeng Zhang
- The University of Memphis, 5415, Memphis, Tennessee, United States
| | - Ruth Elsey
- Departement of wildlife and fisheries, Louisiana, USA, 5476 Grand Chenier Highway, Grand Chenier, United States, 70643
| | - Mary Mendonca
- Auburn University, 1383, Auburn, Alabama, United States
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Lemaire J, Bustamante P, Mangione R, Marquis O, Churlaud C, Brault-Favrou M, Parenteau C, Brischoux F. Lead, mercury, and selenium alter physiological functions in wild caimans (Caiman crocodilus). ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 286:117549. [PMID: 34438486 DOI: 10.1016/j.envpol.2021.117549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 06/04/2021] [Accepted: 06/05/2021] [Indexed: 06/13/2023]
Abstract
Environmental contaminants affect ecosystems worldwide and have deleterious effects on biota. Non-essential mercury (Hg) and lead (Pb) concentrations are well documented in some taxa and are described to cause multiple detrimental effects on human and wildlife. Additionally, essential selenium (Se) is known to be toxic at high concentrations but, at lower concentrations, Se can protect organisms against Hg toxicity. Crocodilians are known to bioaccumulate contaminants. However, the effects of these contaminants on physiological processes remain poorly studied. In the present study, we quantified Hg, Pb and Se concentrations in spectacled caimans (Caiman crocodilus) and investigated the effects of these contaminants on several physiological processes linked to osmoregulatory, hepatic, endocrine and renal functions measured through blood parameters in 23 individuals. Mercury was related to disruption of osmoregulation (sodium levels), hepatic function (alkaline phosphatase levels) and endocrine processes (corticosterone levels). Lead was related to disruption of hepatic functions (glucose and alanine aminotransferase levels). Selenium was not related to any parameters, but the Se:Hg molar ratio was positively related to the Na+ and corticosterone concentrations, suggesting a potential protective effect against Hg toxicity. Overall, our results suggest that Hg and Pb alter physiological mechanisms in wild caimans and highlight the need to thoroughly investigate the consequences of trace element contamination in crocodilians.
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Affiliation(s)
- Jérémy Lemaire
- Centre d'Études Biologiques de Chizé (CEBC), UMR 7372 CNRS-La Rochelle Université, 79360 Villiers en Bois, France; Littoral Environnement et Sociétés (LIENSs), UMR 7266 CNRS-La Rochelle Université, 2 rue Olympe de Gouges, 17000 La Rochelle, France.
| | - Paco Bustamante
- Littoral Environnement et Sociétés (LIENSs), UMR 7266 CNRS-La Rochelle Université, 2 rue Olympe de Gouges, 17000 La Rochelle, France; Institut Universitaire de France (IUF), 1 rue Descartes, 75005 Paris, France
| | - Rosanna Mangione
- Division of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Wohlenstrasse 50a, CH-3032, Hinterkappelen, Switzerland
| | - Olivier Marquis
- Sorbonne Université, Muséum National d'Histoire Naturelle, Parc Zoologique de Paris, 53 Avenue de Saint Maurice, 75012 Paris, France
| | - Carine Churlaud
- Littoral Environnement et Sociétés (LIENSs), UMR 7266 CNRS-La Rochelle Université, 2 rue Olympe de Gouges, 17000 La Rochelle, France
| | - Maud Brault-Favrou
- Littoral Environnement et Sociétés (LIENSs), UMR 7266 CNRS-La Rochelle Université, 2 rue Olympe de Gouges, 17000 La Rochelle, France
| | - Charline Parenteau
- Centre d'Études Biologiques de Chizé (CEBC), UMR 7372 CNRS-La Rochelle Université, 79360 Villiers en Bois, France
| | - François Brischoux
- Centre d'Études Biologiques de Chizé (CEBC), UMR 7372 CNRS-La Rochelle Université, 79360 Villiers en Bois, France
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Finger JW, Kelley MD, Zhang Y, Hamilton MT, Elsey RM, Mendonca MT, Kavazis A. Short-term capture stress and its effects on corticosterone levels and heat shock proteins in captive American Alligators (Alligator mississippiensis). CAN J ZOOL 2021. [DOI: 10.1139/cjz-2021-0014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Heat shock proteins (HSPs) are important mediators of the normal cellular function and the cellular stress response. As such, HSPs are often utilized to measure the effects of stressors on organisms in vivo. However, multiple variables can influence their expression, including time or season, confounding results. To investigate the utility of HSPs in measuring effects of stressors in a top-trophic carnivore, we captured 20 American Alligators (Alligator mississippiensis (Daudin, 1802)), placed them in burlap sacks for 2 h and collected blood samples over four time points (baseline, 1 and 2 h after placement into burlap sacks, and 24 h after initial capture) to measure plasma corticosterone (the main crocodilian glucocorticoid) and levels of HSP60, HSP70, and HSP90. Time point significantly affected plasma corticosterone levels in Alligators (p < 0.0001), with levels significantly elevated at 1, 2, and 24 h, relative to baseline (all p < 0.05). However, capture stress did not affect HSP60, HSP70, or HSP90 in red blood cells (all p > 0.05). Our results suggest HSPs may be important biomarkers for investigating the impacts of stressors on captive and wild crocodilians, as they are not acutely elevated by capture or handling stress.
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Affiliation(s)
- John W. Finger
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Meghan D. Kelley
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Yufeng Zhang
- College of Health Sciences, University of Memphis, Memphis, TN 38152, USA
| | - Matthew T. Hamilton
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN 47907, USA
| | - Ruth M. Elsey
- Louisiana Department of Wildlife and Fisheries, Rockefeller Wildlife Refuge, Grand Chenier, LA 70643, USA
| | - Mary T. Mendonca
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Andreas Kavazis
- School of Kinesiology, Auburn University, Auburn, AL 36849, USA
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Finger JW, Kelley MD, Zhang Y, Hamilton MT, Elsey RM, Mendonca MT, Kavazis AN. Antioxidant Enzymes in Destructible and Non-Destructible Tissues in American Alligators (Alligator mississippiensis). SOUTH AMERICAN JOURNAL OF HERPETOLOGY 2021. [DOI: 10.2994/sajh-d-19-00118.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- John W. Finger
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Meghan D. Kelley
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Yufeng Zhang
- School of Health Studies, University of Memphis, Memphis, TN 38152, USA
| | - Matthew T. Hamilton
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN 47907, USA
| | - Ruth M. Elsey
- Louisiana Department of Wildlife and Fisheries, Rockefeller Wildlife Refuge, Grand Chenier, LA 70643, USA
| | - Mary T. Mendonca
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
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Kieran TJ, Goodman SJ, Finger JW, Thomas JC, Hamilton MT, Tuberville TD, Glenn TC. Microbiota of Four Tissue Types in American Alligators (Alligator mississippiensis) Following Extended Dietary Selenomethionine Exposure. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2020; 105:381-386. [PMID: 32794125 DOI: 10.1007/s00128-020-02961-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 08/06/2020] [Indexed: 06/11/2023]
Abstract
Selenium represents an essential trace nutrient that is necessary for biological functions. Deficiencies can induce disease, but excess can induce toxicity. Selenium deficiency is a major concern in underdeveloped countries, while also posing as a toxic pollutant in waterways surrounding landfills, agricultural areas, and fossil fuel production sites. We examined the microbiome of selenomethionine (SeMet) fed American alligators (Alligator mississippiensis) at the beginning and end of a 7-week exposure experiment. Alligators were randomly divided into three groups: control and 1000 or 2000 ppm SeMet. DNA from before exposure (oral and cloaca swabs) and post-exposure (oral, cloaca, small & large intestines) sampling were extracted and amplified for bacterial 16 s rRNA. While treatment did not seem to have much effect, we observed a predominance of Fusobacteriaceae and Porpyromonodaceae across all tissue types. Cetobacterium and Clostridium are the most abundant genera as potential indicators of the aquatic and carrion feeding lifestyle of alligators.
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Affiliation(s)
- Troy J Kieran
- Department of Environmental Health Science, University of Georgia, Athens, GA, 30602, USA
| | - Samantha J Goodman
- Department of Poultry Science, University of Georgia, 30602, Athens, GA, USA
- College of Veterinary Medicine & Biomedical Sciences, Toxicology Program, Texas A&M University, College Station, TX, 77843, USA
| | - John W Finger
- Department of Environmental Health Science, University of Georgia, Athens, GA, 30602, USA
- Savannah River Ecology Laboratory, University of Georgia, 29802, Aiken, SC, USA
- Department of Biological Sciences, Auburn University, Auburn, AL, 36849, USA
| | - Jesse C Thomas
- Department of Environmental Health Science, University of Georgia, Athens, GA, 30602, USA
- Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA
| | - Matthew T Hamilton
- Savannah River Ecology Laboratory, University of Georgia, 29802, Aiken, SC, USA
- Department of Forestry and Natural Resources, West Lafayette, IN, 47907, USA
| | - Tracey D Tuberville
- Savannah River Ecology Laboratory, University of Georgia, 29802, Aiken, SC, USA
| | - Travis C Glenn
- Department of Environmental Health Science, University of Georgia, Athens, GA, 30602, USA.
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Finger JW, Hamilton MT, Kelley MD, Stacy NI, Glenn TC, Tuberville TD. Examining the Effects of Chronic Selenium Exposure on Traditionally Used Stress Parameters in Juvenile American Alligators (Alligator mississippiensis). ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2019; 77:14-21. [PMID: 30976886 DOI: 10.1007/s00244-019-00626-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 04/01/2019] [Indexed: 06/09/2023]
Abstract
Environmental contaminants, such as the trace element selenium (Se), are a continuing concern to species worldwide due to their potential pathophysiological effects, including their influence on the stress response mediated through glucocorticoids (GCs; stress hormones). Environmental concentrations of Se are increasing due to anthropogenic activities, including the incomplete combustion of coal and subsequent disposal of coal combustion wastes. However, most studies examining how Se affects GCs have been focused on lower trophic organisms. The objectives of this study were to investigate the effects of long-term Se exposure on traditionally used stress parameters and to identify which of these parameters best indicate Se accumulation in liver and kidney of the American alligator (Alligator mississippiensis), a top trophic carnivore found in the southeastern United States and known to inhabit Se-containing areas. Alligators were divided into three dietary treatments and fed prey spiked with 1000 or 2000 ppm of selenomethionine (SeMet) or deionized water (control treatment) for 7 weeks. Following the 7-week treatment protocol, blood and tissue samples were obtained to measure plasma corticosterone (CORT; the main crocodilian GC), tail scute CORT, the ratio of peripheral blood heterophils (H) to lymphocytes (L) as H/L ratio, and body condition. To evaluate which parameter best indicated Se accumulation in the liver and kidney, principal component and discriminant analyses were performed. The only parameter significantly correlated with liver and kidney Se concentrations was scute CORT. Our results suggest that measurement of CORT in tail scutes compared with plasma CORT, H/L ratios, and body condition is the best indicator of Se-exposure and accumulation in crocodilians.
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Affiliation(s)
- John W Finger
- Department of Biological Sciences, Auburn University, Auburn, AL, 36849, USA.
- Department of Environmental Health Science, University of Georgia, Athens, GA, 30602, USA.
- Savannah River Ecology Laboratory, University of Georgia, PO Drawer E, Aiken, SC, 29802, USA.
| | - Matthew T Hamilton
- Savannah River Ecology Laboratory, University of Georgia, PO Drawer E, Aiken, SC, 29802, USA
| | - Meghan D Kelley
- Department of Biological Sciences, Auburn University, Auburn, AL, 36849, USA
| | - Nicole I Stacy
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Travis C Glenn
- Department of Environmental Health Science, University of Georgia, Athens, GA, 30602, USA
| | - Tracey D Tuberville
- Savannah River Ecology Laboratory, University of Georgia, PO Drawer E, Aiken, SC, 29802, USA
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11
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Visual Obstruction has No Effect on Post Capture Corticosterone Levels of Juvenile American Alligators (Alligator mississippiensis). J HERPETOL 2018. [DOI: 10.1670/18-080] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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