RESUMO
Following the 2010 Deepwater Horizon disaster and subsequent unusual mortality event, adverse health impacts have been reported in bottlenose dolphins in Barataria Bay, LA including impaired stress response and reproductive, pulmonary, cardiac, and immune function. These conditions were primarily diagnosed through hands-on veterinary examinations and analysis of standard diagnostic panels. In human and veterinary medicine, gene expression profiling has been used to identify molecular mechanisms underlying toxic responses and disease states. Identification of molecular markers of exposure or disease may enable earlier detection of health effects or allow for health evaluation when the use of specialized methodologies is not feasible. To date this powerful tool has not been applied to augment the veterinary data collected concurrently during dolphin health assessments. This study examined transcriptomic profiles of blood from 76 dolphins sampled in health assessments during 2013-2018 in the waters near Barataria Bay, LA and Sarasota Bay, FL. Gene expression was analyzed in conjunction with the substantial suite of health data collected using principal component analysis, differential expression testing, over-representation analysis, and weighted gene co-expression network analysis. Broadly, transcript profiles of Barataria Bay dolphins indicated a shift in immune response, cytoskeletal alterations, and mitochondrial dysfunction, most pronounced in dolphins likely exposed to Deepwater Horizon oiling. While gene expression profiles in Barataria Bay dolphins were altered compared to Sarasota Bay for all years, profiles from 2013 exhibited the greatest alteration in gene expression. Differentially expressed transcripts included genes involved in immunity, inflammation, reproductive failure, and lung or cardiac dysfunction, all of which have been documented in dolphins from Barataria Bay following the Deepwater Horizon oil spill. The genes and pathways identified in this study may, with additional research and validation, prove useful as molecular markers of exposure or disease to assist wildlife veterinarians in evaluating the health of dolphins and other cetaceans.
Assuntos
Golfinho Nariz-de-Garrafa , Golfinhos Comuns , Poluição por Petróleo , Animais , Golfinho Nariz-de-Garrafa/genética , Golfinho Nariz-de-Garrafa/metabolismo , Perfilação da Expressão Gênica/veterinária , Golfo do México , Humanos , Poluição por Petróleo/efeitos adversosRESUMO
The Deepwater Horizon (DWH) oil spill profoundly impacted the health of bottlenose dolphins (Tursiops truncatus) in Barataria Bay, LA (BB). To comprehensively assess the cardiac health of dolphins living within the DWH oil spill footprint, techniques for in-water cardiac evaluation were refined with dolphins cared for by the U.S. Navy Marine Mammal Program in 2018 and applied to free-ranging bottlenose dolphins in BB (n = 34) and Sarasota Bay, Florida (SB) (n = 19), a non-oiled reference population. Cardiac auscultation detected systolic murmurs in the majority of dolphins from both sites (88% BB, 89% SB) and echocardiography showed most of the murmurs were innocent flow murmurs attributed to elevated blood flow velocity [1]. Telemetric six-lead electrocardiography detected arrhythmias in BB dolphins (43%) and SB dolphins (31%), all of which were considered low to moderate risk for adverse cardiac events. Echocardiography showed BB dolphins had thinner left ventricular walls, with significant differences in intraventricular septum thickness at the end of diastole (p = 0.002), and left ventricular posterior wall thickness at the end of diastole (p = 0.033). BB dolphins also had smaller left atrial size (p = 0.004), higher prevalence of tricuspid valve prolapse (p = 0.003), higher prevalence of tricuspid valve thickening (p = 0.033), and higher prevalence of aortic valve thickening (p = 0.008). Two dolphins in BB were diagnosed with pulmonary arterial hypertension based on Doppler echocardiography-derived estimates and supporting echocardiographic findings. Histopathology of dolphins who stranded within the DWH oil spill footprint showed a significantly higher prevalence of myocardial fibrosis (p = 0.003), regardless of age, compared to dolphins outside the oil spill footprint. In conclusion, there were substantial cardiac abnormalities identified in BB dolphins which may be related to DWH oil exposure, however, future work is needed to rule out other hypotheses and further elucidate the connection between oil exposure, pulmonary disease, and the observed cardiac abnormalities.
Assuntos
Golfinho Nariz-de-Garrafa , Traumatismos Cardíacos/veterinária , Poluição por Petróleo/efeitos adversos , Animais , Golfinho Nariz-de-Garrafa/anormalidades , Golfinho Nariz-de-Garrafa/fisiologia , Ecocardiografia/veterinária , Eletrocardiografia/veterinária , Fibrose/diagnóstico por imagem , Fibrose/veterinária , Coração/diagnóstico por imagem , Coração/fisiologia , Traumatismos Cardíacos/diagnóstico por imagem , Hipertensão/veterináriaRESUMO
Health assessments were conducted on bottlenose dolphins in Barataria Bay, Louisiana, USA, during 2011 to 2018, to assess potential health effects following the Deepwater Horizon oil spill, compared to the unoiled Sarasota Bay, Florida, USA, reference dolphin population. We previously reported significant increases in T-lymphocyte proliferation, as well as lower T helper 1 (Th1) cytokines, higher Th2 cytokine IL-4, and lower T regulatory (Treg) cytokine IL-10 in Barataria Bay in 2011 compared to Sarasota Bay, consistent with Deepwater Horizon oil exposure. Although values between 2013 and 2016 were more similar to those observed in Sarasota Bay, T-cell proliferation was again elevated and cytokine balance tilted toward Th2 in Barataria Bay during 2017-2018. In 2018, Barataria Bay dolphins had significantly more circulating Treg cells than Sarasota Bay dolphins. Mice experimentally exposed to oil also had significantly increased T-lymphocyte proliferation and circulating Treg cell number, including effects in their unexposed progeny. In vitro stimulation resulted in greater Th2 responsiveness in Barataria Bay compared to Sarasota Bay dolphins, and in vitro oil exposure of Sarasota Bay dolphin cells also resulted in enhanced Th2 responsiveness. Evidence points to Treg cells as a potential target for the immunomodulatory effects of oil exposure. The immunological trends observed in Barataria Bay appeared exaggerated in dolphins born after the spill, suggesting the possibility of continued oil exposure or multigenerational health consequences of exposure to oil, as observed in mice. Environ Toxicol Chem 2021;40:1308-1321. © 2021 SETAC.
Assuntos
Golfinho Nariz-de-Garrafa , Poluição por Petróleo , Animais , Florida , Golfo do México , Louisiana , CamundongosRESUMO
Common bottlenose dolphins (Tursiops truncatus), including those impacted by the 2010 Deepwater Horizon (DWH) oil spill, inhabit the coastal and estuarine waters of the northern Gulf of Mexico (GoM). In response to the spill, dolphin health assessments conducted in Barataria Bay, Louisiana - a site that experienced heavy and prolonged oiling - uncovered a high prevalence of health abnormalities and individuals in poor body condition. Although the health effects observed were suggestive of petroleum toxicity, a lack of pre-spill information regarding dolphin health raises the possibility that other environmental factors may have contributed to the adverse health of dolphins in this oil-impacted area. To assess how exposure to other environmental pollutants may affect the health of northern GoM dolphin populations impacted by the DWH oil spill, a suite of 69 persistent organic pollutants (POPs), including PCBs, PBDEs and organochlorine pesticides, was determined in blood and a subset of blubber samples collected during health assessments of 145 bottlenose dolphins at three GoM sites: two oil impacted sites - Barataria Bay, LA (BB), and Mississippi Sound, MS (MS) and an unimpacted reference site - Sarasota Bay, FL (SB). Overall, levels of POPs at all three sites appeared comparable or lower than concentrations previously reported for coastal bottlenose dolphin populations outside of the northern GoM. POP levels measured in BB dolphins were also comparable or lower than those measured at the unimpacted reference site (SB) within the northern GoM. Additionally, the relationship between blubber and blood contaminant levels in a smaller subset of BB and SB suggests that BB animals were not experiencing elevated blood-contaminant concentrations as a result of their poor body condition. Cumulatively, these results suggest that background levels of POPs measured are unlikely to produce the health abnormalities previously reported for BB dolphins.
Assuntos
Tecido Adiposo/química , Golfinho Nariz-de-Garrafa , Poluição por Petróleo , Poluentes Químicos da Água/sangue , Animais , Desastres , Monitoramento Ambiental , Golfo do México , Louisiana , Mississippi , Poluentes Químicos da Água/análiseRESUMO
Few accounts describe predator-prey interactions between common bottlenose dolphins (Tursiops truncatus Montagu 1821) and marine catfish (Ariopsis felis Linnaeus 1766, Bagre marinus Mitchill 1815). Over the course of 50,167 sightings of bottlenose dolphin groups in Mississippi Sound and along the Florida coast of the Gulf of Mexico, severed catfish heads were found floating and exhibiting movements at the surface in close proximity to 13 dolphin groups that demonstrated feeding behavior. These observations prompted a multi-disciplinary approach to study the predator-prey relationship between bottlenose dolphins and marine catfish. A review was conducted of bottlenose dolphin visual survey data and dorsal fin photographs from sightings where severed catfish heads were observed. Recovered severed catfish heads were preserved and studied, whole marine catfish were collected and examined, and stranding network pathology reports were reviewed for references to injuries related to fish spines. Photographic identification analysis confirms eight dolphins associated with severed catfish heads were present in three such sightings across an approximately 350 km expanse of coast between the Mississippi Sound and Saint Joseph Bay, FL. An examination of the severed catfish heads indicated interaction with dolphins, and fresh-caught whole hardhead catfish (A. felis) were examined to estimate the presumed total length of the catfish before decapitation. Thirty-eight instances of significant trauma or death in dolphins attributed to ingesting whole marine catfish were documented in stranding records collected from the southeastern United States of America. Bottlenose dolphins typically adhere to a ram-feeding strategy for prey capture followed by whole prey ingestion; however, marine catfish skull morphology may pose a consumption hazard due to rigid spines that can puncture and migrate through soft tissue, prompting a prey handling technique for certain dolphins, facilitating consumption of the posterior portion of the fish without the head.
Assuntos
Golfinho Nariz-de-Garrafa/fisiologia , Peixes-Gato/fisiologia , Comportamento Predatório , AnimaisRESUMO
Franciscana dolphin (Pontoporia blainvillei) whistles were documented for the first time during 2003-2013 in Babitonga Bay estuary, South Brazil, together with burst pulses. Recordings were made from small boats under good sea conditions, and recording equipment that allowed analysis of sounds up to 96 kHz. The recordings were made in the presence of 2-31 franciscana dolphins. During 23 h and 53 min, 90 whistles and 51 burst pulse series were recorded. Although Guiana dolphins (Sotalia guianensis) inhabit nearby waters, none were observed in the area during the recordings. The authors recorded ten types of whistles. The initial frequency varied between 1.6 and 94.6 kHz, and the final frequency varied between 0.7 and 94.5 kHz; the authors were not able to determine if dolphin whistles exceeded the 96 kHz recording limit of the authors' equipment, although that is likely, especially because some whistles showed harmonics. Whistle duration varied between 0.008 and 0.361 s. Burst pulses had initial frequencies between 69 and 82.1 kHz (77 ± 3.81). These results showed that P. blainvillei produces whistles and burst pulses, although they seem to be produced infrequently.
Assuntos
Golfinhos/fisiologia , Comportamento Social , Vocalização Animal , Acústica/instrumentação , Animais , Brasil , Golfinhos/classificação , Golfinhos/psicologia , Desenho de Equipamento , Feminino , Masculino , Movimento (Física) , Reconhecimento Automatizado de Padrão , Densidade Demográfica , Processamento de Sinais Assistido por Computador , Razão Sinal-Ruído , Som , Espectrografia do Som , Fatores de Tempo , Transdutores de Pressão , ÁguaRESUMO
A number of studies were initiated in response to the Deepwater Horizon (DWH) oil spill to understand potential injuries to bottlenose dolphins (Tursiops truncatus) that inhabit the northern Gulf of Mexico (NGoM) estuarine waters. As part of these studies, remote biopsy skin and blubber samples were collected from dolphins at six field sites that received varying degrees of oiling: Barataria Bay (BB), Chandeleur Sound West (CSW), Chandeleur Sound East (CSE), Mississippi Sound South (MSS), Mississippi Sound North (MSN), and St. Joseph Bay (SJ). Blubber samples from 108 male dolphins were analyzed for persistent organic pollutant (POP) concentrations, as high levels of POPs have been previously reported in other southeastern U.S. dolphins and the potential contribution of these compounds to adverse health effects in NGoM dolphins must be considered. Dolphin blubber levels of summed POPs (ΣPOPs) did not differ significantly across sites (F-test, P=0.9119) [µg/g lipid; geometric mean and 95% CI]; CSW [65.9 (51.4-84.6)], SJ [74.1 (53.0-104)], MSN [74.3 (58.7-93.9)], BB [75.3 (56.4-101)], CSE [80.5 (57.8-112)], and MSS [82.5 (65.9-103)]. Overall, POP concentrations were in the lower half of the range compared to previously reported concentrations from other southeastern U.S. sites. Increased dolphin mortalities have been ongoing in the NGoM and have been suggested to be linked with the DWH oil spill. In addition, lung disease, impaired adrenal function, and serum biochemical abnormalities have been reported in dolphins from BB, an area that was heavily oiled. The results of this study suggest that POPs are likely not a primary contributor to the poor health conditions and increased mortality observed in some populations of NGoM dolphins following the DWH oil spill.
Assuntos
Tecido Adiposo/metabolismo , Golfinho Nariz-de-Garrafa/metabolismo , Monitoramento Ambiental , Poluição por Petróleo , Poluentes Químicos da Água/metabolismo , Animais , Golfo do México , Masculino , MississippiRESUMO
Incidental entanglement in fishing gear is arguably the most serious threat to many populations of small cetaceans, judging by the alarming number of captured animals. However, other aspects of this threat, such as the potential capture of mother-offspring pairs or reproductive pairs, could be equally or even more significant but have rarely been evaluated. Using a combination of demographic and genetic data we provide evidence that i) Franciscana dolphin pairs that are potentially reproductive and mother-offspring pairs form temporal bonds, and ii) are entangled simultaneously. Our results highlight potential demographic and genetic impacts of by-catch to cetacean populations: the joint entanglement of mother-offspring or reproductive pairs, compared to random individuals, might exacerbate the demographic consequences of by-catch, and the loss of groups of relatives means that significant components of genetic diversity could be lost together. Given the social nature of many odontocetes (toothed cetaceans), we suggest that these potential impacts could be rather general to the group and therefore by-catch could be more detrimental than previously considered.
Assuntos
Cetáceos/genética , Cetáceos/fisiologia , Golfinhos/genética , Golfinhos/fisiologia , Animais , Argentina , DNA Mitocondrial/metabolismo , Feminino , Pesqueiros , Variação Genética , Masculino , Repetições de Microssatélites/genética , Modelos Genéticos , Modelos Estatísticos , Mães , Comportamento Sexual AnimalRESUMO
Our abilities to assess health risks to free-ranging dolphin populations, to treat live-stranded or captive dolphins, and to evaluate the risks of disease transmission between humans and dolphins have suffered from a lack of basic information on microorganisms associated with normal, presumably healthy free-ranging individuals. In order to provide these data, we sampled free-ranging bottlenose dolphins (Tursiops truncatus) off Florida, Texas, and North Carolina during 1990-2002. Blowhole and anal/fecal samples yielded 1,871 bacteria and yeast isolates and included 85 different species or groups of organisms. Vibrios, unidentified pseudomonads, Escherichia coli, Staphylococcus spp., and a large group of nonfermenting gram-negative bacteria represented >50% of isolates. Vibrio alginolyticus and Vibrio damsela were the most commonly recovered bacteria from both anal/fecal and blowhole samples. Many organisms occurred sporadically in dolphins that were sampled repeatedly, but some were consistently isolated from individual animals and may indicate the carrier state. Vibrios were common, but some geographic variability in the presence of these and other organisms was noted. Potential pathogens of significance to humans and other animals were recovered.
Assuntos
Bactérias/isolamento & purificação , Golfinhos/microbiologia , Leveduras/isolamento & purificação , Canal Anal/microbiologia , Bem-Estar do Animal , Animais , Animais Selvagens/microbiologia , Bactérias/classificação , Portador Sadio/veterinária , Reservatórios de Doenças/veterinária , Florida/epidemiologia , Biologia Marinha , North Carolina/epidemiologia , Filogenia , Especificidade da Espécie , Texas/epidemiologia , Leveduras/classificaçãoRESUMO
Polychlorinated biphenyls (PCBs) and hydroxylated metabolic products (OH-PCBs) were measured in plasma collected from live-captured and released bottlenose dolphins (Tursiops truncatus) from five different locations in the Western Atlantic and the Gulf of Mexico in 2003 and 2004. In 2004, the sum (sigma) of concentration of PCBs in plasma of dolphins sampled off Charleston, SC [geometric mean: 223 ng/g of wet weight (w.w.)] was significantly higher (p<0.05) than concentrations detected in animals from the Indian River Lagoon, FL (sigmaPCBs: 122 ng/g w.w.) and the Sarasota Bay, FL (sigmaPCBs: 111 ng/g w.w.). The PCB homolog profiles were similar among locations. Concentrations of OH-PCBs were significantly higher (p<0.05) in plasma of dolphins from Charleston, SC (sigmaOH-PCBs for 2003: 126 ng/g w.w.; 2004: 138 ng/g w.w.) than animals from Florida (sigmaOH-PCBs ranged from 6 to 47 ng/g w.w.) and Bermuda (8.3 ng/g w.w.); however, concentrations in the Charleston samples did not differ from animals captured in Delaware Bay, NJ (57 ng/g w.w.). The sigmaOH-PCBs constituted 2-68% of the total PCB concentrations in plasma. Dichloro- to nonachloro-OH-PCBs were quantified using high-resolution gas chromatography mass spectrometry, but only around 20% of OH-PCBs could be identified by comparison to authentic standards. Results from this study show that OH-PCB are important environmental contaminants in dolphins and suggest that PCBs, decades after their ban, may still constitute a threat to wildlife.