Trace and Non-Trace Elements in Blood Cells of Bottlenose Dolphins (Tursiops Truncatus): Variations With Values From Liver Function Indicators

Abstract

Alterations in trace and non-trace element homeostasis have been associated with both normal physiologic and pathologic processes of many species. Changes in copper and zinc, for instance, have been associated with liver disease in humans and dogs. While liver disease has been documented in marine mammals, associations of liver disease with trace and non-trace elements have not been determined. The goal of this study was to assess potential elemental associations with clinically relevant changes in liver enzymes of bottlenose dolphins (Tursiops truncatus) and to compare observed associations to what has been reported in other species. Blood cell samples were collected from 37 healthy bottlenose dolphins, maintained by the Navy Marine Mammal Program (MMP), between 1991 and 1992. Twenty-one trace and non-trace elements were assessed along with a standard liver enzyme function profile, and trace element associations to specific liver enzymes were determined. In this study, of the 21 blood cell elements assessed, 19 were measured within detectable limits in at least one of the blood samples, and 10 trace elements were found to be associated with at least one of the liver function indicators. Many of these same associations have been documented in various forms of liver disease in other species, including the associations of increases in copper and decreases in zinc with both elevated alanine aminotransferase (ALT) and gamma-glutamyl transferase (GGT). The observed analogous associations between changes in blood trace and non-trace elements and liver function indicators of bottlenose dolphins and other species may indicate similar pathologic processes and functions of some elements. Given the results of this study, additional research is warranted to further elucidate associations of trace and non-trace elements to liver disease in bottlenose dolphins.

Detection and quantification of heavy metals in blood and milk of Amazon river dolphin (Inia geoffrensis) (Cetartiodactyla: Iniidae) using wavelength‐dispersive X‐ray fluorescence spectrometry

“…[31][32][33]65,66 Some of these elements are also detected in the blood of bottlenose dolphin (Tursiops truncatus) by atomic emission spectroscopy. 29 However, some trace elements (e.g., As, Se, Br, Rb, Sr, and Pb) detected in these species, as well as mercury and its toxic organic forms detected in the milk and tissues (blubber, skin, muscle, kidney, and liver) of Amazon river dolphins by AAS 14,15,17,18 are not detected in the blood sample by the WD-XRF method in this study. Additionally, the XRF method has already been used to identify heavy metals in the muscle, liver, blubber, and skin of Tursiops truncatus and Delphinus delphis, 62 detecting some trace elements (e.g., Co, Ni, As, Se, Rr, Rb, Sr, Hg, and Pb) in these two species, but they are not detected by the WD-XRF method in the blood and milk samples of female Amazon river dolphin in this study.…”

“…Analyzing the blood of female Amazon river dolphin, the concentrations of aluminum, silicon, chromium, and zinc were higher than those reported for marine dolphins (e.g., Tursiops truncatus and Stenella attenuata). 29,30,34 However, the concentrations of magnesium, phosphorus, sulfur, and manganese were lower than those reported for marine dolphins. 29,34 The concentration of iron was seven times lower than those reported, for example, for Tursiops truncatus, 29,34 but much higher than those reported for Stenella attenuata.…”

“…29,30,34 However, the concentrations of magnesium, phosphorus, sulfur, and manganese were lower than those reported for marine dolphins. 29,34 The concentration of iron was seven times lower than those reported, for example, for Tursiops truncatus, 29,34 but much higher than those reported for Stenella attenuata. 30 For potassium and calcium, the concentrations were close to those reported for marine dolphins.…”

“…30 For potassium and calcium, the concentrations were close to those reported for marine dolphins. 29,30,34 By comparing with the blood of pinniped species (Carnivora, Phocid), the concentrations of aluminum, zinc, manganese, and chromium were higher, while phosphorus and sulfur were lower, and potassium and calcium were similar. [31][32][33] The concentration of iron, depending on the species, may be lower (e.g., Phoca vitulina) or higher (e.g., Halichoerus grypus) 31,33 than those observed in the blood of female Amazon river dolphin.…”

Research with Navy Marine Mammals Benefits Animal Care, Conservation and Biology

“…The veterinary staff of the MMP has spent decades working on the detection, isolation and identification of viral and bacterial pathogens and environmental contaminants that can affect the marine mammals within its population and elsewhere. Studies conducted at the MMP on the bioaccumulation of trace metals, polychlorinated biphenyls (PCBs) and organochlorines (OCs) in dolphin tissues has provided not only basic information on the levels of these compounds in tissues and milk, but also information on contaminant dynamics between tissues (e.g., blood vs. blubber), its maternal passage to offspring via milk production, its potential impact to reproduction, and its relationship to age and gender (Reddy, Echols, Finklea, Busbee, Reif, & Ridgway, 1998;Reddy, Reif, Bachand, & Ridgway, 2001;Ridgway & Reddy, 1995;Sorensen, Venn-Watson, & Ridgway, 2008). Veterinary work with MMP dolphins has resulted in observations of unusual species interactions (e.g., skin infestations of delphinids), allowed identification of bacterial and viral disease states, permitted the characterization of novel dolphin viruses, and resulted in the development of methods for detection of the viruses (Jensen, Lipscomb, Van Bonn, Miller, Fradkin, & Ridgway, 1998;Miller, Padhye, Van Bonn, Jensen, Brandt, & Ridgway 2002;Nollens et al, 2008;Ridgway, Lindner, Mahoney, & Newman, 1997;Van Bonn, Jensen, House, House, Burrage, & Gregg, 2000;Venn-Watson et al, 2008).…”