Significance of Symmetric Dimethylarginine (SDMA) in Evaluating Renal Insufficiency in Rehabilitated Wild Florida Manatees (Trichechus manatus latirostris) and Reference Values in Two Wild Manatee Populations
American Association of Zoo Veterinarians Conference 2017
Lauren N. Smith1, DVM; Robert K. Bonde2, PhD; Melissa R. Nau1, DVM; Ray L. Ball1, DVM
1Tampa’s Lowry Park Zoo, Tampa, FL, USA; 2U.S. Geological Survey, Wetland and Aquatic Research Center, Gainesville, FL, USA


Few reports of renal pathology in Florida manatees (Trichechus manatus latirostris) exist in the veterinary literature, yet renal compromise is a significant complication when rehabilitating debilitated manatees.3,4 Animals are frequently dehydrated and may have sustained direct trauma to the kidneys via boat strikes or ischemic events. Clinicians are limited to analysis of blood urea nitrogen, creatinine levels, and urinalysis (if urine can be obtained) to determine the extent of renal insufficiency, which may not accurately reflect renal function as it does in other species.5 This poses a diagnostic challenge for clinicians in discerning how critical renal compromise is to the animal’s overall health and prognosis.

Symmetric dimethylarginine (SDMA) is an accurate measure of glomerular filtration rate in humans, cats, and dogs, and is proven to be a reliable biomarker for early detection and monitoring of chronic kidney disease in those species.1,2,6 Retrospective analysis of SDMA values in 10 wild Florida manatees with known renal disease were shown to be statistically significantly elevated compared to six manatees with no reported renal lesions on histopathology. Serum SDMA values from manatees in Crystal River (February 2013 to February 2017) and Brevard County (January 2009 and December 2014) were comparable to those established in small animal medicine, with Crystal River populations at 12.23±3.13 µg/dl and Brevard County populations at 10.79±3.21 µg/dl.

These data support SDMA as clinically useful in evaluating renal function in manatees. Values obtained from wild populations appear to be comparable to established reference ranges in dogs and cats.6


The authors wish to thank Tampa’s Lowry Park Zoo veterinary team members including Michelle Devlin, Heather Henry, Ryan O’Shea; the Florida Mammals keeper staff; Dr. Justin F. Rosenberg; Martine de Wit and the staff at the Florida Fish and Wildlife Conservation Commission Marine Mammal Pathobiology Laboratory.

Literature Cited

1.  Hall JA, Yerramilli M, Obare E, Yerramilli M, Jewell DE. Comparison of serum concentrations of symmetric dimethylarginine and creatinine as kidney function biomarkers in cats with chronic kidney disease. J Vet Intern Med. 2014;28:1676–1683.

2.  Hall JA, Yerramilli M, Obare E, Yerramilli M, Melendez LD, Jewell DE. Relationship between lean body mass and renal biomarkers in healthy dogs. J Vet Intern Med. 2015;29:808–814.

3.  Harr K, Remember R, Ginn P, Lightsey J, Keller M, Reid J, Bonde R. Serum Amyloid A (SAA) as a biomarker of chronic infection due to boat strike trauma in a free-ranging Florida manatee (Trichechus manatus latirostris) with incidental polycystic kidneys. J Wildl Dis. 2011;47(4):1026–1031.

4.  Keller M, Moliner J, Vasquez G, Cruz D, Bello O, Costidis A, Rommel S, Mays M, Gearhart S. Nephrolithiasis and pyelonephritis in two West Indian manatees (Trichechus manatus spp.). J Wildl Dis. 2008;44(3):707–711.

5.  Manire CA, Walsh CJ, Rhinehart HL, Colbert DE, Noyes DR, Luer CA. Alterations in blood and urine parameters in two Florida manatees (Trichechus manatus latirostris) from simulated conditions of release following rehabilitation. Zoo Biol. 2003;22:103–120.

6.  Nabity MB, Lees GE, Boggess MM, Yerramilli M, Obare E, Yerramilli M, Rakitin A, Aguiar J, Relford R. Symmetric dimethylarginine assay validation, stability, and evaluation as a marker for the early detection of chronic kidney disease in dogs. J Vet Intern Med. 2015;29:1036–1044.


Speaker Information
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Lauren N. Smith, DVM
Tampa’s Lowry Park Zoo
Tampa, FL, USA

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