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
Abstract
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
Acknowledgments
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.
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