Abstract

The Florida manatee (Trichechus manatus latirostris) is an endangered species with multifactorial pressures leading to its rapidly diminishing populations. Presently, pertinent health information comes primarily from opportunistic encounters associated with either live or dead strandings. This study was conducted to evaluate the feasibility of evaluating the vitreous fluid of recently deceased manatees for determination of antemortem health.

The enucleated eyes of 76 Florida manatees presented for post-mortem evaluation at the Florida Marine Research Institute's Pathobiology Laboratory were utilized for this study. After being stored in a cool environment, the vitreous was extracted from each set of eyes and analyzed using a Kodak Ektachem serum chemistry analyzer. Results were compared to published wild manatee serum chemistry values as well as published vitreous fluid chemistry values in humans and other species. Analytes examined were glucose, sodium, potassium, chloride, calcium, urea nitrogen, creatinine, total protein, phosphorus, ALT and AST. All analytes observed followed similar trends to those described in humans and other animals. Glucose and calcium were consistently below published serum levels. As indicated in the literature, there is a strong potential for use of these analytes in cases of antemortem hypercalcemia and hyperglycemia when postmortem values are elevated with respect to normal serum levels. In other species, there is strong evidence that vitreous potassium rises at a predictable rate during the post-mortem interval. Potassium was above published serum levels, although with information lacking on the postmortem rate of increase in manatees, post mortem interval can not yet be determined using this electrolyte. Urea nitrogen and creatinine were consistent between published vitreous and serum levels. All of these results indicate that manatee vitreous fluid may be a useful tool in establishing several metabolic and organ system (kidney and liver) based diseases that occurred in these animals for a time before death.