| Autor: |
Lum AM; Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32608, USA., Weisbrod TC; Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32608, USA., Jacob SI; Veterinary Diagnostic Laboratory, Michigan State University, Lansing, MI 48910, USA., Isaza R; Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32608, USA., Goertz CEC; Alaska SeaLife Center, PO Box 1329, Seward, AK 99664, USA., Tuttle AD; Mystic Aquarium, 55 Coogan Boulevard, Mystic, CT 06355, USA., Deegan TC; Vancouver Aquarium, 845 Avison Way, Vancouver, BC V6G 3E2, Canada., Francis-Floyd R; Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32608, USA., Stacy NI; Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32608, USA. |
| Abstrakt: |
An evaluation of morbidity and mortality in Steller sea lions (SSLs) Eumetopias jubatus under professional care identified a high prevalence of thyroid disease in aged animals. While studies have investigated the effects of age, season, nutrition, stressors, and pollutants on thyroid hormones in pinnipeds, data from individuals with known thyroid disease are lacking. Histopathological reports of adult SSLs in North American aquariums from 1979 to 2022 with banked serum (n = 14) were reviewed. Radioimmunoassays, which have been validated in this species, were used to determine triiodothyronine (TT3), total thyroxine (TT4), and free thyroxine (fT4). A solid-phase chemiluminescent immunometric assay for thyroid-stimulating hormone (TSH) quantification was validated by testing inter- and intra-assay repeatability, recovery, and parallelism. Lesions included follicular cysts (n = 5), adenoma with thyroglossal duct or follicular cysts (n = 2), medullary or follicular C-cell carcinoma with follicular cysts and nodular hyperplasia (n = 1), neuroendocrine carcinoma with follicular cysts (n = 1), and sarcomatoid carcinoma metastasis to the thyroid (n = 1). Significantly lower concentrations of TT3, TT4, and fT4 in SSLs with thyroid disease (n = 10) versus those without (n = 4) were attributed to space-occupying lesions, advanced age, and/or season. TSH was not significantly different between groups. Fifty percent of diseased SSL profiles were within reference ranges, and all individuals with lesions were clinically euthyroid. These data expand the current understanding of thyroid disease in SSLs and underscore the need for additional diagnostics (e.g. cervical ultrasound) concurrently with hormone assays to effectively screen for underlying abnormalities. |
