Comparison of Serum Thyroid Hormone Levels in Greenwinged Macaws Using Radio and Chemiluminescent Immunoassays

This study compared the use of radioimmunoassay (RIA) and chemiluminescent immunoassay (CLIA) to measure serum thyroid hormone levels in green-winged macaws (Ara chloropterus). The sample group comprised 20 male and 13 female (n = 33) healthy, captive greenwinged macaws of reproductive age but outsi...

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Bibliographic Details
Published inJournal of avian medicine and surgery Vol. 35; no. 2; p. 187
Main Authors Vieira, Kassia R.A, Faillace, Ana C.L, Oliva, Ligia R, Dislich, Mathias, Cubas, Zalmir S, Lobo-Junior, Adalfredo R, Santana, Marcelo I.S
Format Journal Article
LanguageEnglish
Published Association of Avian Veterinarians 01.06.2021
Subjects
Health aspects
Immunoassay
Macaws
Measurement
Medical examination
Physiological aspects
Thyroid hormones
Brazil
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Summary:This study compared the use of radioimmunoassay (RIA) and chemiluminescent immunoassay (CLIA) to measure serum thyroid hormone levels in green-winged macaws (Ara chloropterus). The sample group comprised 20 male and 13 female (n = 33) healthy, captive greenwinged macaws of reproductive age but outside of breeding season. Mean free triiodothyronine (T3), total T3, and free thyroxine (T4) measured by CLIA and RIA corresponded to 5.11 and 5.08 prnol/L (3.33 and 3.31 pg/mL), 1.59 and 1.56 nmol/L (103.5 and 101.5 ng/dL), and 8.25 and 8.82 prnol/L (0.64 and 0.69 ng/dL), respectively. Mean total T4 by RIA corresponded to 6.29 nmol/L (0.49 gg/dL). Mean free T4 and thyroid-stimulating hormone (TSH) levels differed according to immunoassay method, with higher values measured by RIA compared with CLIA. Sex influence was statistically significant in immunoassay results only on free T3 levels. Free T3 levels measured by RIA were higher than levels measured by CLIA in male birds, but this difference was not found with the female bird samples. Conversely, free T3 levels measured by CLIA were higher in the female macaws compared with male birds. Comparative analysis of thyroid hormone measurements in this study revealed that RIA and CLIA are equivalent methods to measure free T4 and total T3 levels but not TSH levels. These findings support the use of CLIA for free T4 and total T3 level determinations in green-winged macaws. However, the CLIA kit used in this study provided invalid total T4 level results for the macaws sampled. Radioimmunoassay and CLIA were equally ineffective for determining TSH levels in this species. Key words: thyroid hormones, chemiluminescent assay, radioimmunoassay, psittacine birds, avian, green-winged macaw, Ara chloropterus
ISSN:1082-6742
1938-2871