Hematologic and Total Plasma Protein Values in Free-Living Red-tailed Amazon Parrot Nestlings (Amazona brasiliensis) in Paraná State, Brazil

Abstract

The red-tailed Amazon parrot (Amazona brasiliensis) is an endangered psittacid species that is endemic in the south and southeast Brazilian Atlantic coastal region. Hematologic evaluation is important to monitor the health of these birds, and information about laboratory values for this species is scarce. Hematologic and total plasma protein profiles were determined for 33 free-living nestling parrots in Paraná state, Brazil. Parrots were temporarily removed from the nest and manually restrained to record body weight and collect blood samples. Mean body weight was <400 g in 13 birds (group 1) and >400 g in 20 birds (group 2). Significantly higher levels of mean corpuscular hemoglobin concentrations, white blood cell counts, monocytes, and basophils were observed in younger birds (group 1). A stress leukogram (high white blood cell and heterophil count) was found in all nestlings, suggesting stress induced by capture and restraint. Parameters obtained in this study will be essential to assess the physiologic and pathologic condition of wild parrots, to evaluate the effects of environmental changes on their health, and to contribute to conservation efforts of this endangered species.

Hematologic and biochemical reference intervals of free‐living Red‐Tailed Amazon parrot (Amazona brasiliensis) nestlings on Rasa Island, Paraná, Brazil

“…Values observed for the nestlings and the absence of morphologic abnormalities in WBC support the clinical criteria that were used for the identification of a healthy reference population for this current study . The high WBC count observed in some birds (like the maximum value showed in Table ) was most likely the result of capture‐related stress, as reported in other studies with Amazona sp . Specifically, increased numbers of circulating heterophils may be released from the microvasculature into the main circulation under epinephrine release triggered by excitement, fear, forced flight, and excessive muscular activity…”

“…The RIs for RBC count and PCV for the nestlings were comparable to values reported for the parrots A brasiliensis , A vinacea , and A guildingii . Hemoglobin concentration was comparable to reported values earlier in young parrots of A brasiliensis .…”

“…The RIs for RBC count and PCV for the nestlings were comparable to values reported for the parrots A brasiliensis , A vinacea , and A guildingii . Hemoglobin concentration was comparable to reported values earlier in young parrots of A brasiliensis . These appropriate RBC count, PCV, and HGB values reflect efficient oxygen carrying capacity of the nestlings, and adequate nutrition is indicated by the PCV (declined during fasting and inefficient erythropoiesis under an iron‐deficient nutrition) .…”

“…Reference intervals for relative differential WBC counts for eosinophils, monocytes, and basophils were comparable to the means reported for several captive and free‐living Amazon parrots, such as A brasiliensis , A vinacea , A aestiva , and Amazona sp …”

“…Heterophils were the second most numerous cells in the WBC count, as previously reported for Amazona sp ,. although some studies reported a heterophilic leukogram in A brasiliensis and A aestiva . This could either be considered a species‐specific feature, or skewed data due to stress of capture, handling, social interactions, and environmental conditions as another study on A brasiliensis …”