Introduction

The Amazona aestiva, popularly known as the True Parrot is classified in the order Psittaciformes, family Psittacidae and genus Amazona, occupying an area in the Brazilian territory that goes from the Northeast Region to Rio Grande do Sul (Godoy, 2008). These birds have in average 40 cm of length and 450 g of weight. They are easily identified by the color of their feathers: yellow on the head, green on the neck and body, and red on the final third of the wings and on the tail (Sick, 1997). Parrots, parakeets and macaws are commonly kept out of their natural environment, being considered as pet animals, a term used for dogs and cats that have been domesticated by men (Werther, 2008). The maintenance of wild fauna in domestic captivity has been increasing over years, and it is important to notice that in this situation, animals are susceptible to a variety of diseases. According to Benez (2001), birds present the ability to hide and conceal symptoms, making it harder to diagnose the disease on its initial stages, and consequently decreasing the chances of treatment and healing. The use of laboratorial data is important to clarify some diagnoses, specially on stages in which symptoms are not very evident, as well as when monitoring the efficacy of a treatment. Among the most important laboratorial tests in avian clinics we find hematologic and biochemistry parameters (Rupley, 1999). Current reference ranges used for the interpretation of hematologic findings were determined in a variety of Brazilian regions or are actually from foreign literature. Considering the variations between environmental, nutritional and handling conditions, as well as how these variables influence laboratorial parameters, it becomes necessary to standardize specific reference ranges for each region. This should avoid misinterpretation of laboratorial data, and possible fatal mistakes that could lead to the patient's death due to inadequate treatment. The present study is designed to better define hematologic reference ranges for the species Amazona aestiva in the coastal region of São Paulo State, Brazil.

Materials and Methods

Ten male and female adult animals of the species Amazona aestiva were used in this study. These animals had been sent by IBAMA to the Wild Animals Triage Center, Mata Atlântica Lello-Unimonte Shelter, after domestic illegal seizure in the cities of Praia Grande, Guarujá, Itanhaém, Santos and São Vicente, all part of São Paulo State. These birds were appropriately identified with a metal band and submitted to clinical, physical and parasitological examination. This study only included totally healthy animals, which have been in captivity for at least 40 days. The blood collection was done in the ulnar vein, according to the techniques proposed by Rupley (1999) and Almosny & Monteiro (2008). The venepuncture was performed after local antisepsis, using 3 mL syringes and hypodermic needles filled with sodium heparin (technique by Werther, 2008). We obtained approximately 0.45 mL samples from each bird, respecting the parameter of 1% of the animal's body weight, according to Rupley (1999). Blood smears were stained with May Grunwald-Giemsa and sent along with the blood samples to the veterinary clinical pathology laboratory ANCLIVET, where the material was processed. The total white blood cells and erythrocytes counts were manually performed using a Neubauer chamber, the hemoglobin levels were determined by spectrophotometry, the hematocrit was evaluated by the micro-hematocrit technique, and the leukocyte differential counts were assessed by microscopic examination of blood smears. Moreover, we calculated the mean corpuscular volume (MCV) and the mean corpuscular hemoglobin concentration (MCHC), as well as the standard deviation of the means.

Results

We obtained the following values (mean ± 1 standard deviation): Erythrocytes Count (x10⁶/μL) 2.7 ± 1.2; Hematocrit (%) 35.3 ± 16.4; Hemoglobin Concentration (g/dL) 11.7 ± 6.1; Mean Corpuscular Volume (fL) 133.35 ± 16.5; Mean Corpuscular Hemoglobin Concentration (%) 35.35 ± 5; Total Leukocytes Count (x10³/μL) 11.5 ± 1.74; Heterophils (x10³/μL) 4.9 ± 2.7; Eosinophils (x10³/μL) 0.09 ± 0.13; Basophils (x10³/μL) 0.03 ± 0.05; Lymphocytes (x10³/μL) 6.2 ± 3.2; and Monocytes (x10³/μL) 0.28 ± 0.18.

Discussion and Conclusions

The Erythrocytes Count values were very similar to those reported by Santos (1999), therefore, some values were above the ones found by this author. Considering the Hematocrit, our values were below the ones reported by Santos (1999) and I.S.I.S. (2002), who had described a greater reference range than the one we have found. The Hemoglobin Concentration parameters found in our study matches the values described by Santos (1999), which range from 11.7 to 14.3 g/dL. The intervals obtained for MCV and MCHC are different from those presented by Santos (1999) but close to the values described by Goulart (2006). The Total Leukocytes Count values are similar to the ones found in literature, but our standard deviation was slightly minor. The ranges found for heterophils, eosinophils, basophils and monocytes match with previous studies, but the lymphocytes count were higher than described by other authors (Santos, 1999; I.S.I.S., 2002; Goulart, 2006). According to our results, we conclude that the establishment of hematologic reference ranges for the species Amazona aestiva in different regions is important for the appropriate use of the hematological findings as a tool for the diagnosis and treatment of these birds, considering the variations we may find in health animals among different areas of the country.

References

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