Hematological and morphometric differences of blood cells from rheas, Rhea americana (Struthioniformes: Rheidae) on two conservation farms / Diferenças hematológicas e morfométricas de células sanguineas de emas, Rhea americana (Struthioniformes: Rheidae) em dois criatórios conservacionistas

Abstract Today, blood tests are an indispensable tool in avian medicine. This study aimed to describe and compare hematological and morphometric data of erythrocytes, leukocytes and thrombocytes of rhea, Rhea americana. To do so, 58 rheas of both sexes on two farms, one in Cachoeiro do Itapemirim, Espírito Santo (ES), and the other in São Carlos, São Paulo (SP), were selected. Blood samples were taken and their RBC counts, PCV and Hb levels were determined and used in hematimetric index calculations. The total and differentiated leukocyte counts and the TPP and fibrinogen serum levels were also obtained. The results from the two farms analyzed were compared by means of the t test. There were differences in the parameters of the erythrocyte series between the two flocks because of a process of hypochromic macrocytic anemia observed among the rheas in ES. The values for the erythrocyte series and indexes were: RBC, 2.81 ± 0.15 x106/μl; PCV, 44.20 ± 2.86%; Hb, 12.12 ± 0.74 g/dL; MCV, 15.75 ± 0.89 fL; MCH, 43.18 ± 1.82 pg; and MCHC, 27.44 ± 0.80 g/dL. The values for the leukocyte series were: WBC, 12,072 ± 4116 /μL; heterophils, 64.10 ± 9.90%; eosinophils, 2.05 ± 2.06%; monocytes, 6.40 ± 2.99%; lymphocytes, 26.93 ± 9.62%; and basophils, 0.52 ± 1.27%. These can all be suggested as references for rheas reared in Brazil. Statistical differences were observed in erythrocyte length measurements, which were higher in the rheas in SP than in those in ES. Regarding width, the heterophils, lymphocytes and monocytes of the birds in ES were statistically greater than those of the birds in SP. It was concluded that rheas may exhibit morphometric alterations to blood cells and differences in blood elements according to the type of management to which they are subjected.

Resumo Atualmente exames de sangue são ferramentas indispensáveis na medicina aviária. Este estudo teve como objetivo descrever e comparar valores hematológicos e morfométricos de eritrócitos, leucócitos e trombócitos de emas, Rhea americana. Para isso, foram selecionadas 58 emas de ambos os sexos de dois criatórios, um em Cachoeiro do Itapemirim, Espírito Santo (ES) e o outro em São Carlos, São Paulo (SP). Amostras de sangue foram coletadas e realizadas a hematimetria, Hto e dosagem de Hb que foram utilizados nos cálculos dos índices hematimétricos. Também foram efetuadas as contagens total e diferencial de leucócitos, além da dosagem de proteínas total e do fibrinogênio séricos. Os resultados referentes às duas propriedades analisadas foram comparados pelo Teste t. Ocorreram diferenças nos parâmetros da série vermelha entre as aves dos dois criatórios devido a um processo de anemia macrocítica hipocrômica observado nas emas do ES. Os valores para a série vermelha e índices hematimétricos como: hematimetria, 2,81±0,15 x106/μl; Hto, 44,20±2,86%; Hb, 12,12±0,74 g/dL; VCM, 15,75±0,89 fL; HCM, 43,18±1,82 pg; CHCM, 27,44±0,80, além dos valores da série branca como: leucometria total, 12.072±4.116/μL, heterofilo, 64,10±9,90%, eosinófilo, 2,05±2,06%, monócito, 6,40±2,99%, linfócito, 26,93±9,62%, basófilo, 0,52±1,27% foram sugeridos como os de referência para as emas criadas no Brasil. Diferenças estatísticas foram observadas no comprimento de eritrócitos, o qual estava maior nas emas de SP do que aquelas do ES. Em relação à largura, os heterófilos, linfócitos e monócitos das aves do ES foram estatisticamente maior do que aquelas das aves de SP. Concluiu-se que emas podem apresentar alterações morfométricas de células sanguíneas e diferenças nos elementos do sangue de acordo com o tipo de manejo a que são submetidos.

Hematological and morphometric differences of blood cells from rheas, Rhea americana (Struthioniformes: Rheidae) on two conservation farms.

Today, blood tests are an indispensable tool in avian medicine. This study aimed to describe and compare hematological and morphometric data of erythrocytes, leukocytes and thrombocytes of rhea, Rhea americana. To do so, 58 rheas of both sexes on two farms, one in Cachoeiro do Itapemirim, Espírito Santo (ES), and the other in São Carlos, São Paulo (SP), were selected. Blood samples were taken and their RBC counts, PCV and Hb levels were determined and used in hematimetric index calculations. The total and differentiated leukocyte counts and the TPP and fibrinogen serum levels were also obtained. The results from the two farms analyzed were compared by means of the t test. There were differences in the parameters of the erythrocyte series between the two flocks because of a process of hypochromic macrocytic anemia observed among the rheas in ES. The values for the erythrocyte series and indexes were: RBC, 2.81 ± 0.15 x106/µl; PCV, 44.20 ± 2.86%; Hb, 12.12 ± 0.74 g/dL; MCV, 15.75 ± 0.89 fL; MCH, 43.18 ± 1.82 pg; and MCHC, 27.44 ± 0.80 g/dL. The values for the leukocyte series were: WBC, 12,072 ± 4116 /µL; heterophils, 64.10 ± 9.90%; eosinophils, 2.05 ± 2.06%; monocytes, 6.40 ± 2.99%; lymphocytes, 26.93 ± 9.62%; and basophils, 0.52 ± 1.27%. These can all be suggested as references for rheas reared in Brazil. Statistical differences were observed in erythrocyte length measurements, which were higher in the rheas in SP than in those in ES. Regarding width, the heterophils, lymphocytes and monocytes of the birds in ES were statistically greater than those of the birds in SP. It was concluded that rheas may exhibit morphometric alterations to blood cells and differences in blood elements according to the type of management to which they are subjected.

Hematological, morphological and morphometric characteristics of blood cells from rhea, Rhea Americana (Struthioniformes: Rheidae): a standard for Brazilian birds.

Blood exams are an indispensable tool in bird medicine. This study aimed at describing values and aspects of rheas' hematology, Rhea americana, as well as analyzing the morphology and morphometry of all blood cells. Fifty eight adult rheas of both sexes from two farms, one in Cachoeiro de Itapemirim, Espírito Santo State and the other in São Carlos, São Paulo State, were selected. Blood samples were taken and RBC count, PCV and Hb levels measured and used in hematimetric indexes calculations. The total and differentiated leukocyte counts, as well as the TPP and fibrinogen were determined. Erythrocytes, leukocytes and thrombocytes were identified and characterized morphologically. The values for the red series and hematimetric indexes were: RBC (2.81 ± 0.15 × 106/µL), PCV (44.20 ± 2.86%), Hb (12.12 ± 0.74 g/dL), MCV (15.75 ± 0.89 fL), MCH (43.18 ± 1.82 pg), MCHC (27.44 ± 0.80 g/dL); the values of white series were: WBC (12.072 ± 4116/µL), heterophils (64.10 ± 9.90%), eosinophils (2.05 ± 2.06%), monocytes (6.40 ± 2.99%), lymphocytes (26.93 ± 9.62%), basophils (0.52 ± 1.27%). One may conclude that on average, rheas' blood cells are larger than those of other birds, but these cells in smears cannot be differentiated only by their size. Besides rheas' leukocytes have different components and coloring as in other bird species, however, there are no components or staining aspects unique to the species.

Hematological, morphological and morphometric characteristics of blood cells from rhea, Rhea Americana (Struthioniformes: Rheidae): a standard for Brazilian birds / Características hematológicas, morfológicas e morfométricas de células sanguíneas de emas, Rhea americana (Struthioniformes: Rheidae): um padrão para aves brasileiras

Abstract Blood exams are an indispensable tool in bird medicine. This study aimed at describing values and aspects of rheas' hematology, Rhea americana, as well as analyzing the morphology and morphometry of all blood cells. Fifty eight adult rheas of both sexes from two farms, one in Cachoeiro de Itapemirim, Espírito Santo State and the other in São Carlos, São Paulo State, were selected. Blood samples were taken and RBC count, PCV and Hb levels measured and used in hematimetric indexes calculations. The total and differentiated leukocyte counts, as well as the TPP and fibrinogen were determined. Erythrocytes, leukocytes and thrombocytes were identified and characterized morphologically. The values for the red series and hematimetric indexes were: RBC (2.81±0.15×106/μL), PCV (44.20±2.86%), Hb (12.12±0.74 g/dL), MCV (15.75±0.89 fL), MCH (43.18±1.82 pg), MCHC (27.44±0.80 g/dL); the values of white series were: WBC (12.072±4116/μL), heterophils (64.10±9.90%), eosinophils (2.05±2.06%), monocytes (6.40±2.99%), lymphocytes (26.93±9.62%), basophils (0.52±1.27%). One may conclude that on average, rheas' blood cells are larger than those of other birds, but these cells in smears cannot be differentiated only by their size. Besides rheas' leukocytes have different components and coloring as in other bird species, however, there are no components or staining aspects unique to the species.

Resumo Exames de sangue são uma ferramenta indispensável na medicina de aves. Este estudo teve como objetivo descrever valores e aspectos da hematologia de emas, Rhea americana, bem como analisar a morfologia e morfometria de todas as células sanguíneas. Cinquenta e oito emas adultas de ambos os sexos de dois criatórios, um em Cachoeiro do Itapemirim, ES e o outro em São Carlos, SP foram selecionadas. Amostras de sangue foram coletadas e CTH, Ht e níveis de Hb foram mensurados e usados para o cálculo dos índices hematimétricos. A contagem total e diferencial de leucócitos, assim como, PPT e fibrinogênio foram determinados. Eritrócitos, leucócitos e trombócitos foram identificados e caracterizados morfologicamente. Os valores para série vermelha e índices hematimétricos foram: CTH (2,81±0,15×106/μL), Ht (44,20±2,86%), Hb (12,12±0,74 g/dL), VCM (15,75±0,89 fL), HCM (43,18±1,82 pg), CHCM (27,44±0,80 g/dL); os valores da série branca foram: CTL (12,072±4116/μL), heterófilos (64,10±9,90%), eosinófilos (2,05±2,06%), monócitos (6,40±2,99%), linfócitos (26,93±9,62%), basófilos (0,52±1,27%). Pode-se concluir que, na média, células sanguíneas de emas são maiores que as de outras aves, porém, não é possível diferenciar estas células em esfregaços somente pelo seu tamanho. Além disso, leucócitos de emas possuem diferentes componentes e coloração como acontece em outras espécies de aves, no entanto, não há nenhum componente ou aspectos tintoriais exclusivo para a espécie.

Seasonal changes in plasma levels of sex hormones in the greater Rhea (Rhea americana), a South American Ratite with a complex mating system.

Seasonal rhythm in sex hormones has been extensively studied in birds, as well as its relationship with the type of mating system. The Greater Rhea (Rhea americana), a South American ratite species, reproduces seasonally and has a complex mating system: female-defense polygyny and sequential polyandry. The present study aimed at analyzing the endocrine basis of reproduction in this species and its relationship with its mating system. We used HPLC and electrochemiluminescence techniques to identify and measure plasma testosterone and estradiol levels. Annual oscillations in sex hormones, testosterone and estradiol, in adult males and females were observed. Lower levels of these hormones were exhibited during the non reproductive season (February to July), whereas their maximum values were reached in September for males and November-December for females. These fluctuations reflect the seasonal changes in gonadal function. By contrast, no significant sex hormones oscillations were observed in juvenile males and females (negative control of seasonal changes). Greater rheas maintain high testosterone and estradiol levels throughout the reproductive period. The high testosterone levels during incubation and chick rearing did not inhibit parental behavior in males, which appears not to conform to the "Challenge Hypothesis". In females, the high estradiol levels throughout the reproductive season would be needed to sustain their long egg-laying period.

Occurrence of antibodies to Toxoplasma gondii in rheas (Rhea americana) and ostriches (Struthio camelus) from farms of different Brazilian regions.

This study aimed to verify the occurrence of antibodies against Toxoplasma gondii in rheas (Rhea americana) and ostriches (Struthio camelus) commercially breeding in Brazil. Blood samples from 20 rheas and 46 ostriches (young and adults) were serologically tested using a technique known as modified agglutination test (MAT) at an initial titration of 1:16 for ostriches and 1:25 for rheas. Antibodies against T. gondii were found in 50% (10/20) of the rheas, with titers ranging from 1:25 to 1:6,400. The incidence of antibodies against T. gondii in ostriches was 17.4% (8/46) with titers ranging from 1:16 to 1:256. Birds showing titers higher than 1:200 for T. gondii were mainly the young ones. Therefore, rheas and ostriches may be parasitized by T. gondii, showing high levels of antibodies against this parasite.

Occurrence of antibodies to Toxoplasma gondii in rheas (Rhea americana) and ostriches (Struthio camelus) from farms of different Brazilian regions / Ocorrência de anticorpos Toxoplasma gondii em emas (Rhea americana) e avestruzes (Struthio camelus) de propriedades de diferentes regiões brasileiras

This study aimed to verify the occurrence of antibodies against Toxoplasma gondii in rheas (Rhea americana) and ostriches (Struthio camelus) commercially breeding in Brazil. Blood samples from 20 rheas and 46 ostriches (young and adults) were serologically tested using a technique known as modified agglutination test (MAT) at an initial titration of 1:16 for ostriches and 1:25 for rheas. Antibodies against T. gondii were found in 50% (10/20) of the rheas, with titers ranging from 1:25 to 1:6,400. The incidence of antibodies against T. gondii in ostriches was 17.4% (8/46) with titers ranging from 1:16 to 1:256. Birds showing titers higher than 1:200 for T. gondii were mainly the young ones. Therefore, rheas and ostriches may be parasitized by T. gondii, showing high levels of antibodies against this parasite.

Este estudo teve como objetivo verificar a presença de anticorpos contra o Toxoplasma gondii em emas (Rhea americana) e avestruzes (Struthio camelus) criados comercialmente no Brasil. Amostras de sangue de 20 emas e 46 avestruzes (jovens e adultos) foram testadas sorologicamente pela técnica conhecida como teste de aglutinação modificada (MAT) em titulações iniciais de 1:16 para avestruzes e 1:25 para emas. Anticorpos contra T. gondii foram encontrados em 50% (10/20) das emas com títulos variando de 1:25 a 1:6.400. A incidência de anticorpos contra T. gondii em avestruzes foi de 17,4% (8/46) com os títulos oscilando entre 1:16 e 1:256. Aves jovens foram aquelas que apresentaram títulos superiores a 1:200 para T. gondii. Portanto, emas e avestruzes podem ser parasitados por T. gondii, apresentando elevados níveis de anticorpos contra o parasita.

Corticosterone stress response of Greater Rhea (Rhea americana) during short-term road transport.

The effect of transport stress on blood corticosterone levels in captive Greater Rheas was investigated. Twelve adult individuals (7 males; 5 females) were loaded in pairs inside wooden crates and transported along a paved road for 30 min. Blood samples were taken before the individuals were introduced into the crate (baseline value) and immediately after they were unloaded (30 min after capture). To assess whether corticosterone levels were affected by the blood sampling procedure per se, another 6 (nontransport) control birds (3 males; 3 females) were also captured and sampled at the same times as their transported counterparts. Plasma corticosterone concentrations were measured using a commercially available corticosterone (125)I radio-immunoassay kit. Baseline corticosterone levels were similar in the control and transported birds (9.0 ± 1.6 and 10.4 ± 0.8 ng/mL, respectively). Transportation induced a highly significant (P < 0.001), more than 40-fold increase in the corticosterone levels (433.6 ± 35.4 ng/mL) that was about 5 times higher (P < 0.001) than in their nontransported counterparts (88.4 ± 14.8 ng/mL). The present findings suggest that Greater Rhea is a species highly sensitive to stressful manipulations. Both blood sampling and transportation induced highly significant adrenocortical responses. Considering that transportation is one of the unavoidable common practices in the management of Greater Rheas and, as shown in the present study, that it induces a significant 40-fold corticosterone stress response, efforts should focus on helping to generate management transport standards for optimization of the welfare of this ratite.

Isolation and characterization of avian paramyxovirus type 3b from farmed Namibian ostriches (Struthio camelus f. dom.).

Meat and skin from farmed ostriches are valuable products for European consumers. The EU regulations require that ostrich products deamed for export need to come from ostriches that are free of antibodies against Newcastle disease virus (avian paramxovirus type 1, aPMV-1). After the detection of antibodies against aPMV-1 in one of five ostrich farms in Namibia, attempts were made to isolate the causative virus. No aPMV-1 but an avian paramyxovirus type 3 (aPMV-3) was isolated from five pharyngeal/cloacal swabs of clinically healthy farmed Namibian ostriches. Subtype determination proved that all isolates are members of the subtype aPMV-3 of psittacine bird origin and were designated as aPMV-3b. In the haemagglutination inhibition test, the aPMV-3b isolates cross-reacted with aPMV-1. This allows the conclusion that the antibodies originally detected in sera of the ostriches are due to the cross-reaction with aPMV-3b, rather than to an infection with aPMV-1.To our knowledge, this is the first description of the occurrence of aPMV-3b in farmed ostriches.

Physiological stress in captive Greater rheas (Rhea americana): highly sensitive plasma corticosterone response to an ACTH challenge.

Up to the present no studies have been conducted either on baseline concentrations of adrenal hormones or on hormonal responses to stress in Greater rhea (Rhea americana) and most ratite species. The aims of this work were to assess the presence of corticosterone in plasma of Greater rhea, to validate a corticosterone (125)I-radioimmunoassay for determining corticosterone levels in plasma samples and to study the activation of the adrenal gland after an adrenocorticotrophic hormone (ACTH) challenge. Six captive Greater rhea juveniles of 10 months of age received an intravenous ACTH injection. Blood samples were taken at 0min (baseline pre-ACTH levels), and post-injection at 15, 30, 60min and at 24 and 48h. The high pressure liquid chromatography (HPLC) analysis of pooled plasma showed that corticosterone is the glucocorticoid found in the plasma of Greater rhea. Biochemical assays of standard validation (e.g., parallelism, exogenous corticosterone recovery) showed that measurements of corticosterone present in the plasma of the Greater rhea provided by commercial corticosterone (125)I-radioimmunoassay were accurate and precise. ACTH challenge induced a more than 40-fold increase in plasma corticosterone at 60min post-ACTH (from 4.0 to 166.5ng/ml, on average). The corticosterone response to ACTH in Greater rhea was higher than is usual in birds, an apparently typical characteristic of ratites.

Hematology and serum chemistry values of the lesser rhea (Pterocnemia pennata) raised in Patagonian farms (Argentina).

Hematologic and serum chemistry values were determined for chicks, juveniles, and adult farmed lesser rheas (Prerocnemia pennata). Blood samples were taken during March-April 1998 from the brachial veins of lesser rhea, including 64 chicks, 24 juveniles, and 36 adults, raised in Patagonian farms (Argentina). Lesser rhea chicks had significantly lower erythrocyte counts, hematocrit, hemoglobin, red cell indices, and copper than did the juveniles and adult individuals. No significant differences were observed between females and males. Most values were similar to those reported for other ratites. The data obtained provide hematologic and serum chemistry values for lesser rhea from farms.