Somatotroph pituitary tumors in budgerigars (Melopsittacus undulatus)

A series of 11 pituitary tumors in budgerigars were classified on the basis of their clinical, gross, microscopic, and immunohistochemical characteristics. Affected birds were young to middle-aged. Clinically, neurologic signs--including difficulties flying, ataxia, and blindness--were most commonly reported. Additional clinical signs included weight loss, abnormal feathers or molting, increased respiratory efforts, and exophthalmos. Nine birds were diagnosed with chromophobic pituitary adenomas, and 2 birds had chromophobic pituitary carcinomas. Only 1 tumor was delimited to the pituitary gland; the other 10 variably invaded the brain, skull, and retrobulbar space. Distant metastases were identified in 2 birds. All tumors were immunohistochemically strongly positive for growth hormone, consistent with the diagnosis of somatotroph tumors. The common occurrence and early onset may suggest a genetic predisposition of budgerigars to develop somatotroph pituitary tumors with a high incidence of local invasion and with metastatic potential.     

Chronic rhinitis and sinusitis in budgerigars (Melopsittacus undulatus)

The microscopic lesions in the nasal cavity, nasal bones, and infraorbital sinuses of five budgerigars with chronic upper respiratory tract infection are described. All five had chronic inflammation of the lining of the air spaces within the bones surrounding the nares and infraorbital sinuses.     

Semen collection and spermatozoa characteristics in budgerigars (Melopsittacus undulatus)

Semen samples were obtained from budgerigars by applying gentle pressure to both sides of the cloaca. The semen appeared to be stored in the seminal glomera, two structures on either side of the proctodeum. These structures have been described before in Passeriformes. The spermatozoon in budgerigars is similar to the spermatozoon of the domestic fowl, but differs from the spermatozoon of Passeriformes.     

Clinical approach to renal neoplasia in budgerigars (Melopsittacus undulatus)

Renal neoplasia in budgerigars (Melopsittacus undulatus) is seen regularly in general practice and is of interest to many practicing veterinary surgeons. This review article provides an overview of the current knowledge and the most recent reports in avian literature regarding renal tumours in budgerigars, with the emphasis on clinical diagnosis and treatment. The high prevalence of renal neoplasia in budgerigar is discussed, with notes on the most commonly diagnosed tumours, possibility of metastases, sex and age predisposition. The possibility of ultrasonography and radiography in the diagnosis of this pathological condition are compared as well as the possible role of blood and urine analyses. Two studies are described, both of which investigate the possible involvement of a retrovirus as the aetiological agent.     

Cerebral neuroblastoma and pituitary adenocarcinoma in two budgerigars (Melopsittacus undulatus)

Case 1: A tumor mass involving the rostral part of left cerebrum was found in a two-year-old female budgerigar (Melopsittacus undulatus) at necropsy. Histologically, the neoplastic cells were arranged in sheets or cords and occasionally showed nest growth patterns. These uniform tumor cells had a little cytoplasm and ovoid or round basophilic nuclei with clearly distinct cytoplasmic membranes. The tumor cells were strong diffusely immunostained with both neuron-specific enolase (NSE) and neurofilament protein and partially for synaptophysin. They lacked chromogranin A, glial fibrillary acidic protein (GFAP), vimentin, S-100, and cytokeratin antigen expression. Moreover, they had no reaction to antibodies against pituitary hormones, such as adrenocorticotrophic hormone (ACTH), growth hormone, and prolactin. The histological and immunohistochemical examination determined the tumor as neuroblastoma. Case 2: An extremely enlarged pituitary mass was found above the sella turcica of a male budgerigar. It was soft and well delineated from the adjacent structures. On histological examination, this tumor consisted of a sheet of large closely packed polyhedral cells that had scant to a large amount of pale to strongly eosinophilic cytoplasm. The pleomorphic nuclei were apparently variable in shape, from small round hyperchromatic to very large vesicular forms. The cell boundaries were not clearly distinct. The multifocal immunolabelling of neoplastic cells for NSE, synaptophysin, GFAP, and ACTH appeared, whereas a few cells reacted with vimentin and S-100 and stained negative for other markers, which were also utilized for case 1. Histological and immunohistochemical findings led to identification of corticotroph adenocarcinoma in the pituitary gland.     

Polyomavirus infection in budgerigars (Melopsittacus undulatus): clinical and aetiological studies

In order to get insight into the aetiology of French Moult (FM) and Budgerigar Fledgling Disease (BFD), and to determine relationships between the two diseases, 298 budgerigars from 49 different breeding flocks were examined. From all birds with BFD and from several birds with FM, viruses were isolated which produced characteristic cytopathic changes in chicken embryo fibroblasts. They were insensitive to chloroform treatment, and their replication was inhibited in the presence of 5-iododeoxyuridine. One of these isolates, from a bird exhibiting clinical signs of BFD, was determined by biochemical and biophysical methods to be a polyomavirus (BFDV). Nestling budgerigars 3 to 10 days of age, were inoculated with this BFDV isolate. They developed an acute systemic disease with high mortality rates, similar to naturally occurring infections. In this regard, BFDV differs markedly from all the other polyomaviruses known until now which only cause clinically asymptomatic, persistent infections in their natural hosts. Most of the birds examined with clinical signs of BFD or FM exhibited low titers of antibodies neutralizing the BFDV isolate, whereas in clinically healthy birds from flocks that never had any problems with FM or BFD, no antibodies against BFDV could be detected. On account of the results of our experiments described here we suspect that FM might be a milder, more protracted form of a BFDV infection.     

Ultrastructure and secretory nature of the seminal glomus in budgerigars (Melopsittacus undulatus)

The seminal glomera from captive budgerigars were dissected and prepared for ultrastructural and histochemical studies of the lining epithelia. The general structure suggested that they are formed by convolutions of the terminal portions of the ductus deferens which appear as a network of tubules. The epithelium lining the tubules was identified as pseudostratified ciliated and non-ciliated columnar epithelium. With the electron microscope it was possible to identify two different cell types in the epithelium: type 1, ciliated cells and type 2, non-ciliated epithelial cells. Light microscopy revealed periodic acid Schiff (PAS) positive material, resistant to diastase digestion in the distal parts of some of the epithelial cells, indicating its glycoprotein nature. Alcian blue/PAS staining showed mixed acidic and neutral glycoproteins. Alcian blue staining at different hydrogen ion concentrations (pH) showed that the acidic glycoprotein was of the weakly sulphated type. Periodic acid thiocarbohydrazide silver proteinase staining, at the ultrastructural level, confirmed the presence of an intracellular glycoprotein.     

Clinical and pathological aspects of 'going light' in exhibition budgerigars (Melopsittacus undulatus)

'Going light' is a chronic but eventually fatal disease of budgerigars. Clinically the only consistent features are weight loss while maintaining a good food intake. The signs are caused by enteritis typified by lymphocyte and plasma cell infiltration and associated villous atrophy leading to a malabsorption syndrome.     

Effects of two diets on the haematology, plasma chemistry and intestinal flora of budgerigars (Melopsittacus undulatus)

Two groups of 22 budgerigars (Melopsittacus undulatus) were housed for 12 months under identical conditions. One group was fed a commercial seed mixture plus carrots and a mineral supplement, and the other group was fed a commercially formulated diet plus carrots. Samples of blood and faeces were collected initially and after three, six, nine and 12 months. There were no significant differences between the haematological values of the two groups. The group fed the seed mixture had significantly higher concentrations of glucose, albumin, triglycerides and uric acid, and higher activity of aspartate aminotransferase, but the values were within the published reference ranges for normal birds. There were no significant differences between the faecal samples from the two groups, except that the fungus Macrorhabdus ornithogaster was identified in 48.3 per cent of the samples from the group fed the commercially formulated diet but from only 3.4 per cent of the samples from the group fed the seed mixture.     

The myocardial thickness in budgerigars (Melopsittacus undulatus) and Australian king parrots (Alisterus s. scapularis)

Due to lack of reference values an objective assessment of myocardial dilatation and hypertrophy in cage and aviary birds so far is not possible. Therefore the thickness of the myocardium of the left and the right ventricle of the heart of 14 budgerigars (Melopsittacus undulatus) and 5 Alisterus parrots (Alisterus s. scapularis) of both sexes was examined according to a standard protocol to establish morphometric data and first reference values. In order to compare the results of birds of different sizes all data were set in relation to the size of the bird's body (length of the sternum). Results of different zones were compared by means of statistical methods within one species. Besides that a comparison between the two species was performed. Only minor significant differences could be noticed.     

Biological variation, individuality and critical differences of eight biochemical blood constituents in budgerigars (Melopsittacus undulatus)

The aim of the study was to obtain basic data on individual biological variation, the required number of specimens to define the homeostatic setpoint (the aspired value of a variable adjusted to the individuals homeostasis) and critical differences of selected chemistry parameters in budgerigars (Melopsittacus undulatus). Blood from 99 healthy budgerigars was sampled 12 times at four-week intervals. Aspartate aminotransferase (ast), calcium, creatine kinase (ck), glutamate dehydrogenase (gldh), glucose, lactate dehydrogenase (ldh), total protein and uric acid were investigated. The indices of individuality obtained in the present study were relatively low (total protein 0.93, ast 1.02, gldh 1.04, ck 1.12, ldh 1.24, uric acid 1.26, glucose 1.39, calcium 1.61) and suggest that population-based reference limits might be useful. Comparison of data showed that the application of intraindividual reference values identified much greater variation in the reference values than using conventional population-based reference limits. Otherwise, the moderate to low degrees of individuality may allow the use of reference values of one individual as a standard for another individual of the same species. The critical differences that define the change needed between two serial results to indicate a biological change was highest in gldh with 120 per cent or 1.7 U/l. In calcium, a change of 30.5 per cent or 0.5 mmol/l would be significant. In the other parameters critical differences varied between 38 per cent in glucose, up to 93 per cent in uric acid.     

Evaluation of a fast,objective tool for assessing body condition of budgerigars (Melopsittacus undulatus)

There is currently no suitable system available for the assessment of budgerigar body condition. A tool has been developed that uses an algorithmic decision tree of yes‐no answers based on physical examination to objectively guide the assessor to a body condition score. The aim of this work was to evaluate the guide. Repeatability and reproducibility were measured by four assessors on three sequential days, using 38 budgerigars of mixed sex, age and weight. Data were analysed using a 3‐factor anova , with Person and Bird as variable factors and occasion as a fixed factor. The association between body condition score and body fat was measured using three assessors and 63 dead budgerigars, which were chemically analysed for fat content after assessment. Data were statistically analysed to determine correlation using Spearman's Rank Coefficient. Occasion and person had no significant effect on body condition score (p = 0.988 and 0.347 respectively). Body condition score and percentage body fat were highly significantly correlated (R² = 0.768): percentage fat increased with increasing body condition score. The guide would appear to be a repeatable measure of body condition in budgerigars, suitable for use during physical examinations.     

Influence of outlying values and variations between sampling days on reference ranges for clinical chemistry in budgerigars (Melopsittacus undulatus)

Reference ranges for clinical chemistry variables were established for 99 budgerigars sampled monthly for 12 months. The data from the repeated measurements were compiled to obtain the most reliable population-based reference range defined to be relevant for the population of budgerigars over the whole year. Outlying values were excluded by reference to the population-based reference range and to previously determined values from the same individual, following the guidelines of the International Federation of Clinical Chemistry. The exclusion of outliers significantly reduced the calculated reference ranges.     

Experimental infection of budgerigars (Melopsittacus undulatus) with a low virulent K21 strain of Toxoplasma gondii

In total 53 budgerigars (Melopsittacus undulatus) were divided into six groups and orally infected with a suspension of oocysts of low virulent Toxoplasma gondii K21 strain in the doses of 10(2), 10(3), 10(4), 10(5) and 10(6), respectively. Blood was collected from the birds prior to the inoculation and then on days 10, 20 and 30 post infection. Latex-agglutination test (LAT) was used for the detection of antibodies in the inoculated birds. The infected birds showed no apparent signs of disease. The antibodies were found in all but two birds inoculated a dose of 10(2) oocysts. Haematological values remained unchanged after infection. T. gondii was isolated by bioassay in mice from all 37 birds fed 10(3) or more oocysts and 6 of 9 fed 10(2) oocysts. The results demonstrate that budgerigars are resistant to T. gondii infection.     

Leiomyosarcoma in a budgerigar (Melopsittacus undulatus)

A tumor mass defined as a leiomyosarcoma was found in the thoracic cavity of a 3-year-old female budgerigar. Disseminated leiomyosarcomas were found in various body tissues, including bone marrow, spleen, and liver.     

Differences in bone mineral content and density between male and female budgerigars (Melopsittacus undulatus) during the non-reproductive season

It is known that female birds increase medullary mineral stores in long bones shortly before egg laying. Here, we present results from two groups of budgerigars, in both of which females had significantly higher bone mineral contents and densities, as measured by peripheral quantitative computed tomography of the tibiotarsus, during a reproductively dormant period. The results could indicate that female birds can accumulate mineral stores outside of the breeding season.     

Mycoplasma gallisepticum as a model to assess efficacy of inhalant therapy in budgerigars (Melopsittacus undulatus).

One hundred budgerigars (Melopsittacus undulatus) were infected in the nares (0.02 ml/naris), eye (0.02 ml/eye), and throat (0.2 ml) with Mycoplasma gallisepticum (MG) R strain (3.175 x 10(7) colony-forming units/ml). Fifty birds were treated with sterile broth and served as the controls; 25 of those were exposed to an inhalant, and the others were not treated. Infected birds were divided into four groups; 1) no treatment, 2) penicillin in drinking water, 3) inhalant, 4) both penicillin and inhalant. At days 3, 7, 10, 14, and 21 postinfection (PI), birds were assessed for clinical signs of disease. Five birds in each group were euthanatized at each interval PI; quantitative cultures were performed on lavages from the nares and trachea and on throat swabs; tracheas and air sacs were examined histopathologically. No clinical signs, lesions, or cultural isolations occurred in any control birds. All infected birds developed clinical signs and lesions of the trachea and air sac, but none died. The most severe clinical signs were seen in birds that were infected with MG and received no other intervention or birds that received penicillin in conjunction with infection. Increased respiratory tract lesions were associated with penicillin treatment; aerosol therapy resulted in fewer lesions.