Action of acth(1 -24) upon plasma corticosterone concentrations in racing pigeons (Columba Livia domestica)

To establish the optimal dose and sampling times for the ACTH stimulation test in racing pigeons, plasma corticosterone concentrations were measured in experimental animals at 0, 30, 60, 90, 120 and 150 min after intramuscular administration of different doses of ACTH(1-24). Baseline corticosterone concentrations varied between less than 0.2 and 1.24 mutg/dl. To evaluate adrenocortical function the clinician is advised to take a blood sample before and at 60 or 90 min after stimulation with 50 mug ACTH or at 30, 60, 90 or 120 min after stimulation with 125 mug ACTH. In healthy individuals a ten- to hundred-fold increase over baseline (t=0) corticosterone concentrations and absolute concentrations in the range of 2.2 to 15.0 mug/dl can be expected in the post stimulation sample.     

Plasma urea, creatinine and uric acid concentrations in relation to feeding in peregrine falcons (Falco peregrinus)

Significant post-prandial increases in plasma uric acid and plasma urea concentrations were observed in peregrine falcons. Post-prandial uric acid concentrations were similar to those in birds suffering from hyperuricaemia and gout and were well above the theoretical limit of solubility of sodium urate in plasma. It is not clear why under normal circumstances no urate deposits occur in peregrine falcons (and probably other raptorial birds), which show hyperuricaemia for at least 12 h after ingesting a natural meal. It is important to evaluate renal function in peregrine falcons (and perhaps other birds) after a 24-h fast to avoid misinterpretation due to physiological food-induced elevated concentrations of nonprotein nitrogen substances.     

Plasma chemistry and urine analysis in Salmonella-induced polyuria in racing pigeons (Columba livia)

Polyuria-polydipsia is a frequent observation in pigeons with salmonellosis. These are accompanied by a decreased albumin/globulin ratio, increased creatinine and haptoglobin concentrations, and decrease in the chloride concentration in the blood plasma. The urine was found to have a low density with red and white blood cells frequently present in the sediment. A water deprivation test was conducted on three animals: polyuria disappeared and plasma urea increased significantly.     

家鸽实验性主动脉粥样硬化的电镜和组化研究

应用扫描电镜以及非特异性酯酶的组织化学染色,观察喂胆固醇和猪油的家鸽的主动脉斑块的形态发生。结果表明,斑块处内皮细胞收缩、细胞间隙增宽、内皮细胞局部脱落和增生;单核细胞粘附增多;早期斑块主要由巨噬细胞源性泡沫细胞组成,典型斑块则由巨噬细胞源性和平滑肌源性两种泡沫细胞组成。本文对这些变化的意义进行了讨论。     

Modelling Aspergillus fumigatus infections in racing pigeons (Columba livia domestica)

In vivo modelling of aspergillosis in birds allows the evaluation of control measures and the study of host–pathogen interactions. In this study the impact of the use of different inoculation routes and immunosuppression on the course of an infection with Aspergillus fumigatus in racing pigeons (Columba livia domestica) was examined. A. fumigatus conidia were inoculated in the thoracic air sac, lung or trachea in immunocompetent or immunosuppressed pigeon squabs. Immunosuppression was induced by three dexamethasone injections before inoculation. Mortality in the A. fumigatus-inoculated groups varied between 1/4 and 4/4. The highest and more acute mortality was seen in immunocompetent pigeons inoculated in the thoracic air sac and in pigeons inoculated in the thoracic air sac or lung after immunosuppression. Pigeons inoculated in the lung or inoculated intratracheally after immunosuppression developed an aspergillosis infection with a slower course of disease and more prominent clinical symptoms. Using microsatellite length polymorphism, it was confirmed that all mycoses were caused by the inoculated strain except for one isolate in a dexamethasone-treated pigeon. In conclusion, inoculation in the lung is selected as the preferred model for chronic aspergillosis in pigeons, and inoculation in the thoracic air sac as the preferred model for acute aspergillosis. The use of immunosuppressed birds seems to be contra-indicated due to the risk of opportunistic infections.     

Isolation of mycoplasma spp. from racing pigeons (Columba livia)

Live and dead racing pigeons (Columba livia) from five lofts in Norfolk and Suffolk were examined clinically and cultured for Mycoplasma spp. Both clinically healthy birds and those showing signs of mild respiratory disease were included. The oropharynx was the culture site for 130 live birds, the nasal sinuses and other tissues for 58 carcases. Mycoplasma columbinum, M. columborale and M. columbinasale were isolated from the oropharynges and nasal sinuses; M. columbinum and M. columbinasale from the brain and M. columbinum and M. columborale from lungs and air sacs. One or more of these three Mycoplasma spp. was isolated at necropsy from 28% of 58 pigeons. Only 11% of 37 pigeons reacted sero-logically by the metabolism inhibition test to M. columbinum and none to M. columborale. Twenty-five birds examined for M. gallisepticum antibody by the haemagglutination-inhibition test were negative. No sex or age predilection to infection with Mycoplasma was apparent. About 10% of pigeons in all five lofts showed clinical signs of the respiratory disease sometimes described as 'mycoplasmosis catarrh', but most dead birds from which Mycoplasma spp. were isolated also had concomitant infections of various kinds. Although suggestive, the results of these investigations provide no clear evidence that Mycoplasma spp. are aetiologically involved in natural respiratory disease of pigeons. No conclusive satisfactory treatment was found for the elimination of mycoplasmas.     

Clinical evaluation of thyroid function in racing pigeons (Columba livia domestica)

Reference values for basal thyroxine (T4) concentrations in racing pigeons are presented for use in clinical pathology. Values for basal plasma T4 concentrations in healthy racing pigeons over the four seasons were 6-35 nmol/litre. Significant differences were seen between seasons. To differentiate between primary hypothyroidism and other causes of lowered plasma T4 concentrations the optimum dose and sampling times for a TSH stimulation test in this species were determined. A convenient application of this test in the pigeon is to collect a blood sample at the end of a working day and then to administer 1 IU of TSH intramuscularly. The second blood sample is collected the following morning, about 16 hours later. In healthy pigeons T4 concentrations between 100 and 300 nmol/litre can be expected in the post-TSH sample representing a 3.5- to 15.3-fold increase above basal values.     

Enzyme activities in tissues and elimination half-lives of homologous muscle and liver enzymes in the racing pigeon (Columba Livia domestica)

Tissue enzyme profiles of heart, liver, pectoral muscle, quadriceps muscle, duodenum, kidney and brain from racing pigeons were established. The enzymes were alanine aminotransferase (ALAT), aspartate aminotransferase (ASAT), glutamate dehydrogenase (GLDH), lactate dehydrogenase (LDH), gamma glutamyltransferase (y-GT), alkaline phosphatase (AP), and creatine kinase (CK). Elimination half-lives (tyss) of certain enzymes were also determined. The mean values (+/- SD) were: ASAT, 7.66 +/- 1.55 (liver) and 6.51 +/- 0.83 (muscle); ALAT, 15.69 + 1.70 (liver) and 11.99 +/- 1.32 (muscle); LDH, 0.71 + 0.10 (liver) and 0.48 +/- 0.07 (muscle); GLDH, 0.68 +/- 0.17 (liver), CK 3.07 +/- 0.59 hours (muscle). GLDH is the most liver-specific enzyme in the pigeon, but increased activities in the plasma are likely only in the acute stage of severe liver cell damage, since this enzyme is localised within the mitochondria and has a short half life. LDH and ASAT seem to be the most sensitive indicators of liver cell damage, though contributions come from muscle damage. Muscle cell damage can be differentiated from liver cell damage by measuring plasma CK activity, since CK is both a specific and a sensitive indicator of muscle cell damage. In a clinical setting the combined use of LDH, ASAT and CK permits differentiation between liver and muscle cell damage in racing pigeons.     

An epidemic of fatal hepatic necrosis of viral origin in racing pigeons (Columba livia)

In October 1992, a new disease characterised by acute death in racing pigeons of all ages was noted among the Belgian pigeon population. Clinical symptoms were minimal since affected birds usually died within 24 h. Mortality in pigeon lofts usually amounted to 30%. The most typical necropsy finding was a yellow, pale and swollen liver. Histological and cytological examinations revealed extensive focal or diffuse hepatic necrosis and the presence of eosinophilic or amphophilic nuclear inclusion bodies. This hepatic necrosis of viral origin was diagnosed in 151 (15%) of 988 submissions of pigeons at our Institute in 1993 and 1994. Oral and intramuscular inoculation of pigeons with a bacteria-free homogenate prepared from the liver of pigeons that died from the disease did not result in clinical signs. However, when similar inoculations were done in pigeons previously treated orally with dexamethasone, pigeons died very suddenly within 4-5 days of inoculation. Necropsy findings in experimentally infected pigeons were identical to those observed in naturally occurring cases. Electron microscopic examination of the liver of inoculated pigeons showed the presence of numerous adenovirus-like particles inside nuclei of hepatocytes. The virus could not be cultured in the allantoic cavity or on the chorioallantoic membrane of embryonated chicken eggs. Clinical signs and lesions described here are clearly different from adenovirus enteritis in young pigeons abundantly described since 1976.     

Rhabdomyosarcoma in a racing pigeon (Columba livia)

An adult racing pigeon (Columba livia) was presented with a subcutaneous mass on the ventral aspect of the right wing. A fine-needle aspirate and radiographic study of the mass were suggestive of highly invasive sarcomatous neoplasm. Euthanasia was decided because of the poor prognosis. Necropsy confirmed the highly invasive nature of the neoplasm, which also occupied a large portion of the right breast. There also was extensive osteolysis of the sternum with neoplastic invasion of the left breast and the coelomic cavity. Histopathology revealed a highly cellular, poorly demarcated, unencapsulated invasive sarcoma. Immunohistochemistry was positive for muscle actin, and myoglobin, weakly positive for vimentin, and negative for desmin, neuron-specific enolase and S-100 protein, suggesting a diagnosis of undifferentiated rhabdomyosarcoma.     

Changes in plasma chemistry after drug-induced liver disease or muscle necrosis in racing pigeons (Columba livia domestica)

Changes in plasma variables as a result of liver damage induced by ethylene glycol (group A) or D-galactosamine (group B) and of muscle damage induced by doxycycline were compared. Plasma bile acid concentration was both a specific and a sensitive indicator of liver disease. Another specific, but less sensitive indicator of liver disease was 7-GT. Plasma AS AT activity was the most sensitive indicator of disease of the liver, but was not specific, since increased ASAT activities were also seen during muscle disease. ALAT activity was slightly more sensitive to liver damage than 7-GT, but was also not specific, being increased also after muscle damage. Plasma GLDH activity was increased only as a result of extensive liver necrosis. AP activity was of no value for detecting liver disease in the pigeon. CK activity was specific for muscle injury, though the activities of ALAT, ASAT and LD were also increased. Because of its long elimination half-life, increased ALAT activity persisted for 9 days after muscle damage, whereas CK activity returned to reference values within 3 days. LDH was a poor indicator of damage to liver and muscle, despite its relatively high tissue concentrations in both tissues. The rapid disappearance rate of LDH from plasma probably explains this observation.     

The ecto-, gastro-intestinal and haemo-parasites of live pigeons (Columba livia) in Kampala,Uganda

In a study from October, 1996 to March, 1997, 34 pigeons in three different locations were studied for parasites. The majority of birds in Nakulabye appeared clinically sick, while those within Makerere University and Wandegeya were apparently healthy. Biometric data were taken for each bird and, during the process, ectoparasites were collected. Faecal and blood samples were obtained. The study of ectoparasites revealed that Pseudolynchia canariensis (the 'pigeon fly') was the most prevalent parasite (100%). The louse Columbicola columbae was next in prevalence (94.1%). It is postulated that the pigeon fly transports this parasite. Three lice of economic importance were found: Menopon gallinae, Menacanthus stramineus and Chelopistes meleagridis. Cestodes were the only helminths found, occurring in 23.5% of the birds. Identification of the cestodes was not possible. Haemoparasites were mainly of two genera, Haemoproteus and Plasmodium. Haemaproteus was the most prevalent (76.5%). This was possibly due to the high abundance of its vector, P. canariensis.     

Failure of nitro-imidazole drugs to control trichomoniasis in the racing pigeon (Columba livia domestica)

The nitro-imidazole drugs ronidazol. dimetridazol, metronidazol and carnidazol failed to control Trichomonas gallinae in the racing pigeon, presumably due to acquired drug resistance.     

Effects of lesions involving efferent fibers to the retina in pigeons (Columba livia)

In Experiment 1 data are presented which demonstrate that, with lesions involving the centrifugal fibers, pigeons show elevated log_{1 0} latencies of response in a two-choice key-pecking task. This effect persisted over 4 days while within each daily session there was a reduction in the initial log_{1 0} latency elevation. In addition, a second part of this experiment failed to support a role for these fibers in mechanisms of response habituation to visual distraction. A second experiment is reported which demonstrates that birds with lesions including the centrifugal fibers also have more difficulty with low luminance discriminations than do controls. The results are interpreted as support for the dynamic adaptation theory of Miles [12].     

Tissue distribution of amoxycillin after oral and intramuscular administration to pigeons (Columba livia)

Tissue distribution of amoxycillin in homing pigeons was studied after oral administration of amoxycillin trihydrate and after intramuscular injection of an oily amoxycillin suspension, both after a single dose of 100 mg/Kg. After the injection muscular damage at the injection site was studied by serum chemistry, and by macroscopic and histologie examination. After oral administration high peak levels were found in most tissues, but at 8 hours post-administration (p.a.) in most organs no drug levels could be detected. After intramuscular injection of the oily suspension lower peak levels were found in all organs, except the pectoral muscle contralateral to the injection site, but drug levels lasted at least till 60 hours p.a. After administration by both routes there was a fairly fixed relation between the tissue levels and the blood concentration for every organ. Very low concentrations were found in the brains. High levels were found after both routes of administration in the kidneys and the liver. After oral administration high levels were found also in the proventricular and intestinal wall. After intramuscular injection relative high concentrations were found in the duodenal and endgut wall. The damage to the pectoral muscle from the injection and the drug was small and restricted to mechanical destruction of muscle fibres by the needle and direct compression of the muscle fibres by the injected suspension.     

Blood chemistry reference values in racing pigeons (columba livia domestica)

Reference values for 23 blood chemical parameters in racing pigeons (Columba livia domestica) were established for use in clinical pathology. The inner limits are given for the percentiles P(2).(5) and P(97.5) with a probability of 90%. A minimum of 50 blood samples collected between September and January from different animals aged between 6 months and 12 years (median 1.5 years) was used for each parameter. Reference values obtained in the present study are compared with values published previously.     

The Inability of Surgical Bursectomy in the Newly Patched Pepiod to Affect Antibody Formation in the Pigeon (Columba Livia)

Surgical bursectomy was performed in newly hatched pigeons within 24 hours of hatching. The effect of bursectomy on the immune responsiveness was evaluated by studying antibody formation to sheep red blood cells (SRBC) and Brucella abortus organisms and by the presence of serum immunoglobulins after immunoelectrophoresis. Surgically bursectomized pigeons responded as well to SRBC and Brucella as did the non-bursectomized controls. There was no statistically significant difference in the geometric mean antibody titers between the bursectomized and non-bursectomized groups of pigeons. Treatment of the serum with 2-mercaptoethanol (2-ME) indicated that the major amount of antibody produced was resistant to 2-ME and there was no significant difference in the amount of 2-ME-resistant antibody produced in the bursectomized and the control pigeons. Immunoelectrophoretic analysis of the sera from the bursectomized pigeons showed both IgG and IgM present in similar quantities to that of the non-bursectomized controls. Histological sections of the spleens showed germinal centers in both groups of pigeons. Sections of the bursal area from the bursectomized birds indicated that none of the pigeons in the bursectomized group had any remaining identifiable bursal tissue, follicular structures or other organized lymphoid tissue.     

Persistence of antibodies to West Nile virus in naturally infected rock pigeons (Columba livia)

Wild caught rock pigeons (Columba livia) with antibodies to West Nile virus were monitored for 15 months to determine antibody persistence and compare results of three serologic techniques. Antibodies persisted for the entire study as detected by epitope-blocking enzyme-linked immunosorbent assay and plaque reduction neutralization test. Maternal antibodies in squabs derived from seropositive birds persisted for an average of 27 days.