Adult Pigeons Research Articles

Ectopic otoconial formation in the lagena of the pigeon inner ear.

ABSTRACTThe vertebrate inner ear contains vestibular receptors with dense crystals of calcium carbonate, the otoconia. The production and maintenance of otoconia is a delicate process, the perturbation of which can lead to severe vestibular dysfunction in humans. The details of these processes are not well understood. Here, we report the discovery of a new otoconial mass in the lagena of adult pigeons that was present in more than 70% of birds. Based on histological, tomographic and elemental analyses, we conclude that the structure likely represents an ectopically-formed otoconial assembly. Given its frequent natural occurrence, we suggest that the pigeon lagena is a valuable model system for investigating misregulated otoconial formation.This article has an associated First Person interview with the first author of the paper.

Effect of Monochromatic Light on Plasma and Mrna Levels of Luteinising Hormone, Follicle-Stimulating Hormone, and their Receptors in the Hypothalamic–Pituitary–Gonadal Axis of Pigeons

This study was conducted to evaluate the effect of monochromatic light on luteinising hormone (LH) and follicle-stimulating hormone (FSH) concentrations, LH and FSH mRNA levels, and mRNA levels of their receptors (LHR and FSHR) in Pigeons (Columba livia). A total of 60 paired adult White King pigeons were randomly divided into four groups; each group was exposed to violet light (VL), green light (GL), red light (RL), or white light for 16 h. Nine paired pigeons from each group were selected for analysis of FSH and LH concentrations and six paired pigeons from each group were selected for analysis of mRNA. The results showed that the concentration of LH in females was lower in the VL group (P<0.05), and in males, it was lower in the VL and GL groups (P<0.05). The concentration of FSH in females was significantly higher in the RL group than in the VL group (P<0.05), whereas no significant difference was observed in males (P>0.05). In females, the LH and FSH mRNA levels were relatively high in the pituitary gland, whereas LHR and FSHR mRNA levels were relatively high in the ovary. In males, the LH, LHR, FSH, and FSHR mRNA levels were high in the pituitary gland, whereas their respective mRNA levels were relatively low in the testis. These results suggest that RL has the potential to improve LH and FSH concentrations and mRNA levels, and indicates that RL could promote reproductive performance of pigeons.

Streptococcosis in Commercial and Noncommercial Avian Species in California: 95 Cases (2000-2017).

Streptococcal bacterial species represent common inhabitants of the intestinal tract of animals and humans with a potential for opportunistic infections. Streptococcosis has been identified in turkey poults ( Meleagris gallopavo), ducklings and goslings (Anatidae), broiler chickens, semimature-adult chickens ( Gallus gallus domesticus), and young and adult pigeons (Columbidae). However, the exact underlying factors that lead to bacterial invasion of the blood stream and tissue colonization have not been completely elucidated. The electronic database of the California Animal Health and Food Safety laboratory (Fresno, Tulare, and Turlock branches) was searched for necropsy cases in which streptococcosis was diagnosed in different avian species between January 2000 and August 2017. A total of 95 cases, involving both commercial operations and noncommercial premises, were analyzed. Streptococcus spp., Streptococcus bovis, and Streptococcus gallolyticus were identified from multiple organs, with macroscopic or histopathologic lesions (or both) indicative of septicemia in 23 (24%), 40 (42%), and 30 (32%) cases, respectively. Streptococcus pluranimalium and Streptococcus lutetiensis were also isolated from one (1%) and two (2%) cases, respectively. Turkey poults, broiler chickens, and ducklings were the most-commonly affected species with streptococcosis. Splenitis and hepatitis were the most-common lesions observed and these were the organs with the highest isolation rate. An overview of the clinical and pathologic presentation, and possible predisposing conditions associated with this bacterial infection, is provided.

Study of ecto and haemo parasites in domestic pigeons (Columba livia domestica) in Sulaimani province, Kurdistan region/Iraq

Pigeons are very well adapted and proliferate without control in urban centers. In this current study, ectoparasites and haemoparasites of 140 adult domestic pigeons (Columba livia domestica) of both sexes were studied, from different localities in Sulaimani province during April to October 2014, since there is no enough data regarding the frequency and identification of ectoparasites and haemoparasites in domestic pigeons in Sulaimani province. All pigeons were examined for the presence of ectoparasites and haemoparasites through checking of blood samples using Giemsa stain. As a result, various species of ectoparasites and haemoparasites were observed. From which, 4 species of lice were detected named Columbicola olumbae (62.5%) followed by Hoborstiella lata (10.42%), Campanulotes compar (4.17%) and Menacanthus stramineus (3.13%). On the other hands, 19.79% of infected pigeons with ectoparasites were diagnosed with the presence of more than 1 lice species. Additionally, examined Giemsa stained smears showed that 55.72% of studied pigeons were harbor haemoparasites including Haemoproteus species (28.20%) followed by Plasmodium species (26.92%) and then Leucocytozoon species (11.53%) consequently.

Epidemiological Investigation and Genotype of Chlamydia Exposure in Pigeons in Three Provinces in Northern China.

Chlamydia is considered as one of the most widely prevalent zoonotic pathogens. It can spread from infected birds to human beings through direct or indirect contact with fecal shedding of Chlamydia. However, data concerning prevalence and genotypes of Chlamydia in pigeons are limited. In the present study, a total of 963 serum samples was collected from Jilin Province, Liaoning Province, and Inner Mongolia Autonomous Region (IMAR) in China between August 2015 and December 2016 and the seroprevalence for Chlamydia was analyzed by indirect hemagglutination assay test. The seroprevalence of Chlamydia was 20.4% (215/963) in total, at the cutoff 1:16, with the titers of 1:16 in 109, 1:64 in 49, 1:256 in 38, and 1:1024 in 18. Samples from all six administrative cities were detected Chlamydia-seropositive, ranging from 19.0% to 25.0%. Adult pigeons (23.5%) have a significant higher seroprevalence than juveniles (15.2%). Four PCR-positive samples represented Chlamydia psittaci genotype B. This is the first report of Chlamydia infection in pigeons in Liaoning Province and IMAR. The occurrence of C. psittaci genotype B in the droppings of pigeons suggests potential environmental contamination with C. psittaci and may raise a public health concern.

Survey of parasites in domestic pigeons (Columba livia) in Tripoli, Libya.

This study was a preliminary survey for identification of parasites (endoparasites and ectoparasites) and their prevalence in domestic pigeons (Columba livia) in Tripoli; Libya. One hundred adult domestic pigeons were purchased from different markets of Tripoli. Blood smears were prepared from each bird and examined using light microscopy with oil immersion lens for the presence of blood parasites. Oropharyngeal swab was taken from each pigeon and were processed through direct smear method and staining with Giemsa to identify Trichomonas gallinae. Each pigeon was examined for ectoparasites. Moreover, intestinal parasites were investigated and all helminths were counted before being fixed in 70% ethyl alcohol for further identification. Out of 100 pigeons examined, 76% (76/100) were infected with Haemoproteus spp. and 55% (55/100) with T. gallinae. The overall prevalence of ecto–parasitic infestation was 89% (82% Columbicloa columbae, 18% Goniodes gallinae, 3% Menopon gallinae and 1% Pseudolynchia canariensis). The overall prevalence of intestinal helminths in examined pigeons were 56% (56/100). Three species of Cestoda (2% Raillietina tetragona, 32% R. echinobothrida and 4% R. cesticillus) and three species of Nematoda (18% Heterakis gallinarum., 22% Ascaridia galli and 4% Capillaria spp.) were identified. Also, this study revealed that the pigeons examined were found infected with mixed parasites. The study highlights that pigeons are hosts of helminths of veterinary importance and may act as an important source of infection for other avian host, which share the common parasitic fauna.

Olfactory information from the path is relevant to the homing process of adult pigeons

The contribution of path information to the homing process of adult experienced pigeons is by no means consensual. Adult pigeons are expected to determine the homeward direction solely based on information gathered at the release site (i.e., map information). However, several are the evidences suggesting that path information is somehow important to the homing process. Using adult homing pigeons and manipulation of the pigeons’ access to olfactory information from the displacement to the release site by means of nasal plugs that were applied unilaterally, we accessed the contribution of olfactory path information to the homing process. Pigeons transported to the release site with only the right nostril plugged were impaired on the determination of the initial homeward direction, while pigeons transported to the release site with only the left nostril plugged were impaired on the homing speed. The present findings highlight the importance of information from the path to the navigational process wherein olfactory path information contributes to the accurate determination of the homeward direction and in keeping the pigeon’s motivation to fly home. SIGNIFICANCE STATEMENT: Animal migration has fascinated mankind for generations. However, and although vast research has been done on the subject, it is still controversial the way as animals accomplish such endeavor task. Using homing pigeons, a biological model for spatial processing, and behavioral experiments for manipulation of information from the path (here, olfactory), we showed that information from the path contributes to the accurate determination of the initial homeward direction and to keep the pigeon’s motivation to fly home. Therefore, information from the path (here, olfactory) appears to lie at the heart of the processing of spatial information in migrating animals, contributing to the accurate determination of flying course and motivation to reach the destination.

Visuospatial attention in the lateralised brain of pigeons \u2013 a matter of ontogenetic light experiences

The ontogenetic mechanisms leading to complementary hemispheric specialisations of the two brain halves are poorly understood. In pigeons, asymmetrical light stimulation during development triggers the left-hemispheric dominance for visuomotor control but light effects on right-hemispheric specialisations are largely unknown. We therefore tested adult pigeons with and without embryonic light experience in a visual search task in which the birds pecked peas regularly scattered on an area in front of them. Comparing the pecking pattern of both groups indicates that the embryonic light conditions differentially influence biased visuospatial attention under mono- and binocular seeing conditions. When one eye was occluded, dark-incubated pigeons peck only within the limits of the visual hemifield of the seeing eye. Light-exposed pigeons also peck into the contralateral field indicating enlarged monocular visual fields of both hemispheres. While dark-incubated birds evinced an attentional bias to the right halfspace when seeing with both eyes, embryonic light exposure shifted this to the left. Thus, embryonic light experience modifies processes regulating biased visuospatial attention of the adult birds depending on the seeing conditions during testing. These data support the impact of light onto the emergence of functional dominances in both hemispheres and point to the critical role of interhemispheric processes.

Determination of The Properties of Rat Brain Thermostable Protein Complex which Inhibit Cell Proliferation.

Objective Cell proliferation is known to be controlled by many networks of regulatory proteins. These multiple and complicated mechanisms of control are still being investigated. The aim of the present study is to determine the different properties of adult rat brain thermostable protein complex (TPC) which affect cell proliferation. Materials and Methods This experimental study used brain, kidney and liver tissue from adult (150-170 g) and adolescent (7, 10, 21, 28 days) white rats, adult pigeons and mice. Brain TPC was isolated by alcohol extraction, and primary antibodies Ki67 and GAD65/67 were used for immunohistochemistry, evaluation of transcriptional activity of the tissues and determination of the mitotic index. Results The results show that brain TPC from rats reversibly decreases cell proliferation by inhibiting transcription. The evidence suggests that TPC is not species-specific, but expresses tissue specificity with regards to terminally differentiated cells. Rat brain TPC inhibits mitotic activity of the progenitor cells in the dentate gyrus of adolescent rats, and corresponding with this decrease in the mitotic index the number of Ki67 positive cells increases. Simultaneously, the number of GAD65/67-positive cells in the hippocampus decreases by approximately threefold. ConclusionThese results indicate that rat brain TPC causes the reversible suppression of cell proliferation through the inhibition of transcription. Inhibitory effects of rat brain TPC leads to an increase the number of cells in the cell cycle, in tissues of adolescent rats.

A note on mixed coccidian and Capillaria infection in pigeons.

Two adult pigeons were presented to the Teaching Veterinary Hospital (TVH), GADVASU, Ludhiana, Punjab with the history of weakness, anorexia, ruffled feathers and intermittent diarrhoea. Coproscopic examination revealed the presence of coccidian oocysts alongside eggs of Capillaria spp. Based on the morphological characters the eggs were designated as C. obsignata. Sporulation studies on the coccidian oocysts revealed mixed infection of Eimeria columbae and E. columbarum.

Changes in hepatic glucose and lipid metabolism-related parameters in domestic pigeon (Columba livia) during incubation and chick rearing.

This study aimed to evaluate the hepatic glucose and lipid metabolism-related parameters of adult male and female White King pigeons (Columba livia) during incubation and chick rearing. At day 4 (I4), 10 (I10) and 17 (I17) of incubation and day 1 (R1), 7 (R7), 15 (R15) and 25 (R25) of chick rearing, livers were sampled from six pigeons for each sex. Glycogen and fat contents, activities of glycolytic enzymes (hexokinase, HK; 6-phosphofructokinase, 6-PFK), and genes expressions of key enzymes involved in glycolysis (pyruvate kinase, PK; glucokinase, GK), gluconeogenesis (phosphoenolpyruvate carboxykinase cytosolic, PCK1; fructose-1,6-bisphosphatase, FBP1; glucose-6-phosphatase, G6Pase), fatty acid synthesis (fatty acid synthase, FAS; acetyl-CoA carboxylase, ACC) and fatty acid β-oxidation (carnitine palmitoyltransferase 1, CPT1; acyl-CoA 1, ACO) were measured. In male and female pigeon livers, glycogen content and HK activity dramatically increased after I17 and after R1, respectively; expressions of FBP1 and G6Pase genes were maximized at R15; activity of 6-PFK and expressions of PK and CPT1 genes were highest at R7; fat content and expressions of FAS and ACC genes steeply increased from I10 to R1. In females, hepatic expressions of GK and PCK1 genes were greatest at R7 and I17, respectively; however, in males, both of them were maximized at R15. Hepatic expression of ACO gene was significantly enhanced at R1 compared to I17 and R7 in males, whereas it was notably up-regulated at I17 and R7 in females. Furthermore, expressions of PCK1, GK, FAS and ACC genes were in significant relation to fat content in the livers of female pigeons, while fat content in male pigeons was highly correlated with expression of PCK1, ACC, CPT1 and ACO genes. In conclusion, regulations of glucose and lipid metabolic processes were enhanced in parent pigeon livers from terminal phases of incubation to mid phase of chick rearing with sexual effects.

Novel avian oropharyngeal trichomonads isolated from European turtle doves (Streptopelia turtur) and racing pigeons (Columba livia): genetic and morphometric characterisation of clonal cultures

Extensive diversity has been described within the avian oropharyngeal trichomonad complex in recent years. In this study we developed clonal cultures from four isolates selected by their different ITS1/5.8S/ITS2 (ITS) genotype and their association with gross lesions of avian trichomonosis. Isolates were obtained from an adult racing pigeon and a nestling of Eurasian eagle owl with macroscopic lesions, and from a juvenile wood pigeon and an European turtle dove without clinical signs. Multi-locus sequence typing analysis of the ITS, small subunit of ribosomal rRNA (SSUrRNA) and Fe-hydrogenase (Fe-hyd) genes together with a morphological study by optical and scanning electron microscopy was performed. No significant differences in the structures were observed with scanning electron microscopy. However, the genetic characterisation revealed novel sequence types for the SSUrRNA region and Fe-hyd gene. Two clones were identified as Trichomonas gallinae in the MLST analysis, but the clones from the racing pigeon and European turtle dove showed higher similarity with Trichomonas tenax and Trichomonas canistomae than with T. gallinae at their ITS region, respectively. SSUrRNA sequences grouped all the clones in a clade that includes T. gallinae, T. tenax and T. canistomae. Further diversity was detected within the Fe-hyd locus, with a clear separation from T. gallinae of the clones obtained from the racing pigeon and the European turtle dove. In addition, morphometric comparison by optical microscopy with clonal cultures of T. gallinae revealed significant statistical differences on axostyle projection length in the clone from the European turtle dove. Morphometric and genetic data indicate that possible new species within the Trichomonas genus were detected. Taking in consideration the diversity in Trichomonas species present in the oral cavity of birds, a proper genetic analysis is highly recommended when outbreaks occur.

Ectoparasites of chickens in Wukari Local Government Area of Taraba State, north-east Nigeria

A study was conducted to determine the gastrointestinal helminth parasites in domestic pigeons (Columba livia) in Jalingo Metropolis, Taraba State. Sixty pigeons made up of 35 males and 25 females were selected, slaughtered and the gastrointestinal tract examined for the presence of helminth parasites using standard parasitological methods. Forty- seven birds (78.3%) were found to harbour single or multiple infections. Of the total infection, 43.3% were due to nematode parasites while 35.0% were caused by parasitic cestodes. Nematode parasites recorded were Ascaridia columbae (20.0%), Ascaridia galli (11.7%), Heterakis gallinarium (10.0%) and Capillaria spp. (5.0%) while Raillietina tetragona (18.3%), Hymenolepsis columbae (13.3%) and Rallietina cesticilus (3.3%) were the only parasitic cestodes recorded. Prevalence of these helminthes was significantly higher (p<0.05) in male (55.0%) than in female (23.3%) birds. Similarly, adult pigeons recorded higher prevalence (68.3%) than young pigeons (10.0%) (p<0.05). The intensity of worm infection by the different helminth parasite as reflected by the mean worm burden showed that pigeons infected with Hymenolepsis columbae had the highest mean worm burden (6 ± 0.9922) among the parasitic cestodes, while those infected with Ascaridia galli and Ascaridia columbae had the highest mean worm burden (05 ± 1.2936 and 05 ± 1.4697) among the nematodes recovered. The lowest mean worm burden (02 ± 0.6166) among the entire helminth parasites recovered was recorded in the pigeons infected with Rallietina tetragona.Keywords: Prevalence; helminth parasites; domestic pigeons; post mortem; Jalingo Metropolis.

Prevalence of helminth parasites of domestic pigeons (&lt;i&gt;Columba livia&lt;/i&gt;) in Jalingo Metropolis, Taraba State

A study was conducted to determine the gastrointestinal helminth parasites in domestic pigeons (Columba livia) in Jalingo Metropolis, Taraba State. Sixty pigeons made up of 35 males and 25 females were selected, slaughtered and the gastrointestinal tract examined for the presence of helminth parasites using standard parasitological methods. Forty- seven birds (78.3%) were found to harbour single or multiple infections. Of the total infection, 43.3% were due to nematode parasites while 35.0% were caused by parasitic cestodes. Nematode parasites recorded were Ascaridia columbae (20.0%), Ascaridia galli (11.7%), Heterakis gallinarium (10.0%) and Capillaria spp. (5.0%) while Raillietina tetragona (18.3%), Hymenolepsis columbae (13.3%) and Rallietina cesticilus (3.3%) were the only parasitic cestodes recorded. Prevalence of these helminthes was significantly higher (p&lt;0.05) in male (55.0%) than in female (23.3%) birds. Similarly, adult pigeons recorded higher prevalence (68.3%) than young pigeons (10.0%) (p&lt;0.05). The intensity of worm infection by the different helminth parasite as reflected by the mean worm burden showed that pigeons infected with Hymenolepsis columbae had the highest mean worm burden (6 ± 0.9922) among the parasitic cestodes, while those infected with Ascaridia galli and Ascaridia columbae had the highest mean worm burden (05 ± 1.2936 and 05 ± 1.4697) among the nematodes recovered. The lowest mean worm burden (02 ± 0.6166) among the entire helminth parasites recovered was recorded in the pigeons infected with Rallietina tetragona.Keywords: Prevalence; helminth parasites; domestic pigeons; post mortem; Jalingo Metropolis.

Putative adult neurogenesis in two domestic pigeon breeds (Columba livia domestica): racing homer versus utility carneau pigeons.

Generation of neurons in the brains of adult birds has been studied extensively in the telencephalon of song birds and few studies are reported on the distribution of PCNA and DCX in the telencephalon of adult non-song learning birds. We report here on adult neurogenesis throughout the brains of two breeds of adult domestic pigeons (Columba livia domestica), the racing homer and utility carneau using endogenous immunohistochemical markers proliferating cell nuclear antigen (PCNA) for proliferating cells and doublecortin (DCX) for immature and migrating neurons. The distribution of PCNA and DCX immunoreactivity was very similar in both pigeon breeds with only a few minor differences. In both pigeons, PCNA and DCX immunoreactivity was observed in the olfactory bulbs, walls of the lateral ventricle, telencephalic subdivisions of the pallium and subpallium, diencephalon, mesencephalon and cerebellum. Generally, the olfactory bulbs and telencephalon had more PCNA and DCX cells than other regions. Two proliferative hotspots were evident in the dorsal and ventral poles of the lateral ventricles. PCNA- and DCX-immunoreactive cells migrated radially from the walls of the lateral ventricle into the parenchyma. In most telencephalic regions, the density of PCNA- and DCX-immunoreactive cells increased from rostral to caudal, except in the mesopallium where the density decreased from rostral to middle levels and then increased caudally. DCX immunoreactivity was more intense in fibres than in cell bodies and DCX-immunoreactive cells included small granular cells, fusiform bipolar cells, large round and or polygonal multipolar cells. The similarity in the distribution of proliferating cells and new neurons in the telencephalon of the two breeds of pigeons may suggest that adult neurogenesis is a conserved trait as an ecological adaptation irrespective of body size.

Evaluation of gastroscopy and biopsy of the proventriculus and ventriculus in pigeons (Columba livia)

OBJECTIVE To evaluate the efficacy and safety of gastroscopy and biopsy of the proventriculus and ventriculus in pigeons (Columba livia). ANIMALS 15 adult pigeons. PROCEDURES Each pigeon was anesthetized, and the upper gastrointestinal tract (from the cervical portion of the esophagus to the ventriculus) was endoscopically evaluated by use of a rigid endoscope inserted orally. Saline (0.9% NaCl) solution was orally infused to achieve lumen dilation and visibility. Two mucosal biopsy specimens were collected from each of the proventriculus and ventriculus, histologically evaluated, and graded for crush artifacts and depth. Pigeons were monitored for adverse effects for 3 to 6 days after the procedure, after which they were euthanized for necropsy. RESULTS Gastroscopy via the oral approach provided excellent visibility of the lumen and mucosal surfaces of the proventriculus and cranial portion of the ventriculus and was safe provided that appropriate precautions were taken. Two intraoperative deaths occurred at the beginning of the study; following procedure refinement, no additional deaths occurred. No major adverse effects of the procedure were detected in the remaining 13 pigeons during the postoperative monitoring period or at necropsy. Diagnostic quality of proventriculus specimens was adequate for 10 of 13 pigeons. Eight of 13 ventriculus specimens were of inadequate quality, and only 3 were of adequate quality. CONCLUSIONS AND CLINICAL RELEVANCE Gastroscopy was useful for evaluating the lumen and mucosal surface of the proventriculus and ventriculus in pigeons, and biopsy of those organs was safely performed with the appropriate technique. Further evaluation of these techniques is needed in birds with clinical disease and birds of other species.

Class I Integron and β-lactamase encoding genes of multidrug resistance Salmonella isolated from pigeons and their environments.

Seroprevalence of Salmonella spp. was investigated in pigeon and its surrounding environment of Sharkia province, Egypt. Samples were randomly collected from fifty freshly dead squabs, forty freshlydead adults pigeons, sixty diseased adult pigeons and 100 apparently healthy adult pigeons. Bacterial isolates were tested for their susceptibility to 17 different antimicrobial discs, by using the disc diffusion method. The bacterial isolates were tested for Class I and β-lactamase encoding genes by using PCR. In vitro sensitivity of all Salmonella isolates were completely resistant to Streptomycin, Amoxicillin, clavulanic acid, Amoxicillin, Ampicillin and Ceftazidime (100%). Class1 integron were characterized in 70% Salmonella isolates from squabs, 42.9 % in adult pigeons and 14.3% in pigeon environment which confer their resistance to streptomycin and ampicillin. Meanwhile TEM-1 β-lactamase was characterized in 20% of tested Salmonella isolates from squabs including S. Entertidis, 42.9% of tested Salmonella isolates from adult pigeons including S. Entertidis which confer their resistance to cephalosporin and not detected in all isolates from pigeons environments. In conclusion TEM-1 β-lactamase was characterized in 20% of Salmonella isolates from squabs while Class1 integron was characterized in 70% Salmonella isolates from squabs.

Identification of a novel aviadenovirus, designated pigeon adenovirus 2 in domestic pigeons (Columba livia)

The young pigeon disease syndrome (YPDS) affects mainly young pigeons of less than one year of age and leads to crop stasis, vomitus, diarrhea, anorexia and occasionally death. This disease is internationally a major health problem because of its seasonal appearance during competitions such as homing pigeon races or exhibitions of ornamental birds. While the etiology of YPDS is still unclear, adenoviruses are frequently discussed as potential causative agents.Electron microscopy of feces from a YPDS outbreak revealed massive shedding of adenovirus-like particles. Whole genome sequencing of this sample identified a novel adenovirus tentatively named pigeon adenovirus 2 (PiAdV-2). Phylogenetic and comparative genome analysis suggest PiAdV-2 to belong to a new species within the genus Aviadenovirus, for which we propose the name Pigeon aviadenovirus B. The PiAdV-2 genome shares 54.9% nucleotide sequence identity with pigeon adenovirus 1 (PiAdV-1). In a screening of further YPDS-affected flocks two variants of PiAdV-2 (variant A and B) were detected which shared 97.6% nucleotide identity of partial polymerase sequences, but only 79.7% nucleotide identity of partial hexon sequences.The distribution of both PiAdV-2 variants was further investigated in fecal samples collected between 2008 and 2015 from healthy or YPDS-affected racing pigeons of different lofts. Independent of their health status, approximately 20% of young and 13% of adult pigeon flocks harbored PiAdV-2 variants. Birds were free of PiAdV-1 or other aviadenoviruses as determined by PCRs targeting the aviadenovirus polymerase or the PiAdV-1 fiber gene, respectively.In conclusion, there is no indication of a correlation between YPDS outbreaks and the presence of PiAdV-2 or other aviadenoviruses, arguing against an causative role in this disease complex.

Effects of Exposure to Monochromatic Light on Pigeon Squab Performance and Growth-Related Hormones

The objective of this study was to investigate the effects of the exposure to monochromatic light on growth performance, and on the growth hormone (GH) and insulin-like growth factor 1 (IGF-1) concentrations in growing Pigeons ( Columba livia). A total of 144 paired adult White King Pigeons were randomly divided into 12 compartments forming groups of 12 pairs. Then, three compartments were exposed to blue LED (BL), green LED (GL), red LED (RL), and white LED (WL). Allocation of light colours was done within blocks of four compartments. The pigeons were kept under WL for a two week adaptation period before the study began. Body weight (BW) and body weight gain (BWG) were evaluated weekly. Two pigeons from each replicate group were randomly selected for blood collection to determine the hormone concentrations at 1 day, 7 days, 14 days, 21 days, and 28 days of age. The results indicated that there were no between-treatment differences in the final BWs ( P = 0.570), but the squabs exposed to RL had greater BWGs between 7 and 14 days of age ( P = 0.009, P = 0.049, respectively). The correlation trend lines for the body weight and growth hormone comparisons were inverted U-shaped, which corresponded to the birds’ growth cycle. The results indicated that monochromatic red light had potential effects on growth performance during the early phase of production. Growth performance was closely related to the blood plasma concentrations of GH and IGF-1.

Asymmetrical Processing of Olfactory Input in the Piriform Cortex Mediates "Activation" of the Avian Navigation Circuitry.

The role of odors in the long-distance navigation of birds has elicited intense debate for more than half a century. Failure to resolve many of the issues fueling this debate is due at least in part to the absence of controls for a variety of non-specific effects that odors have on the navigational process. The present experiments were carried out to investigate whether the olfactory inputs are involved only in "activation" of neuronal circuitry involved in navigation or are also playing a role in providing directional information. Experienced adult pigeons were exposed to controlled olfactory stimuli during different segments of the journey (release site vs. displacement + release site). Protein levels of IEGs (immediate early genes used to mark synaptic activity) were analyzed in areas within the olfactory/navigation avian circuitry. The results indicate that 1) exposure to natural odors at the release site (and not before) elicit greater activation across brain regions than exposure to filtered air, artificial odors, and natural odors along the entire outward journey (from home to the release site, inclusive); 2) activation of the piriform cortex in terms of odor discrimination is lateralized; 3) activation of the navigation circuitry is achieved by means of lateralized activation of piriform cortex neurons. Altogether, the findings provide the first direct evidence that activation of the avian navigation circuitry is mediated by asymmetrical processing of olfactory input occurring in the right piriform cortex.