Persistent vocal learning in an aging open-ended learner reflected in neural FoxP2 expression.

BACKGROUND: Most vocal learning species exhibit an early critical period during which their vocal control neural circuitry facilitates the acquisition of new vocalizations. Some taxa, most notably humans and parrots, retain some degree of neurobehavioral plasticity throughout adulthood, but both the extent of this plasticity and the neurogenetic mechanisms underlying it remain unclear. Differential expression of the transcription factor FoxP2 in both songbird and parrot vocal control nuclei has been identified previously as a key pattern facilitating vocal learning. We hypothesize that the resilience of vocal learning to cognitive decline in open-ended learners will be reflected in an absence of age-related changes in neural FoxP2 expression. We tested this hypothesis in the budgerigar (Melopsittacus undulatus), a small gregarious parrot in which adults converge on shared call types in response to shifts in group membership. We formed novel flocks of 4 previously unfamiliar males belonging to the same age class, either "young adult" (6 mo - 1 year) or "older adult" (≥ 3 year), and then collected audio-recordings over a 20-day learning period to assess vocal learning ability. Following behavioral recording, immunohistochemistry was performed on collected neural tissue to measure FoxP2 protein expression in a parrot vocal learning center, the magnocellular nucleus of the medial striatum (MMSt), and its adjacent striatum. RESULTS: Although older adults show lower vocal diversity (i.e. repertoire size) and higher absolute levels of FoxP2 in the MMSt than young adults, we find similarly persistent downregulation of FoxP2 and equivalent vocal plasticity and vocal convergence in the two age cohorts. No relationship between individual variation in vocal learning measures and FoxP2 expression was detected. CONCLUSIONS: We find neural evidence to support persistent vocal learning in the budgerigar, suggesting resilience to aging in the open-ended learning program of this species. The lack of a significant relationship between FoxP2 expression and individual variability in vocal learning performance suggests that other neurogenetic mechanisms could also regulate this complex behavior.

Subclinical peripheral inflammation has systemic effects impacting central nervous system proteome in budgerigars.

Regulation of neuroimmune interactions varies across avian species. Little is presently known about the interplay between periphery and central nervous system (CNS) in parrots, birds sensitive to neuroinflammation. Here we investigated the systemic and CNS responses to dextran sulphate sodium (DSS)- and lipopolysaccharide (LPS)-induced subclinical acute peripheral inflammation in budgerigar (Melopsittacus undulatus). Three experimental treatment groups differing in DSS and LPS stimulation were compared to controls. Individuals treated with DSS showed significant histological intestinal damage. Through quantitative proteomics we described changes in plasma (PL) and cerebrospinal fluid (CSF) composition. In total, we identified 180 proteins in PL and 978 proteins in CSF, with moderate co-structure between the proteomes. Between treatments we detected differences in immune, coagulation and metabolic pathways. Proteomic variation was associated with the levels of pro-inflammatory cytokine mRNA expression in intestine and brain. Our findings shed light on systemic impacts of peripheral low-grade inflammation in birds.

Prevalence, genotypes, and infection risk factors of psittacine beak and feather disease virus and budgerigar fledgling disease virus in captive birds in Hong Kong.

Psittacine beak and feather disease virus (PBFDV) and budgerigar fledgling disease virus (BFDV) are significant avian pathogens that threaten both captive and wild birds, particularly parrots, which are common hosts. This study involved sampling and testing of 516 captive birds from households, pet shops, and an animal clinic in Hong Kong for PBFDV and BFDV. The results showed that PBFDV and BFDV were present in 7.17% and 0.58% of the samples, respectively. These rates were lower than those reported in most parts of Asia. Notably, the infection rates of PBFDV in pet shops were significantly higher compared to other sources, while no BFDV-positive samples were found in pet shops. Most of the positive samples came from parrots, but PBFDV was also detected in two non-parrot species, including Swinhoe's white-eyes (Zosterops simplex), which had not been reported previously. The ability of PBFDV to infect both psittacine and passerine birds is concerning, especially in densely populated urban areas such as Hong Kong, where captive flocks come into close contact with wildlife. Phylogenetic analysis of the Cap and Rep genes of PBFDV revealed that the strains found in Hong Kong were closely related to those in Europe and other parts of Asia, including mainland China, Thailand, Taiwan, and Saudi Arabia. These findings indicate the presence of both viruses among captive birds in Hong Kong. We recommend implementing regular surveillance for both viruses and adopting measures to prevent contact between captive and wild birds, thereby reducing the transmission of introduced diseases to native species.

Occurrence of Macrorhabdus ornithogaster in exotic birds.

Avian gastric yeast (Macrorhabdus ornithogaster) is a microorganism that infects aviary birds worldwide, both captive and wild. A total number of 352 birds, belonging to 18 avian species, were examined from 2019 to 2022 for M. ornithogaster, using fecal smears of live birds or cytological samples of the proventriculus taken at necropsy. These cytological samples were taken from birds that died from different causes. Some of the birds exhibited symptoms such as lethargy, regurgitation, weight loss and anorexia. Faecal samples were collected from all the birds and analysed for gastric yeast using a direct smear and Gram-staining method. The microorganism was diagnosed most frequently in budgerigars (55.5%), the African gray parrot (33.3%), and nymphs (34.3%). The prevalence of M. ornithogaster in canaries was 10%. The infection was detected in 31% of the examined birds, which shows that the occurrence of M. ornithogaster in exotic birds is common. No clinical signs were observed in the vast majority of birds that tested positive for gastric yeast.

COMPARISON OF THREE MIDAZOLAM-BASED SEDATION PROTOCOLS IN BUDGERIGARS (MELOPSITTACUS UNDULATUS) AND BLACK-CHEEKED LOVEBIRDS (AGAPORNIS NIGRIGENIS).

This randomized, crossover study evaluated three sedation protocols administered subcutaneously in nine budgerigars (Melopsittacus undulatus) and nine black-cheeked lovebirds (Agapornis nigrigenis). All protocols included midazolam (5 mg/kg), combined with butorphanol (5 mg/kg) (BM), medetomidine (20 lg/kg) (MM), or alfaxalone (13 mg/kg) (AM). Mortalities from suspected cardiorespiratory arrest were observed when AM was used in lovebirds, even after reduction of alfaxalone dosage to 3 mg/kg, and therefore this protocol was excluded from further use in this species. Induction and recovery times were recorded and their quality assessed. Sedation depth and heart and respiratory rates were measured every 5 min and radiographic positioning was attempted at 10 and 20 min. At 30 min, midazolam and medetomidine were reversed with flumazenil (0.05 mg/kg, SC), and atipamezole (0.2 mg/kg, SC), respectively. MM consistently provided deep sedation in both species, with successful radiographic positioning at every attempt. As expected, heart rate was often lower with MM than with other protocols, but no associated complications were noted. In budgerigars, BM had the lowest radiographic positioning success rate (10 min: 5/9, 20 min: 3/9), whereas in lovebirds it provided significantly deeper sedation (P < 0.001), allowing radiographic positioning in all subjects. In both species, BM provided the shortest recovery times. AM resulted in reliable radiographic positioning of all budgerigars at 10 min, but not at 20 min (5/ 9), and provided consistently poor recoveries. This study highlights how differently two psittacine species of similar size may react to the same sedation protocols. AM sedation cannot be fully reversed and produced significant undesirable effects, several of which have been previously reported with alfaxalone administration to avian species. The authors therefore caution against using alfaxalone-midazolam combinations in budgerigars and black-cheeked lovebirds. Both BM and MM provided reliable sedation in these species, and appear to be suitable alternatives to AM.

Do domestic budgerigars perceive predation risk?

Predation risk may affect the foraging behavior of birds. However, there has been little research on the ability of domestic birds to perceive predation risk and thus adjust their feeding behavior. In this study, we tested whether domestic budgerigars (Melopsittacus undulatus) perceived predation risk after the presentation of specimens and sounds of sparrowhawks (Accipiter nisus), domestic cats (Felis catus), and humans, and whether this in turn influenced their feeding behavior. When exposed to visual or acoustic stimuli, budgerigars showed significantly longer latency to feed under sparrowhawk, domestic cat, and human treatments than with controls. Budgerigars responded more strongly to acoustic stimuli than visual stimuli, and they showed the longest latency to feed and the least number of feeding times in response to sparrowhawk calls. Moreover, budgerigars showed shorter latency to feed and greater numbers of feeding times in response to human voices than to sparrowhawk or domestic cat calls. Our results suggest that domestic budgerigars may identify predation risk through visual or acoustic signals and adjust their feeding behavior accordingly.

Sex determination in budgerigars using radiographic pelvimetry.

BACKGROUND: The purpose of this study was to assess the pelvimetric values obtained from radiographic pelvis images of budgerigars in terms of sexual dimorphism. The objectives included determining linear osteometric and angle measurements of the pelvis, as well as calculating the length-to-width ratios among different pelvimetric measurements. Additionally, the study aimed to reveal the correlations between age and body weight with both the pelvimetric measurements and ratio measurements in these animals. METHODS: In this study, measurements of linear distance, angle and length-to-width ratios were obtained from ventrodorsal images of the pelvis in a sample of 60 budgerigars, consisting of 30 males and 30 females. Subsequently, the statistical analysis of the obtained measurement values was performed. RESULTS: When analysing the morphometric measurement values based on sex, it was observed that all linear measurements (L1, L2, L3, L4, L5, L6, L7, L8, L9, L10 and L11) were higher in males, whereas the angle measurements (A1, LA2 and RA2) were found to be significantly greater in females (p < 0.05). Additionally, both male and female budgerigars exhibited a greater pre-acetabular length of the ilium compared to the post-acetabular length. Moreover, there were mostly positive significant correlations between age and body weight with the pelvic measurement values in both sexes (p < 0.05). CONCLUSIONS: The obtained biometric measurement values from pelvimetric X-ray images in budgerigars were analysed to assess sexual dimorphism. Furthermore, this study presents fundamental morphometric data that can be valuable for clinical, taxonomic, phylogenetic, ornithological, allometric and characterization studies of budgerigars.

Normal behavioral discrimination of envelope statistics in budgerigars with kainate-induced cochlear synaptopathy.

Cochlear synaptopathy is a common pathology in humans associated with aging and potentially sound overexposure. Synaptopathy is widely expected to cause "hidden hearing loss," including difficulty perceiving speech in noise, but support for this hypothesis is controversial. Here in budgerigars (Melopsittacus undulatus), we evaluated the impact of long-term cochlear synaptopathy on behavioral discrimination of Gaussian noise (GN) and low-noise noise (LNN) signals processed to have a flatter envelope. Stimuli had center frequencies of 1-3kHz, 100-Hz bandwidth, and were presented at sensation levels (SLs) from 10 to 30dB. We reasoned that narrowband, low-SL stimuli of this type should minimize spread of excitation across auditory-nerve fibers, and hence might reveal synaptopathy-related defects if they exist. Cochlear synaptopathy was induced without hair-cell injury using kainic acid (KA). Behavioral threshold tracking experiments characterized the minimum stimulus duration above which animals could reliably discriminate between LNN and GN. Budgerigar thresholds for LNN-GN discrimination ranged from 40 to 60ms at 30dB SL, were similar across frequencies, and increased for lower SLs. Notably, animals with long-term 39-77% estimated synaptopathy performed similarly to controls, requiring on average a ∼7.5% shorter stimulus duration (-0.7±1.0dB; mean difference ±SE) for LNN-GN discrimination. Decision-variable correlation analyses of detailed behavioral response patterns showed that individual animals relied on envelope cues to discriminate LNN and GN, with lesser roles of FM and energy cues; no difference was found between KA-exposed and control groups. These results suggest that long-term cochlear synaptopathy does not impair discrimination of low-level signals with different envelope statistics.

Ingluvolitos em periquito australiano: relato de caso / Ingluvoliths in budgerigar: case report

O trato gastrointestinal das aves apresenta anatomia e fisiologia únicas. O inglúvio, ou papo, é uma distensão do esôfago com função de armazenar alimentos. Lesões e massas nesses locais podem ocorrer por diversos motivos, provocando dificuldades alimentares e emagrecimento da ave. O alimento ou material estranho impactado no interior de trato gastrintestinal pode formar os bezoares. Assim, objetivou-se descrever a ocorrência de massas em inglúvio de um periquito australiano atendido no Hospital Veterinário da Universidade Federal de Uberlândia, e identificadas como fitobezoar ou ingluvolitos após exame necroscópico e avaliação das massas encontradas.

The gastrointestinal tract of birds presents unique anatomy and physiology. The crop or chat, is a distension of the esophagus with function of storing food. Injuries and masses in these locations can occur for various reasons causing feeding difficulties and thinning of the bird. Food or foreign body impacted inside tract gatrintestinal can form the bezoars. Thus, the objective was reporting the occurrence of masses in crop in a budgerigar attended at the Veterinary Hospital of the Universidade Federal de Uberlândia, and diagnosed as phytobezoar or ingluvoliths after necropsy examination and evaluation of the mass found.

Associação de megabacteriose, aspergilose e candidíase em periquitos australianos (Melopsittacus undulatus) em cativeiro, Marília, SP - Relato de caso / Association megabacteriosis, aspergillosis and candidiasis in australianparakeet (Melopsittacus undulatus) in captivity, Marilia, SP: case report

Infecções fúngicas causadas por Macrorhabdus ornithogaster, Aspergillus flavus, Candida albicans tem sido descritas em várias espécies aviárias sendo responsáveis por promover alterações gastrointestinais, respiratórias, neurológicas e dermatológicas entre outras. O presente artigo descreve aspectos clínicos, anatomopatológicos, procedimentos diagnósticos, medidas preventivas e terapêuticas de um caso crônico de três infecções fúngicas concomitantes em periquitos australianos (Melopsittacus undulatus) provenientes de um criatório comercial encaminhado ao laboratório de Ornitopatologia do Hospital Veterinário da Faculdade de Medicina Veterinária e Zootecnia da Universidade Estadual Paulista (FMVZ UNESP), campus Botucatu São Paulo, Brasil.

Fungal infections caused by Macrorhabdus ornithogaster, Aspergillus flavus, Candida albicans has been described as responsiblefor promoting gastrointestinal, respiratory, neurological and dermatological disorders in several avian species. The present paperdescribes the clinical signs, histopathological exams, treatment and preventions and of a chronic case of three fungal infectionsconcomitant in australian parakeet (Melopsittacus undulatus). The animals came from a commercial breeding facility and sent toOrnitopathology Laboratory of the Veterinary Hospital, Veterinary Medicine and Animal Science Faculty, Paulista State University(FMVZ - UNESP), Botucatu campus - São Paulo, Brazil.

Descripción anatómica del esqueleto de los tractos respiratorios superiores del periquito australiano (Melopsittacus undulatus) / Anatomical description of upper respiratory tracts skeleton of budgerigar (Melopsittacus undulatus)

Se describe detalladamente los elementos esqueléticos de los tractos respiratorios superiores de 10 periquitos australianos (Melopsittacus undulatus), dicha descripción permitió encontrar claras diferencias en su anatomía no referidas con anterioridad, debido posiblemente al interés por estudiar la siringe y no los tractos respiratorios completos, el objetivo principal fue describir la morfología y osificación de los tractos respiratorios superiores del periquito australiano, a través de la técnica de transparentación con doble tinción (rojo de alizarina "S" y azul de alciano), que permite observar la osificación de los tractos respiratorios; obteniendo como resultado dos diferencias óseas importantes: (1) la lengua exhibe dos pequeños huesos paraglosales asociados con la movilidad de la misma y (2) una importante osificación desde la lengua hasta los elementos "A" siringeales. En cuanto al patrón del esqueleto traqueal y siríngeo, no se observan grandes diferencias con respecto a otros psittaciformes. Se propone el estudio del esqueleto lingual para determinar su importancia en el establecimiento de relaciones de parentesco y su valor taxonómico, y de esta forma, abrir una puerta para nuevos estudios de morfología comparativa.

In this work describes in detail skeletical elements of upper respiratory tracts of 10 budgerigars (Melopsittacus undulatus), the description obtains evident differences in its anatomy doesn't relate before, this should to be possible at interest to study syrinx and not full respiratory tracts the objective was to describer morphology and ossification of full upper respiratory tracts of budgerigar, this obtained utilizing clearing technique's with stain double (alizarin red "S" and alcian blue) it allows to observe ossification of respiratory tracts, it obtained like result two principal evident differences: (1) the lingual shows two small paragloss bones associates with its mobility and (2) a important ossification from the lingual to "A" syrinx elements. Respectful at patron tracheal and syrinx skeletical doesn't show evident differences in comparation with other psittacidae. It proposes a study of lingual skeletical to determination of importance for to establish relationship and its taxonomic value and this form meets a door for new studies of comparative morphology.

Carcinoma de células basais em periquito australiano(Melopsittacus undulatus): relato de caso / Basal cell carcinoma in budgerigars (Melopsittacus undulatus): case report

As neoplasias do sistema tegumentar são relativamente comuns em aves de cativeiro. Os tumores localizados na derme, emaves de estimação, podem ser de origem epitelial e mesenquimal, sendo que os carcinomas de células basais parecem serextremamente raros em aves. Um periquito macho adulto foi encaminhado a uma clínica particular apresentando uma massatumoral na epiderme, e localizada na região medial do úmero direito. Optou-se pela amputação da asa afetada e o diagnósticode carcinoma de células basais foi feito pela histopatologia.

Tumors of the integumentary system are relatively common in captive birds. Dermal tumors in pet birds can be epithelial andmesenchymal in origin. Basal cells carcinomas appear seem to be extremely rare in birds. An adult male budgerigar wasexamined exhibiting a tumor mass situated at the epidermis and in the medial region of the right humerus. The wing wasamputated and histopathology diagnosis identified basal cell carcinoma.