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BackgroundSeveral genetic models that recapitulate neurodegenerative features of Parkinson’s disease (PD) exist, which have been largely based on genes discovered in monogenic PD families. However, spontaneous genetic mutations have not been linked to the pathological hallmarks of PD in non-human vertebrates.ObjectiveTo describe the genetic and pathological findings of three yellow crowned parrot (Amazona ochrocepahala) siblings with a severe and rapidly progressive neurological phenotype.MethodsThe phenotype of the three parrots included severe ataxia, head tilt, and stargazing, while their parents were phenotypically normal. Tests to identify avian viral infections and brain imaging studies were all negative. Due to their inability to survive independently, they were all euthanized at age 3 months and their brains underwent neuropathological examination and proteasome activity assays. Whole genome sequencing (WGS) was performed on the three affected parrots and their parents.ResultsThe brains of affected parrots exhibited neuronal loss, spongiosis, and Lewy bodies in the neocortex, amygdala, hypothalamus, periaqueductal gray matter, dorsal vagal nucleus, in some cerebellar Purkinje cells, and in the basal ganglia. Proteasome activity was significantly reduced in the affected parrots compared to a control (pCADPS2) gene. Previous studies suggest that CADPS2 is expressed at high levels in the substantia nigra where it regulates BDNF release. Thus, disruption of CADPS2 function could impact survival of dopaminergic neurons. Furthermore, CADPS2 expression is in part regulated by two well established PD genes, LRRK2 and SNCA.ConclusionsOur data suggest that a homozygous mutation in the CADPS2 gene causes a severe neurodegenerative phenotype with Lewy bodies in parrots. Although CADPS2 variants have not been reported to cause PD in humans, further investigation of the gene in model organisms might provide important insights into the pathophysiology of Lewy body disorders.

A retrospective study was conducted on parrots submitted from necropsy to the Department of Veterinary Pathology, School of Biosciences and Veterinary, University of Camerino, Italy, from 2007 to 2018. From a total of 2,153 parrots examined at post-mortem, four cases were diagnosed with atypical mycosis and were considered for determination of the fungus species by PCR. A Fischer's lovebird (Agapornis fischeri), Peach-faced lovebirds (Agapornis roseicollis), and two Blue and Gold Macaws (Ara ararauna) from four different aviaries died after some days of lethargy and ruffled feathers. Records of gross necropsy and histopathological exams (H&E, PAS, and Grocott stain) were described and biomolecular analyses were carried out. No specific gross lesions were appreciated at necropsy, while histopathology evidenced a systemic mycosis in several organs, particularly in the lungs. In affected organs, broad and non-septate hyphae, suggestive of mycoses, were observed. Molecularly, Mucor racemosus (Fischer's lovebird) and M. circinelloides (Peach-faced lovebirds) were identified from formalin-fixed and paraffin-embedded (FFPE) lung and liver tissue. In addition, Alternaria alternata and Fusicladium spp. (respectively in male and female Blue and Gold macaws) were identified in FFPE tissue from several organs; whereas the role of Mucor spp. as true pathogens is well-demonstrated, and the behavior of A. alternata and Fusicladium spp. in macaws as opportunistic pathogens have been discussed. To our knowledge, this report is the first one reporting mucormycosis caused by M. racemosus and M. circinelloides in lovebirds, and A. alternata and Fusicladium spp. in macaws.

To understand the effectiveness of a probiotic mixture on intestinal morphology, mucus layer composition, and cecal microbiota diversity, 40 10-day-old Guinea fowls (Numida meleagris) were assigned to two groups: the control group (C), receiving drinking water, and the treated group (P), receiving water plus a commercial multi-strain probiotic (Slab51®, 2 × 1011 CFU/L). Birds were slaughtered after 4 months, and the intestines were collected. Samples from the duodenum, ileum, and cecum were processed for morphological and morphometric studies, and conventional glycohistochemistry. Cecal samples were also used to assess the microbiota by 16S metataxonomic approach. Group P showed significant increase in the villus height (p < 0.001 in the duodenum and p < 0.05 in the ileum and cecum), villus width (p < 0.05 in all investigated tracts), depth of crypts (p < 0.001 in the duodenum and cecum; p < 0.05 in the ileum), and goblet cells per villus (p < 0.001 in all investigated tracts) compared with group C. Cecal microbiota of the birds varied considerably and comparing the relative abundance of the main observational taxonomic units (OTUs), a positive enrichment of several beneficial taxa, such as Oscillospira, Eubacterium, Prevotella, and members of the Ruminococcaceae, was observed. The enrichment of those taxa can improve microbiota stability and resilience facing environmental stresses, enhancing its resistance against invading pathogens. Ruminococcaceae, which represent the most important taxon in both groups, and Prevotella have a key role in the gut physiology due to the production of short-chain fatty acids (SCFAs), which are a vital energy source for enterocytes, improve glucose metabolism, and exert an overall anti-inflammatory effect. Probiotic administration enriches the presence of Coprococcus, Oscillospira, and Eubacterium taxa that produce butyrate, which exerts a beneficial effect on growth performance, structure of villi, and pathogen control and has anti-inflammatory properties too. This study indicates that Slab51® supplementation positively affects the morphology and microbiota diversity of the guinea fowl intestine.