An Evaluation of Three Diet Conversion Methods in Psittacine Birds Converting from Seed-Based Diets to Pelleted Diets.

The nutritional deficiencies of popular seed-based diets for captive psittacine birds have been linked to physical and psychological disease conditions in these species. However, bird owners often reject transitioning their pets to nutritionally complete pelleted diets because of concerns over the difficulty of diet conversion. To assess dietary conversion of psittacine birds from seed-based to pelleted diets, avian veterinarians presented 3 diet conversion methods to owners with birds of varying ages and species. The owners implemented their chosen conversion method at home and then received a survey when they successfully completed diet conversion or abandoned their attempt. "Birdies Choice" was a reward-based method in which birds were offered 3 different pelleted diets on a tabletop. If there was a positive interaction and the bird ate one or more of the diets, the bird was rewarded. The preferred pellet was then gradually transitioned into their food dishes. In the "Slow and Steady" method, pellets were alternated with familiar food at varying intervals to increase the birds' exposure to the pellets. The "Tough Love" method maximized exposure to new pellets by introducing a small portion of familiar food for a limited time, along with multiple dishes of new pellets. Survey results showed 96% of birds converted regardless of method, with 57.5% converting within the first 7 days. When conversion times were evaluated by life stage (juvenile, adult, and geriatric), sex, or bird family (Psittacidae, Cacatuidae, and Psittaculidae), differences noted between groups were not significant. The only variable significantly affecting time to conversion was method used, with Tough Love converting birds faster than the other methods. Ultimately, all 3 methods of dietary conversion were successful with the majority of birds during the first month of implementation. These results provide evidence-based information to owners and veterinarians to facilitate pellet conversion attempts for psittacine birds.

A budding yeast model for human disease mutations in the EXOSC2 cap subunit of the RNA exosome complex.

RNA exosomopathies, a growing family of diseases, are linked to missense mutations in genes encoding structural subunits of the evolutionarily conserved, 10-subunit exoribonuclease complex, the RNA exosome. This complex consists of a three-subunit cap, a six-subunit, barrel-shaped core, and a catalytic base subunit. While a number of mutations in RNA exosome genes cause pontocerebellar hypoplasia, mutations in the cap subunit gene EXOSC2 cause an apparently distinct clinical presentation that has been defined as a novel syndrome SHRF (short stature, hearing loss, retinitis pigmentosa, and distinctive facies). We generated the first in vivo model of the SHRF pathogenic amino acid substitutions using budding yeast by modeling pathogenic EXOSC2 missense mutations (p.Gly30Val and p.Gly198Asp) in the orthologous S. cerevisiae gene RRP4 The resulting rrp4 mutant cells show defects in cell growth and RNA exosome function. Consistent with altered RNA exosome function, we detect significant transcriptomic changes in both coding and noncoding RNAs in rrp4-G226D cells that model EXOSC2 p.Gly198Asp, suggesting defects in nuclear surveillance. Biochemical and genetic analyses suggest that the Rrp4 G226D variant subunit shows impaired interactions with key RNA exosome cofactors that modulate the function of the complex. These results provide the first in vivo evidence that pathogenic missense mutations present in EXOSC2 impair the function of the RNA exosome. This study also sets the stage to compare exosomopathy models to understand how defects in RNA exosome function underlie distinct pathologies.

Ocular Iridociliary Adenoma in a Congo African Grey Parrot (Psittacus erithacus).

A 19-year-old female Congo African grey parrot (Psittacus erithacus) presented for an oval, solid, pigmented, suspected intraocular mass with extrascleral extension through the inferior cornea of the left eye. The eye was nonvisual, and intraocular portions of the mass significantly altered the posterior chamber. Neoplasia was confirmed by biopsy, and enucleation was performed because of the severity of ocular disease, loss of vision, enhancement of patient comfort, and potential metastasis. Histopathologic examination of the entire globe revealed a pigmented iridociliary adenoma. Iridociliary adenomas have been rarely reported in birds, and this case report details diagnosis and treatment. Iridociliary adenomas in other species are often benign, indicating this neoplasia can be successfully treated with no reoccurrence by complete excision.

Lipid Panel Reference Intervals for Amazon Parrots (Amazona species).

The lipoprotein panel is a useful diagnostic tool that allows clinicians to evaluate blood lipoprotein fractions. It is a standard diagnostic test in human medicine but is poorly understood in avian medicine. Amazon parrots (Amazona species) are popular pets that frequently lead a sedentary lifestyle and are customarily fed high-fat diets. Similar to people with comparable diets and lifestyles, Amazon parrots are prone to obesity and atherosclerosis. In human medicine, these conditions are typically correlated with abnormalities in the lipoprotein panel. To establish reference intervals for the lipoprotein panel in Amazon parrots, plasma samples from 31 captive Amazon parrots were analyzed for concentrations of cholesterol, triglycerides, high-density lipoprotein (HDL), low-density lipoprotein (LDL), and very low-density lipoprotein (VLDL). The data were also grouped according to sex, diet, body condition score, and age. Aside from HDL levels, which were significantly different between male and female parrots, no intergroup differences were found for any of the lipoprotein fractions.

Gastrointestinal cryptosporidiosis in captive psittacine birds in the United States: a case review.

Histopathologic analysis performed on tissue samples from 34 captive psittacine birds over a 14-year period demonstrated gastrointestinal cryptosporidiosis. Although 8 birds had died unexpectedly, at least 10 showed gastrointestinal signs before death. Most birds had other significant pathologic lesions, unrelated to cryptosporidiosis, in which case Cryptosporidium was likely a secondary pathogen. However, in 11 birds the only significant histopathologic finding was gastrointestinal cryptosporidiosis. In 2 lovebird (Agapornis species) cases, direct sequencing of proventricular samples confirmed the presence of Cryptosporidium avian genotype III. A description and analysis of the pathologic findings in these 34 birds, as well as a review of avian gastrointestinal cryptosporidiosis, is provided.

Diagnosis and treatment of an insulinoma in a guinea pig (Cavia porcellus).

CASE DESCRIPTION: A 5-year-old male guinea pig (Cavia porcellus) was examined because of lethargy, weight loss, and episodic neurologic signs, including paddling in lateral recumbency, head tilt, and circling. Prior to initial examination, the animal was treated with corn syrup whenever it appeared lethargic, plus an unknown dosage of sulfadimethoxazole. CLINICAL FINDINGS: The animal was thin, with abdominal distention and subtle torticollis. Chemistry panel results documented hypoglycemia (45 mg/dL). Corn syrup was discontinued in favor of a high-fiber formula fed via a syringe. Measurement of blood insulin concentration demonstrated hyperinsulinemia (> 1,440 pmol/L [> 201 µU/L]), with concurrent hypoglycemia (0.6 mmol/L [11 mg/dL]). TREATMENT AND OUTCOME: Diazoxide treatment for presumptive insulinoma was started at a dosage of 5 mg/kg (2.3 mg/lb), p.o., every 12 hours. A blood glucose curve demonstrated persistent hypoglycemia, and the diazoxide dosage was gradually increased to 25 mg/kg (11.4 mg/lb), p.o., every 12 hours. A second glucose curve measurement 12 days later confirmed adequate euglycemic control. Three weeks after the initial diazoxide dosage increase, the animal was reexamined for constipation and abdominal distension and died the following day. Histologic analysis confirmed a pancreatic beta-cell tumor (insulinoma). CLINICAL RELEVANCE: To the authors' knowledge, this is the first report of premortem diagnosis and treatment of an insulinoma in a guinea pig. This case demonstrates that diazoxide treatment can help achieve euglycemia in hypoglycemic guinea pigs and is a potential treatment option for guinea pigs with insulinoma.