Protein location and elemental composition of urine spheres in different avian species.

We examined the internal morphology, location of protein, and identity and location of elements, in avian urate-containing spheres in 9 species of birds. The urine spheres were collected from voided samples. The spheres ranged in size from 0.5-5.0 microm, except in the domestic fowl, where they ranged up to 10 microm in diameter. The internal morphology of the spheres was examined using freeze-fracture microscopy. Protein location within the spheres was identified using fluorescein isothiocyanate (FITC). The urine spheres were analyzed for content and internal location of elements using Energy Dispersal System Analysis (EDS). Internally, the spheres consisted of a central nidus surrounded by 3-4 concentric narrow rings of protein. Elements found within the spheres included nitrogen, potassium, calcium, sodium, phosphorus, chloride and sulfur; however, only nitrogen, potassium and chloride were common in the spheres of all species. Nitrogen comprised the majority of the elemental content of the spheres (77-90%) followed by potassium (8-45%), with all other ions present in trace amounts. Unlike protein, the location of elements was random within the spheres. Protein and urate are both negatively charged and known to associate to form the spheres and as potassium is the only cation common to all spheres, it too may play a role in their formation.

Clinical chemistry of companion avian species: a review.

Birds have evolved alternate physiologic strategies to contend with dehydration, starvation, malnutrition, and reproduction. Basic anatomic and functional differences between birds and mammals impact clinical chemistry values and their evaluation. Interpretation of the results of standard biochemical analyses, including BUN, alanine aminotransferase, aspartate aminotransferase, creatine kinase, gamma glutamyltransferase, bilirubin, ammonia, alkaline phosphatase, cholesterol, bile acids, glucose, albumin, globulins, calcium, phosphorus, prealbumin (transthyretin), fibrinogen, iron, and ferritin, is reviewed and discussed in relation to these physiological differences. The use and interpretation of alternative analytes appropriate for avian species, such as uric acid, biliverdin, glutamate dehydrogenase, and galactose clearance, also are reviewed. Normal avian urine and appropriate use of urinalysis, an integral part of laboratory diagnosis in mammalian species that frequently is omitted from avian diagnostic protocols, is discussed.

Collecting diagnostic samples in avian patients.

With the increasing owner demand of thorough medical evaluation of avian patients, clinicians are being required to collect meaningful diagnostic samples from bird species. The art of diagnosis stems from taking a complete medical history, performing a thorough physical examination, collecting appropriate diagnostics, and interpreting the collective information. This article focuses on methods of collecting diagnostic samples in avian patients.