Preliminary study on the urine proteome of giraffes (Giraffa camelopardalis)

Data on proteinuria are lacking in giraffes, therefore the aim of our research was to study urine proteome with sensitive analytical methods to obtain important information regarding not only the kidney function but also the general health status. Twenty-nine samples were collected during 2013 and 2014, through non-invasive methods (from the ground by a syringe) from 4 specimens of Giraffa camelopardalis. Urinary total proteins (UTP), creatinine and the urine protein to creatinine ratio (UP/C) were measured by automated methods (Olympus AU400) routinely used in small animal practice. Urinary proteins were separated by sodium-dodecyl-sulphate polyacrilamide gel electrophoresis (SDS-PAGE) and gels were stained with silver nitrate. Mean UTP±SD was 12.1±0.6 mg/dL ranging from 2.4 to 30 mg/dL, while mean UP/C values were 0.06±0.01. SDS-PAGE yielded an overall view of the protein profile allowing the separation of 7±2 protein bands. Electropherograms showed few protein bands as compared to dog and cat and big felids. The most represented band had an apparent molecular weight (MW) of 67-69 kDa and could be identified as putative albumin. Between 65 and 14 kDa only few low abundance bands were present, while more intense bands had a MW lower than 14 kDa. Our data could be considered as representative of animals with no clinical signs of disease resulted in a useful diagnostic tool that could help clinicians in quantitative and qualitative evaluation of proteinuria also in giraffes.