Urinary reference values and first insight into the urinary proteome of captive giraffes

Abstract. Urinalysis is widely recognized to be a useful tool in routine health investigation since it can diagnose numerous pathologies. Considering the paucity of knowledge concerning giraffes, urine from 44 giraffes (Giraffa camelopardalis) (18 males and 26 females, from 3 months of age to 21 years of age) underwent routine urinalysis, 1D-electrophoresis and protein identification using mass spectrometry, with the aim of identifying the urinary reference values and the urine proteome. Urine specific gravity (USG), urine total proteins (uTP), urine creatinine (uCr) and the urine protein:creatinine ratio (UPC) reference values, reported as median, and lower limit (LL) and upper limit (UL), were 1.030 (1006 - 1.049), 17.58 (4.54 – 35.31) mg/dL, 154.62 (39.59 – 357.95) mg/dL and 0.11 (0.07 – 0.16), respectively. Mass spectrometry together with electrophoresis revealed a pattern of common urinary proteins; albumin, lysozyme C and ubiquitin were the most represented proteins in the giraffe urine. It has been hypothesized that these proteins could act as a defense against microbes. Moreover, in giraffes, urinalysis could be a valid tool for gauging renal function and physiological status changes.