Measurement of Selected Renal Biochemical Parameters in Healthy Adult Donkeys Considering the Influence of Gender, Age and Blood Freezing.
Authors: Frączkowska Kaja, Trzebuniak Zuzanna, Żak Agnieszka, Siwińska Natalia
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary Establishing reliable reference ranges for donkey biochemistry has long challenged practitioners, particularly for renal function assessment where species-specific variation can significantly impact clinical interpretation. Researchers in Poland collected serum and urine samples from 65 healthy adult donkeys to generate normative data for key renal biomarkers including creatinine, blood urea nitrogen, albumin, total protein, electrolytes and the emerging marker symmetric dimethylarginine (SDMA), alongside calculated ratios such as urine protein-to-creatinine ratio and fractional electrolyte excretion. Results revealed important differences from equine reference ranges: donkeys naturally maintain higher BUN and total protein but lower albumin and urinary fractional excretion of sodium and potassium, suggesting distinct renal physiology that cannot simply be extrapolated from horse data. Gender significantly influenced creatinine and BUN values, whilst age affected albumin, total protein, and chloride concentrations—variables worth considering during individual assessment. Additionally, most serum parameters showed concerning instability after deep freezing, except potassium, sodium and SDMA, highlighting the importance of immediate sample processing or standardised freezing protocols in donkey diagnostics. For equine professionals managing donkey health, these findings underscore the critical need for species-specific reference intervals rather than relying on established horse data, and warrant careful attention to sample handling procedures when biochemical analysis cannot be performed immediately.
Read the full abstract on PubMed
Practical Takeaways
- •Do not use equine reference ranges for donkey biochemical testing—donkeys require their own diagnostic reference values for accurate renal assessment
- •When submitting donkey serum samples, discuss sample handling and freezing protocols with your laboratory, as freeze-thaw cycles significantly alter most biochemical parameters
- •Consider age and sex when interpreting donkey renal biomarkers, as these factors measurably influence reference ranges
Key Findings
- •Donkeys showed higher BUN and total protein but lower albumin and fractional electrolyte excretion compared to horse reference values
- •Gender significantly affected creatinine and BUN levels in donkeys
- •Age influenced albumin, total protein, potassium and chlorine concentrations
- •Only potassium, sodium and SDMA remained stable after serum freezing; most other parameters were affected by freezing procedures