Proteomic Characterization of Bottlenose Dolphin ( <i>Tursiops truncatus</i> ) Urine

Urinary proteins offer multifaceted insights into tissue repair, dysfunction, and renal health, with significant implications for both human and veterinary medicine. However, marine mammal medicine lacks comprehensive studies on urine protein composition. This study aimed to describe the urine proteome of wild common bottlenose dolphins (<i>Tursiops truncatus</i>) at two Gulf of Mexico sites (Sarasota Bay, FL, and Barataria Bay, LA) and to compare urine proteins by sex. Ten urine samples (Barataria Bay, LA: <i>N</i> = 6; Sarasota Bay, FL: <i>N</i> = 4) were analyzed by nano LC-MS/MS. Peptide spectral matching identified 1872 protein families across all individuals (FDR < 0.01). Cystatin 11 was notably present in males (median rank abundance: 8.1%) and absent in females (median: 0.0%), with semen contamination elevating protein diversity in male urine. Two putative antimicrobial proteins, cathelicidin and lysozyme, accounted for 2.66% of the urine proteome, suggesting an innate immune defense mechanism. In total, 27 proteins that are recognized as acute kidney injury markers in humans, and 12 putative stone formation proteins were detected in dolphin urine. This research provides a reference database of urinary proteins that can be used to develop advanced methods for investigating dolphin renal health. Data are available via ProteomeXchange with identifier PXD054283.