Effect of dietary sodium bicarbonate supplementation on the toxicokinetics of ochratoxin A in pigs

The mycotoxin ochratoxin A (OA) is regarded as a causative agent for endemic nephropathy in farm animals and humans. Reabsorption of OA along the nephron results from nonionic diffusion and by carrier-mediated mechanisms indicating that urine alkalinization may help to accelerate OA excretion and thus reduce its toxicity. The aim of the present study was to investigate the effect of a dietary sodium bicarbonate (NaHCO3) supplementation as a means to increase urinary pH on the systemic availability and excretion of OA in pigs. Dietary supplementation of 2% NaHCO3increased urinary pH (5.7 ± 0.2 to 8.3 ± 0.1) and daily urine volume (1108 ± 276 to 2479 ± 912 ml) significantly. The systemic availability of OA and its dechloro-analog Ochratoxin B (OB) in the NaHCO3 group calculated as the area under the serum concentration-time curve (AUC) was reduced to 75 and 68%, respectively, of the control (P < 0.05). This effect was mainly due to an accelerated elimination of OA and OB in the urine. The faster renal elimination might be explained by a reduced reabsorption of the ochratoxins by nonionic diffusion, and other W-dependent mechanisms. Thus, urinary alkalinization might be an efficient means to partially reduce the toxic effects and carry-over of OA in pigs.