Extrusion cooking with glucose supplementation of fumonisin-contaminated corn grits protects against nephrotoxicity and disrupted sphingolipid metabolism in rats

Scope: Fumonisin B1 (FB1) is a mycotoxin found in maize and maize-based foods. It causes animal diseases and is a suspected risk factor for cancer and birth defects in humans. Extrusion cooking reduces FB1 concentrations in maize however toxicity caused by unknown degradation or FB1-matrix reaction products might persist. Methods and results: To test the efficacy of extrusion to reduce FB1 toxicity, Fusarium verticillioides fermented corn (= maize) grits (Batch-1=9.7 ppm FB1; Batch-2=50 ppm FB1) were extruded without (Batch-1E; Batch-2E) or with 10% glucose supplementation (Batch-1EG; Batch-2EG). FB1 concentrations were reduced 64% (Batch-2E) to 94% (Batch-1EG) after cooking. When the uncooked and processed grits were fed (50% w/w in rodent chow) to rats for up to 8 weeks, FB1 intakes averaged 354, 103, and 25.1 cg/kg body weight/day for Batch-1, Batch-1E and Batch-1EG and 1804, 698, and 222 cg/kg body weight/day for the Batch-2, Batch-2E and Batch-2EG, respectively. Nephrotoxicity including apoptotic lesions and elevated sphingoid base concentrations decreased in a dose-dependent manner in groups fed Batch-1, Batch-1E, Batch-2, Batch-2E, or Batch-2EG and was absent in the Batch-1EG group. Conclusion: Extrusion cooking, especially with glucose supplementation, is potentially useful to reduce FB1 concentrations and toxicity of FB1-contaminated maize.