Experimental avian nephropathy. Changes of renal function and structure induced by ochratoxin A-contaminated feed.

One-day-old chickens were fed ochratoxin A-contaminated diets at 2 levels: 0.3 and 1 mg ochratoxin A per kg feed, for 341 days. The only observable lesion to develop was a kidney damage comparable with the naturally occurring avian nephropathy. The changes in renal function were characterized by impairment of glomerular and tubular function, indicated by a decreased inulin clearance, TmPAH and decreased urine concentrating capacity. The changes of renal structure included degeneration of the tubular epithelium accompanied by regeneration. At slaughter, the kidneys, liver and muscular tissue of the birds contained residues of ochratoxin A (up to 50 mug per kg). As all the birds would have passed the meat inspection because no macroscopical lesions were present, this represents a possible health problem.