DISPOSITION OF C-14 DERIVED RESIDUES IN TISSUES OF PIGS FED RADIOLABELED FUMONISIN B-1

The uptake and distribution of radioactive material-derived residues w ere determined in tissues of growing pigs consuming C-14-labelled fumo nisin B-1 (FB1) in the diet. Animals were fed 3.0 mg (3.0 mu Ci) C-14- FB1/kg feed from days 1-12, followed by 2.0 mg (2.0 mu Ci) C-14-FB1/kg feed during days 13-24, followed by a 9-day withdrawal period where p igs received clean feed only. Of the tissues analysed, residues were f ound to accumulate only in liver and kidney. Radioactivity was detecte d at the first sampling time (day 3), and continued to increase until the C-14-toxin was removed from the diet. Peak tissue levels (dpm/g ti ssue +/- SD, N = 2) in liver and kidney were 347 +/- 28 and 146 +/- 14 , respectively, on day 24, which were equivalent to about 160 and 65 n g FB1 and/or metabolites per g tissue, respectively. Once pigs were pl aced on clean feed, tissue levels declined rapidly; down to approximat ely 35% of peak levels after 3 days, and only marginally above detecti on limits (similar to 25 dpm/g) after 9 days. Delayed recovery of the radioactive material consumed indicated a persistence within the body of FB1-derived residues, which could be eliminated only upon removal o f the contaminated diet.