Absorption, distribution and excretion of aflatoxin-derived ammoniation products in lactating cows

Abstract

Peanut meal naturally contaminated with 3.5mg/kg aflatoxin B₁ (AFB₁) was spiked with radiolabelled AFB₁ (meal¹⁴C-I0) and decontaminated by a smallscale copy of an industrial ammoniation process (meal ¹⁴C-I1). During the process 15% of the radioactivity was lost, whereas 90% of the remaining radiolabel could not be extracted from the meal. In the extractable part, AFB₁ accounted for 10% of the radiolabel, consistent with a total AFB₁ reduction of more than 99%. No degradation products were observed in the extracts. Four lactating cows were fed with a diet containing 15% of either meal ¹⁴C-I0 or ¹⁴C-I1 for 10 days. On day 9 of this treatment, respectively 23 and 67% of the radiolabel was excreted in the urine and faeces of cows fed meal ¹⁴C-I0, as compared with 2 and 101% in the case of cows fed meal ¹⁴C-I1. Milk contained respectively 1.35 (meal ¹⁴C-I0) and 0.25% (meal ¹⁴C-I1) of the radiolabel. Milk samples taken during the equilibrium stage contained respectively 5 and 0.5 ng/ml of AFB₁-derived compounds. Aflatoxin M₁ (AFM₁) accounted for 50–80% of these compounds in the case of milk from cows fed ¹⁴C-I0, as compared with 6–20% in the case of ¹⁴C-I1. AFB₁ to AFM₁ carry-over rates for ¹⁴C-I0 or ¹⁴