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

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␘f the radioactivity was lost, whereas 90␘f the remaining radiolabel could not be extracted from the meal. In the extractable part, AFB1 accounted for 10␘f the radiolabel, consistent with a total AFB1 reduction of more than 99ÐNo degradation products were observed in the extracts. Four lactating cows were fed with a diet containing 15␘f either meal 14C-I0 or 14C-I1 for 10 days. On day 9 of this treatment, respectively 23 and 67␘f the radiolabel was excreted in the urine and faeces of cows fed meal 14C-I0, as compared with 2 and 101␒n the case of cows fed meal 14C-I1. Milk contained respectively 1.35 (meal 14C-I0) and 0.25ømeal 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␘f these compounds in the case of milk from cows fed 14C-I0, as compared with 6-20␒n the case of 14C-I1. AFB1 to AFM1 carry-over rates for 14C-I0 or 14C-I1 were estimated to be respectively 0.5 and 5.9ÐOnly liver and kidney samples contained detectable levels of the radiolabel, being respectively 260 and 37 w g/kg for cows fed meal 14C-I0, and 10 and 3 w g/kg for those fed meal 14C-I1. In the latter case, more than 55␘f the radiolabel in the liver could not be extracted, as compared with 90␒n the group fed meal 14C-I1. A small part of the extractable radiolabel in the livers of 14C-I0 could be attributed to AFB1 and cows fed meal AFM1 (less than 1␘f total radioactivity). In the case of the animals fed 14C-I1 there were indications for the presence of AFB1 and AFM1 (6␘f total radioactivity). Decontamination of the highly contaminated (non-radiolabelled) peanut meal by two different industrial ammoniation processes, resulted in a similar reduction of the initial AFB1 levels of 3.5mg/kg to 15 mu g/kg. Feeding of diets containing 15␘f the nontreated and two treated peanut meals to cows for a period of 10 days, resulted in AFM1 levels in milk of respectively 2.1, 0.04 and 0.07 ng/ml. AFB1 to AFM1 carry-over rates were calculated to be respectively 0.5, 2.0, and 3.6ÐIt is concluded that the efficient reduction of aflatoxin levels by ammoniation of contaminated peanut meal results in a strong reduction of aflatoxin-related residues in milk and meat of cows, most likely caused by a decreased bioavailability of the degradation product