Mucosal absorption of aflatoxin B1 in lactating dairy cows

The objective of this experiment was to monitor plasma levels of aflatoxin B1 (AFB1) aflatoxin B2 (AFB2), aflatoxin G1 (AFG1), aflatoxin G2 (AFG2) and aflatoxin M1 (AFM1) in lactating dairy cows fed afltaoxin contaminated corn. Seven lactating Holstein cows were given a bolus of a naturally contaminated corn meal assuring an intake of 4.9mg AFB1, 1.01 mg AFB2, 10.63 mg AFG1 and 0.89 mg AFG2. Vitamin A, at 1,000,000 IU, was also added as a biomarker of intestinal absorption. Blood samples were collected at 0, 15, 30, 60, 120, 180, 270 and 360 min after bolus. Plasma was analyzed by HPLC for AFB1, AFB2, AFG1, AFG2 and AFM1 concentrations. Within the considered time points, the peak plasma AFB1 concentration was obtained as soon as 15 minutes from drenching. The plasma AFM1 concentration was considerable as early as the first collection (15 minutes) and peaked at 270 minutes indicating both a rapid absorption of AFB1 through the rumen wall and metabolization into AFM1 in liver. The plasma palmitate level suggests the intestinal contribution to the aflatoxin plasma level after 120 min.