title: Carry-over of aflatoxin B1 to aflatoxin M1 in high yielding Israeli cows in mid- and late-lactation.
abstract: The potent hepatotoxin and carcinogen aflatoxin B1 (AFB1) is a common mycotoxin contaminant of grains used in animal feeds. Aflatoxin M1 (AFM1) is the major metabolite of AFB1 in mammals, being partially excreted into milk, and is a possible human carcinogen. The maximum permitted concentration of AFM1 in cows' milk is 0.05 μg/kg in Israel and the European Union. Since milk yield and the carry-over of AFB1 in the feed to AFM1 in the milk are highly correlated, it was considered important to determine the AFM1 carry-over in Israeli-Holstein dairy cows, distinguished by world record high milk production. Twelve such cows were used to determine AFM1 carry-over following daily oral administration of feed containing ~86 μg AFB1 for 7 days. The mean carry-over rate at steady-state (Days 3-7) was 5.8% and 2.5% in mid-lactation and late-lactation groups, respectively. The carry-over appears to increase exponentially with milk yield and could be described by the equation: carry-over% = 0.5154 e(0.0521 × milk yield), with r(2) = 0.6224. If these data truly reflect the carry-over in the national Israeli dairy herd, the maximum level of AFB1 in feed should not exceed 1.4 μg/kg, a value 3.6 times lower than the maximum residue level currently applied in Israel.
authors: National Residue Control Laboratory, Kimron Veterinary Institute, Bet Dagan 50250, Israel. malkab@moag.gov.il
authors: Malka
authors: M
authors: Britzi
authors: Shmulik
authors: S
authors: Friedman
authors: Joshua
authors: J
authors: Miron
authors: Ran
authors: R
authors: Solomon
authors: Olga
authors: O
authors: Cuneah
authors: Jakob A
authors: JA
authors: Shimshoni
authors: Stefan
authors: S
authors: Soback
authors: Rina
authors: R
authors: Ashkenazi
authors: Sima
authors: S
authors: Armer
authors: Alan
authors: A
authors: Shlosberg
mesh_terms: D016604:Aflatoxin B1 / Q000032:analysis / Q000378:metabolism*; D016607:Aflatoxin M1 / Q000032:analysis / Q000378:metabolism*; D000821:Animal Feed; D000818:Animals; D002273:Carcinogens / Q000032:analysis / Q000378:metabolism*; D002417:Cattle / Q000502:physiology; D005260:Female; D005506:Food Contamination; D007774:Lactation / Q000378:metabolism*; D008892:Milk / Q000737:chemistry / Q000378:metabolism*
chemical_list: D002273:Carcinogens; D016607:Aflatoxin M1; D016604:Aflatoxin B1