Transfer of aflatoxin from feed to milk and curd in Sarda ewes with different milk production level

Aflatoxin B1 (AFB1) is a toxin produced by some strains ofAspergillusgrowing in feedstuffs. Dairy animals fed with diet containing AFB1 excrete aflatoxin M1 (AFM1) into the milk. The carry over ratio (AFM1 excreted in milk/ AFB1 ingested) has been found lower in sheep (Battaconeet al., 2002a) than in cattle (Veldmanet al., 1992). Being AFM1 linked to milk proteins, its concentration in curd is higher than in milk. The AFM1 concentration in milk resulted not influenced by milk production level in cattle, therefore the total amount of AFM1 excreted in milk and, consequently, the carry-over ratio increased with milk yield (Munksgaardet al., 1987; Veldmanet al., 1992). A previous study carried out on isoproductive dairy ewes showed an increase of the AFM1 concentration both in milk and in curd as the amount of AFB1 ingested increased (Battaconeet al., 2002b). Aim of the present work is to study the influence of AFB1 dose and milk production level on the transfer of AFB1 from feeds to milk and curd as AFM1 in dairy ewes.