Some effects of phenobarbital dosing of dairy cattle on aflatoxin M1 and fat in milk.

Eight Holstein cows were selected randomly to determine effects of phenobarbital on the fate of orally administered aflatoxin B1, milk fatty acid profiles, total milk fat, and milk production. Animals were grouped in pairs for one of four treatments: 1) control, 2) oral dosing with sodium phenobarbital for 5 days, 3) dosing with sodium phenobarbital followed by oral dosing with aflatoxin B1, and 4) oral dosing with aflatoxin B1 for 5 days. Daily composite raw milk samples were taken and assayed for aflatoxin M1 by thin-layer chromatography, and milk fatty acid profiles were measured by gas-liquid chromatography. Milk production for all treatments was less than that of controls. Total milk fat was not affected. Both aflatoxin B1 and phenobarbital affected fatty acid distribution, suppressing the amount of fatty acids carbons 8 through 14 while increasing the amount of 16-carbon fatty acids. No treatment effect was significant for the short chain fatty acids of 4 and 6 carbons and the 18-carbon acids oleic, stearic, and linoleic. Pretreatment with phenobarbital resulted in a significant difference between treated and untreated difference between treated and untreated animals. A greater than 50% reduction in the amount of aflatoxin B1 excreted as M1 in the milk was realized.