Transfer of polycyclic hydrocarbons from diet to milk in rats, rabbits and sheep

The transfer of the polycyclic hydrocarbons 3,4-benzpyrene and 3-methylcholanthrene from diet to milk of rabbits and sheep has been shown to be much less than that in rats. In rats the minimum transfer to the milk was found to be 0.19%. Earlier work has suggested that at least 1% of ingested polycyclic hydrocarbon could be secreted in the milk of rats. In rabbits only 0.003% of dietary polycyclic hydrocarbon was found in milk and in sheep the proportion was 0.01%. The low rate of transfer of polycyclic hydrocarbons to milk in sheep suggests that ruminants effectively prevent the passage to milk of polycyclic hydrocarbons present in their diets. © 1976.