Division 1.3.2.1 Metabolic and residue studies

Metabolic and residue studies are not required if:

1. (1)

   the substance or its metabolites are not present in the feedingstuff at time of feeding; or

2. (2)

   the substance excreted unchanged, or its metabolites can be demonstrated to be essentially not absorbed; or

3. (3)

   the substance is absorbed in the form of physiological compounds; or

4. (4)

   the active component(s) of the additive consists only of micro-organisms or enzymes).

Metabolic studies also are not required if the substance is naturally present in significant amounts in food or feedingstuffs or the substance is a normal constituent of body fluids or tissues. However, in these cases, there is a requirement for residue studies which can be limited to the comparison of the tissues/products levels in an untreated group and in the group supplemented with the highest recommended dose.