FDA's  Center for Veterinary Medicine (CVM) contends dietary supplements should not be added to animal feed. However, for companion animals, this could change, according to a  recent article .

A formerly established court decision holding that inclusion of supplements can be tied to taste and aroma might be an in, considering a test of this could be a demonstrated preference of foods.

The article pointed to the rationale of the CVM protecting human food supply via the ingredients in animal feed as still being sound, but questioned what this might mean for companion animals, or those not used for food.