Ethoxyquin (E324) is a synthetic antioxidant that is used primarily in animal feed. Globally, ethoxyquin is not approved for use as a direct food additive in foods for human consumption. Specific to the omega-3 industry, some krill meals and crude fish and fish oils for animal feed are preserved using ethoxyquin.
Naturally occurring vitamins and synthetic vitamins are different … really different.They’re not in the same chemical form … so your dog’s body will have trouble recognizing and using the fake, synthetic vitamins. These synthetic vitamins and minerals, even at the best quality, regularly have partially hydrolyzed protein carriers of unknown sources and are almost exclusively available from overseas sources. This means they can be contaminated with toxins, or at the very least, be a source of allergens to some pets.