an additive enhances the flavour / colour constituency of the product and a supplement enhances the nutritional qualities of the product hope this helps x
for animal feed - additive is usu chemically and artificially manufactured eg in a lab supplement is usu taken fr natural products eg leftovers of plant or animal material and then reconstituted for feed
You can start a fire in the woods (during sunlight hours) if you have a coke can and a candy bar. (I read it online) ;-)
