Yeah, I know that. I just always use both terms as you'll see both printed on packages. USUALLY you see the words "Enriched" on frozen stuff, as you are saying...
You can actually gut-load anything like that, it's just particularly important with foods like brine that are, on their own, nutritionally worthless.
You know, to go on with that tangent, I don't ever feed any sorts of brine as it. First of all, they aren't actually a saltwater food, which I think is relevant to some extent. And secondly, there are great alternatives, such as mysid and ocean plankton (don't know the specific species here). I also REALLY like a product sold by H2O Life, mini-mysis. They are, basically, just baby/juvenile mysis shrimp.