Jak powiedzieć " This is not food for animals." po Polsku? " To nie jest jedzenie dla zwierząt." Correct ?
animals' food = food that belongs to animals
you can say "animal food" though
Why animals (zwierzat) is like that in plural? is some kind of declination rule or is because is like that?
But it's "na użytek", not "na studentów" :)
In fact, this "na" in your sentence about animals sounds to me more like an anti-animal thing. For example "spray na komary" is a spray that kills mosquitos. "packa na muchy" is a fly swatter. "strzelba na słonie" is, well, a shotgun used against elephants :/