My question is lore wise is it possible for vampires to sustain themselves on food besides blood. One example are te blood potions in DG. Is that artificial blood or just bottled blood? If I remember Janus was bottling blood mixed with other stuff in the pale lady's cell.

I believe it is blood that has been mixed with other substances to preserve it and prevent it from drying/clotting.

In short, no. It has to be blood.

Good news is that it doesn't really matter what blood it is, human, animal, daedra... so long as it's blood. Oblivion, at least, moved away from this, likely because a player becoming a Vampire is rarely accidental, so they'd (naturally) assume that most players want to svck the blood of NPCs, not animals.

I think playing as a vampire would be better if you could actually chase and run down humans, animals, ect and bite them in their neck, arms, and legs. Bethesda has already got the regal part of vampires down now we just need the predator part.