no dogs wont eat anything.
Anyways I guess eating things such as liver has come from the start of humankind where you ate what you could from an animal, you took everything because it is so valuble. Liver obviously doesnt harm humans, and it has carried on thru the ages.
I was looking thru a cookbook today of the romans and their meals, there were things like nettle soup which some people (very few) still eat today, altho I wouldnt like to go around picking nettles! and they are sposed to be very good for you, I guess the lack of popularity is the difficulty in picking them LoL