Don't give away my secret! Lol I've been feeding green tripe for a long time. My wife calls it "zoo food" because of the smell. But that stuff has just about everything your dog needs. It's fairly expensive in my area but I spare no expense when it comes to my hounds.
I also feed fruit and veggies mix I purée and put 2heaping tablespoons in with feed a couple times a week. Or I use it a few hours prior to a good work out with salmon or wheat germ oil and a splash of water.