There are plenty of alternative treats for ratties! You can buy them Yogies or Yogurt chips from a pet store, or you can buy yogurt chips from an organic food store to cut down on the sugar.
Fresh fruits and veggies are good treats in addition to fresh fruits and veggies in their daily diet.
tofu (not bulk)
bread soaked in oil
veggies drizzled with oil
peanut butter cut with a liquid (so they don't choke!!!)
----> more about this....I mixed a small amount of peanut butter with banana, honey, and enough soy milk to make it soupy! They went bonkers over this....but it starts to look brown and yucky after 10 mins because of the banana.......not something you should leave in the cage!
well anyhoo the list goes on and on, so don't limit yourself!