
My Bullmastiff and Whippet have been given tripe as added extras since puppies.
I've not come across any problems with it, in fact I am well on my way to now feeding a completly raw diet as they much prefer it.
My Bullmastiff was on Beta with either tripe, minced chicken, minced beef or minced rabbit mixed in. He loves carrot and will often take a whole one to nibble on, he also loves apple and raw eggs anything really. Chicken wings are also one of his favourites.
If they eat it and enjoy it why not, just cut the dry food down slightly to compensate for feeding the meat :)