Grain or no Grain for mastiff's?

[mastiffmama12]

I read somewhere that mastiff's should not have grain, then I read somewhere else that mastiff's should have grain in their diet that it's important. Does anyone have any opinions on this as I'm not sure if I should be feeding grain or grain free, both my dogs are on grain free right now. I was feeding orijen then switched to taste of the wild pacific stream.

 

[Arkitek]

Grain free is better for EMs based on everything I've read and heard..