I would love to see a long term study on your diet...are you sure it covers all their nutritional requirements? Vitamin K is one that is extremely vital for rats (clotting of blood, etc) and dog food doesn't have it at all.
Wild rats are opportunistic, and eat what's around but is it truly optimal for the longer, healthier life we want our domestics to have. Wild rats rarely live past a year of age.
As I said; dog food is only temporary until we can get out and get insects and grubs.
I don't see the point in feeding them pastas or breads, because they are full of sugar, cooked down nutritionally, and not even good for humans(again, according to my research), nor are they a natural, available food. I don't see the point in feeding lab blocks, because lab rats are not cared for in labs to sustain long life nor reach optimal health..only long enough to survive the trial. And as rats are used in laboratories for their similarities to humans, if humans can get celiac disease, why can't rats? The only thing is, rats can't tell you. Better safe than sorry, as far as I'm concerned..
Nor do I believe diet for anything is scientific. Diet is raw & natural, and what is logical for that particular species. As far as grains go, according to what I've found, corn and rice seem to primarily be what it is sought after by their wild ancestors. There is nothing grains contain that cannot be found elsewhere, especially by rats. And no, I do not feed dried corn, only fresh.
Anyway; my boys are healthy, energetic, their temperaments are excellent. If I see a decline in overall health I will go back and re-evaluate my choices, but for now, they are doing superb.