From Mazuri.com on their tortoise food:
Ingredients
Ground soybean hulls, ground corn, ground oats, dehulled soybean meal, wheat middlings, cane molasses, brewers dried yeast, soybean oil, wheat germ, dehydrated alfalfa meal, dicalcium phosphate, calcium carbonate, salt, DL-methionine, choline chloride, menadione dimethylpyrimidinol bisulfite (vitamin K), pyridoxine hydrochloride, d-alpha tocopheryl acetate (natural source vitamin E), cholecalciferol (vitamin D3), biotin, calcium pantothenate, ethoxyquin (a preservative), vitamin A acetate, riboflavin, L-lysine, nicotinic acid, thiamin mononitrate, cyanocobalamin (vitamin B12), folic acid, manganous oxide, zinc oxide, ferrous carbonate, copper sulfate, zinc sulfate, calcium iodate, cobalt carbonate, sodium selenite.
So there is a lot of soy, corn, and wheat products in it.
Feeding Directions
Feed 1-4% of body weight per Tortoise per day. It is not necessary to wet the diet, although this may help to acclimate tortoises to the diet. Feed consumption will vary with temperature. Feed with good quality grass hay. Fresh fruits and vegetables (less than 20% by weight of total diet) may also be provided if desired.
Notice that you are directed to feed this item every day. If you have a 50 lb sulcata, you are supposed to give it 0.5 to 2.0 pounds (1-4% of body weight) of Mazuri in addition to hay, fruits and veggies. Last time this topic came up, it appeared that no one on the forum was following these instructions. Everyone (including me) fed the item as an occassional supplement, not as recommended. Now at zoos or large breeding facilities they might use it more often.
I decided that soy/corn/wheat ingredients indicated that Mazuri, like many pet food manufacturers, had taken the standard pet food base materials (soy/corn/wheat) and added enough vitamins and minerals to make it acceptable. It is barely different than the foods they've made for herbivorous mammals (see the website). I no longer use Mazuri for my russians and leopards.