I'll agree with you there. I feel like you can really only take the "wouldn't happen in the wild" logic so far when dealing with an animal you have in captivity to begin with haha.I don't think that in itself is a good reason to avoid a certain food item. Wild tegus probably don't eat most of the food we give them in captivity. As long as it's a good approximation, that's the key.
Unless there is something specific about beef that makes it indigestible or otherwise toxic to tegus, but I doubt that is the case.
But I also think due to its size, beef would be tricky to feed a gu. Because managing to break down beef into pieces a gu could eat, and getting the bones and organs and such to proper size would prove complicated IMO
Kale can be added back onto the list. Found a study stating that it's far lower in oxalates than previously assumed: http://news.medill.northwestern.edu/chicago/kale-sheds-bum-rap-on-kidney-stones/
Kale is super low in oxalates, and that goes for almost all cabbages. The only one I know of that is higher is collard greens. However it does contain a sugar called raffinose that can cause some intestinal discomfort. You can minimize this and increase digestibility by cooking it, I'd recommend steaming for about 3 min.
I have a quick question. We are new to tegus and just got a beautiful 3 year old male. I know they can eat raw meat but I have heard of people freezing it first and then thawing it for them to eat. Does that kill bacteria and is it even necessary? Thanks!! Any advice is appreciated as I have not one clue about feeding meat. All the rest of our reptiles stick to meal worms and veggies.