High protein does not cause liver problems or high liver levels, but after there is already a liver problem, the liver has a harder time dealing with as much protein. The high levels could be from something else, they could be a temporary increase due to some insult to her liver, like a toxic exposure, they could be because of some other disease process all together. You just can’t know yet. You may have to start adding carbs to her diet to reduce the protein levels, but you may need to do nothing at all, you just don’t know yet. If it turns out that she really is having liver issues, have your vet get you a recipe for a homemade diet for her. It will still be way better than anything you could buy.
She is much more likely to have come in contact with something on walks or whatever like that, than for the supplements that you gave her to have caused a problem. Unfortunately, this could be age, it could be longterm exposure to heartworm prevention, it could be from pesticides, even ones your neighbors used years ago, you may never know and liver problems can literally take a lifetime to pop up.
And yes, I do mean that most vets just feel, look, and listen to dogs at their yearly and never run blood work until there is already a known problem, so they never have normals to compare to.
Dori, at 14 1/2 years old, you would never want to treat her for heartworms and she would never have enough of them to have a serious case, so the first thing I would do would be to never give her another dose. BTW, when was her last dose in relation to when she had the blood work done? That alone could explain the elevated levels.
