Yeah, that's one I won't test... I think it's the oil in the skin, pit and bark of the tree, but it's in the flesh til it gets to full ripeness or something? Not sure, but heard tons about it being toxic and yet a few that give it all the time without issues... :/
So much conflicting stuff... some say never feed tomatoes too, but others say they give tomatoes all the time w/out issue...
I give mine very thing but citrus fruits. They get tomatoes but no lemons, oranges, and the like. Mine esp love avacado and rice or pasta.