A recent answer said:
as an alternative source of fiber, you can also give your rabbit banana leaves.
I did a quick google search and found a few blog posts by house rabbit parents who have feed their bunnies banana leaves. A couple of posts suggest that it should be limited do to high levels of some thing that may not be good for rabbits.
When I looked for scientific references I found a diet with 40% banana leaves can be feed for 105 days without adverse effects. But this is for production rabbits not pet rabbits.
Abstract : An experiment is described in which 40 rabbits, 12 weeks old, were fed on diets containing 0, 20, 40 or 60% banana leaves (DM basis) for 105 days. Growth rate was highest for 40% banana leaves while DM intake was reduced on 60% banana leaves. It is suggested that rabbits can be fed up to 40% banana leaves without adverse effects on growth, feed intake and physiology. source
Clearly they can eat some banana leaves, but is at a healthy form of fiber in the long term (8-12 years)? Do banana leaves contain any substances that should be moderated?