I would not offer banana peels unless they are organic, and still wash thoroughly. Bananas are gassed by grocery stores to ripen them. It has been noted by a friend of mine, that certain banana brands{Dole} caused her breeding birds to be infertile. When the bananas were changed to a different brand{such as chiquita}, fertility returned after a year.She spoke with the grocers and pursued this for further info about how the bananas are handled.
I would also recommend that all fruits and vegetables be soaked first in GSE{grapefruit seed extract} to remove any pesticides and even for supposed organics.Use of a fruit/vegetable wash is ok as well. Rinse, rinse, rinse...
Purchase organic fruits and vegetables from a reliable source whenever possible.
Food for thought...