We discuss the phenomenology of neutrino mixing with bulk fermions in the context of supernova physics. The constraints on the parameter space following from the usual energy loss argument can be relaxed by four orders of magnitude due to a feedback mechanism that takes place in a broad region of the parameter space. Such a mechanism also affects the protoneutron star evolution through a nontrivial interplay with neutrino diffusion. The consistency with the SN 1987A signal is discussed, as well as the implications for the deleptonization, cooling, composition of the neutrino flux and the delayed explosion scenario.