  It is shown that, contrary to the widespread opinion, particle collisions
considerably increase accretion rate from the cosmological background onto 5D
primordial black holes formed during the high-energy phase of the
Randall-Sundrum Type II braneworld scenario. Increase of accretion rate leads
to much tighter constraints on initial primordial black hole mass fraction
imposed by the critical density limit and measurements of high-energy diffuse
photon background and antiproton excess.
