  By using rather conservative estimates based on the simplest polar cap model,
we search the ATNF Pulsar Catalogue for strongly magnetized stars that could
accelerate relativistic protons up to the curvature pion production threshold.
The best candidate turns out to be the 16 ms pulsar J0537-6910, but the
corresponding characteristic parameter $\chi=a/m_p$ is yet too small to give
origin to observable signals. We show that, for pulsars with period $P\approx
1\,$ms, a surface polar magnetic field $B \approx 10^{12}$G is required in
order to induce detectable curvature pion radiation from accelerated protons in
the magnetosphere. Some other emission processes are also considered.
