  We analyze the rapidity and transverse momentum dependence for the cumulants
of the net-proton and net-baryon distributions in Au+Au collisions at
$\sqrt{s_{\text{NN}}} = 5\,\text{GeV}$ with a microscopic hadronic transport
(JAM) model. To study the effects of mean field potential and softening of
equation of state (EoS) on the fluctuations of net-proton (baryon) in heavy-ion
collisions, the calculations are performed with two different modes. The
softening of EoS is realized in the model by implementing the attractive orbit
in the two-body scattering to introduce a reduction pressure of the system. By
comparing the results from the two modes with the results from default cascade,
we find the mean field potential and softening of EoS have strong impacts on
the rapidity distributions ($\text{d}N/\text{d}y$) and the shape of the
net-proton (baryon) multiplicity distributions. The net-proton (baryon)
cumulants and their ratios calculated from all of the three modes are with
similar trends and show significant suppression with respect to unity, which
can be explained by the presence of baryon number conservations. It indicates
that the effects of mean field potential and softening of EoS might be not the
ingredients that are responsible to the observed strong enhancement in the most
central Au+Au collisions at 7.7 GeV measured by the STAR experiment at RHIC.
