  We study nuclear symmetry energy of dense matter using holographic QCD. We
calculate it in a various holographic QCD models and show that the scaling
index of the symmetry energy in dense medium is almost invariant under the
smooth deformation of the metric as well as the embedding shape of the probe
brane. We find that the scaling index depends only on the dimensionality of the
branes and space-time. Therefore the scaling index of the symmetry energy
characterizes the universality classes of holographic QCD models. We suggest
that the scaling index might be also related to the non-fermi liquid behavior
of the interacting nucleons.
