  The chiral nonlinear ($\sigma,\pi,\omega$) mean-field model is an extension
of the conserving nonlinear (nonchiral) $\sigma$-$\omega$ hadronic mean-field
model which is thermodynamically consistent, relativistic and Lorentz-covariant
mean-field theory of hadrons. In the extended chiral ($\sigma,\pi,\omega$)
mean-field model, all the masses of hadrons are produced by chiral symmetry
breaking mechanism, which is different from other conventional chiral partner
models. By comparing both nonchiral and chiral mean-field approximations, the
effects of chiral symmetry breaking to the mass of $\sigma$-meson, coefficients
of nonlinear interactions, coupling ratios of hyperons to nucleons and
Fermi-liquid properties are investigated in nuclear matter, hyperonic matter,
and neutron stars.
